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1 2012 Information PEANUT Prepared by David L. Jordan Coordinating Author and Extension Specialist—Crop Science Rick L. Brandenburg Extension Specialist— Entomology A. Blake Brown Extension Economist—Agricultural and Resource Economics S. Gary Bullen Extension Associate—Agricultural and Resource Economics. Gary T. Roberson Extension Specialist—Biological and Agricultural Engineering Barbara Shew Extension Specialist—Plant Pathology Jan Ferguson Spears Extension Specialist—Crop Science Published by North Carolina Cooperative Extension Service College of Agriculture & Life Sciences North Carolina State University The North Carolina Peanut Growers Association provided financial support for publishing 2012 Peanut Information.2 CONTENTS EXTENSION PERSONNEL WORKING WITH PEANUTS 4 1. VIRGINIA TYPE PEANUTS: SITUATION AND OUTLOOK 12 2. PEANUT SEED 16 3. PEANUT PRODUCTION PRACTICES 48 4. WEED MANAGEMENT IN PEANUTS 80 5. PEANUT INSECT AND MITE MANAGEMENT 100 6. PEANUT DISEASE MANAGEMENT 129 7. PLANTING, HARVESTING, AND CURING PEANUTS 129 8. GUIDELINES AND SURVEY RESULTS ASSOCIATED WITH THE NORTH CAROLINA PEANUT PRODUCTION CONTEST 1463 EXTENSION PERSONNEL WORKING WITH PEANUTS County Extension personnel with peanut responsibilities as of January 1, 2012: County Name City Telephone Beaufort Gaylon Ambrose Washington (252) 946-0111 Bertie Richard Rhodes Windsor (252) 794-5317 Bladen Ryan Harrelson Elizabethtown (910) 862-4591 Chowan Tim Smith Edenton (252) 482-6585 Columbus Michael Shaw Whiteville (910) 640-6605 Cumberland Colby Lambert Fayetteville (910) 321-6875 Duplin Curtis Fountain Kenansville (910) 296-2143 Edgecombe Art Bradley Tarboro (252) 641-7815 Gates Paul Smith Gatesville (252) 357-1400 Halifax Arthur Whitehead Halifax (252) 583-5161 Harnett Brian Parrish Lillington (910) 893-7530 Hertford Wendy Drake Winton (252) 358-7822 Jones Jacob Morgan Trenton (252) 448-9621 Martin Al Cochran Williamston (252) 792-1621 Nash Charlie Tyson Nashville (252) 459-9810 Northampton Craig Ellison Jackson (252) 534-2711 Onslow Melissa Huffman Jacksonville (910) 455-5873 Pender Mark Seitz Burgaw (910) 259-1235 Perquimans Lewis Smith Hertford (252) 426-5428 Pitt Mitch Smith Greenville (252) 757-2801 Sampson Kent Wooten Clinton (910) 592-7161 Scotland Glen Garris Laurinburg (910) 277-2422 Washington Lance Grimes Plymouth (252) 793-2163 Wayne Kevin Johnson Goldsboro (919) 731-1520 Wilson Norman Harrell Wilson (252) 237-0111 N.C. State University Extension specialists with peanut responsibilities as of January 1, 2012, and directors of peanut grower organizations: Rick Brandenburg Insects, N.C. State University (919) 515-8876 Blake Brown Economics, N.C. State University (919) 515-4536 Gary Bullen Economics, N.C. State University (919) 515-6095 David Jordan Agronomy & Weeds, N.C. State University (919) 515-4068 Gary Roberson Engineering, N.C. State University (919) 515-6715 Barbara Shew Diseases, N.C. State University (919) 515-6984 Jan Spears Seeds, N.C. State University (919) 515-4070 Bob Sutter N.C. Peanut Growers Association Inc. (252) 459-5060 Dell Cotton Peanut Growers Cooperative Marketing Association (757) 562-41034 1. SITUATION AND OUTLOOK A. VIRGINIA TYPE PEANUTS: SITUATION AND OUTLOOK A. Blake Brown Extension Economist—Agricultural and Resource Economics U.S. peanut production was 3.65 billion pounds in 2011, down from 4.16 billion pounds in 2010 as reported by USDA National Agricultural Statistics Service (NASS). With strong competition for land from other crops, such as corn and cotton , and severe drought in Texas planted acres declined in 2011 to 1.15 million acres down from 1.29 million planted acres in 2010. Yields were down slightly in 2011 at 3,275 pounds per acre. In North Carolina planted acreage, as reported by NASS, decreased from 87 thousand acres in 2010 to 82 thousand acres in 2011. This is about 1000 acres more than planted acres as reported by USDA Farm Service Agency (Table 1-1). Yields in North Carolina were excellent at 3,500 pounds per acre in contrast to the poor yield of 2,700 pounds per acre in 2010. As a result production in North Carolina increased 22 percent to 283 million pounds despite a decrease in acreage. Peanut stocks in commercial storage as of September 30, 2011 at 1.23 million pounds were down 55 million pounds from 2010. Stocks of shelled peanuts were down 13 percent while stocks of in shell peanuts were down 14 percent from 2010. September 2011 ending stocks of in shell Virginia and Valencia type peanuts were down about 50 percent at only 60 million pounds. Lower production and declining stocks led to higher prices with prices over $800 per ton reported. Short supplies of peanuts have led to speculation that prices will increase even more for the 2012 crop. However continued strong prices for competing crops and the strong possibility of continued drought in Texas and other parts of the southern U.S. will hamper efforts to increase peanut acreage in 2012. 5 Table 1-1. 2010 North Carolina Peanuts Planted Acreage by Type and County County Runners Virginia Total Beaufort 132.5 416 548.5 Bertie 6688.3 6688.3 Bladen 5395.28 5395.28 Brunswick 1 1 Carteret 0.1 83.4 83.5 Chowan 3104.6 3104.6 Columbus 1039.09 4151.8 5190.89 Craven 409.5 409.5 Cumberland 161.5 161.5 Currituck 28.3 28.3 Duplin 4069.8 4069.8 Edgecombe 512.04 5052.55 5564.59 Gates 2572.9 2572.9 Greene 399.6 1836.07 2235.67 Halifax 1160.6 4258.78 5419.38 Harnett 137.6 26.5 164.1 Hertford 3584.3 3584.3 Johnston 235.1 814.6 1049.7 Jones 645.2 645.2 Lenoir 349.1 349.1 Martin 8097.9 8097.9 Nash 69.2 2497.38 2566.58 Northampton 522.1 2426.5 2948.6 Onslow 609.6 609.6 Pasquotank 23.2 23.2 Pender 251.3 251.3 Perquimans 506.7 506.7 Pitt 672.46 6459.73 7132.19 Robeson 461.3 2662.4 3123.7 Sampson 3664.78 3664.78 Scotland 664.6 664.6 Wake 65.6 174.2 239.8 Washington 1117.8 1117.8 Wayne 1844.98 1844.98 Wilson 119.86 524.27 644.13 State Total 5899.45 74802.52 80701.97 Sources: USDA-FSA “North Carolina planted peanut acreage report; 2010.” 6 B. PEANUT PRODUCTION BUDGETS S. Gary Bullen Extension Economist—Agricultural and Resource Economics David Jordan Peanut Specialist—Crop Science Emily Weddington Agricultural and Resource Economics The budgets in the following tables represent costs and returns that are achieved by many growers in different regions of North Carolina using strip-till or conventional production technologies. The budgets do not represent average costs and returns. Budgets are intended to be used as guides for planning purposes only. They do not include sprays for Sclerotinia blight or fumigation for CBR. The cost of land plaster is assumed to be $51.51 per ton; less expensive sources are available although transportation costs can be significant. Current information on the peanut outlook and situation, budgets, farm management, and more is available at the North Carolina State University Department of Agricultural and Resource Economics Web site: www.ag-econ.ncsu.edu. 7 Table 1-2. Estimated Costs and Returns Per Acre of RUNNER STRIP-TILL Peanuts, 2012—3,500-Pound Yield, 4-Row Equipment Item Quantity and Unit Price or Cost/Unit ($) Total/Acre ($) Your Farm 1. GROSS RECEIPTS Peanuts 3,500 lb 0.33 1,155.00 Total Receipts: 1,155.00 2. VARIABLE COSTS* Seed 110.00 lb 1.20 132.00 Inoculant 1.00 acre 5.00 5.00 Fertilizer Nitrogen 15.00 lb 0.32 4.80 Phosphate 30.00 lb 0.41 12.30 Potash 90.00 lb 0.54 48.60 Manganese 3.00 Lb 1.5 4.50 Boron 2.50 lb 1.13 2.83 Lime (prorated) 0.50 ton 48.50 24.25 Land Plaster 0.25 ton 51.51 12.88 Herbicides 1.00 acre 59.99 59.99 Insecticides 1.00 acre 35.48 35.48 Fungicides 1.00 acre 56.43 56.43 Scouting 1.00 acre 10.00 10.00 Hauling 1.75 ton 12.00 21.00 Drying & Cleaning 1.75 ton 45.00 78.75 State Check-off Fee 1.75 ton 3.00 5.25 National Assessment* 735.00 acre 0.01 7.35 Crop Insurance 1.00 acre 22.00 22.00 Tractor/Machinery 1.00 acre 116.10 116.10 Labor 3.40 hours 9.30 31.62 Interest on Operating Capital $257.58 5.00% 12.88 Total Variable Costs 704.01 3. INCOME FROM ABOVE VARIABLE COSTS 450.99 4. FIXED COSTS Tractor/Machinery 1.00 acre 180.33 180.33 Total Fixed Costs 180.33 5. TOTAL COSTS 884.34 6. NET RETURNS TO LAND, RISK, & MGMT. 270.66 * National Assessment is 1.05% of gross receipt and is also named National Loss, Promotion, Research Assessment. Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, or land rent. 8 Table 1-3. Estimated Costs and Returns Per Acre of RUNNER CONVENTIONAL-TILL Peanuts. 2012—3,500-Pound Yield, 4-Row Equipment Item Quantity per Unit Price or Cost/Unit ($) Total per Acre ($) Your Farm 1. GROSS RECEIPTS Peanuts 3,500 lb 0.33 1,155.00 Total Receipts 1155.00 2. VARIABLE COSTS Seed 110.00 lb 1.20 132.00 Inoculant 1.00 acre 5.00 5.00 Fertilizer Nitrogen 15.00 lb 0.32 4.80 Phosphate 30.00 lb 0.41 12.30 Potash 90.00 lb 0.54 48.60 Boron 2.50 lb 1.13 2.83 Manganese 3.5 lb 1.5 4.50 Lime (prorated) 0.50 ton 48.50 24.25 Land Plaster 0.25 ton 51.51 12.88 Herbicides 1.00 acre 59.99 59.99 Insecticides 1.00 acre 31.52 31.52 Fungicides 1.00 acre 56.43 56.43 Scouting 1.00 acre 10.00 10.00 Hauling 1.75 ton 12.00 21.00 Drying & Cleaning 1.75 ton 45.00 78.75 State Check-off Fee 1.75 ton 3.00 5.25 National Assessment* 831.25 acre 0.01 8.31 Crop Insurance 1.00 acre 22.00 22.00 Tractor/Machinery 1.00 acre 121.95 121.95 Labor 3.76 hour 9.30 34.97 Interest on Operating Capital $258.53 5.00% 12.93 Total Variable Costs 710.26 3. INCOME ABOVE VARIABLE COSTS 444.74 4. FIXED COSTS Tractor/Machinery 1.00 acre 175.38 175.38 Total Fixed Costs 175.38 5. TOTAL COSTS 885.64 6. NET RETURNS TO LAND, RISK, & MANAGEMENT 269.36 * National Assessment is 1.05% of gross receipt and is also named national loss, promotion, research assessment. Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, or land rent.9 Table 1-4. Estimated Costs and Returns Per Acre of VIRGINIA STRIP-TILL Peanuts, 2012—3,500-Pound Yield, 4-Row Equipment Item Quantity and Unit Price or Cost/Unit ($) Total per Acre ($) Your Farm 1. GROSS RECEIPTS Peanuts 3,500 lb 0.35 1,225 Total Receipts 1,225 2. VARIABLE COSTS Seed 140.00 lb 1.20 168.00 Inoculant 1.00 acre 5.00 5.00 Fertilizer Nitrogen 15.00 lb 0.32 4.80 Phosphate 30.00 lb 0.41 12.30 Potash 90.00 lb 0.54 48.60 Manganese 3.00 lb 1.50 4.50 Boron 2.50 lb 1.13 2.83 Lime (prorated) 0.50 ton 48.60 24.25 Land Plaster 0.50 ton 51.51 25.76 Herbicides 1.00 acre 59.99 59.99 Insecticides 1.00 acre 35.48 35.48 Fungicides 1.00 acre 56.43 56.43 Scouting 1.00 acre 10.00 10.00 Hauling 1.75 ton 12.00 21.00 Drying & Cleaning 1.75 ton 45.00 78.75 State Check-off Fee 1.75 ton 3.00 5.25 National Assessment* 1006.25 acre 0.01 10.06 Crop Insurance 1.00 acre 22.00 22.00 Tractor/Machinery 1.00 acre 116.10 116.10 Labor 3.40 hours 9.30 31.62 Interest on Operating Capital $282.02 5.00% 14.10 Total Variable Costs 756.82 3. INCOME ABOVE VARIABLE COSTS 468.18 4. FIXED COSTS Tractor/Machinery 1.00 acre 180.33 180.33 Total Fixed Costs 180.33 5. TOTAL COSTS 937.15 6. NET RETURNS TO LAND, RISK, & MGMT. 287.85 * National Assessment is 1.05% of gross receipt and is also named National Loss, Promotion, Research Assessment.Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, and land rent.10 Table 1-5. Estimated Costs and Returns Per Acre of VIRGINIA CONVENTIONAL-TILL Peanuts, 2012—3,500-Pound Yield, 4-Row Equipment Item Quantity and Unit Price or Cost/Unit ($) Total per Acre ($) Your Farm 1. GROSS RECEIPTS Peanuts 3,500 lb 0.35 1,225 Total Receipts 1,225 2. VARIABLE COSTS Seed 140.00 lb 1.20 168.00 Inoculant 1.00 acre 5.00 5.00 Fertilizer Nitrogen 15.00 lb 0.32 4.80 Phosphate 30.00 lb 0.41 12.30 Potash 90.00 lb 0.54 48.60 Manganese 3.00 lb 1.50 4.50 Boron 2.50 lb 1.13 2.83 Lime (prorated) 0.50 ton 48.60 24.25 Land Plaster 0.50 ton 51.51 25.76 Herbicides 1.00 acre 59.99 59.99 Insecticides 1.00 acre 35.48 35.48 Fungicides 1.00 acre 56.43 56.43 Scouting 1.00 acre 10.00 10.00 Hauling 1.75 ton 12.00 21.00 Drying & Cleaning 1.75 ton 45.00 78.75 State Check-off Fee 1.75 ton 3.00 5.25 National Assessment* $1,006.25 0.01 10.06 Crop Insurance 1.00 acre 22.00 22.00 Tractor/Machinery 1.00 acre 121.95 121.95 Labor 3.76 hour 9.30 34.97 Interest on Operating Capital $282.02 5.00% 14.10 Total Variable Costs 766.02 3. INCOME ABOVE VARIABLE COSTS 458.98 4. FIXED COSTS Tractor/Machinery 1.00 acre 175.38 175.38 Total Fixed Costs 175.38 5. TOTAL COSTS 941.40 6. NET RETURNS TO LAND, RISK, & MGMT. 283.60 *National Assessment is 1.05% of gross receipt and is also named national loss, promotion, research assessment. Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, and land rent.11 Table 1-6. Return to Land, Overhead and Management for Peanut at Various Yields and Costs of Production Net Return ($/acre) at $600/ton Contract Price Total cost ($/acre) Peanut Yield 800 850 900 950 1000 1050 (pounds/acre) __________________ Net Return ($/acre) __________________ 3000 100 50 0 -50 -100 -150 3500 250 200 150 100 50 0 4000 400 350 300 250 200 150 4500 550 500 450 400 350 300 5000 700 650 600 550 500 450 Net Return ($/acre) at $700/ton Contract Price Total cost ($/acre) 800 850 900 950 1000 1050 __________________ Net Return ($/acre) __________________ 3000 250 200 150 100 50 0 3500 425 375 325 275 225 175 4000 600 550 500 450 400 350 4500 775 725 675 625 575 525 5000 950 900 850 800 750 700 Net Return ($/acre) at $800/ton Contract Price Total cost ($/acre) 800 850 900 950 1000 1050 __________________ Net Return ($/acre) __________________ 3000 400 350 300 250 200 150 3500 600 550 500 450 400 350 4000 800 750 700 650 600 550 4500 1000 950 900 850 800 750 5000 1200 1150 1100 1050 1000 95012 2. PEANUT SEED Jan Spears and David Jordan Extension Specialists — Crop Science A uniform stand of healthy, vigorous plants is essential if growers are to achieve the yields and quality needed for profitable peanut production. It is important for growers to plant high quality seed of varieties adapted to their farm situations, management styles, and intended market uses. WHAT’S IN A BAG OF PEANUT SEED? A bag of seed peanuts contains thousands of potential plants. To grow a uniform stand of healthy plants, you need genetically pure seed that has been produced under a management system that maximizes seed health, germination, and vigor. The genetic composition of a peanut variety dictates maturity date, disease and insect resistance, peanut quality, grade, and many other characteristics. The best assurance of obtaining genetically pure seed is to purchase Certified Seed. Seed health is related to seed-borne pathogens present on or in peanut seeds. Pathogens can reduce germination potential and can in some cases transmit peanut diseases. Professional seed producers take specific measures to reduce the level of seed-borne pathogens. The extra steps they take minimize the chance for the spread of unwanted diseases. Seed lots high in germination and vigor potential will germinate more rapidly and produce more robust seedlings. These seedlings are more likely to survive moderate stress during the weeks following planting. Always purchase seed from a reputable, professional seed dealer. Bargain seed from a stranger, or even a neighbor, may not be such a bargain. Along with their “seed,” you could be buying weed seed or mixed varieties. You could even introduce diseases onto your farm. PEANUT SEED PRODUCTION The key component to producing high quality peanut seed is to make the seed crop your highest farm priority. Attention to details is essential and critical steps include: • field selection, • seed selection, 13 • cleaning and tuning up planting equipment, • applying gypsum and boron at the right time, • digging the crop when a majority of the pods are close to maturity, • adjusting harvesting equipment to minimize mechanical damage, • curing the peanuts slowly, and • storing the seeds in a cool, dry environment. Production of high-quality peanut seeds requires a high level of management that begins before planting and continues through delivery of seeds to the peanut farmer. A detailed description of peanut seed production can be found in Peanut Seed Production: A Guide For Producers of Virginia-type Peanut Seed (AG–622), which can be obtained free from your county Extension center or viewed online: www.peanuts.ncsu.edu/PDFFiles/004968/Peanut_Seed_Production_Guide.pdf SAVING SEED In years when profits are low, some growers may decide that saving their own seed will help reduce production costs. Cleaning, treating, and bagging seed, however, can be expensive; and a grower may not save more than a few cents per acre. In fact, a loss may occur if the seeds they planted were of poor quality. Seed germination and vigor of saved seed can be an issue, and growers are urged to have germination tests run on saved seed immediately after harvest and again about 6 weeks before planting. Checking the quality of the seed early will tell the grower if the seed is worth saving. The second test will tell the grower if the seed is worth planting. Seed production is a specialized process; varietal purity, seed quality, and seed health are carefully monitored throughout the growing season and during the digging, combining, curing, cleaning, storage, and treating operations. Saving seed should not be an afterthought, but rather a process that begins well before the seed crop is planted. Growers who decide to save seed should be aware that they might be in violation of the North Carolina State Seed Law, the Plant Variety Protection Act (PVPA), and Title V of the Federal Seed Act if they sell that saved seed. According to regulations, growers may save enough seed of a PVPA-protected variety to plant back on their own holdings (land owned, leased, or rented). If planting intentions change and if a variety is PVPA-1970 protected, the farmer may sell that saved seed, 14 but only that amount saved to plant his or her holdings. If the variety is protected under the amended 1995 PVPA, a farmer may not sell any seed without the permission of the variety owner.Very few varieties currently grown in the mid-Atlantic states are PVPA-1970 protected varieties. Growers who are considering selling saved-seed are encouraged to consult with their Department of Agriculture Seed Sections to be sure of the variety protection level. See Table 2-1 for a list of popular Virginia makret type varieties and their level of protection. North Carolina Seed Regulations require variety labeling on all peanut seed sold in the state, regardless of whether the seed is certified or farmer stock. No peanut seed can be sold as variety not stated, even if the variety is not known or the seed is a mixture of varieties. CO-OP SEED DISTRIBUTION Some growers are members of a co-op, and questions have been raised about co-op distribution of seed to growers. A farmer may bring saved seed into the co-op to be shelled, cleaned, treated, and bagged. But the entire quantity of saved seed must be returned to the farmer who produced it. The seed may not be co-mingled with seed from any other grower, and the seed may not be sold, traded, nor given to any other grower. These actions are a violation of PVPA and the Federal Seed Act. The amount of peanuts shelled, cleaned, treated, and bagged must not exceed the amount the grower may legally save. A co-op may become a licensed seed dealer, allowing co-op members to produce their own seed as a group with seed from several growers combined and distributed among the membership. If so, steps must be taken before planting to ensure proper certification and State Seed Law requirements have been met. Certified seed must be grown from Foundation or Registered seed, fields must be inspected, and the seed must meet minimum germination standards. The co-op must be licensed under the North Carolina State Seed Law. Contact the North Carolina Crop Improvement Association (919-515-2851) for details on how to certify peanut seed and the North Carolina Department of Agriculture and Consumer Services Seed Section (919-733-3930) for details about becoming a licensed seed dealer. 15 Table 2-1. List of Varieties and Requirements for Sale Variety Can you save seed? Can you sell that saved seed? Must the saved seed be sold as a class of certified seed? Bailey Yes Only with permission Yes Brantley Yes Only with permission Yes CHAMPS Yes Only with permission Yes Gregory Yes Only with permission Yes Perry Yes Only with permission Yes Phillips Yes Only with permission Yes NC-V 11 Yes Only with permission Yes Sugg Yes Only with permission Yes16 3. PEANUT PRODUCTION PRACTICES David L. Jordan Extension Specialist—Crop Science Successful production of quality peanuts requires growers to plan an effective production and marketing program and to implement that program on a timely basis during the season. Each cultural practice and marketing decision must be effectively integrated into the total farm management plan to produce optimum profits from the whole farm. STAND ESTABLISHMENT Soil temperatures need to be above 65oF for germination to proceed at an acceptable rate. Large-seeded Virginia market type peanuts planted under favorable moisture and temperature conditions will show beginning radicle (root) growth in about 60 hours. If conditions are ideal, sprouting young seedlings should be visible in 7 days for smaller-seeded varieties like Bailey, and 10 days for larger-seeded varieties like Gregory. Peanuts should not be planted until the soil temperature at a 4-inch depth is 65°F or above at noon for 3 days. Favorable weather for peanut germination should also be forecast for the next 72 hours after planting. The soil should be moist enough for rapid water absorption by the seed. The planter should firm the seedbed so there is good soil-to-seed contact. Growers should establish at least four plants per foot of row regardless of variety. Peanuts can emerge from depths as low as 3 inches. VARIETY SELECTION Yield and quality are two major factors that influence variety selection. Growers with significant disease history may need to choose a variety with disease tolerance or resistance. Planting at least three varieties with different maturity dates permits efficient use of limited harvesting and curing equipment. Planting varieties with different genetic pedigrees reduces the risk of crop failure because of adverse weather or unexpected disease epidemics. The percentage of acres planted for certified seed production generally reflect overall plantings of varieties (Table 3-1). The selection of a variety should be based on more than 1 year’s data. Performance of our most popular peanut varieties from reports 17 prepared by Dr. Tom Isleib (peanut breeder at N.C. State University) and Dr. Maria Balota’s PVQE (Peanut Variety and Quality Evaluation) program is presented in Tables 3-2 and 3-3, respectively. Yield from research station and on-farm tests by David Jordan and Dewayne Johnson (N.C. Cooperative Extension) is presented in Table 3-4. Varietal characteristics are listed in Table 3-5. Disease reaction of varieties can be found in Chapter 6, “Peanut Disease Management.” Table 3-1. Certified Peanut Seed Acreage in 2010 in NC, SC, and VA. Modified from Isleib, 2011 Variety Percent of Total Planted Perry 21.6 CHAMPS 21.0 Phillips 18.8 NC-V 11 14.2 Gregory 13.4 Bailey 4.9 Sugg 2.2 VA 98R 1.0 Florida Fancy 1.4 Georgia 08V 1.1 Table 3-2. Pod Yield and Market Grade Characteristics of Bailey and Sugg Compared with Other Commercially Available Virginia Market Type Varieties Variety Percent Fancy Percent ELK Percent SMK Meat Content Yield (lb/acre) Bailey 75 40 62 69 4,629 Sugg 81 46 62 69 4,449 NC-V11 75 35 60 69 4,430 Gregory 85 45 58 66 4,056 Perry 75 40 61 69 3,924 Phillips 79 46 62 69 4,213 VA 98R 73 38 60 68 4,157 CHAMPS 79 39 61 68 4,141 *Data are from Isleib et al. (January, 2010) and are pooled over 43 tests over 5 years. Table 3-3. Percentages of FP, ELK, SMK, and Total Kernels and Pod Yield for the Major Virginia Market Type Varieties Variety FP ELK SMK Total Kernels Yield NC-V 11 79 41 67 73 5,233 Gregory 92 52 66 72 4,993 Perry 81 44 66 74 4,906 CHAMPS 81 43 68 74 4,917 Phillips 85 51 68 75 5,066 Bailey 77 44 67 74 5,460 Florida Fancy 87 46 65 73 4,851 VA 98R 78 42 66 74 4,911 Sugg 84 49 66 75 5,230 *Data are from Balota et al. (PVQE Summary, Information series No. 491) and are pooled over 12 trials from 2008–2009.18 Table 3-4. Pod Yield of Commercially Available Peanut Varieties from Eight Research Station and On-farm Tests Variety Pod Yield* Phillips 4,630 Gregory 4,210 CHAMPS 4,470 Bailey 4,780 * Selected data from D. Jordan and D. Johnson, N.C. Cooperative Extension Service and are pooled over 8 trials during 2009-2011. Experiments included two digging dates, generally September 20–30 versus October 7–15 (2009) and approximately October 1 and October 15 (2010 and 2011). Data are pooled over eight locations and two digging dates. Variety Characteristics Bailey is a new large-seeded Virginia market type peanut with resistance to several key peanut diseases. This variety offers tolerance to CBR, Sclerotinia blight, tomato spotted wilt, and possibly stem rot. Seed size is slightly larger than NC-V 11. CHAMPS is a large-seeded peanut that matures slightly earlier than Wilson. It is intermediate in resistance to tomato spotted wilt and is moderately susceptible to most other diseases. Gregory is a large-seeded Virginia market type peanut with growth habit intermediate between bunch and runner, a pink seed coat, and a high percentage of jumbo pods and extra-large kernels. It is susceptible to most diseases and insect pests. Because of its large seed size, Gregory has a high calcium requirement and may show reduced seedling vigor compared with other varieties. Other than Bailey, Gregory offers the best resistance to tomato spotted wilt virus of commercially available Virginia market types when planted at optimum seeding rates. NC-V 11 is a large-seeded Virginia market type peanut with a runner growth habit that is similar to Gregory in maturity. Its major advantage is a high yield and value per acre. NC-V 11 has a lower percentage of fancy pods than Gregory, Wilson, CHAMPS, and Phillips. Perry is a large-seeded peanut with partial resistance to CBR and some tolerance of Sclerotinia blight. It is characterized by a semi-runner growth habit. It matures later than NC-V 11. Perry is susceptible to tomato spotted wilt virus. Phillips is a large-seeded peanut that matures slightly earlier than Gregory. It has only minor resistance to many of the diseases found in peanut.19 Sugg is a new large-seeded Virginia market type peanut with a disease management package that approaches that of Bailey. Although not as resistant to disease as Bailey, Sugg has larger pods. Table 3-5. Varietal Characteristics Factors Bailey CHAMPS Gregory NC-V 11 Perry Phillips Sugg Growth habit (R=runner; SR=semi-runner) SR R R R SR SR SR Heat unit requirement 2,650 2,500 2,650 2,650 2,770 2,600 2,650 Comparative days to optimum maturity 0* -9 0 0 +7 -3 0* Seed coat color Tan Pink Pink Pink Pink Pink Pink Seed per pound 540 535 450 625 525 545 545 Need for calcium (M=moderate; H=high) M M H M M M M Heat unit requirement=degree day accumulation (56°F base and a 95°F ceiling) required to reach optimum maturity assuming adequate soil moisture for sustained growth and development In comparative days to optimum maturity, - = optimum maturity for the variety occurs prior to ‘0’; += optimum maturity for variety occurs after ‘0’. *Limited data SELECTING AND MANAGING SOIL RESOURCES Peanuts are best adapted to well-drained, light-colored, sandy loam soils, such as the Norfolk, Orangeburg, and Goldsboro sandy loam. These soils are loose, friable, and easily tilled with a moderately deep rooting zone for easy penetration by air, water, and roots. A balanced supply of nutrients is needed, as peanuts do not usually respond to direct fertilization. Soil pH should be in the range of 5.8 to 6.2. Peanuts grown in favorable soil conditions are healthier and more able to withstand climatic and biotic stresses. Crop Rotation A long crop rotation program is essential for efficient peanut production. The peanut plant responds to both the harmful and beneficial effects of other crops grown in the fields. Research shows that long rotations are best for maintaining peanut yields and quality. Benefits and potential problems associated with crops typically found within 20 Rotation (1997–2011) (CR – Corn, CT – Cotton, SB – Soybeans, WH – Wheat, PN – Peanut) Yield (lb/acre) Yield (bu/acre) Peanut 2006 Wheat 2008 Wheat 2009 Soybean 2008 Soybean 2009 Corn 2007 Corn 2009 Corn 2011 CR – CT – CR – PN – CR – CR – CR – CR – CR – PN – CR – WH/SB – CR– WH/SB-CR 5,920 a 32 a 35 ab 43 a 44 a 16 a 111 a 138 a PN – CR – CR – PN – CR – CR – PN – CR – CR – PN– CR – WH/SB – CR– WH/SB-CR 5,030 b 34 a 33 ab 44 a 31 bc 7 a 115 a 127 a CR – PN – CR – PN – CR – PN – CR – PN – CR – PN– CR – WH/SB – CR– WH/SB-CR 4,350 c 31 a 42 a 46 a 40 ab 21 a 102 a 128 a PN – SB – CR – PN – SB – CR – PN – SB – CR – PN – CR – WH/SB – CR– WH/SB-CR 3,800 c 32 a 36 ab 38 a 25 c 32 a 92 a 138 a PN – PN – PN – PN – PN – PN – PN – PN – PN – PN – CR – WH/SB – CR– WH/SB-CR 2,600 d 31 a 30 b 38 a 33 abc 23 a 135 a 143 a *Means within a column followed by the same letter are not significantly different p < 0.05. Table 3-6. Influence of Rotation on Crop Yield at Lewiston21 Table 3-7. Influence of Rotation Interval and Soybeans on Crop Yield at Rocky Mount Yield (lb/acre) Yield (bu/acre) Peanut 2006 Wheat 2008 Wheat 2010 Soybean 2008 Soybean 2010 Corn 2007 Corn 2009 Corn 2011 CT – CT – CT – CT – CT – PN – CR – WH/SB – CR– WH/SB-CR 3,770 a 40 b 59 ab 15 a 9 a 77 a 125 ab 114 a CT – CT – SB – CT – CT – PN – CR – WH/SB – CR– WH/SB-CR 3,090 b 39 b 65 ab 19 a 9 a 73 a 120 b 124 a CT – CT – PN – CT – CT – PN – CR – WH/SB – CR– WH/SB-CR 3,050 b 42 b 51 b 15 a 10 a 75 a 67 c 110 a CT – PN – CT – PN – CT – PN – CR – WH/SB – CR– WH/SB-CR 2,880 bc 51 ab 61 ab 15 a 10 a 76 a 90 bc 110 a PN – PN – PN – PN – PN – PN – CR – WH/SB – CR– WH/SB-CR 2,420 c 65 a 65 a 19 a 7 a 85 a 169 a 122 a Table 3-8. Influence of Rotation and Variety on Crop Yield at Whiteville Rotation (2001-2009) (CR – Corn, CT – Cotton, PN – Peanut, TB – Tobacco) Yield (lb/acre) Yield (bu/acre) Peanut 2006 Tobacco 2008 Corn 2007 Corn 2009 Variety Gregory Perry CR – CR – CR – CR – CR – PN – CR – TB – CR 3,310 a 3,540 a 3,340 a 141 a 101 a CR – CR – TB – CR – CR – PN – CR – TB – CR 3,670 a 3,940 a 3,450 a 154 a 92 a TB – CR – PN – TB – CR – PN – CR – TB – CR 2,000 b 2,970 a 3,380 a 139 a 92 a *Means within a column followed by the same letter are not significantly different according to Fisher’s Protected LSD Test at P < 0.05. *Means within a column followed by the same letter are not significantly different p < 0.05.22 Table 3-9. Peanut Yield Following Snap Beans, Sage, Sweet Potato, and Traditional Crop Rotations Disease (%) Yield (lb/acre) Previous Crops Bailey Phillips Bailey Phillips Cotton-Corn-Sweet Potato 1 11 4567 4337 Snap Bean-Wheat-Sage 0 8 3995 3725 Cotton-Corn-Cotton 0 11 4170 4267 Soybean-Corn-Cotton 0 6 4343 4303 Snap Bean-Corn-Cotton 0 8 4070 4270 Soybean-Wheat-Sage 0 7 4297 3964 Peanut-Corn-Cotton 0 9 4226 414023 Table 3-10. Plant Condition Rating (Percentage of Plants Expressing Symptoms of CBR), Root Knot Nematode Population in Soil, and Peanut Pod Yield During 2006 at Lewiston-Woodville. The CBR-resistant peanut variety NC 12C was planted during all years. Cropping system (2001-2006) (CR-Corn, CT-Cotton, SB-Soybean, PN-Peanut) Plant Condition (2006) (%) Nematode Population in Soil (2006) (Log No./500 cc soil) Peanut Yield (2006) (lb/acre) CR-PN (3 cycles) 4 a 7.6 a 4,180 c CT-PN (3 cycles) 3 a 1.9 bc 4,200 c CR-CR-PN (2 cycles) 6 a 2.6 bc 4,850 ab CT-CT-PN (2 cycles) 4 a 2.5 bc 4,730 bc SB-CR-PN (2 cycles) 10 a 4.5 ab 4,130 c SB-CT-PN (2 cycles) 5 a 0 c 4,330 bc CT-CR-PN (2 cycles) 4 a 1.2 bc 4,930 ab Continuous PN 2 a 7.1 a 3,040 d CR-CR-CR-CR-CR-PN 4 a 0.6 c 5,540 a Table 3-11. Cotton, Corn, Peanut, and Soybean Response the Year Following 4 Years of Tall Fescue Sod Versus Reduced Tillage Agronomic Crop Production (2009) and Corn Yield in 2010 Crops from 2005-2008 2009 2010 2011 Cotton (lb lint/A) Peanut (lb/A) Soybean (bu/A) Corn (bu/A) Corn (bu/A) Corn (bu/A) Tall fescue sod 920 4170 45 131 88 87 Combinations of corn and cotton 760* 4040 39 155* 68* 78* No. of trials 4 4 4 3 2 2 *Indicates significance of p < 0.05 *Means within a column followed by the same letter are not significantly different according to Fisher’s Protected LSD Test at p < 0.0524 peanut-based cropping systems can be found in Chapter 6, “Peanut Disease Management.” Research conducted at the Peanut Belt Research Station demonstrates the benefits of long rotations with corn (Table 3-6). Similar results are generally expected with cotton, and the value of rotation is also noted at Rocky Mount (Table 3-7). The value of planting the CBR-resistant variety Perry, compared to Gregory, is presented in Table 3-8. Disease reaction and peanut yield following several relatively unique crop rotations is presented in Table 3-9. The influence of rotation on parasitic nematode populations and yield can be found in Table 3-10. In recent years, there has been interest in crop yields, especially grains, when transitioning out of traditional peanut rotations. Results presented in Tables 3-6, 3-7, 3-8, and 3-9 indicate that corn, cotton, soybeans, and wheat are not affected by rotation to the extent that peanuts are affected. The value of sod-based rotations on yields of peanuts and other crops has been demonstrated in the southeastern United States. In North Carolina, a trial was recently completed where peanuts and other row crops were planted in either killed fescue sod or standard reduced-tillage cropping systems, including combinations of cotton and corn. Results for corn, cotton, peanuts, and soybeans from 2009 are presented in Table 3-11. During both 2010 and 2011, corn yield was higher after sod compared with combinations of traditional agronomic crops when planted several years after sod termination. FERTILIZING PEANUTS Lime Peanuts grow best on soils limed to a pH of 5.8 to 6.2, provided other essential elements are in balance and available to the plant. Yields of peanuts and other crops planted in soil with four differing pH regimens are provided in Table 3-12. Dolomitic limestone is the desired liming material because it provides both calcium and magnesium. Strongly acidic soils reduce the efficient uptake and use of most nutrients and may enhance the uptake of zinc to potentially toxic levels. The efficiency of nitrogen fixation is reduced in acid soils. Molybdenum is an essential element in biological nitrogen fixation, and it can be limiting at low soil pH. Soils too high in pH are not desirable because some elements are less available to the peanut plant and incidence of Sclerotinia blight may be greater. Manganese deficiency is often observed in fields that are overlimed. Some research has demonstrated that higher rates of calcium sulfate (gypsum or landplaster) 25 can reduce peanut yield when soil pH in the pegging zone is relatively low (Table 3-13 and 3-14). These results remind us that soil pH should be maintained around 6.0 and that gypsum should be applied at rates not exceeding those currently recommended for Virginia market type peanuts. Increased broiler production in North Carolina and use of manure as a fertilizer source has increased concern over micronutrient toxicity. Several peanut fields have exhibited severe and yield-limiting zinc toxicities. These toxicities are increased in fields with low pH because zinc is more available at a lower pH. Maintaining soil pH around 6.0 is important in minimizing the adverse effects of zinc, and growers are cautioned not to overload fields with high levels of waste products. Micronutrient levels can build up quickly. Peanuts generally are able to tolerate zinc indices of 250. However, zinc toxicity can occur with lower index values if soil pH is low. Table 3-12. Crop Response to Soil pH Soil pH Percent of Yield at Compared with pH 5.9 Corn Cotton Peanut Soybean Wheat Grain sorghum 4.3 37 31 55 41 41 68 4.9 77 57 62 66 73 86 5.4 85 88 82 90 91 96 5.9 100 100 100 100 100 100 Years 2 2 2 2 2 126 Table 3-13. Peanut Yield (lb/acre) Following Application of Three Rates of Gypsum Location Year Soil pH Relative Calcium Sulfate Rate 0 1.0× 1.5× Lewiston-Woodville 2001 6.0 4,000 a 3,780 a 3,670 a Rocky Mount 2001 5.5 4,170 a 3,970 ab 3,730 b Lewiston-Woodville 2002 6.1 3,420 a 3,570 a 3,390 a Rocky Mount 2002 6.2 4,320 a 4,320 a 4,300 a Lewiston-Woodville 2003 6.0 4,130 b 4,350 b 4,610 a Rocky Mount 2003 5.8 3,780 a 3,660 a 3,740 a Lewiston-Woodville 2004 5.6 3,820 a 3,760 a 3,350 b Rocky Mount 2004 6.3 3,150 a 3,110 a 3,270 a Lewiston-Woodville 2005 6.0 4,530 b 5,110 a 5,120 a Rocky Mount 2005 6.6 2,540 b 4,490 a 4,630 a *Means for cultivar or for relative calcium sulfate rate within each combination of year and location followed by the same letter are not significantly different according to Fisher’s Protected LSD Test at p < 0.05. Table 3-14. Peanut response to gypsum rate at three soil pH values Soil pH Relative Gypsum Rate 5.0 5.5 6.0 0 1920 2720 2900 0.5X 1930 2690 3320 1.0X 2110 2190 3250 Data are pooled over 3 years. Nitrogen Roots of peanuts can be infected by Bradyrhizobium bacteria. Nodules form on the roots at the infection sites. Within these nodules, the bacteria can convert atmospheric nitrogen into a nitrogen form that can be used by plants through a process called biological nitrogen fixation (BNF). This symbiotic relationship provides sufficient nitrogen for peanut production if the roots are properly nodulated. Growers should inoculate their peanut seed or fields to ensure that adequate levels of Rhizobia are present in each field. The data in Table 3-15 are from multiple locations and give an indication of the possible response of peanuts to inoculant applied as a liquid or granular in the seed furrow. Response of peanuts to rotation and inoculant treatment is provided in Table 3-16. These data demonstrate that while peanut response to rotation is often predictable (Tables 3-6, 3-7, 3-8, and 3-9), 27 response to inoculant and rotation combinations is less predictable. Therefore, peanuts should be inoculated in all years regardless of previous rotation history to minimize risk and maintain yield. Table 3-15. Peanut Yield Response in Fields without a History of Peanuts versus Fields with Frequent Plantings of Peanuts (1999 – 2011) Inoculant Use New Peanut Fields Fields with a Recent History of Peanuts No inoculant 3,052 3,713 Inoculant 4,473 3,892 Difference 1,320 179 Number of Trials 28 26 Years 1999 – 2011 1999 – 2011 Table 3-16. Peanut Response in 2006 to Inoculation Following Various Intervals of Peanut Planting in Previous Years Test Range of Years Not Planted in Peanuts Response to Rotation Response to Inoculation Test 1 0 – 5 Yes No Test 2 1 – 3 Yes Yes Test 3 0 – 5 Yes No Test 4 2 – 5 Yes Yes Commercial inoculants can be added to the seed or put into the furrow with the seed at planting. In-furrow inoculants are available in either granular or liquid form. When inoculants are applied directly in the seed furrow, either as a spray or granular, it is essential that the product reach the bottom of the seed furrow so that infection occurs as the root system develops. Some growers have had difficulty in obtaining nodulation because soil moved in the seed furrow after seed drop but before inoculant spray or granules entered the seed furrow. Additionally, shallow planting along with in-furrow spray inoculants have performed poorly under hot and dry soil conditions. Peanuts are capable of emerging from depths of at least 3 inches, therefore, it is advisable to plant deep to protect sprayed inoculant from breakdown caused by high temperatures.28 Direct applications of nitrogen to peanuts are not generally needed. However, application of nitrogen fertilizers can increase yield, but only when peanuts are not nodulating and nitrogen deficiency is obvious. Research indicates that a minimum of 120 pounds actual nitrogen per acre as a single application may be needed to obtain yields similar to adequately nodulating peanuts when a true nitrogen deficiency exists in some fields. Lower rates also may be effective but perform inconsistently (Table 3-17). Research also suggests that ammonium sulfate is a more effective source than ammonium nitrate. Split applications may be more efficient than a single application. Best results are obtained when applications are made early in the season. Peanuts grown on deep sandy soils often respond to nitrogen fertilization and may lap middles more quickly even when inoculation is adequate. Rapid canopy closure results in cooler soil temperatures in the pegging zone. When soils have high temperatures, pegs cannot survive. Table 3-17. Peanut Yield Response to Nitrogen Rate and Source when Applied in Early July when Nitrogen Deficiency Symptoms Are First Noted. Fields were not planted in peanuts during previous years. Nitrogen Source Actual N Rate (lb/acre) Peanut Pod Yield Pooled Over 6 Experiments (2007–2011) Actual Yield (lb/acre) % of Inoculated Peanut None 0 3,161 c 73 Inoculant 0 4,335 a 100 Ammonium sulfate 60 3,867 ab 89 Ammonium sulfate 90 4,163 ab 96 Ammonium sulfate 120 4,225 ab 98 Ammonium sulfate 150 4,261 a 98 Ammonium nitrate 60 3,889 ab 90 Ammonium nitrate 90 3,978 ab 92 Ammonium nitrate 120 3,741 b 86 Ammonium nitrate 150 3,870 ab 89 *Means followed by the same letter are not significantly different according to Fisher’s Protected LSD Test at p < 0.05.29 Potassium and Phosphorus The most efficient and easiest way to apply potassium is to apply it to the crop preceding peanuts. This usually increases the yield of the preceding crop and allows the potassium to leach into the area where the peanut root system obtains most of its nutrients. However, if North Carolina Department of Agriculture and Consumer Services (NCDA & CS) soil test recommendations indicate that potassium and phosphorus are needed, then the appropriate levels of these nutrients should be applied. Many growers and researchers feel that high levels of soil potassium in the fruiting zone (the upper 2 or 3 inches of soil) result in more pod rot and interfere with the uptake of calcium by pegs and pods, which results in a higher percentage of “pops” and calcium deficiency in the seeds. If the potassium level is high in the fruiting zone, a higher rate of gypsum may be needed. Most of the peanut soils in North Carolina have adequate levels of phosphorus for good peanut production. Once a medium or higher level of phosphorus is achieved, it remains quite stable over a number of years. The addition of phosphorus-containing fertilizer to peanuts is generally not needed if it is applied to other crops in the rotation. However, soil testing is the only way to be sure. Calcium Perhaps the most critical element in the production of large-seeded Virginia market type peanuts is calcium. Lack of calcium uptake by peanuts results in “pops” and darkened plumules in the seed. Seeds with dark plumules usually fail to germinate. Calcium must be available for both vegetative growth and pod growth. Calcium moves upward in the peanut plant but does not move downward. Thus, calcium does not move through the peg to the pod and developing kernel. The peg and developing pod absorb calcium directly from soil, so it must be readily available in the soil. Adequate soil calcium is usually available for good plant growth but not for pod development or good quality peanuts. It is important to provide calcium in the fruiting zone through gypsum applications. Gypsum should be applied to all Virginia market types, regardless of the soil characteristics or soil nutrient levels. The calcium supplied through gypsum application is relatively water soluble (compared to other calcium sources) and more readily available for uptake by peanut pegs and pods. Each pod must absorb adequate calcium to develop normally.30 Gypsum is available in three forms—finely ground, granular, and phosphogypsum. Several additional by-product gypsums are now on the market. The by-product materials vary in elemental calcium content. Studies show that all forms of gypsum effectively supply needed calcium when used at rates that provide equivalent calcium levels uniformly in the fruiting zone. General recommendations for application rates are given in Table 3-18. The use of gypsum on large-seeded peanuts is very effective in improving peanut seed quality and grades. Some research data indicate that high rates of gypsum may control or reduce the pod rot disease complex. Gypsum should not be broadcast before land preparation or before planting because too much rain may leach the calcium below the fruiting zone. Best results are obtained when gypsum is applied in late June or early July. The availability of calcium supplied by gypsum application is also influenced by the amount of rainfall. Moisture is needed to make gypsum soluble and calcium available to the peanut fruit. In unusually dry years, peanuts may show symptoms of calcium deficiency, even when recommended rates of gypsum are applied. Increasingly, there are questions concerning the need to apply gypsum as supplemental calcium to peanuts. Sometimes peanuts do not respond to supplemental calcium. Sometimes peanuts respond well to half the amount given in Table 3-18. The interactions of environmental conditions, seed size, soil series, native fertility, and soil moisture are unpredictable. However, for a consistent response over a wide range of soil characteristics and weather conditions, the full rate of gypsum is recommended for Virginia market types. Growers are encouraged to evaluate peanut response to gypsum on their own farms before leaving off this input or reducing rates below those presented in Table 3-18. Data from several trials (Table 3-19) indicate that gypsum at rates below those recommended in Table 3-18 can, in some cases, be effective. For more information on techniques that can be used to compare treatments on the farm, see AG-615, Knowing Your Field: A Guide to On-Farm Testing for Peanut Growers. There is also a question of whether or not the gypsum rate needs to be increased for extremely large-seeded Virginia market type varieties, such as Gregory. Results from 2001–2005 at two locations during each year indicated that a rate of 1.5 times the recommended rate did not increase pod yield over the normal use rate in most experiments (Table 3-14). While the data did indicate that the large-seeded variety Gregory was more responsive to gypsum than the much smaller-seeded variety NC-V 11, there was no advantage to applying gypsum at rates exceeding those rates listed in Table 3-18. 31 Table 3-18. Gypsum Sources and Application Rates Source % CaSO4* Application Rate (lb/acre) Band (16-18 in) Broadcast USG Ben Franklin 85 600 - USG 420 Granular 83 - 1,215 USG 500 70 - 1,300 Super Gyp 85 85 - 1,200 TG Phosphogypsum 50 - 2,000 Agri Gypsum 60 - 1,800 Gyp Soil 85 - 1,200 Buckshot ** - 2,000 * Guaranteed analysis percentage in registration with N.C. Department of Agriculture and Consumer Services. **Buckshot is considered a lime by-product material and not a gypsum product. Table 3-19. Actual Pod Yield Following Application of Gypsum at 0.5 and 1 Times (X) the Recommended Use Rate for Virginia Market Types. No. of Trials Pod Yield (pounds/acre) No Gypsum 0.5X Gypsum 1.0X Gypsum Actual Yield 12 3970 4510 4590 Increase Over the No-Gypsum Control - - 540 620 Increase Over the 0.5X Rate of Gypsum - - - 80 In recent years, runner market type varieties referred to as “jumbo runners” have become more popular. These varieties, such as Florida 07, will require supplemental calcium compared to the smaller-seeded runners like Georgia Green. Growers should apply at least half the rate recommended for Virginia market types (Table 3-18). Small-seeded runner and Spanish varieties do not require as much calcium for optimum seed development as do the large-seeded Virginia market types. Recommendations vary in areas where runner peanuts are grown. Some states recommend calcium application regardless of seed size, while other states use the following relationships to determine if supplemental calcium is needed. If 32 the calcium level in parts per million (ppm) exceeds 250 and the ratio of calcium to potassium is at least 3 to 1, additional calcium is not recommended. If growing runners for seed, apply gypsum to ensure proper kernel development and seedling vigor. To determine if supplemental calcium is needed for runner market types, use the following procedure: Step 1. Take soil samples to a depth of 3 inches in the pegging zone in fields where runner market types are planted when flowering begins, generally in late June, keeping in mind that it could take several days to process soil samples. Step 2. Determine the concentration of calcium in the soil in ppm using the following formula: Calcium (% of total CEC) x CEC x 200 Step 3. Determine the ratio of calcium to potassium using the following formula: %Potassium (%K) = %Base saturation (%BS) – %Calcium (%Ca) – %Magnesium (%Mg) Step 4. Determine the ratio of calcium to potassium using the following formula: %Ca divided by %K Example: Step 1. The following data were recorded from a soil sample taken at a depth of 3 inches in the pegging zone at initial flowering in a field where a runner market type was planted. %BS = 74, %Ca = 60, %Mg = 11, CEC = 5.6 Step 2. ppm = %CEC of calcium x CEC x 200 ppm: 0.60 × 5.6 × 200 = 672 Step 3. %K = %BS - %Ca - %Mg %K = 74 – 60 – 11 = 3 Step 4. %Ca divided by %K 60 divided by 3 = 20 Recommendation: Do not apply gypsum because the Ca concentration exceeds 250 ppm (672 in this example) and the ratio of Ca to K exceeds 3 (20 in this example). Manganese and Boron Two other elements often found to be deficient in peanuts are manganese and boron. Manganese deficiency usually occurs when soil is overlimed. Increasing the soil pH reduces the plant’s uptake of manganese. The symptom of manganese deficiency is interveinal chlorosis. This symptom can be confused with carryover of atrazine (from corn) or Cotoran/Meturon (from cotton). A deficiency can be corrected by a foliar application of manganese sulfate. The usual practice is to apply 3.5 to 4 pounds per acre of dry material when the deficiency is observed. Boron plays an important role in kernel quality and flavor. Boron deficiency may occur in peanuts produced on deep, sandy soils. Deficient kernels are referred to as having hollow hearts. The inner 33 surfaces of the cotyledons are depressed and darkened, so they are graded as damaged kernels. A general recommendation is to apply 0.5 pound of actual boron per acre as a foliar spray in early July. Several formulations of boron are available. Some growers apply boron with their preplant incorporated herbicides, and others have boron added to their fertilizers. Growers are advised to make sure boron and manganese sources provide sufficient elemental boron. Several liquid boron and manganese formulations are available. Although liquid sources are more convenient to use than some dry products, some of the liquid products contain only a fraction of the needed boron or manganese. The amount of formulated product needed to supply 0.5 lb elemental boron per acre is provided in Table 3-20. Similarly, the amount of formulated manganese product needed to supply 1.0 lb manganese per acre is provided in Table 3-21. Lower rates of boron or manganese are often applied for “maintenance.” However, if a significant deficiency exists, 0.5 pound of actual boron per acre or 1 pound of actual manganese if manganese is needed, and growers need to apply a formulation that delivers this amount economically. Table 3-20. Amount of Formulated Product Needed to Provide Equivalent Amounts of Elemental Boron per Acre Source Amount Needed to Supply 0.5 lb Boron per Acre Boric acid 3.0 lb Disodium octaborate (Solubor, 17.5% boron) 2.8 lb Liquid (9.0% boron) 2.2 qt Table 3-21. Amount of Formulated Manganese Products Needed to Provide Equivalent Amounts of Elemental Manganese per Acre Source Amount Needed to Supply 1.0 lb Manganese per Acre Manganese sulfate (Techmangum, 27% manganese) 3.7 lb Manganese sulfate (8% manganese) 1.2 gal The percentage of element (in this case, manganese or boron) or the weight of the element per unit volume of product can be used to determine the amount of liquid product needed to correct a nutrient deficiency. For example, if 1 pound of manganese is needed per acre, the following formulas can be used to determine the amount of 8% water-soluble manganese product needed per acre.34 Step 1. Figure the weight of manganese per gallon by multiplying the percent of manganese in product in pounds by the weight of product in pounds per gallon: % manganese in product × lb product per gal = lb manganese per gal Step 2. Figure the gallons of manganese product per acre by dividing the desired amount of manganese in pounds per acre by the weight of the manganese per gallon: desired lb manganese per acre = gal manganese product per acre lb manganese per gal Example: Step 1. 0.08 × 10.5 lb manganese sulfate per gal = 0.84 lb manganese sulfate per gal Step 2. 1 lb manganese/acre desired = 1.2 gal 8% manganese product per acre 0.84 lb manganese per gal LAND PREPARATION Historically, peanut growers have used the moldboard plow equipped with trash covers to prepare a smooth, uniform, and residue-free seedbed for planting. The burial of old crop residue and weed seed has been effective in the long-term suppression of soilborne diseases and short-term suppression of some weed problems. However, there is a growing trend toward reduced-tillage crop production in North Carolina, and some growers are successfully using these practices. There has also been a significant decrease in the number of growers using moldboard plowing. Changes in tillage systems over the past decade are presented in Table 3-22. Table 3-22. Percentage of Farmers Using Certain Tillage Practices on at Least a Portion of Their Farms Tillage 1998 2004 2009 Disk 90 78 71 Chisel 25 23 27 Moldboard plow 58 17 7 Field cultivate 75 55 42 Rip and Bed 49 39 40 Bed 44 35 32 Reduced tillage 10 23 41 There is concern about stratification of nutrients in reduced-tillage systems. For example, repeated applications of potassium in reduced-35 tillage cotton may result in excessive amounts of this nutrient in the pegging zone when peanuts are planted in a reduced-tillage system. Growers are encouraged to test soils for excessive potassium levels and incorporate this nutrient with tillage, if needed. Many peanut growers bed their peanut fields either in the fall or spring. Many growers prefer planting on raised beds rather than flat planting. The beds often give faster germination and early growth, provide drainage, and may reduce pod losses during digging. While reduced-tillage systems can be as successful as conventional-tillage systems, reduced-tillage systems often have less consistent yields than in conventional-tillage systems. However, most peanut production has shifted to sandy soils that respond more favorably to reduced-tillage systems. A summary of peanut response to tillage is presented in Table 3-23. Because of concern about digging losses on finer-textured soils, it is recommended that beds be established in the fall with a grass cover crop with peanuts strip-tilled into previously prepared beds. Research during 2005 and 2006 demonstrates that wheat, cereal (cover crop), rye, oats, and triticale can serve equally well as cover crops grown the winter and spring prior to planting peanuts. A risk advisory index has been developed to assist growers in deciding the risk of peanut yield in reduced-tillage systems being lower than yield in conventional-tillage systems (Table 3-24). Additional information can be obtained from Soil Facts: Conservation Tillage use in Peanut Production, AG-439-73W. Research also suggests that prior cropping history generally does not affect peanut response to tillage. However, peanuts are often more responsive to tillage system, primarily because of the digging requirement. The risk advisory index has been modified from the initial version. Table 3-23. Peanut Yield Response to Tillage Practices in North Carolina from 1999-2011. A positive value indicates that yield was higher in conventional tillage compared with reduced tillage. Number of Trials Years Actual Yield Difference (lb/acre) Yield Difference (%) Range of Yield Difference (%) 61 1997-2011 +106 +2.9 -16.1 to +27.536 Table 3-24. Advisory Index for Determining the Risk of Peanut Yield in Reduced-Tillage Systems Being Lower Than Yield in Conventional-Tillage Systems Soil series Roanoke and Craven…40 Goldsboro and Lynchburg…20 Norfolk…10 Conetoe and Wanda…0 Pod loss on finer-textured soils, such as those on the Roanoke and Craven series, is often greater than on coarser-textured soils, such as Conetoe and Wanda series, regardless of tillage system. Difficulty in digging can increase when these soils become hard in the fall if rainfall is limited. Soil series Your score: ________ Tillage intensity No tillage into flat ground…40 points Strip tillage into flat ground…10 points Strip tillage into stale seedbeds…0 points Peanut response to reduced tillage systems is invariable correlated with the degree of tillage. Efficient digging can be difficult when peanuts are planted in flat ground in reduced tillage systems. While fields may appear to be flat and uniformly level, often fields are more rugged than they appear, and setting up the digger to match unforeseen contours in the field can be difficult. Strip tillage into flat ground is a better alternative than no tillage into flat ground, although digging peanuts planted on flat ground can be more challenging regardless of the tillage system. Strip tillage into preformed beds often results in yields approaching those of conventional tillage. Tillage intensity Your score: _______ Risk of yield being lower in reduced tillage than in conventional tillage: 40 or Less—Low Risk 40 to 50—Moderate Risk 60 or More—High Risk Total Index Value Your score: _______ PLANTING Varieties grown in North Carolina generally require 142 to 160 days to reach full maturity depending upon soil moisture and temperature. Early plantings usually give higher yield, more mature pods, and permit earlier harvesting. However, planting date can affect disease and insect development (see Chapters 5 and 6). Less damage from thrips and lower incidence of tomato spotted wilt virus have been associated with later plantings. Peanut yields are often the highest when peanuts are planted in early to mid-May. However, in some years peanuts planted later can yield quite well. Conditions in the fall, especially night temperatures, can have a great impact on yield when they prevent peanut pods from reaching optimum maturity. Response of the 37 early maturing cultivar CHAMPS and the later maturing cultivar Perry planted on three dates and dug at four times were compared in trials during 2009-2011 (Table 3-25). With higher peanut prices anticipated in spring 2012, some growers are considering planting peanut after wheat. This approach can be risky. In one study over three years, lower yield was noted when comparing June 8 plantings to May 5 or May 22 (Table 3-25). If contract prices approach $850/ton, the lower yield due to delayed planting would translate into an economic loss of $363/acre compared with earlier plantings. Lower yield from later plantings is most likely associated with insufficient heat unit accumulation. Also, growers may experience difficulty harvesting due to wet conditions and freeze damage. A cool period in late September limiting further pod maturation could also adversely affect yield and quality. Freeze damage is catastrophic, especially at projected high prices for peanuts. Results also demonstrate that planting the early maturating variety CHAMPS compared with Perry does not compensate for late planting. Based on results from these trials, double cropping wheat and peanut is discouraged. Growers may have to plant in early June because of adverse weather conditions in May or because of other unforeseen circumstances, but planning to plant in June after wheat poses considerable risk. Cost of production for peanut approaches 5 times that of soybean making soybean the more appropriate double crop legume. Table 3-25. Peanut yield response based on planting date, digging date when planted in early June, and variety selection when planted in early June Treatment Factor Yield (lb/acre) Planting date (pooled over 2 varieties, 4 digging dates, and 3 years) May 5 3869 May 22 3836 June 8 2992 ($363/acre less at $0.43/lb compared with the May 22 planting date) Digging date influence when planted June 8 (pooled over 2 varieties, 4 planting dates, and 3 years) September 8 1826 September 20 2748 October 7 3745 October 20 3649 (continued)38 Table 3-25. Peanut yield response based on planting date, digging date when planted in early June, and variety selection when planted in early June (continued) Comparison of Perry (latest maturing variety) with CHAMPS (earliest maturing variety) when planted June 8 (pooled over 4 digging dates and 3 years) CHAMPS planted May 5 3764 Perry planted May 5 3973 CHAMPS planted May 22 3773 Perry planted May 22 3898 CHAMPS planted June 8 3079 Perry planted June 8 2905 Seeding Rates and Twin Rows Table 3-26 provides the conversion of seed per foot of row to pounds per acre in order to establish the desired plant population for a given variety. Germination percentage is not considered in this conversion, but it should be considered when planning planting. In the Southeast, less tomato spotted wilt virus has been associated with twin row plantings than single rows. Similar results have been observed in North Carolina. Higher plant populations and closer row spacings often result in less virus. Seeding peanuts in narrow rows or at extremely high seeding rates has not increased yield over twin row plantings that establish a plant population of 5 plants per foot of row (sum of both twin rows). Although higher seeding rates are needed and higher rates of in-furrow insecticide and inoculant are required, twin rows tend to produce a greater taproot crop rather than a limb crop. This can improve uniformity of harvested peanuts, and in a dry season when peanut vines do not lap, can result in higher yields. One of the detriments of twin row plantings, especially with the higher plant populations, is excessive vine growth, which can make digging more difficult. Table 3-26. Approximate Pounds of Peanut Seed Required per Acre to Provide 3, 4, and 5 Seeds per Foot of Row on 36-inch Rows Variety Seed/lb Pounds Per Acre (36-Inch Rows) 3 Seeds/ft 4 Seeds/ft 5 Seeds/ft Bailey 600 72 95 120 Brantley 500 87 116 145 CHAMPS 535 76 102 127 Gregory 450 97 129 161 (continued)39 Table 3-26. Approximate Pounds of Peanut Seed Required per Acre to Provide 3, 4, and 5 Seeds per Foot of Row on 36-inch Rows (continued) NC-V 11 625 70 93 116 Perry 525 83 111 138 Phillips 545 78 105 135 Sugg 575 76 101 126 VA 98R 575 76 101 126 Florida Fancy 525 83 111 138 Georgia 08V 550 79 107 136 Florida 07* 650 64 87 110 Georgia Green* 850 52 68 85 *Denotes runner market types. All other varieties are Virginia market types. IRRIGATION Having adequate water available throughout the peanut life cycle is important for optimal plant growth and development. Drought or flood can have tremendously negative impacts on peanut yields and quality. Likewise, pest infestation and severity of damage from these pests is influenced by available water, either in the form of rainfall or irrigation. Understanding how environmental conditions, and in particular irrigation, affect pest complexes is important in developing appropriate management strategies. Although less than 20 percent of North Carolina peanut acreage is irrigated, irrigation is a powerful production tool. Irrigation minimizes risk and enhances consistency of yield. Additionally, irrigation improves consistency of pesticide performance and in many ways the predictability of pest complexes. The major production and pest management practices employed in North Carolina peanut production are listed in Table 3-27, with brief comments on how irrigation or ample rainfall affect efforts to manage pests or supply peanuts with adequate nutrition. Research supported by the North Carolina Peanut Growers Association has been conducted to determine the feasibility of subsurface drip irrigation. While there are many logistical issues associated with this approach, data collected at Lewiston-Woodville in corn, cotton, and peanut are presented in Table 3-28. The amount of water delivered through this irrigation system and rainfall during that period of time are also presented. These data give a good indication of yield under growing conditions where water is not limiting relative to dryland production for these crops.40 Production or Pest Management Practice Benefits of Irrigation or Optimum Rainfall Land Preparation Helps in establishment of seedbeds, either conventional or reduced tillage. Seed Germination Ensures germination of seed when existing soil moisture is marginal for complete stand establishment. Weed Management Irrigation or adequate rainfall activates preemergence herbicides and minimizes plant stress. Less moisture stress often enhances control by postemergence herbicides and enables peanut to recover more rapidly from herbicide damage. Insect Management Important for activation of in-furrow insecticides. Improves plant growth and root establishment, which is important in absorption of in-furrow insecticides. Improves peanut recovery from early-season insect damage and insecticide phytotoxicity. Increases the likelihood of southern corn rootworm survival and subsequent damage to pods, but can protect against damage from lesser cornstalk borer. Minimizes potential damage from corn earworms and armyworms by establishment of a dense canopy that can withstand damage from feeding. Reduces the likelihood of spider mite damage by keeping spider mite populations low. Disease Management Wet conditions early in the season can favor infection of peanut by CBR, but can minimize potential for crown rot. Irrigation increases likelihood of having a favorable microclimate for development of foliar and soilborne disease. A dense canopy that is supplemented by irrigation increases humidity within the canopy and minimizes airflow, all of which favor pathogen and disease development. Symptoms associated with tomato spotted wilt of peanut are often more pronounced when peanut are growing under dry and especially hot conditions. Timely irrigation will reduce plant stress and possibly enable plants to withstand tomato spotted wilt more effectively than non-irrigated, water-stressed plants. Pod Maturation Irrigation buffers against extremes in moisture and reduces stress (heat and drought), which allows normal flower production and kernel development. Maturation is more predictable and generally earlier. Limited rainfall during reproductive growth often causes delays in maturation and establishment of “multiple crops” or “split crops” on the same plant. Sufficient rainfall is critical for complete kernel development and pod fill. Limited soil moisture during flowering can reduce pegging. Irrigation modeling programs often include soil temperature as a trigger for irrigation during pegging. Supplemental Calcium Kernels need adequate calcium to become mature and completely developed. Irrigation buffers against drought, which reduces calcium concentration in soil water and mass flow movement into developing pegs. Digging Ability to supply soil water to improve digging conditions (reduces hardness of soil), improves digging efficiency and minimizes pod loss during the digging process. Table 3-27. Impact of Irrigation on Production and Pest Management Strategies41 Table 3-28. Corn, Cotton, and Peanut Response to Subsurface Drip Irrigation from 2001–2011 at Lewiston-Woodville Crop Year Water Delivered (June through August for corn or June through September for other crops) in Inches Crop Yield (peanut in lb/A, cotton in lb lint/A, corn in bu/A) Percent increase in yield due to irrigation Rainfall Rainfall plus Subsurface Drip Nonirrigated Irrigated % Peanut 2001 8.6 13.8 2,350 3,400 * 31 Peanut 2002 13.0 18.5 2,024 2,956 * 32 Peanut 2003 19.6 24.8 3,017 3,210 6 Peanut 2004 20.0 25.0 2,660 2,830 6 Peanut1 2010 9.3 21.9 2,537 3,875* 34 Peanut1 2011 19.9 39.1 3,436 4,016* 14 Cotton 2001 8.6 13.8 804 1,018 * 21 Cotton 2002 13.0 18.5 460 902 * 49 Cotton 2003 18.9 24.4 840 850 1 Cotton 2004 24.9 31.8 920 1,010 9 Cotton 2005 12.2 18.3 850 1,300 * 35 Cotton 2006 19.5 27.8 810 860 6 Cotton 2007 11.5 21.3 465 1,016 * 54 Cotton 2008 13.8 25.2 386 835 * 54 Cotton1 2011 19.9 39.1 480 802 * 40 Corn 2008 11.3 21.9 96 146 * 34 Corn 2009 12.9 27.6 62 148 * 58 Corn 2010 3.6 16.8 64 155 * 59 Corn 2011 13.6 30.7 64 101* 37 1 Does not include excessive rainfall during the last few days of September (13.3 inches) during 2010 and only includes a value of 3 inches from Hurricane Irene in August 2011 (9.0 inches total) due to estimates of runoff. *Significance of p < 0.05.42 DETERMINING MATURITY Maturity affects flavor, grade, milling quality, and shelf life. Not only do mature peanuts have the quality characteristics that consumers desire; they are worth more to the producer. However, the indeterminate fruiting pattern of peanuts makes it difficult to determine when optimum maturity occurs. The fruiting pattern can vary considerably from year to year, mostly because of the weather. Therefore, each field should be checked before digging begins. The hull-scrape method, currently the most objective method, requires the use of a peanut profile board that is available at county Extension centers. The peanut profile board in Figure 3-1 was developed for runner market types grown in the southeastern United States. A version of the peanut profile board was developed for Virginia market types grown in the V-C Region (Figure 3-2). It is important to follow a specific maturity prediction method to achieve maximum dollar value for peanuts. The current chart for Virginia market type varieties is being modified to include additional information on newer varieties and adjustments of prediction curves. Heat units or growing degree days (DD) can be a means of determining maturity. One growing degree day (base 56oF) accumulates when the average daily high and low temperature is 57oF. If the average daily high and low temperatures were 76oF, then 20 growing degree days accumulate for that day. Research has shown that 2,520 to 2,770 growing degree days are needed for Virginia market types to mature if soil moisture is not limiting. Variation in heat unit accumulation for 2009-2011 is presented in Table 3-29. Pod maturation generally ceases in the fall when night temperatures are in the mid- to high 40s for two nights in a row. Even though day temperatures may increase considerably, the plant seldom recovers from these cooler night temperatures. In 2011 at Lewiston-Woodville, low temperatures ranged from 44 to 47 oF from October 1-4 and essentially eliminated any further maturation of pods. 43 Table 3-29. Average Heat Unit Accumulation per Day (DD56) from May 1 through November 1 at Lewiston-Woodville for various categories Dates Average for the Interval Described 2009 2010 2011 May 16 to June 15 17.8 19.1 20.7 June 16 to July 15 20.1 24.5 25.2 July 16 to August 15 22.9 26.3 28.0 August 16 to September 15 18.5 20.9 21.3 September 16 to October 15 11.9 14.4 11.1 October 16 to November 1 7.1 9.3 1.3 Table 3-30. Yield (lb/acre) of the Variety Gregory Planted May 5, 2003, or May 10, 2004, at Lewiston-Woodville 2003 2004 Digging Date Yield Digging Date Yield September 14 3,150 September 13 2,910 September 23 3,110 September 17 4,920 September 30 4,210 September 24 3,890 October 6 4,950 October 1 3,530 October 13 4,440 October 8 1,860 October 20 3,360 October 15 1,290 Pod yields in 2003 and 2004 demonstrate that heat units play a major role in determining optimum maturity (Table 3-30). Optimum yield across the six digging dates occurred when approximately 2,650 DD were accumulated. This number of heat units occurred 20 days earlier in 2004 compared with 2003, and highest pod yield also occurred 15 days earlier in 2004 compared with 2003. Adequate rainfall during both years allowed plant and pod development to continue at a predictable rate, but heat unit accumulation will be a poor indicator of peanut maturity at some locations and in some years, especially when rainfall is limited or stress during the season causes delays in growth and development. Based on results from studies evaluating the influence of digging dates on six varieties grown at several locations in North Carolina, growers can lose between 4 and 19 pounds pod yield per acre per day by digging too soon (data not shown). A typical response of peanut to digging date can be seen for the variety Gregory (Table 3-31). 44 Figure 3-1 The traditional profile board shown below was developed for runner market type production in the Southeastern United States Figure 3-2. The peanut profile board shown below was developed for Virginia market types.45 Although market grade characteristics often remain high when peanuts are dug later in the fall, yield is often lower due to pod shed. A balance between digging too soon and digging before frost or inclement weather needs to be reached to maximize yield and quality. At harvest, growers should follow the weather forecast closely and not dig peanuts when freezing temperatures are expected. It is also important to have adequate harvesting and curing equipment so that the peanut crop can be handled within a reasonable period of time. At least 3 days, and in many cases more than 3 days, are needed between the time of digging and frost to allow sufficient drying to prevent freeze damage. Digging and harvest capacity for growers is important to consider. The speed at which growers can plant peanuts is not the same as the time it takes to dig, combine, dry, and haul peanuts. Most crops require a one-step process to harvest, while peanuts require two stages. Soil conditions during digging must be ideal to effectively remove peanuts from the soil and invert vines. Growers need to realistically determine the amount of time these operations will require. With respect to digging, it is estimated that with four-row equipment and six-row equipment, 30 and 40 acres can be dug per day if growers dig for 10 hours a day driving at 3 mph. A six-row self-propelled combine can harvest 20 acres in a day driving at 1.5 mph, while four- and six-row pull-type combines can haravest 15 to 20 acres in a day, respectively. Table 3-31. Average from 13 Trials for Heat Unit Accumulation, Days from Emergence, Yield, and Grade of the Variety Gregory Planted from 2003 – 2010 at Lewiston-Woodville Days after Emergence Heat Unit Accumulation Yield (lb/acre) Yield (% of max) Extra Large (%) Total Sound Mature (%) 122 2559 3800 85 49 53 129 2674 4414 99 53 57 140 2826 4466 100 56 62 146 2886 4285 96 58 64 154 2944 3564 80 60 64 Demand for runner market type peanuts had declined in North Carolina, but new farm legislation and the federal peanut program has rekindled interest in production of runner market types in the Virginia-Carolina region. Part of this interest relates to market demand, while an appealing aspect of growing runners is potential 46 savings in productions costs relative to Virginia market type peanuts (approximately 80 to 100 pounds of seed for runners versus 115 to 160 pounds of seed for Virginia market types and lower requirements for supplemental calcium by runner market types). Yield of runner market types were compared at two locations during 2010 (Lewiston and Whiteville). The highest yield of the two digging dates is included in Table 3-32. These varieties performed as well as the Virginia types. Table 3-32. Yield of Runner Market Types at Lewiston-Woodville and Whiteville in 2010. Yield (lb/acre) reflects the highest yield of two digging dates for each variety. Variety Lewiston-Woodville Whiteville Georgia Green 4.815 3,769 Georgia 06G 4,712 4,065 Georgia Greener 4,740 4,561 Georgia 07W 4,954 4,799 Georgia 09B 5,418 4,005 Tifguard 5,359 4,374 Florida 07 5,199 4,374 AP-4 5,396 4,725 CULTURAL PRACTICES AND TOMATO SPOTTED WILT VIRUS Tomato spotted wilt virus can be a problem in North Carolina with no control practices available after peanuts have been planted. Planting peanuts in reduced tillage systems (no till or strip till), seeding peanuts at higher rates (establishing 4 or more plants per row foot in single rows), planting twin rows, applying Thimet or Phorate in furrow, delaying planting until late May, planting tolerant varieties, and maintaining good soil fertility can lessen the impact of tomato spotted wilt on peanut growth and yield. However, each of these cultural practices presents a range of risks and benefits. A tomato spotted wilt virus advisory, AG-638, Managing Tomato Spotted Wilt Virus in Peanuts in North Carolina and Virginia, was initially prepared in 2003 with an updated version of the advisory provided in Chapter 5. PLANT GROWTH REGULATORS Apogee (prohexadione calcium) is registered for use in peanuts. Research has demonstrated that Apogee improves row definition, which can lead to increased efficiency in the digging and inversion process. Apogee should be applied when 50 percent of vines from adjacent rows are touching. Sequential applications (7.2 ounces per acre fol47 lowed by 7.2 ounces per acre) spaced two to three weeks apart are generally needed. Include crop oil concentrate and nitrogen solution (UAN) with Apogee. Depending upon growing conditions, soil fertility, frequency of rainfall and irrigation, and variety selection, row visibility obtained in mid-August may not be sufficient through digging. Research suggests that in addition to increased row visibility, Apogee minimizes pod shed and pod loss during digging and harvesting operations. Work conducted in cooperation with Dr. Gary Roberson in 2009-2011 compared benefits of Apogee with precision digging, and results are presented in Table 3-33. A more comprehensive data set for performance of Apogee is provided in Table 3-34. Some environmental conditions and subsequent vine growth were not excessive in some of the trials in this data set suggesting that the yield difference may be underestimated. Investment in guidance systems for digging can be expensive. However, these systems have been very effective in minimizing challenges in digging, especically when vine growth is excessive and/or tractor operators are fatigued. Apogee can improve row visibility but may not minimize operator fatigue. Guidance systems will not affect pod retention in a manner similar to Apogee. Table 3-33. Peanut Yield (lb/acre) as Influenced by Application of Apogee and Precision Digging Location and Year Steering Apogee Applications Manual Auto-steer None Two Lewiston-Woodville, 2009 4,818 5,181 5,104 5,392 Lewiston-Woodville, 2010 2,818 2,644 2,694 2,768 Rocky Mount, 2010 2,628 3,111 2,881 2,816 Rocky Mount, 2011 4,125 4,710 4,555 4,370 Average 3,619 3,912 3,809 3,836 Table 3-34. Peanut Yield (lb/acre) Following Application of Plant Growth Regulators and Fertilizers Item Parameter No. of Trials 103 No. of Varieties or Lines 12 Years 1997–2011 Not Treated 4,065 Treated 4,169 Difference 10448 4. WEED MANAGEMENT IN PEANUTS David L. Jordan Extension Specialist— Crop Science Effective weed management is essential for profitable peanut production. Peanuts are not very competitive with weeds and thus require higher levels of weed control than most other agronomic crops to avoid yield losses. Weeds may also decrease digging efficiency, so effective late-season weed control can minimize losses during harvest. A weed management program in peanuts consists of good weed control in rotational crops; cultivation, if needed; establishment of a satisfactory stand and growing a competitive crop; and proper selection and use of herbicides. CROP ROTATION Rotate peanuts with corn or cotton to help manage various pests, including weeds. Crop rotation allows use of different herbicides on the same field in different years. Crop and herbicide rotation, along with good weed control in the rotational crops, helps prevent the buildup of problem weeds and helps keep the overall weed population at lower levels. Crop rotation will also help reduce the chance of developing populations of weeds that are resistant to herbicides. CULTIVATION Cultivation is an excellent way to supplement chemical weed control. One or two “non-dirting” cultivations often improve weed control. Additionally, cultivation in combination with banded herbicide applications can reduce costs. However, cultivation can damage the crop and reduce yield if not done properly. Movement of soil onto the lower branches and around the base of the plants causes physical damage and enhances development of stem and pod diseases. Deep cultivation also destroys residual herbicide barriers and brings up additional weed seeds. Cultivate when peanuts are small. Set sweeps to run flat and shallow to avoid throwing soil onto the peanut plants. WEED SCOUTING All fields, regardless of the crop being grown, should be surveyed for weeds between mid-August and the first killing frost. Record the weed 49 species present, and note the general level of infestation of each species (light, moderate, or heavy). Weeds present in the fall will be the ones most likely to be problems the following year. Knowing what problems to expect allows you to better plan a weed management program for the following crop. Scout peanut fields weekly from planting through mid-July to determine if or when postemergence herbicide treatment is needed. Proper weed identification is necessary because species respond differently to various herbicides. Contact your county Extension center for aid in weed identification. Timely application of postemergence herbicides is critical for effective control. Cultivation may be more appropriate if herbicide-resistant biotypes increase in prevalence. WebHADSS (Herbicide Application Decision Support System), a computer-based program designed to assist in making decisions pertaining to postemergence herbicide applications, is available online through North Carolina Cooperative Extension (http://www.webhadss.ncsu.edu/). Weed density, predicted crop value, predicted weed-free crop yield, herbicide and application costs, and herbicide efficacy are used to develop a ranking of the economics of herbicide options for a specific weed complex. This approach does not consider the long-term effect of weed seed production if weeds are not controlled. The patchiness of weeds in each field and the time needed to scout fields are limitations to this approach. However, this decision support system is beneficial in explaining herbicide options. Listed below is the competitive index value assigned to weeds typically found in North Carolina peanut fields (Table 4-1). Cocklebur, with a ranking of 10, is considered the most competitive weed in peanut. Table 4-1. Competitive Indices for Weeds in Peanut* Weed Rank Weed Rank Common cocklebur 10.0 Fall panicum 1.8 Jimsonweed 5.8 Florida pusley 1.5 Common lambsquarters 5.2 Tropic croton 1.2 Smartweed 4.7 Dayflower 1.2 Redroot pigweed 4.0 Common purslane 1.2 Common ragweed 3.8 Prickly sida 1.2 Sicklepod 3.6 Horsenettle 1.1 Pitted morningglory 3.6 Yellow nutsedge 0.3 Entireleaf morningglory 3.2 Purple nutsedge 0.2 Velvetleaf 3.0 Goosegrass 0.2 Broadleaf signalgrass 1.8 Crabgrass 0.2 Eclipta 1.8 *10 = most competitive weed.50 The combined effect of interference by the weed complex is used to predict yield loss in the WebHADSS program. For example, a weed complex containing two Palmer amaranth, two crabgrass, and two eclipta per 100 square feet (33 feet of row with rows spaced 3 feet apart) would reduce peanut yield by 21 percent, based on a projected weed-free yield of 4,000 pounds per acre (Table 4-2). Using WebHADSS and given a crop value of $750 per ton, adequate growing conditions (good soil moisture for satisfactory herbicide performance), and large size weeds (at least 4 inches tall), WebHADSS would provide the suggestions in Table 4-3 with various economic returns. In this example, peanuts were planted May 10 and emerged May 17. The field was scouted June 4 and herbicide sprayed soon thereafter. Although issues relative to accuracy and time required for weed scouting do exist, the WebHADSS program does allow a relatively quick and clear comparison of herbicide options while taking herbicide efficacy, herbicide cost, and economic return from that investment into account. Table 4-2. Potential Yield and Economic Losses if Weeds Are Not Controlled as Compared to Weed-Free Peanuts* Weed species Population Yield Loss (lb per acre) Yield Loss (% of weed-free yield) Economic Loss ($ per acre) Palmer amaranth 2 320 8.0 88 Crabgrass 2 16 0.4 4 Eclipta 2 216 5.4 79 Total Estimated Loss − 552 13.8 152 *Anticipated yield of 4,000 pounds per acre and crop value of $750 per ton farmer stock peanuts. Table 4-3. Ranking of Selected Herbicide Options Considering Efficacy and Economics* Herbicide Rate per Acre** Gain by Applying Herbicide ($ per acre) Cost of Weed Control ($ per acre) Cobra + Cadre 12.5 oz + 4 oz 127 34 Cobra + 2,4-DB 12.5 oz + 16 oz 110 21 Cobra + Clethodim 12.5 oz + 8 oz 122 29 *Herbicide options other than these were listed. Includes adjuvant and application costs. **Abbreviation: oz, ounces.51 COMMENTS ON PEANUT HERBICIDES Preplant Burndown Herbicides Glyphosate (various formulations) and Gramoxone INTEON are relatively nonselective herbicides that control many of the winter weeds present in reduced tillage fields (Table 4-4). Harmony Extra and 2,4-D (various formulations) can also be applied. Harmony Extra can be applied no closer to planting than 45 days before planting. 2,4-D should be applied at least 30 days before planting. Preplant Incorporated, Preemergence, and Postemergence Herbicices Numerous herbicides are labeled for use in peanuts (Tables 4-5, 4-6, 4-7). Timely application of the appropriate herbicide at the correct rate is essential for successful weed control in peanuts. Additional information on feeding restrictions of peanut hay (Table 4-8), suggested rain-free period to maintain control (Table 4-9), and rotation restrictions on herbicide use (Table 4-10) are provided. Reduced Rates of Herbicides When crop prices are low, producers are looking for ways to reduce production costs. One possibility is to reduce the application rate of herbicides. Under certain environmental conditions and with certain weed species or weed complexes, specific herbicides can be applied below the manufacturer’s suggested use rate without sacrificing weed control. However, growers are cautioned that herbicides applied at reduced rates often do not control weeds adequately when environmental conditions (soil moisture in particular) do not favor herbicide activity. Applying herbicides at reduced rates to large weeds or weeds that are “hardened” often results in poor control as well. Weeds can also be more difficult to control if they were injured by herbicide with previous treatment. Using reduced rates will require that growers apply herbicides in a more timely manner and when weeds are not stressed. Regardless of the previously mentioned factors relative to reduced rates, manufacturers of herbicides will not back up their products when they are applied below the suggested use rate. Liability falls exclusively to the grower.52 COMPATIBILITY OF AGRICHEMICALS Table 4-4. Weed Responses to Herbicides Applied Prior to Peanut Planting in Reduced Tillage Systems1,3 Species Gramoxone SL Glyphosate 2,4-D Glyphosate + Harmony Extra Glyphosate + 2,4-D Glyphosate + Valor SX2 Bluegrass GE E N E E E Buttercup E E G E E E Chickweed E E P E E E Curly dock NP E F E FG G Geranium GE PF PF GE F GE Henbit E E FG E E E Horseweed PF GE GE E E E Mustard FG FG GE GE E E Primrose PF F E FG E G Ryegrass G E N E E E Small grains GE E N E E E Swinecress P FG F GE G E 1Gramoxone SL can be applied after peanut emergence; see notes in Table 4-7. Glyphosate (various formations) can be applied at or before ground cracking. 2,4-D (various formulations) should be applied 3 or more weeks before planting. Harmony Extra cannot be applied closer than 45 days prior to planting. See specific product labels for tank mixtures with these herbicides. 2Valor SX can be applied prior to planting up to 2 days after planting. See product label for information on sprayer cleanout. 3E = excellent control, 90% or better; G = good control, 80 to 90%; F = fair control, 50 to 80%; P = poor control, 25 to 50%; N = no control, less than 25%. Compatibility is an important consideration when applying two or more products in the same tank. AG-653, Tank Mixing Chemicals Applied to Peanut: Are the Chemicals Compatible, is a comprehensive guide to agricultural compatibility. This Extension publication is available on the Web at http://www.peanut.ncsu.edu or from your local Extension Center. Consult product labels, AG-653, and your local Extension Agent for more information on agricultural chemical compatibility.53 CHEMICAL WEED CONTROL IN PEANUTS Control of witchweed is part of the State/Federal Quarantine Program. Contact the N.C. Department of Agriculture, Plant Industry Division, at 1-800-206-9333. TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks PREPLANT INCORPORATED Annual grasses and small-seeded broadleaf weeds alachlor (Intrro) 4 EC, MOA 15 2 to 3 qt 2 to 3 Incorporate no deeper than 2 in.; see label for specific instructions. Unless shallowly incorporated, Intrro is more consistently effective when applied pre-emergence. Weak on Texas panicum. Do not apply more than 4 qt of Intrro per acre per season. Before using Intrro, check with buyers to determine if there are marketing restrictions on Intrro-treated peanuts. ethalfluralin (Sonalan) 3 EC, MOA 3 1.5 to 2 pt 0.56 to 0.75 Controls common annual grasses including Texas panicum. Use 3 pt of Prowl H2O or 2 pt of Sonalan for control of broadleaf signalgrass, Texas panicum, and fall panicum. Incorporate 3 in. deep for Texas panicum; otherwise, incorporate 2 to 3 in. deep. See labels for maximum waiting period between application and incorporation. Immediate incorporation is best. Dual Magnum or Outlook may be tank mixed with Prowl or Sonalan to suppress yellow nutsedge. pendimethalin (Prowl H2O) 3.8, MOA 3 1.5 to 3 pt 0.71 to 1.4354 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual grasses, small-seeded broadleaf weeds, and nutsedge dimethenamid (Outlook) 6.0 L, MOA 15 16 to 21 fl oz 0.75 to 1 Apply and incorporate in top 2 in. of soil within 14 days of planting. Use high rate of Dual Magnum or Outlook for yellow nutsedge and broadleaf signalgrass. Not effective on purple nutsedge. Weak on Texas panicum. May be tank mixed with Prowl or Sonalan. metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC 1 to 1.33 pt 0.95 to 1.27 1 to 1.33 Broadleaf weeds and suppression of nutsedge diclosulam (Strongarm) 84 WDG, MOA 2 0.45 oz 0.024 Effective on common cocklebur, morningglory, common ragweed, eclipta, and common lambsquarters. Suppresses yellow and purple nutsedge. Does not control sicklepod. More effective when applied in combination with Dual Magnum, Outlook, Prowl H2O, Sonalan, or Stalwart. See label for rotation restrictions, especially corn. Growers are cautioned that Strongarm applied at rates exceeding 0.45 oz per acre can injure cotton the following year on soils with a shallow hardpan (less than 10 inches) and/or loam soils. Cotton grown under early season stress resulting from conditions such as excessively cool, wet, dry, or crusted soils may be particularly susceptible to carryover of Strongarm. Some weed species have developed resistance to Strongarm.55 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual grasses, broadleaf weeds, and suppression of nutsedge diclosulam (Strongarm) 84 WDG, MOA 2 + pendimethalin (Prowl H2O) 3.8, MOA 3 or ethalfluralin (Sonalan) 3 EC, MOA 3 or metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC or dimethenamid (Outlook) 6.0 L, MOA 15 0.45 oz + 1.5 to 3 pt or 1.5 to 2 pt or 1 to 1.33 pt or 16 to 21 fl oz 0.024 + 0.71 to 1.43 or 0.56 to 0.75 or 0.95 to 1.27 1 to 1.33 or 0.75 to 1 Effective on annual grasses, common cocklebur, common ragweed, eclipta, morningglory, and common lambsquarters. Suppresses purple and yellow nutsedge. Does not control sicklepod. See Strongarm label for rotation restrictions.56 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks PPI FOLLOWED BY PRE Annual grasses, broadleaf weeds, and suppression of nutsedge pendimethalin (Prowl H2O) 3.8, MOA 3 or ethalfluralin (Sonalan) 3 EC, MOA 3 or metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC or dimethenamid (Outlook) 6.0 L, MOA 15 followed by diclosulam (Strongarm) 84 WDG, MOA 2 or flumioxazin (Valor SX) 51 WDG, MOA 14 1.5 to 3 pt or 1.5 to 2 pt or 1 to 1.33 pt or 16 to 24 fl oz 0.45 oz or 2 oz 0.71 to 1.43 or 0.56 to 0.75 or 0.95 to 1.27 1 to 1.33 or 0.75 to 1 0.024 or 0.063 Controls most broadleaf weeds. Will not control sicklepod and is marginal on certain large-seeded broadleaf weeds. Do not incorporate Valor. Valor SX should be applied to the soil surface immediately after planting. Significant injury can occur if Valor is incorporated or applied 3 or more days after planting. Significant injury from Valor SX was noted in 2001, 2004, and 2006, and 2009 even when applied according to label recommendations. However, injury is generally transient and does not affect yield. Cotton grown under early season stress from conditions like excessively cool, wet, or crusted soils may be particularly susceptible to carryover of Strongarm. Some weed species have developed resistance to Strongarm.57 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks SPLIT APPLICATION (PPI + POST) Most broadleaf weeds and nutsedge imazethapyr (Pursuit) 2 AS, MOA 2 2 + 2 oz 0.031 + 0.031 Effective on most common broadleaf weeds and yellow and purple nutsedge. Does not control eclipta, lambsquarters, ragweed, or croton. Pursuit will usually control seedling johnsongrass and foxtails. For control of other annual grasses, Pursuit may be tank mixed with Dual Magnum, Outlook, Prowl H2O, or Sonalan and incorporated. See label for incorporation directions and rotational restrictions. Some weed species have developed resistance to Pursuit. Research in N.C. has generally shown more effective control of a broader spectrum of weeds with split applications of half of the Pursuit applied preplant incorporated followed by the other half applied early postemergence. PREEMERGENCE Annual grasses and small-seeded broadleaf weeds alachlor (Intrro) 4 EC, MOA 15 2 to 3 qt 2 to 3 Apply as soon after planting as possible. All three herbicides are weak on Texas panicum. Before using Intrro, check with buyers to determine if there are marketing restrictions on Intrro-treated peanuts. dimethenamid (Outlook) 6.0 L, MOA 15 16 to 21 fl oz 0.75 to 1 metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC 1 to 1.33 pt 0.95 to 1.27 1 to 1.33 Broadleaf weeds flumioxazin (Valor SX) 51 WDG, MOA 14 2 oz 0.063 Apply within 2 days after planting. Significant injury can occur if Valor SX is incorporated or applied 3 or more days after seeding. Controls carpetweed, common lambsquarters, Florida pusley, nightshade, pigweeds, prickly sida, and spotted spurge. Does not control sicklepod, yellow and purple nutsedge, or annual grasses. Significant injury from Valor SX was noted in 2001, 2004, and 2006, even when applied according to label recommendations. However, injury is generally transient and does not affect yield. Injury may occur if excessive and forceful rainfall occurs when peanut is emerging. Peanut recovers from injury by midseason in most instances. See product label for comments on sprayer cleanup.58 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual grasses, broadleaf weeds, and suppression of nutsedge flumioxazin (Valor SX) 51 WDG, MOA 14 + metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC or dimethenamid (Outlook) 6.0 L, MOA 15 2 oz + to 1.33 pt or 16 to 21 fl oz 0.063 + 0.95 to 1.27 1 to 1.33 or 0.75 to 1 Apply within 2 days after planting. Significant injury can occur if applied 3 or more days after planting. This combination does not control sicklepod but will control annual grasses (except Texas panicum) and will suppress yellow nutsedge. Significant injury from Valor was noted in 2001, 2004, and 2006, even when applied according to label recommendations. However, injury is generally transient and does not affect yield. Injury may occur if excessive and forceful rainfall occurs when peanut is emerging. Peanut recovers from injury by midseason in most instances. See product label for comments on sprayer cleanup. Broadleaf weeds and suppression of nutsedge diclosulam (Strongarm) 84 WDG, MOA 2 0.45 oz 0.024 Effective on common cocklebur, morningglory, common ragweed, eclipta, and common lambsquarters. Suppresses yellow and purple nutsedge. Does not control sicklepod. More effective when applied in combination with Dual Magnum, Outlook, Prowl H2O, Sonalan, or Stalwart. See label for rotation restrictions, especially corn. Growers are cautioned that Strongarm applied at rates exceeding 0.45 oz per acre can injure cotton the following year on soils with a shallow hardpan (less than 10 inches) and/or loam soils. Cotton grown under early season stress resulting from conditions such as excessively cool, wet, dry, or crusted soils may be particularly susceptible to carryover of Strongarm. Some weed species have developed resistance to Strongarm.59 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks sulfentrazone, MOA 14 + carfentrazone, MOA 14 (Spartan Charge) 0.35 + 3.15F 3 to 5 fl oz 0.07 + 0.12 Do not apply Spartan Charge after peanuts crack soil. Application immediately after planting is advised. See Spartan Charge label for specific rates based on soil texture and organic matter content. See product label for comments on application with other herbicides. Rotation restrictions for planting cotton following Spartan Charge at recommended rates for peanuts are 12 months. Annual grasses, broadleaf weeds, and suppression of nutsedge diclosulam (Strongarm) 84 WDG, MOA 2 + metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC or dimethenamid (Outlook) 6.0 L, MOA 15 0.45 oz + 1 to 1.33 pt or 16 to 21 fl oz 0.024 + 0.95 to 1.27 1 to 1.33 or 0.75 to 1 Effective on annual grasses, common cocklebur, common ragweed, eclipta, morningglory, and common lambsquarters. Suppresses purple and yellow nutsedge. Does not control sicklepod. See label for rotation restrictions. Some weed species have developed resistance to Strongarm. Cotton grown under early season stress, such as excessively cool, wet, or dry weather, or crusted soils may be particularly susceptible to carryover of Strongarm. Most annual broadleaf weeds and nutsedge imazethapyr (Pursuit) 2 AS, MOA 2 4 oz 0.063 Effective on most common broadleaf weeds and yellow and purple nutsedge. Does not control ragweed, eclipta, lambsquarters, or croton. Pursuit may be tank mixed with Dual Magnum, Intrro, Outlook, or Stalwart for annual grass control. See label for rotational restrictions. Some weed species have developed resistance to Pursuit. Research in N.C. has generally shown more effective control of a broader spectrum of weeds with split applications of half of the Pursuit applied preplant incorporated followed by the other half applied early postemergence.60 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks CRACKING STAGE Emerged annual grasses and broadleaf weeds paraquat, MOA 22 (Firestorm or Parazone) 3.0 SL (Gramoxone SL) 2.5 L 5.4 fl oz 8 fl oz 0.13 Apply at ground cracking for control of small emerged annual grasses and broadleaf weeds. May be tank mixed with Dual Magnum, Outlook, or Stalwart for residual control. Tank mix may cause severe injury to emerged peanuts. Add 1 pt nonionic surfactant per 100 gal spray solution. Follow all safety precautions on label. May also be tank mixed with Pursuit for residual control of nutsedge and broadleaf weeds. Applying Basagran at 0.5 pt per acre will reduce injury. Additional residual control of annual grasses and certain small-seeded broadleaf weeds alachlor (Intrro) 4 EC, MOA 15 2 to 3 qt 2 to 3 Use as a supplement to preplant or preemergence herbicides to provide additional residual control of annual grasses and certain small-seeded broadleaf weeds such as pigweed and eclipta. This treatment will not control emerged grasses or broadleaf weeds. Do not apply more than 4 qt Intrro, 21 oz Outlook, or 2.6 pt Dual Magnum or Stalwart per acre per season. Before using Intrro, check with buyers to determine if there are marketing restrictions on Intrro-treated peanuts. dimethenamid (Outlook) 6.0 L, MOA 15 16 to 21 fl oz 0.75 to 1 metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC 1 to 1.33 pt 0.95 to 1.27 1 to 1.33 Most annual broadleaf weeds and nutsedge imazethapyr (Pursuit) 2 AS, MOA 2 4 oz 0.063 Effective on most common broadleaf weeds and yellow and purple nutsedge. Does not control ragweed, eclipta, lambsquarters, or croton. If weeds are emerged, add surfactant or crop oil according to label directions. See label for rotational restrictions. Pursuit may be tank mixed with paraquat. Some weed species have developed resistance to Pursuit. Research in N.C. has generally shown more effective control of a broader spectrum of weeds with split applications of half of the Pursuit applied preplant incorporated followed by the other half applied early postemergence. Some emerged broadleaf weeds and suppression of eclipta and yellow nutsedge diclosulam (Strongarm) 84 WDG, MOA 2 0.45 oz 0.024 Strongarm can be applied through the cracking stage. Add 1 qt nonionic surfactant per 100 gal. The spectrum of weeds controlled is much narrower when Strongarm is applied to emerged weeds. Strongarm will not control emerged common lambsquarters or pigweeds but will control common ragweed and morningglories. Strongarm will suppress yellow nutsedge and eclipta. See product labels for information on mixing Strongarm with other herbicides. Some weed species have developed resistance to Strongarm.61 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks POSTEMERGENCE Annual broadleaf weeds acifluorfen (Ultra Blazer) 2L, MOA 14 1 to 1.5 pt 0.25 to 0.38 Apply when weeds are small and actively growing. Use minimum of 20 GPA and high pressure (40 to 60 psi). See label for species controlled, maximum weed size to treat, and addition of surfactant. Do not apply more than 2 pt postemergence per acre per season. May make sequential applications of 1 pt per acre followed by 1 pt per acre. Allow at least 15 days between sequential applications. acifluorfen (Ultra Blazer) 2L, MOA 14 + 2,4-DB (Butyrac 200) 2 L, MOA 4 1 to 1.5 pt + 16 fl oz 0.25 to 0.38 + 0.25 Addition of 2,4-DB to Ultra Blazer improves the control of certain weeds when weed size exceeds that specified on the Ultra Blazer label. See above comments on Ultra Blazer. See label for suggestions on use of surfactant or crop oil. Apply when peanuts are at least 2 weeks old and before pod filling begins. Make only one application per year. Other trade names for 2,4-DB may be available. bentazon, MOA 6 (Basagran) 4 L, MOA 6 1.5 to 2 pt 0.75 to 1 Apply when weeds are small and actively growing. Use minimum of 20 GPA and high pressure (40 to 60 psi). See label for addition of oil concentrate, species controlled, and maximum weed size to treat. Basagran may also be applied at 1 pt per acre for control of cocklebur, jimsonweed, and smartweed 4 in. or less. Do not apply more than 4 pt of Basagran per acre per season. Peanuts normally are very tolerant of Basagran. However, injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow. bentazon, MOA 6 (Basagran) 4 L, MOA 6 + acifluorfen (Ultra Blazer) 2 L, MOA 14 1 to 2 pt + 1 to 1.5 pt 0.5 to 1 + 0.25 to 0.38 See above comments for Basagran and Ultra Blazer. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants. Peanuts normally are very tolerant of Basagran. However, injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow.62 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual broadleaf weeds (continued) bentazon, MOA 6 + acifluorfen, MOA 14 (Storm) 4 L 1.5 pt 0.5 + 0.25 Apply when weeds are small and actively growing. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants. These rates of bentazon and acifluorfen may not provide consistent control of lambsquarters, prickly sida, and spurred anoda. Do not apply more than 3 pt of Storm per season. Peanuts normally are very tolerant of Storm. However, injury is occasionally noted when Basagran, one of the components of Storm, is applied to peanuts treated with Di-Syston in-furrow. bentazon, MOA 6 + acifluorfen, MOA 14 (Storm) 4 L + 2,4-DB (Butyrac 200) 2 L, MOA 4 1.5 pt + 8 to 16 fl oz 0.5 + 0.25 + 0.125 to 0.25 Adding 2,4-DB will improve control of larger morningglory, cocklebur, common ragweed, pigweed, jimsonweed, and citron. Add surfactant or crop oil according to label directions. Make only one appli-cation per year. Apply when peanuts are at least 2 weeks old. Do not apply after pod filling begins. See comments for Storm alone. Peanuts normally are very tolerant of Storm. However, injury is occasionally noted when bentazon, MOA 6, one of the components of Storm, is applied to peanuts treated with Di-Syston in-furrow. Other trade names for 2,4-DB may be available. bentazon, MOA 6 (Basagran) 4 L, MOA 6 + 2,4-DB (Butyrac 200) 2 L, MOA 4 1 to 2 pt + 8 fl oz 0.75 to 1 + 0.125 Addition of 2,4-DB to Basagran improves control of morningglories. See above comments for Basagran. Add surfactant or crop oil according to label directions. Do not make more than two applications per year. Apply when peanuts are at least 2 weeks old and not within 45 days of harvest. Peanuts normally are very tolerant of Basagran. However, injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow. Other trade names for 2,4-DB may be available. imazapic (Cadre or Impose) 2 AS, MOA 2 4 oz 0.063 Controls most broadleaf weeds except ragweed, croton, lambsquarters, and eclipta. Apply before weeds exceed 2 to 4 in.; see label for specific weed sizes to treat. Add nonionic surfactant at 1 qt per 100 gal or crop oil concentrate at 1 qt per acre. A soil-applied grass control herbicide should be used. However, Cadre and Impose will usually control escaped broadleaf signalgrass, fall panicum, and Texas panicum. See label for rotational restrictions. Some weed species have developed resistance to Cadre and Impose.63 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual broadleaf weeds (continued) imazethapyr (Pursuit) 2 AS, MOA 2 4 oz 0.063 Effective on most common broadleaf weeds and yellow and purple nutsedge. Does not control eclipta, lambsquarters, ragweed, or croton. Apply when weeds are 3 in. tall or less. Add surfactant or crop oil according to label directions. See label for rotational restrictions. Pursuit may be tank mixed with Basagran, Ultra Blazer, paraquat formulations, and 2,4-DB. Some weed species have developed resistance to Pursuit. Research in N.C. has generally shown more effective control of a broader spectrum of weeds with split applications of half of the Pursuit applied preplant incorporated followed by the other half applied early postemergence. 2,4-DB (Butyrac 200) 2 L, MOA 4 1 pt 0.2 to 0.25 Effective on cocklebur and morningglory; pitted morningglory may be only partially controlled. Best results achieved when applied to small weeds. May use two applications per year. Do not apply within 45 days before harvest. Other trade names for 2,4-DB may be available. lactofen (Cobra) 2 EC, MOA 14 12.5 fl oz 0.2 Apply after peanuts have at least six true leaves. Apply to actively growing peanut. Controls most annual broadleaf weeds. Use minimum of 10 GPA and high pressure (40 to 60 psi). See label for species controlled and maximum weed size to treat. Add nonionic surfactant at 1 qt per 100 gal or crop oil concentrate or methylated seed oil at 1 to 2 pt per acre. See label on when to use various adjuvants. Allow at least 14 days between applications. Can be tank mixed with Basagran, Pursuit, Cadre, Impose, 2,4-DB, and/or Select. lactofen (Cobra) 2 EC, MOA 14 + bentazon, MOA 6 (Basagran) 4 L, MOA 6 12.5 fl oz + 1.5 to 2 pt 0.2 + 0.75 to 1 See above comments for Cobra and Basagran. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants.64 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual broadleaf weeds (continued) lactofen (Cobra) 2 EC, MOA 14 + bentazon, MOA 6 (Basagran) 4 L, MOA 6 + 2.4-DB (Butyrac 200) 2 L, MOA 4 12.5 fl oz + 1.5 to 2 pt + 8 to 16 fl oz 0.2 + 0.75 to 1 + 0.125 to 0.25 Adding 2,4-DB will improve control of larger morningglory, cocklebur, common ragweed, jimsonweed, and citron. See above comments for Cobra, Basagran, and 2,4-DB. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants. Other trade names for 2,4-DB may be available. lactofen (Cobra) 2 EC, MOA 14 + imazapic (Cadre or Impose) 2 AS, MOA 2 12.5 fl oz + 4 oz 0.2 + 0.063 See above comments for Cobra and Cadre and Impose. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants. Some weed species have developed resistance to Cadre and Impose. lactofen (Cobra) 2 EC, MOA 14 + imazethapyr (Pursuit) 2 AS, MOA 2 12.5 fl oz + 4 oz 0.2 + 0.063 See above comments for Cobra and Pursuit. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants. Some weed species have developed resistance to Pursuit. Annual grasses and broadleaf weeds paraquat, MOA 22 (Firestorm or Parazone) 3.0 SL (Gramoxone SL) 2.5 L 5.4 fl oz 8 fl oz 0.13 See label for weeds controlled and maximum weed size to treat; best results if weeds 1 in. or less. A postemergence application may be made following an at-crack application. Do not make more than two applications per season, do not apply later than 28 days after ground cracking, and do not apply to peanuts under stress, including damage from thrips feeding. Add 1 pt of nonionic surfactant per 100 gal of spray solution. Will cause foliar burn on peanuts, but the crop recovers and yield not affected. Follow all safety precautions on label. Do not apply to peanuts showing symptoms of thrips damage.65 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual grasses and broadleaf weeds (continued) paraquat, MOA 22 (Firestorm or Parazone) 3.0 SL (Gramoxone SL) 2.5 L + bentazon, MOA 6 (Basagran) 4 L, MOA 6 5.4 fl oz 8 fl oz + 0.5 to 1.5 pt 0.13 + 0.25 to 0.75 See previous comments for paraquat alone. Adding Basagran improves control of common ragweed, prickly sida, smartweed, lambsquarters, and cocklebur and reduces injury to peanuts from paraquat. May be applied any time from ground cracking up to 28 days after ground cracking. Add 1 pt of nonionic surfactant per 100 gal of spray solution. Peanuts normally are very tolerant of Basagran. However, severe injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow. paraquat, MOA 22 (Firestorm or Parazone) 3.0 SL (Gramoxone SL) 2.5 L + bentazon, MOA 6 + acifluorfen, MOA 14 (Storm) 4 L, 5.4 fl oz 8 fl oz + 1.5 pt 0.13 + 0.5 0.25 See previous comments for Gramoxone SL alone. Storm improves control of common ragweed, smartweed, lambsquarters, common cocklebur, tropic croton, and spurred anoda. May be applied anytime from ground cracking up to 28 days after ground cracking. Add 0.5 pt of nonionic surfactant per 100 gal of spray solution. Peanuts normally are very tolerant of Basagran. However, severe injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow. The mixture of paraquat and Storm is more injurious than these herbicides applied alone. Florida beggarweed chlorimuron (Classic) 25 DF, MOA 2 0.5 oz 0.008 Use only for control of Florida beggarweed. Apply from 60 days after crop emergence to within 45 days of harvest. Application to peanuts less than 60 days old will result in crop injury and yield reduction. Apply before Florida beggarweed has begun to bloom and before it has reached 10 in. tall. Larger beggarweed may only be suppressed. Add 1 qt of nonionic surfactant per 100 gal spray solution; do not add crop oil. May be tank mixed with 2,4-DB; see label for rates and precautions. Recommended as a salvage treatment only.66 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Yellow nutsedge bentazon, MOA 6 (Basagran) 4 L, MOA 6 1.5 to 2 pt 0.75 to 1 Apply when nutsedge is 6 to 8 in. tall. A repeat application 7 to 10 days later may be needed. Adding crop oil concentrate at 1 qt per acre will increase control. Do not apply more than 4 pt of Basagran per season. Not effective on purple nutsedge. Peanuts normally are very tolerant of bentazon. However, severe injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow. Yellow and purple nutsedge imazapic (Cadre or Impose) 2 AS, MOA 2 4 oz 0.063 Apply postemergence when nutsedge is 4 in. or less. Add nonionic surfactant at 1 qt per 100 gal or crop oil concentrate at 1 qt per acre. See label for rotational restrictions. imazethapyr (Pursuit) 2 AS, MOA 2 4 oz 0.063 Apply before nutsedge is larger than 3 in. tall. Add surfactant at 1 qt per 100 gal or crop oil concentrate at 1 qt per acre. Do not mix with Basagran for nutsedge control. See label for rotational restrictions. A split application with half of the Pursuit applied preplant incorporated and half applied early post-emergence may be more effective than applying all of the Pursuit at one time. Annual grasses clethodim, MOA 1 (Arrow, Select, or Volunteer) 2 EC (Select MAX or TapOut) 0.97 EC 6 to 8 fl oz 9 to 16 fl oz 0.094 to 0.125 0.068 to 0.121 Apply Arrow, Poast, Poast Plus, Select 2 EC, Select MAX, TapOut, or Volunteer to actively growing grass not under drought stress. Consult labels for maximum grass size to treat. Apply in 5 to 20 GPA at 40 to 60 psi. Add 2 pt of crop oil concentrate per acre to Poast or Poast Plus. Do not cultivate within 7 days before or after application. Poast Plus is often slightly better than Poast. Add crop oil concentrate at 1 qt per acre to Arrow, Select 2 EC, Select MAX, TapOut, and Volunteer. Nonionic surfactant at 1 qt per 100 gal can be applied with Select MAX rather than crop oil concentrate. Some herbicides and fungicides can reduce the efficacy of Arrow, Select 2 EC, Select MAX, Volunteer, Poast, and Poast Plus when applied in tank mixtures. See product labels for specific instructions concerning compatibility with other chemicals. Also see AGW-653, Tank Mixing Chemicals Applied to Peanut, Are the Chemicals Compatible, which is on the Web at www.peanut.ncsu.edu and is available at your county Extension center. sethoxydim, MOA 1 (Poast) 1.5 EC (Poast Plus) 1 EC 1 pt 1.5 pt 0.1967 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Bermudagrass clethodim, MOA 1 (Arrow, Select, or Volunteer) 2 EC (Select MAX or TapOut) 0.97 EC 8 to 16 fl oz 12 to 32 fl oz 0.125 to 0.25 0.091 to 0.24 Apply to actively growing bermudagrass before runners exceed 6 in. In most cases, a second application will be needed. Make second application of 1 pt of Poast or 1.5 pt of Poast Plus per acre if regrowth occurs. Add 2 pt per acre of crop oil concentrate. Poast Plus is often slightly better than Poast. If needed, make a second application of Arrow, Select 2 EC, TapOut, or Volunteer at 8 to 16 oz per acre when regrowth is less than 6 in. Add crop oil concentrate at 1 qt per acre to Arrow, Select 2 EC, TapOut, and Volunteer. Crop oil concentrate (1 qt per acre) or nonionic surfactant (1 qt per 100 gallons) should be applied with Select MAX. See product labels for specific instructions concerning compatibility with other chemicals. Also see AGW-653, Tank Mixing Chemicals Applied to Peanut, Are the Chemicals Compatible, which is on the Web at www.peanut.ncsu.edu and available at your county Extension center. sethoxydim, MOA 1 (Poast) 1.5 EC (Poast Plus) 1 EC 1.5 pt 2.25 pt 0.28 Rhizome johnsongrass clethodim, MOA 1 (Arrow, Select, or Volunteer) 2 EC (Select MAX or TapOut) 0.97 EC 8 to 16 fl oz 12 to 32 fl oz 0.125 to 0.25 0.091 to 0.24 Apply to actively growing johnsongrass before it exceeds 25 in. tall. Add 2 pt per acre of crop oil concentrate. A second application of the same rates can be made if needed before new plants or regrowth exceeds 12 in. Apply Arrow, Select 2 EC, TapOut, or Volunteer when johnsongrass is 12 to 24 in. tall. If needed, make a second application when regrowth is 6 to 18 in. Add crop oil concentrate at 1 qt per acre to Arrow, Select 2 EC, Select MAX, TapOut, and Volunteer. Crop oil concentrate (1 qt per acre) or nonionic surfactant (1 qt per 100 gallons) should be applied with Select MAX. For specific instructions for compatibility concerns with other chemicals, see product labels and AGW-653, Tank Mixing Chemicals Applied to Peanut, Are the Chemicals Compatible, which is on the Web at www.peanut.ncsu.edu and available at your county Extension center. sethoxydim, MOA 1 (Poast) 1.5 EC (Poast Plus) 1 EC 1 pt 1.5 pt 0.1968 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Suppression of large Palmer amaranth and other pigweed species that are resistant to the ALS inhibiting herbicides Cadre, Classic, Impose, Pursuit, and Strongarm 2,4-DB (Butyrac 200 and others) 2 L, MOA 4 + lactofen (Cobra) 2 EC, MOA 14 or acifluorfen (Ultra Blazer) 2 L, MOA 14 16 oz + 12.5 oz or 1.5 pt 0.25 + 0.20 or 0.38 Suppresses and does not completely control Palmer amaranth and other pigweed species that exceed 8 inches. Suppression of weeds exceeding 12 inches will be less than suppression of smaller weeds. Do not expect suppression to exceed 60%. Applying 2,4-DB 3 to 4 days prior to Cobra or Ultra Blazer may be more effective than tank mixtures of 2,4-DB with Cobra or Ultra Blazer. Cobra is generally more effective on larger Palmer amaranth and other pigweed species than Ultra Blazer. Apply crop oil concentrate at 1% (v/v) with Cobra and Ultra Blazer. Do not apply adjuvant with 2,4-DB alone. See product labels for comments on spray volume and effects on peanut especially during pod set and pod fill. Higher spray volumes are more effective by increasing spray coverage of the contact herbicides Cobra and Ultra Blazer. Two applications of 2,4-DB spaced 10 to 14 days apart will suppress Palmer amaranth and other pigweed species. Although suppression by 2,4-DB is lower than sequential or tank mix application of 2,4-DB and Cobra or Ultra Blazer within two weeks after application, suppression by sequential applications of 2,4-DB 4 to 5 weeks after initial application is only slightly lower than suppression by sequential or tank mix applilcation of 2,4-DB and Cobra or Ultra Blazer. For more information on managing herbicide-resistant weeds in peanut, see AG-692, Managing Herbicide-Resistant Weeds in Peanuts in the United States, which is on the Web at www.peanut.ncsu.edu. 2,4-DB (Butyrac 200 and others) 2 L, MOA 4 then lactofen (Cobra) 2 EC or acifluorfen (Ultra Blazer) 2 L, MOA 14 16 oz then 12.5 oz or 1.5 pt 0.25 then 0.20 or 0.38 2,4-DB (Butyrac 200) 2 L, MOA 4 then 2,4-DB (Butyrac 200) 2 L, MOA 4 16 oz then 16 oz 0.25 then 0.25 Paraquat, MOA 22 (Gramoxone SL) 2.5L See comments See comments Apply in a roller/wiper implement. Best control achieved when at least 60% coverage of weed foliage can be achieved. Do not allow paraquat to contact peanut foliage. Mix 1 part Gramoxone SL with 1 to 1.5 parts water to prepare a 40% to 50% solution. Add nonionic surfactant at 0.25% (v/v) or 1 qt/100 gallons. Adjust roller/wiper system to apply up to 2 pt/A of the herbicide-water mixture.69 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual grasses and certain small-seeded broadleaf weeds dimethenamid (Outlook) 6.0 L, MOA 15 16 to 21 fl oz 0.75 to 1 Will not control emerged grasses or weeds; apply following a cultivation or appropriate postemergence herbicide if emerged grasses or broadleaf weeds are present. Benefit likely only on very sandy fields heavily infested with annual grasses that receive above normal rainfall during the first 4 to 5 weeks of the growing season. Lay-by of Dual Magnum or Outlook may also be of value in fields with a history of eclipta problems; the application must be made before eclipta emerges. Rates are on a broadcast basis; apply in an 18-in. band to row middles. The maximum use rate of Dual Magnum is 2.6 pt per acre pe
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Title | Peanut information |
Date | 2012 |
Description | 2012 |
Digital Characteristics-A | 1459 KB; 150 p. |
Digital Format | application/pdf |
Full Text | 1 2012 Information PEANUT Prepared by David L. Jordan Coordinating Author and Extension Specialist—Crop Science Rick L. Brandenburg Extension Specialist— Entomology A. Blake Brown Extension Economist—Agricultural and Resource Economics S. Gary Bullen Extension Associate—Agricultural and Resource Economics. Gary T. Roberson Extension Specialist—Biological and Agricultural Engineering Barbara Shew Extension Specialist—Plant Pathology Jan Ferguson Spears Extension Specialist—Crop Science Published by North Carolina Cooperative Extension Service College of Agriculture & Life Sciences North Carolina State University The North Carolina Peanut Growers Association provided financial support for publishing 2012 Peanut Information.2 CONTENTS EXTENSION PERSONNEL WORKING WITH PEANUTS 4 1. VIRGINIA TYPE PEANUTS: SITUATION AND OUTLOOK 12 2. PEANUT SEED 16 3. PEANUT PRODUCTION PRACTICES 48 4. WEED MANAGEMENT IN PEANUTS 80 5. PEANUT INSECT AND MITE MANAGEMENT 100 6. PEANUT DISEASE MANAGEMENT 129 7. PLANTING, HARVESTING, AND CURING PEANUTS 129 8. GUIDELINES AND SURVEY RESULTS ASSOCIATED WITH THE NORTH CAROLINA PEANUT PRODUCTION CONTEST 1463 EXTENSION PERSONNEL WORKING WITH PEANUTS County Extension personnel with peanut responsibilities as of January 1, 2012: County Name City Telephone Beaufort Gaylon Ambrose Washington (252) 946-0111 Bertie Richard Rhodes Windsor (252) 794-5317 Bladen Ryan Harrelson Elizabethtown (910) 862-4591 Chowan Tim Smith Edenton (252) 482-6585 Columbus Michael Shaw Whiteville (910) 640-6605 Cumberland Colby Lambert Fayetteville (910) 321-6875 Duplin Curtis Fountain Kenansville (910) 296-2143 Edgecombe Art Bradley Tarboro (252) 641-7815 Gates Paul Smith Gatesville (252) 357-1400 Halifax Arthur Whitehead Halifax (252) 583-5161 Harnett Brian Parrish Lillington (910) 893-7530 Hertford Wendy Drake Winton (252) 358-7822 Jones Jacob Morgan Trenton (252) 448-9621 Martin Al Cochran Williamston (252) 792-1621 Nash Charlie Tyson Nashville (252) 459-9810 Northampton Craig Ellison Jackson (252) 534-2711 Onslow Melissa Huffman Jacksonville (910) 455-5873 Pender Mark Seitz Burgaw (910) 259-1235 Perquimans Lewis Smith Hertford (252) 426-5428 Pitt Mitch Smith Greenville (252) 757-2801 Sampson Kent Wooten Clinton (910) 592-7161 Scotland Glen Garris Laurinburg (910) 277-2422 Washington Lance Grimes Plymouth (252) 793-2163 Wayne Kevin Johnson Goldsboro (919) 731-1520 Wilson Norman Harrell Wilson (252) 237-0111 N.C. State University Extension specialists with peanut responsibilities as of January 1, 2012, and directors of peanut grower organizations: Rick Brandenburg Insects, N.C. State University (919) 515-8876 Blake Brown Economics, N.C. State University (919) 515-4536 Gary Bullen Economics, N.C. State University (919) 515-6095 David Jordan Agronomy & Weeds, N.C. State University (919) 515-4068 Gary Roberson Engineering, N.C. State University (919) 515-6715 Barbara Shew Diseases, N.C. State University (919) 515-6984 Jan Spears Seeds, N.C. State University (919) 515-4070 Bob Sutter N.C. Peanut Growers Association Inc. (252) 459-5060 Dell Cotton Peanut Growers Cooperative Marketing Association (757) 562-41034 1. SITUATION AND OUTLOOK A. VIRGINIA TYPE PEANUTS: SITUATION AND OUTLOOK A. Blake Brown Extension Economist—Agricultural and Resource Economics U.S. peanut production was 3.65 billion pounds in 2011, down from 4.16 billion pounds in 2010 as reported by USDA National Agricultural Statistics Service (NASS). With strong competition for land from other crops, such as corn and cotton , and severe drought in Texas planted acres declined in 2011 to 1.15 million acres down from 1.29 million planted acres in 2010. Yields were down slightly in 2011 at 3,275 pounds per acre. In North Carolina planted acreage, as reported by NASS, decreased from 87 thousand acres in 2010 to 82 thousand acres in 2011. This is about 1000 acres more than planted acres as reported by USDA Farm Service Agency (Table 1-1). Yields in North Carolina were excellent at 3,500 pounds per acre in contrast to the poor yield of 2,700 pounds per acre in 2010. As a result production in North Carolina increased 22 percent to 283 million pounds despite a decrease in acreage. Peanut stocks in commercial storage as of September 30, 2011 at 1.23 million pounds were down 55 million pounds from 2010. Stocks of shelled peanuts were down 13 percent while stocks of in shell peanuts were down 14 percent from 2010. September 2011 ending stocks of in shell Virginia and Valencia type peanuts were down about 50 percent at only 60 million pounds. Lower production and declining stocks led to higher prices with prices over $800 per ton reported. Short supplies of peanuts have led to speculation that prices will increase even more for the 2012 crop. However continued strong prices for competing crops and the strong possibility of continued drought in Texas and other parts of the southern U.S. will hamper efforts to increase peanut acreage in 2012. 5 Table 1-1. 2010 North Carolina Peanuts Planted Acreage by Type and County County Runners Virginia Total Beaufort 132.5 416 548.5 Bertie 6688.3 6688.3 Bladen 5395.28 5395.28 Brunswick 1 1 Carteret 0.1 83.4 83.5 Chowan 3104.6 3104.6 Columbus 1039.09 4151.8 5190.89 Craven 409.5 409.5 Cumberland 161.5 161.5 Currituck 28.3 28.3 Duplin 4069.8 4069.8 Edgecombe 512.04 5052.55 5564.59 Gates 2572.9 2572.9 Greene 399.6 1836.07 2235.67 Halifax 1160.6 4258.78 5419.38 Harnett 137.6 26.5 164.1 Hertford 3584.3 3584.3 Johnston 235.1 814.6 1049.7 Jones 645.2 645.2 Lenoir 349.1 349.1 Martin 8097.9 8097.9 Nash 69.2 2497.38 2566.58 Northampton 522.1 2426.5 2948.6 Onslow 609.6 609.6 Pasquotank 23.2 23.2 Pender 251.3 251.3 Perquimans 506.7 506.7 Pitt 672.46 6459.73 7132.19 Robeson 461.3 2662.4 3123.7 Sampson 3664.78 3664.78 Scotland 664.6 664.6 Wake 65.6 174.2 239.8 Washington 1117.8 1117.8 Wayne 1844.98 1844.98 Wilson 119.86 524.27 644.13 State Total 5899.45 74802.52 80701.97 Sources: USDA-FSA “North Carolina planted peanut acreage report; 2010.” 6 B. PEANUT PRODUCTION BUDGETS S. Gary Bullen Extension Economist—Agricultural and Resource Economics David Jordan Peanut Specialist—Crop Science Emily Weddington Agricultural and Resource Economics The budgets in the following tables represent costs and returns that are achieved by many growers in different regions of North Carolina using strip-till or conventional production technologies. The budgets do not represent average costs and returns. Budgets are intended to be used as guides for planning purposes only. They do not include sprays for Sclerotinia blight or fumigation for CBR. The cost of land plaster is assumed to be $51.51 per ton; less expensive sources are available although transportation costs can be significant. Current information on the peanut outlook and situation, budgets, farm management, and more is available at the North Carolina State University Department of Agricultural and Resource Economics Web site: www.ag-econ.ncsu.edu. 7 Table 1-2. Estimated Costs and Returns Per Acre of RUNNER STRIP-TILL Peanuts, 2012—3,500-Pound Yield, 4-Row Equipment Item Quantity and Unit Price or Cost/Unit ($) Total/Acre ($) Your Farm 1. GROSS RECEIPTS Peanuts 3,500 lb 0.33 1,155.00 Total Receipts: 1,155.00 2. VARIABLE COSTS* Seed 110.00 lb 1.20 132.00 Inoculant 1.00 acre 5.00 5.00 Fertilizer Nitrogen 15.00 lb 0.32 4.80 Phosphate 30.00 lb 0.41 12.30 Potash 90.00 lb 0.54 48.60 Manganese 3.00 Lb 1.5 4.50 Boron 2.50 lb 1.13 2.83 Lime (prorated) 0.50 ton 48.50 24.25 Land Plaster 0.25 ton 51.51 12.88 Herbicides 1.00 acre 59.99 59.99 Insecticides 1.00 acre 35.48 35.48 Fungicides 1.00 acre 56.43 56.43 Scouting 1.00 acre 10.00 10.00 Hauling 1.75 ton 12.00 21.00 Drying & Cleaning 1.75 ton 45.00 78.75 State Check-off Fee 1.75 ton 3.00 5.25 National Assessment* 735.00 acre 0.01 7.35 Crop Insurance 1.00 acre 22.00 22.00 Tractor/Machinery 1.00 acre 116.10 116.10 Labor 3.40 hours 9.30 31.62 Interest on Operating Capital $257.58 5.00% 12.88 Total Variable Costs 704.01 3. INCOME FROM ABOVE VARIABLE COSTS 450.99 4. FIXED COSTS Tractor/Machinery 1.00 acre 180.33 180.33 Total Fixed Costs 180.33 5. TOTAL COSTS 884.34 6. NET RETURNS TO LAND, RISK, & MGMT. 270.66 * National Assessment is 1.05% of gross receipt and is also named National Loss, Promotion, Research Assessment. Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, or land rent. 8 Table 1-3. Estimated Costs and Returns Per Acre of RUNNER CONVENTIONAL-TILL Peanuts. 2012—3,500-Pound Yield, 4-Row Equipment Item Quantity per Unit Price or Cost/Unit ($) Total per Acre ($) Your Farm 1. GROSS RECEIPTS Peanuts 3,500 lb 0.33 1,155.00 Total Receipts 1155.00 2. VARIABLE COSTS Seed 110.00 lb 1.20 132.00 Inoculant 1.00 acre 5.00 5.00 Fertilizer Nitrogen 15.00 lb 0.32 4.80 Phosphate 30.00 lb 0.41 12.30 Potash 90.00 lb 0.54 48.60 Boron 2.50 lb 1.13 2.83 Manganese 3.5 lb 1.5 4.50 Lime (prorated) 0.50 ton 48.50 24.25 Land Plaster 0.25 ton 51.51 12.88 Herbicides 1.00 acre 59.99 59.99 Insecticides 1.00 acre 31.52 31.52 Fungicides 1.00 acre 56.43 56.43 Scouting 1.00 acre 10.00 10.00 Hauling 1.75 ton 12.00 21.00 Drying & Cleaning 1.75 ton 45.00 78.75 State Check-off Fee 1.75 ton 3.00 5.25 National Assessment* 831.25 acre 0.01 8.31 Crop Insurance 1.00 acre 22.00 22.00 Tractor/Machinery 1.00 acre 121.95 121.95 Labor 3.76 hour 9.30 34.97 Interest on Operating Capital $258.53 5.00% 12.93 Total Variable Costs 710.26 3. INCOME ABOVE VARIABLE COSTS 444.74 4. FIXED COSTS Tractor/Machinery 1.00 acre 175.38 175.38 Total Fixed Costs 175.38 5. TOTAL COSTS 885.64 6. NET RETURNS TO LAND, RISK, & MANAGEMENT 269.36 * National Assessment is 1.05% of gross receipt and is also named national loss, promotion, research assessment. Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, or land rent.9 Table 1-4. Estimated Costs and Returns Per Acre of VIRGINIA STRIP-TILL Peanuts, 2012—3,500-Pound Yield, 4-Row Equipment Item Quantity and Unit Price or Cost/Unit ($) Total per Acre ($) Your Farm 1. GROSS RECEIPTS Peanuts 3,500 lb 0.35 1,225 Total Receipts 1,225 2. VARIABLE COSTS Seed 140.00 lb 1.20 168.00 Inoculant 1.00 acre 5.00 5.00 Fertilizer Nitrogen 15.00 lb 0.32 4.80 Phosphate 30.00 lb 0.41 12.30 Potash 90.00 lb 0.54 48.60 Manganese 3.00 lb 1.50 4.50 Boron 2.50 lb 1.13 2.83 Lime (prorated) 0.50 ton 48.60 24.25 Land Plaster 0.50 ton 51.51 25.76 Herbicides 1.00 acre 59.99 59.99 Insecticides 1.00 acre 35.48 35.48 Fungicides 1.00 acre 56.43 56.43 Scouting 1.00 acre 10.00 10.00 Hauling 1.75 ton 12.00 21.00 Drying & Cleaning 1.75 ton 45.00 78.75 State Check-off Fee 1.75 ton 3.00 5.25 National Assessment* 1006.25 acre 0.01 10.06 Crop Insurance 1.00 acre 22.00 22.00 Tractor/Machinery 1.00 acre 116.10 116.10 Labor 3.40 hours 9.30 31.62 Interest on Operating Capital $282.02 5.00% 14.10 Total Variable Costs 756.82 3. INCOME ABOVE VARIABLE COSTS 468.18 4. FIXED COSTS Tractor/Machinery 1.00 acre 180.33 180.33 Total Fixed Costs 180.33 5. TOTAL COSTS 937.15 6. NET RETURNS TO LAND, RISK, & MGMT. 287.85 * National Assessment is 1.05% of gross receipt and is also named National Loss, Promotion, Research Assessment.Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, and land rent.10 Table 1-5. Estimated Costs and Returns Per Acre of VIRGINIA CONVENTIONAL-TILL Peanuts, 2012—3,500-Pound Yield, 4-Row Equipment Item Quantity and Unit Price or Cost/Unit ($) Total per Acre ($) Your Farm 1. GROSS RECEIPTS Peanuts 3,500 lb 0.35 1,225 Total Receipts 1,225 2. VARIABLE COSTS Seed 140.00 lb 1.20 168.00 Inoculant 1.00 acre 5.00 5.00 Fertilizer Nitrogen 15.00 lb 0.32 4.80 Phosphate 30.00 lb 0.41 12.30 Potash 90.00 lb 0.54 48.60 Manganese 3.00 lb 1.50 4.50 Boron 2.50 lb 1.13 2.83 Lime (prorated) 0.50 ton 48.60 24.25 Land Plaster 0.50 ton 51.51 25.76 Herbicides 1.00 acre 59.99 59.99 Insecticides 1.00 acre 35.48 35.48 Fungicides 1.00 acre 56.43 56.43 Scouting 1.00 acre 10.00 10.00 Hauling 1.75 ton 12.00 21.00 Drying & Cleaning 1.75 ton 45.00 78.75 State Check-off Fee 1.75 ton 3.00 5.25 National Assessment* $1,006.25 0.01 10.06 Crop Insurance 1.00 acre 22.00 22.00 Tractor/Machinery 1.00 acre 121.95 121.95 Labor 3.76 hour 9.30 34.97 Interest on Operating Capital $282.02 5.00% 14.10 Total Variable Costs 766.02 3. INCOME ABOVE VARIABLE COSTS 458.98 4. FIXED COSTS Tractor/Machinery 1.00 acre 175.38 175.38 Total Fixed Costs 175.38 5. TOTAL COSTS 941.40 6. NET RETURNS TO LAND, RISK, & MGMT. 283.60 *National Assessment is 1.05% of gross receipt and is also named national loss, promotion, research assessment. Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, and land rent.11 Table 1-6. Return to Land, Overhead and Management for Peanut at Various Yields and Costs of Production Net Return ($/acre) at $600/ton Contract Price Total cost ($/acre) Peanut Yield 800 850 900 950 1000 1050 (pounds/acre) __________________ Net Return ($/acre) __________________ 3000 100 50 0 -50 -100 -150 3500 250 200 150 100 50 0 4000 400 350 300 250 200 150 4500 550 500 450 400 350 300 5000 700 650 600 550 500 450 Net Return ($/acre) at $700/ton Contract Price Total cost ($/acre) 800 850 900 950 1000 1050 __________________ Net Return ($/acre) __________________ 3000 250 200 150 100 50 0 3500 425 375 325 275 225 175 4000 600 550 500 450 400 350 4500 775 725 675 625 575 525 5000 950 900 850 800 750 700 Net Return ($/acre) at $800/ton Contract Price Total cost ($/acre) 800 850 900 950 1000 1050 __________________ Net Return ($/acre) __________________ 3000 400 350 300 250 200 150 3500 600 550 500 450 400 350 4000 800 750 700 650 600 550 4500 1000 950 900 850 800 750 5000 1200 1150 1100 1050 1000 95012 2. PEANUT SEED Jan Spears and David Jordan Extension Specialists — Crop Science A uniform stand of healthy, vigorous plants is essential if growers are to achieve the yields and quality needed for profitable peanut production. It is important for growers to plant high quality seed of varieties adapted to their farm situations, management styles, and intended market uses. WHAT’S IN A BAG OF PEANUT SEED? A bag of seed peanuts contains thousands of potential plants. To grow a uniform stand of healthy plants, you need genetically pure seed that has been produced under a management system that maximizes seed health, germination, and vigor. The genetic composition of a peanut variety dictates maturity date, disease and insect resistance, peanut quality, grade, and many other characteristics. The best assurance of obtaining genetically pure seed is to purchase Certified Seed. Seed health is related to seed-borne pathogens present on or in peanut seeds. Pathogens can reduce germination potential and can in some cases transmit peanut diseases. Professional seed producers take specific measures to reduce the level of seed-borne pathogens. The extra steps they take minimize the chance for the spread of unwanted diseases. Seed lots high in germination and vigor potential will germinate more rapidly and produce more robust seedlings. These seedlings are more likely to survive moderate stress during the weeks following planting. Always purchase seed from a reputable, professional seed dealer. Bargain seed from a stranger, or even a neighbor, may not be such a bargain. Along with their “seed,” you could be buying weed seed or mixed varieties. You could even introduce diseases onto your farm. PEANUT SEED PRODUCTION The key component to producing high quality peanut seed is to make the seed crop your highest farm priority. Attention to details is essential and critical steps include: • field selection, • seed selection, 13 • cleaning and tuning up planting equipment, • applying gypsum and boron at the right time, • digging the crop when a majority of the pods are close to maturity, • adjusting harvesting equipment to minimize mechanical damage, • curing the peanuts slowly, and • storing the seeds in a cool, dry environment. Production of high-quality peanut seeds requires a high level of management that begins before planting and continues through delivery of seeds to the peanut farmer. A detailed description of peanut seed production can be found in Peanut Seed Production: A Guide For Producers of Virginia-type Peanut Seed (AG–622), which can be obtained free from your county Extension center or viewed online: www.peanuts.ncsu.edu/PDFFiles/004968/Peanut_Seed_Production_Guide.pdf SAVING SEED In years when profits are low, some growers may decide that saving their own seed will help reduce production costs. Cleaning, treating, and bagging seed, however, can be expensive; and a grower may not save more than a few cents per acre. In fact, a loss may occur if the seeds they planted were of poor quality. Seed germination and vigor of saved seed can be an issue, and growers are urged to have germination tests run on saved seed immediately after harvest and again about 6 weeks before planting. Checking the quality of the seed early will tell the grower if the seed is worth saving. The second test will tell the grower if the seed is worth planting. Seed production is a specialized process; varietal purity, seed quality, and seed health are carefully monitored throughout the growing season and during the digging, combining, curing, cleaning, storage, and treating operations. Saving seed should not be an afterthought, but rather a process that begins well before the seed crop is planted. Growers who decide to save seed should be aware that they might be in violation of the North Carolina State Seed Law, the Plant Variety Protection Act (PVPA), and Title V of the Federal Seed Act if they sell that saved seed. According to regulations, growers may save enough seed of a PVPA-protected variety to plant back on their own holdings (land owned, leased, or rented). If planting intentions change and if a variety is PVPA-1970 protected, the farmer may sell that saved seed, 14 but only that amount saved to plant his or her holdings. If the variety is protected under the amended 1995 PVPA, a farmer may not sell any seed without the permission of the variety owner.Very few varieties currently grown in the mid-Atlantic states are PVPA-1970 protected varieties. Growers who are considering selling saved-seed are encouraged to consult with their Department of Agriculture Seed Sections to be sure of the variety protection level. See Table 2-1 for a list of popular Virginia makret type varieties and their level of protection. North Carolina Seed Regulations require variety labeling on all peanut seed sold in the state, regardless of whether the seed is certified or farmer stock. No peanut seed can be sold as variety not stated, even if the variety is not known or the seed is a mixture of varieties. CO-OP SEED DISTRIBUTION Some growers are members of a co-op, and questions have been raised about co-op distribution of seed to growers. A farmer may bring saved seed into the co-op to be shelled, cleaned, treated, and bagged. But the entire quantity of saved seed must be returned to the farmer who produced it. The seed may not be co-mingled with seed from any other grower, and the seed may not be sold, traded, nor given to any other grower. These actions are a violation of PVPA and the Federal Seed Act. The amount of peanuts shelled, cleaned, treated, and bagged must not exceed the amount the grower may legally save. A co-op may become a licensed seed dealer, allowing co-op members to produce their own seed as a group with seed from several growers combined and distributed among the membership. If so, steps must be taken before planting to ensure proper certification and State Seed Law requirements have been met. Certified seed must be grown from Foundation or Registered seed, fields must be inspected, and the seed must meet minimum germination standards. The co-op must be licensed under the North Carolina State Seed Law. Contact the North Carolina Crop Improvement Association (919-515-2851) for details on how to certify peanut seed and the North Carolina Department of Agriculture and Consumer Services Seed Section (919-733-3930) for details about becoming a licensed seed dealer. 15 Table 2-1. List of Varieties and Requirements for Sale Variety Can you save seed? Can you sell that saved seed? Must the saved seed be sold as a class of certified seed? Bailey Yes Only with permission Yes Brantley Yes Only with permission Yes CHAMPS Yes Only with permission Yes Gregory Yes Only with permission Yes Perry Yes Only with permission Yes Phillips Yes Only with permission Yes NC-V 11 Yes Only with permission Yes Sugg Yes Only with permission Yes16 3. PEANUT PRODUCTION PRACTICES David L. Jordan Extension Specialist—Crop Science Successful production of quality peanuts requires growers to plan an effective production and marketing program and to implement that program on a timely basis during the season. Each cultural practice and marketing decision must be effectively integrated into the total farm management plan to produce optimum profits from the whole farm. STAND ESTABLISHMENT Soil temperatures need to be above 65oF for germination to proceed at an acceptable rate. Large-seeded Virginia market type peanuts planted under favorable moisture and temperature conditions will show beginning radicle (root) growth in about 60 hours. If conditions are ideal, sprouting young seedlings should be visible in 7 days for smaller-seeded varieties like Bailey, and 10 days for larger-seeded varieties like Gregory. Peanuts should not be planted until the soil temperature at a 4-inch depth is 65°F or above at noon for 3 days. Favorable weather for peanut germination should also be forecast for the next 72 hours after planting. The soil should be moist enough for rapid water absorption by the seed. The planter should firm the seedbed so there is good soil-to-seed contact. Growers should establish at least four plants per foot of row regardless of variety. Peanuts can emerge from depths as low as 3 inches. VARIETY SELECTION Yield and quality are two major factors that influence variety selection. Growers with significant disease history may need to choose a variety with disease tolerance or resistance. Planting at least three varieties with different maturity dates permits efficient use of limited harvesting and curing equipment. Planting varieties with different genetic pedigrees reduces the risk of crop failure because of adverse weather or unexpected disease epidemics. The percentage of acres planted for certified seed production generally reflect overall plantings of varieties (Table 3-1). The selection of a variety should be based on more than 1 year’s data. Performance of our most popular peanut varieties from reports 17 prepared by Dr. Tom Isleib (peanut breeder at N.C. State University) and Dr. Maria Balota’s PVQE (Peanut Variety and Quality Evaluation) program is presented in Tables 3-2 and 3-3, respectively. Yield from research station and on-farm tests by David Jordan and Dewayne Johnson (N.C. Cooperative Extension) is presented in Table 3-4. Varietal characteristics are listed in Table 3-5. Disease reaction of varieties can be found in Chapter 6, “Peanut Disease Management.” Table 3-1. Certified Peanut Seed Acreage in 2010 in NC, SC, and VA. Modified from Isleib, 2011 Variety Percent of Total Planted Perry 21.6 CHAMPS 21.0 Phillips 18.8 NC-V 11 14.2 Gregory 13.4 Bailey 4.9 Sugg 2.2 VA 98R 1.0 Florida Fancy 1.4 Georgia 08V 1.1 Table 3-2. Pod Yield and Market Grade Characteristics of Bailey and Sugg Compared with Other Commercially Available Virginia Market Type Varieties Variety Percent Fancy Percent ELK Percent SMK Meat Content Yield (lb/acre) Bailey 75 40 62 69 4,629 Sugg 81 46 62 69 4,449 NC-V11 75 35 60 69 4,430 Gregory 85 45 58 66 4,056 Perry 75 40 61 69 3,924 Phillips 79 46 62 69 4,213 VA 98R 73 38 60 68 4,157 CHAMPS 79 39 61 68 4,141 *Data are from Isleib et al. (January, 2010) and are pooled over 43 tests over 5 years. Table 3-3. Percentages of FP, ELK, SMK, and Total Kernels and Pod Yield for the Major Virginia Market Type Varieties Variety FP ELK SMK Total Kernels Yield NC-V 11 79 41 67 73 5,233 Gregory 92 52 66 72 4,993 Perry 81 44 66 74 4,906 CHAMPS 81 43 68 74 4,917 Phillips 85 51 68 75 5,066 Bailey 77 44 67 74 5,460 Florida Fancy 87 46 65 73 4,851 VA 98R 78 42 66 74 4,911 Sugg 84 49 66 75 5,230 *Data are from Balota et al. (PVQE Summary, Information series No. 491) and are pooled over 12 trials from 2008–2009.18 Table 3-4. Pod Yield of Commercially Available Peanut Varieties from Eight Research Station and On-farm Tests Variety Pod Yield* Phillips 4,630 Gregory 4,210 CHAMPS 4,470 Bailey 4,780 * Selected data from D. Jordan and D. Johnson, N.C. Cooperative Extension Service and are pooled over 8 trials during 2009-2011. Experiments included two digging dates, generally September 20–30 versus October 7–15 (2009) and approximately October 1 and October 15 (2010 and 2011). Data are pooled over eight locations and two digging dates. Variety Characteristics Bailey is a new large-seeded Virginia market type peanut with resistance to several key peanut diseases. This variety offers tolerance to CBR, Sclerotinia blight, tomato spotted wilt, and possibly stem rot. Seed size is slightly larger than NC-V 11. CHAMPS is a large-seeded peanut that matures slightly earlier than Wilson. It is intermediate in resistance to tomato spotted wilt and is moderately susceptible to most other diseases. Gregory is a large-seeded Virginia market type peanut with growth habit intermediate between bunch and runner, a pink seed coat, and a high percentage of jumbo pods and extra-large kernels. It is susceptible to most diseases and insect pests. Because of its large seed size, Gregory has a high calcium requirement and may show reduced seedling vigor compared with other varieties. Other than Bailey, Gregory offers the best resistance to tomato spotted wilt virus of commercially available Virginia market types when planted at optimum seeding rates. NC-V 11 is a large-seeded Virginia market type peanut with a runner growth habit that is similar to Gregory in maturity. Its major advantage is a high yield and value per acre. NC-V 11 has a lower percentage of fancy pods than Gregory, Wilson, CHAMPS, and Phillips. Perry is a large-seeded peanut with partial resistance to CBR and some tolerance of Sclerotinia blight. It is characterized by a semi-runner growth habit. It matures later than NC-V 11. Perry is susceptible to tomato spotted wilt virus. Phillips is a large-seeded peanut that matures slightly earlier than Gregory. It has only minor resistance to many of the diseases found in peanut.19 Sugg is a new large-seeded Virginia market type peanut with a disease management package that approaches that of Bailey. Although not as resistant to disease as Bailey, Sugg has larger pods. Table 3-5. Varietal Characteristics Factors Bailey CHAMPS Gregory NC-V 11 Perry Phillips Sugg Growth habit (R=runner; SR=semi-runner) SR R R R SR SR SR Heat unit requirement 2,650 2,500 2,650 2,650 2,770 2,600 2,650 Comparative days to optimum maturity 0* -9 0 0 +7 -3 0* Seed coat color Tan Pink Pink Pink Pink Pink Pink Seed per pound 540 535 450 625 525 545 545 Need for calcium (M=moderate; H=high) M M H M M M M Heat unit requirement=degree day accumulation (56°F base and a 95°F ceiling) required to reach optimum maturity assuming adequate soil moisture for sustained growth and development In comparative days to optimum maturity, - = optimum maturity for the variety occurs prior to ‘0’; += optimum maturity for variety occurs after ‘0’. *Limited data SELECTING AND MANAGING SOIL RESOURCES Peanuts are best adapted to well-drained, light-colored, sandy loam soils, such as the Norfolk, Orangeburg, and Goldsboro sandy loam. These soils are loose, friable, and easily tilled with a moderately deep rooting zone for easy penetration by air, water, and roots. A balanced supply of nutrients is needed, as peanuts do not usually respond to direct fertilization. Soil pH should be in the range of 5.8 to 6.2. Peanuts grown in favorable soil conditions are healthier and more able to withstand climatic and biotic stresses. Crop Rotation A long crop rotation program is essential for efficient peanut production. The peanut plant responds to both the harmful and beneficial effects of other crops grown in the fields. Research shows that long rotations are best for maintaining peanut yields and quality. Benefits and potential problems associated with crops typically found within 20 Rotation (1997–2011) (CR – Corn, CT – Cotton, SB – Soybeans, WH – Wheat, PN – Peanut) Yield (lb/acre) Yield (bu/acre) Peanut 2006 Wheat 2008 Wheat 2009 Soybean 2008 Soybean 2009 Corn 2007 Corn 2009 Corn 2011 CR – CT – CR – PN – CR – CR – CR – CR – CR – PN – CR – WH/SB – CR– WH/SB-CR 5,920 a 32 a 35 ab 43 a 44 a 16 a 111 a 138 a PN – CR – CR – PN – CR – CR – PN – CR – CR – PN– CR – WH/SB – CR– WH/SB-CR 5,030 b 34 a 33 ab 44 a 31 bc 7 a 115 a 127 a CR – PN – CR – PN – CR – PN – CR – PN – CR – PN– CR – WH/SB – CR– WH/SB-CR 4,350 c 31 a 42 a 46 a 40 ab 21 a 102 a 128 a PN – SB – CR – PN – SB – CR – PN – SB – CR – PN – CR – WH/SB – CR– WH/SB-CR 3,800 c 32 a 36 ab 38 a 25 c 32 a 92 a 138 a PN – PN – PN – PN – PN – PN – PN – PN – PN – PN – CR – WH/SB – CR– WH/SB-CR 2,600 d 31 a 30 b 38 a 33 abc 23 a 135 a 143 a *Means within a column followed by the same letter are not significantly different p < 0.05. Table 3-6. Influence of Rotation on Crop Yield at Lewiston21 Table 3-7. Influence of Rotation Interval and Soybeans on Crop Yield at Rocky Mount Yield (lb/acre) Yield (bu/acre) Peanut 2006 Wheat 2008 Wheat 2010 Soybean 2008 Soybean 2010 Corn 2007 Corn 2009 Corn 2011 CT – CT – CT – CT – CT – PN – CR – WH/SB – CR– WH/SB-CR 3,770 a 40 b 59 ab 15 a 9 a 77 a 125 ab 114 a CT – CT – SB – CT – CT – PN – CR – WH/SB – CR– WH/SB-CR 3,090 b 39 b 65 ab 19 a 9 a 73 a 120 b 124 a CT – CT – PN – CT – CT – PN – CR – WH/SB – CR– WH/SB-CR 3,050 b 42 b 51 b 15 a 10 a 75 a 67 c 110 a CT – PN – CT – PN – CT – PN – CR – WH/SB – CR– WH/SB-CR 2,880 bc 51 ab 61 ab 15 a 10 a 76 a 90 bc 110 a PN – PN – PN – PN – PN – PN – CR – WH/SB – CR– WH/SB-CR 2,420 c 65 a 65 a 19 a 7 a 85 a 169 a 122 a Table 3-8. Influence of Rotation and Variety on Crop Yield at Whiteville Rotation (2001-2009) (CR – Corn, CT – Cotton, PN – Peanut, TB – Tobacco) Yield (lb/acre) Yield (bu/acre) Peanut 2006 Tobacco 2008 Corn 2007 Corn 2009 Variety Gregory Perry CR – CR – CR – CR – CR – PN – CR – TB – CR 3,310 a 3,540 a 3,340 a 141 a 101 a CR – CR – TB – CR – CR – PN – CR – TB – CR 3,670 a 3,940 a 3,450 a 154 a 92 a TB – CR – PN – TB – CR – PN – CR – TB – CR 2,000 b 2,970 a 3,380 a 139 a 92 a *Means within a column followed by the same letter are not significantly different according to Fisher’s Protected LSD Test at P < 0.05. *Means within a column followed by the same letter are not significantly different p < 0.05.22 Table 3-9. Peanut Yield Following Snap Beans, Sage, Sweet Potato, and Traditional Crop Rotations Disease (%) Yield (lb/acre) Previous Crops Bailey Phillips Bailey Phillips Cotton-Corn-Sweet Potato 1 11 4567 4337 Snap Bean-Wheat-Sage 0 8 3995 3725 Cotton-Corn-Cotton 0 11 4170 4267 Soybean-Corn-Cotton 0 6 4343 4303 Snap Bean-Corn-Cotton 0 8 4070 4270 Soybean-Wheat-Sage 0 7 4297 3964 Peanut-Corn-Cotton 0 9 4226 414023 Table 3-10. Plant Condition Rating (Percentage of Plants Expressing Symptoms of CBR), Root Knot Nematode Population in Soil, and Peanut Pod Yield During 2006 at Lewiston-Woodville. The CBR-resistant peanut variety NC 12C was planted during all years. Cropping system (2001-2006) (CR-Corn, CT-Cotton, SB-Soybean, PN-Peanut) Plant Condition (2006) (%) Nematode Population in Soil (2006) (Log No./500 cc soil) Peanut Yield (2006) (lb/acre) CR-PN (3 cycles) 4 a 7.6 a 4,180 c CT-PN (3 cycles) 3 a 1.9 bc 4,200 c CR-CR-PN (2 cycles) 6 a 2.6 bc 4,850 ab CT-CT-PN (2 cycles) 4 a 2.5 bc 4,730 bc SB-CR-PN (2 cycles) 10 a 4.5 ab 4,130 c SB-CT-PN (2 cycles) 5 a 0 c 4,330 bc CT-CR-PN (2 cycles) 4 a 1.2 bc 4,930 ab Continuous PN 2 a 7.1 a 3,040 d CR-CR-CR-CR-CR-PN 4 a 0.6 c 5,540 a Table 3-11. Cotton, Corn, Peanut, and Soybean Response the Year Following 4 Years of Tall Fescue Sod Versus Reduced Tillage Agronomic Crop Production (2009) and Corn Yield in 2010 Crops from 2005-2008 2009 2010 2011 Cotton (lb lint/A) Peanut (lb/A) Soybean (bu/A) Corn (bu/A) Corn (bu/A) Corn (bu/A) Tall fescue sod 920 4170 45 131 88 87 Combinations of corn and cotton 760* 4040 39 155* 68* 78* No. of trials 4 4 4 3 2 2 *Indicates significance of p < 0.05 *Means within a column followed by the same letter are not significantly different according to Fisher’s Protected LSD Test at p < 0.0524 peanut-based cropping systems can be found in Chapter 6, “Peanut Disease Management.” Research conducted at the Peanut Belt Research Station demonstrates the benefits of long rotations with corn (Table 3-6). Similar results are generally expected with cotton, and the value of rotation is also noted at Rocky Mount (Table 3-7). The value of planting the CBR-resistant variety Perry, compared to Gregory, is presented in Table 3-8. Disease reaction and peanut yield following several relatively unique crop rotations is presented in Table 3-9. The influence of rotation on parasitic nematode populations and yield can be found in Table 3-10. In recent years, there has been interest in crop yields, especially grains, when transitioning out of traditional peanut rotations. Results presented in Tables 3-6, 3-7, 3-8, and 3-9 indicate that corn, cotton, soybeans, and wheat are not affected by rotation to the extent that peanuts are affected. The value of sod-based rotations on yields of peanuts and other crops has been demonstrated in the southeastern United States. In North Carolina, a trial was recently completed where peanuts and other row crops were planted in either killed fescue sod or standard reduced-tillage cropping systems, including combinations of cotton and corn. Results for corn, cotton, peanuts, and soybeans from 2009 are presented in Table 3-11. During both 2010 and 2011, corn yield was higher after sod compared with combinations of traditional agronomic crops when planted several years after sod termination. FERTILIZING PEANUTS Lime Peanuts grow best on soils limed to a pH of 5.8 to 6.2, provided other essential elements are in balance and available to the plant. Yields of peanuts and other crops planted in soil with four differing pH regimens are provided in Table 3-12. Dolomitic limestone is the desired liming material because it provides both calcium and magnesium. Strongly acidic soils reduce the efficient uptake and use of most nutrients and may enhance the uptake of zinc to potentially toxic levels. The efficiency of nitrogen fixation is reduced in acid soils. Molybdenum is an essential element in biological nitrogen fixation, and it can be limiting at low soil pH. Soils too high in pH are not desirable because some elements are less available to the peanut plant and incidence of Sclerotinia blight may be greater. Manganese deficiency is often observed in fields that are overlimed. Some research has demonstrated that higher rates of calcium sulfate (gypsum or landplaster) 25 can reduce peanut yield when soil pH in the pegging zone is relatively low (Table 3-13 and 3-14). These results remind us that soil pH should be maintained around 6.0 and that gypsum should be applied at rates not exceeding those currently recommended for Virginia market type peanuts. Increased broiler production in North Carolina and use of manure as a fertilizer source has increased concern over micronutrient toxicity. Several peanut fields have exhibited severe and yield-limiting zinc toxicities. These toxicities are increased in fields with low pH because zinc is more available at a lower pH. Maintaining soil pH around 6.0 is important in minimizing the adverse effects of zinc, and growers are cautioned not to overload fields with high levels of waste products. Micronutrient levels can build up quickly. Peanuts generally are able to tolerate zinc indices of 250. However, zinc toxicity can occur with lower index values if soil pH is low. Table 3-12. Crop Response to Soil pH Soil pH Percent of Yield at Compared with pH 5.9 Corn Cotton Peanut Soybean Wheat Grain sorghum 4.3 37 31 55 41 41 68 4.9 77 57 62 66 73 86 5.4 85 88 82 90 91 96 5.9 100 100 100 100 100 100 Years 2 2 2 2 2 126 Table 3-13. Peanut Yield (lb/acre) Following Application of Three Rates of Gypsum Location Year Soil pH Relative Calcium Sulfate Rate 0 1.0× 1.5× Lewiston-Woodville 2001 6.0 4,000 a 3,780 a 3,670 a Rocky Mount 2001 5.5 4,170 a 3,970 ab 3,730 b Lewiston-Woodville 2002 6.1 3,420 a 3,570 a 3,390 a Rocky Mount 2002 6.2 4,320 a 4,320 a 4,300 a Lewiston-Woodville 2003 6.0 4,130 b 4,350 b 4,610 a Rocky Mount 2003 5.8 3,780 a 3,660 a 3,740 a Lewiston-Woodville 2004 5.6 3,820 a 3,760 a 3,350 b Rocky Mount 2004 6.3 3,150 a 3,110 a 3,270 a Lewiston-Woodville 2005 6.0 4,530 b 5,110 a 5,120 a Rocky Mount 2005 6.6 2,540 b 4,490 a 4,630 a *Means for cultivar or for relative calcium sulfate rate within each combination of year and location followed by the same letter are not significantly different according to Fisher’s Protected LSD Test at p < 0.05. Table 3-14. Peanut response to gypsum rate at three soil pH values Soil pH Relative Gypsum Rate 5.0 5.5 6.0 0 1920 2720 2900 0.5X 1930 2690 3320 1.0X 2110 2190 3250 Data are pooled over 3 years. Nitrogen Roots of peanuts can be infected by Bradyrhizobium bacteria. Nodules form on the roots at the infection sites. Within these nodules, the bacteria can convert atmospheric nitrogen into a nitrogen form that can be used by plants through a process called biological nitrogen fixation (BNF). This symbiotic relationship provides sufficient nitrogen for peanut production if the roots are properly nodulated. Growers should inoculate their peanut seed or fields to ensure that adequate levels of Rhizobia are present in each field. The data in Table 3-15 are from multiple locations and give an indication of the possible response of peanuts to inoculant applied as a liquid or granular in the seed furrow. Response of peanuts to rotation and inoculant treatment is provided in Table 3-16. These data demonstrate that while peanut response to rotation is often predictable (Tables 3-6, 3-7, 3-8, and 3-9), 27 response to inoculant and rotation combinations is less predictable. Therefore, peanuts should be inoculated in all years regardless of previous rotation history to minimize risk and maintain yield. Table 3-15. Peanut Yield Response in Fields without a History of Peanuts versus Fields with Frequent Plantings of Peanuts (1999 – 2011) Inoculant Use New Peanut Fields Fields with a Recent History of Peanuts No inoculant 3,052 3,713 Inoculant 4,473 3,892 Difference 1,320 179 Number of Trials 28 26 Years 1999 – 2011 1999 – 2011 Table 3-16. Peanut Response in 2006 to Inoculation Following Various Intervals of Peanut Planting in Previous Years Test Range of Years Not Planted in Peanuts Response to Rotation Response to Inoculation Test 1 0 – 5 Yes No Test 2 1 – 3 Yes Yes Test 3 0 – 5 Yes No Test 4 2 – 5 Yes Yes Commercial inoculants can be added to the seed or put into the furrow with the seed at planting. In-furrow inoculants are available in either granular or liquid form. When inoculants are applied directly in the seed furrow, either as a spray or granular, it is essential that the product reach the bottom of the seed furrow so that infection occurs as the root system develops. Some growers have had difficulty in obtaining nodulation because soil moved in the seed furrow after seed drop but before inoculant spray or granules entered the seed furrow. Additionally, shallow planting along with in-furrow spray inoculants have performed poorly under hot and dry soil conditions. Peanuts are capable of emerging from depths of at least 3 inches, therefore, it is advisable to plant deep to protect sprayed inoculant from breakdown caused by high temperatures.28 Direct applications of nitrogen to peanuts are not generally needed. However, application of nitrogen fertilizers can increase yield, but only when peanuts are not nodulating and nitrogen deficiency is obvious. Research indicates that a minimum of 120 pounds actual nitrogen per acre as a single application may be needed to obtain yields similar to adequately nodulating peanuts when a true nitrogen deficiency exists in some fields. Lower rates also may be effective but perform inconsistently (Table 3-17). Research also suggests that ammonium sulfate is a more effective source than ammonium nitrate. Split applications may be more efficient than a single application. Best results are obtained when applications are made early in the season. Peanuts grown on deep sandy soils often respond to nitrogen fertilization and may lap middles more quickly even when inoculation is adequate. Rapid canopy closure results in cooler soil temperatures in the pegging zone. When soils have high temperatures, pegs cannot survive. Table 3-17. Peanut Yield Response to Nitrogen Rate and Source when Applied in Early July when Nitrogen Deficiency Symptoms Are First Noted. Fields were not planted in peanuts during previous years. Nitrogen Source Actual N Rate (lb/acre) Peanut Pod Yield Pooled Over 6 Experiments (2007–2011) Actual Yield (lb/acre) % of Inoculated Peanut None 0 3,161 c 73 Inoculant 0 4,335 a 100 Ammonium sulfate 60 3,867 ab 89 Ammonium sulfate 90 4,163 ab 96 Ammonium sulfate 120 4,225 ab 98 Ammonium sulfate 150 4,261 a 98 Ammonium nitrate 60 3,889 ab 90 Ammonium nitrate 90 3,978 ab 92 Ammonium nitrate 120 3,741 b 86 Ammonium nitrate 150 3,870 ab 89 *Means followed by the same letter are not significantly different according to Fisher’s Protected LSD Test at p < 0.05.29 Potassium and Phosphorus The most efficient and easiest way to apply potassium is to apply it to the crop preceding peanuts. This usually increases the yield of the preceding crop and allows the potassium to leach into the area where the peanut root system obtains most of its nutrients. However, if North Carolina Department of Agriculture and Consumer Services (NCDA & CS) soil test recommendations indicate that potassium and phosphorus are needed, then the appropriate levels of these nutrients should be applied. Many growers and researchers feel that high levels of soil potassium in the fruiting zone (the upper 2 or 3 inches of soil) result in more pod rot and interfere with the uptake of calcium by pegs and pods, which results in a higher percentage of “pops” and calcium deficiency in the seeds. If the potassium level is high in the fruiting zone, a higher rate of gypsum may be needed. Most of the peanut soils in North Carolina have adequate levels of phosphorus for good peanut production. Once a medium or higher level of phosphorus is achieved, it remains quite stable over a number of years. The addition of phosphorus-containing fertilizer to peanuts is generally not needed if it is applied to other crops in the rotation. However, soil testing is the only way to be sure. Calcium Perhaps the most critical element in the production of large-seeded Virginia market type peanuts is calcium. Lack of calcium uptake by peanuts results in “pops” and darkened plumules in the seed. Seeds with dark plumules usually fail to germinate. Calcium must be available for both vegetative growth and pod growth. Calcium moves upward in the peanut plant but does not move downward. Thus, calcium does not move through the peg to the pod and developing kernel. The peg and developing pod absorb calcium directly from soil, so it must be readily available in the soil. Adequate soil calcium is usually available for good plant growth but not for pod development or good quality peanuts. It is important to provide calcium in the fruiting zone through gypsum applications. Gypsum should be applied to all Virginia market types, regardless of the soil characteristics or soil nutrient levels. The calcium supplied through gypsum application is relatively water soluble (compared to other calcium sources) and more readily available for uptake by peanut pegs and pods. Each pod must absorb adequate calcium to develop normally.30 Gypsum is available in three forms—finely ground, granular, and phosphogypsum. Several additional by-product gypsums are now on the market. The by-product materials vary in elemental calcium content. Studies show that all forms of gypsum effectively supply needed calcium when used at rates that provide equivalent calcium levels uniformly in the fruiting zone. General recommendations for application rates are given in Table 3-18. The use of gypsum on large-seeded peanuts is very effective in improving peanut seed quality and grades. Some research data indicate that high rates of gypsum may control or reduce the pod rot disease complex. Gypsum should not be broadcast before land preparation or before planting because too much rain may leach the calcium below the fruiting zone. Best results are obtained when gypsum is applied in late June or early July. The availability of calcium supplied by gypsum application is also influenced by the amount of rainfall. Moisture is needed to make gypsum soluble and calcium available to the peanut fruit. In unusually dry years, peanuts may show symptoms of calcium deficiency, even when recommended rates of gypsum are applied. Increasingly, there are questions concerning the need to apply gypsum as supplemental calcium to peanuts. Sometimes peanuts do not respond to supplemental calcium. Sometimes peanuts respond well to half the amount given in Table 3-18. The interactions of environmental conditions, seed size, soil series, native fertility, and soil moisture are unpredictable. However, for a consistent response over a wide range of soil characteristics and weather conditions, the full rate of gypsum is recommended for Virginia market types. Growers are encouraged to evaluate peanut response to gypsum on their own farms before leaving off this input or reducing rates below those presented in Table 3-18. Data from several trials (Table 3-19) indicate that gypsum at rates below those recommended in Table 3-18 can, in some cases, be effective. For more information on techniques that can be used to compare treatments on the farm, see AG-615, Knowing Your Field: A Guide to On-Farm Testing for Peanut Growers. There is also a question of whether or not the gypsum rate needs to be increased for extremely large-seeded Virginia market type varieties, such as Gregory. Results from 2001–2005 at two locations during each year indicated that a rate of 1.5 times the recommended rate did not increase pod yield over the normal use rate in most experiments (Table 3-14). While the data did indicate that the large-seeded variety Gregory was more responsive to gypsum than the much smaller-seeded variety NC-V 11, there was no advantage to applying gypsum at rates exceeding those rates listed in Table 3-18. 31 Table 3-18. Gypsum Sources and Application Rates Source % CaSO4* Application Rate (lb/acre) Band (16-18 in) Broadcast USG Ben Franklin 85 600 - USG 420 Granular 83 - 1,215 USG 500 70 - 1,300 Super Gyp 85 85 - 1,200 TG Phosphogypsum 50 - 2,000 Agri Gypsum 60 - 1,800 Gyp Soil 85 - 1,200 Buckshot ** - 2,000 * Guaranteed analysis percentage in registration with N.C. Department of Agriculture and Consumer Services. **Buckshot is considered a lime by-product material and not a gypsum product. Table 3-19. Actual Pod Yield Following Application of Gypsum at 0.5 and 1 Times (X) the Recommended Use Rate for Virginia Market Types. No. of Trials Pod Yield (pounds/acre) No Gypsum 0.5X Gypsum 1.0X Gypsum Actual Yield 12 3970 4510 4590 Increase Over the No-Gypsum Control - - 540 620 Increase Over the 0.5X Rate of Gypsum - - - 80 In recent years, runner market type varieties referred to as “jumbo runners” have become more popular. These varieties, such as Florida 07, will require supplemental calcium compared to the smaller-seeded runners like Georgia Green. Growers should apply at least half the rate recommended for Virginia market types (Table 3-18). Small-seeded runner and Spanish varieties do not require as much calcium for optimum seed development as do the large-seeded Virginia market types. Recommendations vary in areas where runner peanuts are grown. Some states recommend calcium application regardless of seed size, while other states use the following relationships to determine if supplemental calcium is needed. If 32 the calcium level in parts per million (ppm) exceeds 250 and the ratio of calcium to potassium is at least 3 to 1, additional calcium is not recommended. If growing runners for seed, apply gypsum to ensure proper kernel development and seedling vigor. To determine if supplemental calcium is needed for runner market types, use the following procedure: Step 1. Take soil samples to a depth of 3 inches in the pegging zone in fields where runner market types are planted when flowering begins, generally in late June, keeping in mind that it could take several days to process soil samples. Step 2. Determine the concentration of calcium in the soil in ppm using the following formula: Calcium (% of total CEC) x CEC x 200 Step 3. Determine the ratio of calcium to potassium using the following formula: %Potassium (%K) = %Base saturation (%BS) – %Calcium (%Ca) – %Magnesium (%Mg) Step 4. Determine the ratio of calcium to potassium using the following formula: %Ca divided by %K Example: Step 1. The following data were recorded from a soil sample taken at a depth of 3 inches in the pegging zone at initial flowering in a field where a runner market type was planted. %BS = 74, %Ca = 60, %Mg = 11, CEC = 5.6 Step 2. ppm = %CEC of calcium x CEC x 200 ppm: 0.60 × 5.6 × 200 = 672 Step 3. %K = %BS - %Ca - %Mg %K = 74 – 60 – 11 = 3 Step 4. %Ca divided by %K 60 divided by 3 = 20 Recommendation: Do not apply gypsum because the Ca concentration exceeds 250 ppm (672 in this example) and the ratio of Ca to K exceeds 3 (20 in this example). Manganese and Boron Two other elements often found to be deficient in peanuts are manganese and boron. Manganese deficiency usually occurs when soil is overlimed. Increasing the soil pH reduces the plant’s uptake of manganese. The symptom of manganese deficiency is interveinal chlorosis. This symptom can be confused with carryover of atrazine (from corn) or Cotoran/Meturon (from cotton). A deficiency can be corrected by a foliar application of manganese sulfate. The usual practice is to apply 3.5 to 4 pounds per acre of dry material when the deficiency is observed. Boron plays an important role in kernel quality and flavor. Boron deficiency may occur in peanuts produced on deep, sandy soils. Deficient kernels are referred to as having hollow hearts. The inner 33 surfaces of the cotyledons are depressed and darkened, so they are graded as damaged kernels. A general recommendation is to apply 0.5 pound of actual boron per acre as a foliar spray in early July. Several formulations of boron are available. Some growers apply boron with their preplant incorporated herbicides, and others have boron added to their fertilizers. Growers are advised to make sure boron and manganese sources provide sufficient elemental boron. Several liquid boron and manganese formulations are available. Although liquid sources are more convenient to use than some dry products, some of the liquid products contain only a fraction of the needed boron or manganese. The amount of formulated product needed to supply 0.5 lb elemental boron per acre is provided in Table 3-20. Similarly, the amount of formulated manganese product needed to supply 1.0 lb manganese per acre is provided in Table 3-21. Lower rates of boron or manganese are often applied for “maintenance.” However, if a significant deficiency exists, 0.5 pound of actual boron per acre or 1 pound of actual manganese if manganese is needed, and growers need to apply a formulation that delivers this amount economically. Table 3-20. Amount of Formulated Product Needed to Provide Equivalent Amounts of Elemental Boron per Acre Source Amount Needed to Supply 0.5 lb Boron per Acre Boric acid 3.0 lb Disodium octaborate (Solubor, 17.5% boron) 2.8 lb Liquid (9.0% boron) 2.2 qt Table 3-21. Amount of Formulated Manganese Products Needed to Provide Equivalent Amounts of Elemental Manganese per Acre Source Amount Needed to Supply 1.0 lb Manganese per Acre Manganese sulfate (Techmangum, 27% manganese) 3.7 lb Manganese sulfate (8% manganese) 1.2 gal The percentage of element (in this case, manganese or boron) or the weight of the element per unit volume of product can be used to determine the amount of liquid product needed to correct a nutrient deficiency. For example, if 1 pound of manganese is needed per acre, the following formulas can be used to determine the amount of 8% water-soluble manganese product needed per acre.34 Step 1. Figure the weight of manganese per gallon by multiplying the percent of manganese in product in pounds by the weight of product in pounds per gallon: % manganese in product × lb product per gal = lb manganese per gal Step 2. Figure the gallons of manganese product per acre by dividing the desired amount of manganese in pounds per acre by the weight of the manganese per gallon: desired lb manganese per acre = gal manganese product per acre lb manganese per gal Example: Step 1. 0.08 × 10.5 lb manganese sulfate per gal = 0.84 lb manganese sulfate per gal Step 2. 1 lb manganese/acre desired = 1.2 gal 8% manganese product per acre 0.84 lb manganese per gal LAND PREPARATION Historically, peanut growers have used the moldboard plow equipped with trash covers to prepare a smooth, uniform, and residue-free seedbed for planting. The burial of old crop residue and weed seed has been effective in the long-term suppression of soilborne diseases and short-term suppression of some weed problems. However, there is a growing trend toward reduced-tillage crop production in North Carolina, and some growers are successfully using these practices. There has also been a significant decrease in the number of growers using moldboard plowing. Changes in tillage systems over the past decade are presented in Table 3-22. Table 3-22. Percentage of Farmers Using Certain Tillage Practices on at Least a Portion of Their Farms Tillage 1998 2004 2009 Disk 90 78 71 Chisel 25 23 27 Moldboard plow 58 17 7 Field cultivate 75 55 42 Rip and Bed 49 39 40 Bed 44 35 32 Reduced tillage 10 23 41 There is concern about stratification of nutrients in reduced-tillage systems. For example, repeated applications of potassium in reduced-35 tillage cotton may result in excessive amounts of this nutrient in the pegging zone when peanuts are planted in a reduced-tillage system. Growers are encouraged to test soils for excessive potassium levels and incorporate this nutrient with tillage, if needed. Many peanut growers bed their peanut fields either in the fall or spring. Many growers prefer planting on raised beds rather than flat planting. The beds often give faster germination and early growth, provide drainage, and may reduce pod losses during digging. While reduced-tillage systems can be as successful as conventional-tillage systems, reduced-tillage systems often have less consistent yields than in conventional-tillage systems. However, most peanut production has shifted to sandy soils that respond more favorably to reduced-tillage systems. A summary of peanut response to tillage is presented in Table 3-23. Because of concern about digging losses on finer-textured soils, it is recommended that beds be established in the fall with a grass cover crop with peanuts strip-tilled into previously prepared beds. Research during 2005 and 2006 demonstrates that wheat, cereal (cover crop), rye, oats, and triticale can serve equally well as cover crops grown the winter and spring prior to planting peanuts. A risk advisory index has been developed to assist growers in deciding the risk of peanut yield in reduced-tillage systems being lower than yield in conventional-tillage systems (Table 3-24). Additional information can be obtained from Soil Facts: Conservation Tillage use in Peanut Production, AG-439-73W. Research also suggests that prior cropping history generally does not affect peanut response to tillage. However, peanuts are often more responsive to tillage system, primarily because of the digging requirement. The risk advisory index has been modified from the initial version. Table 3-23. Peanut Yield Response to Tillage Practices in North Carolina from 1999-2011. A positive value indicates that yield was higher in conventional tillage compared with reduced tillage. Number of Trials Years Actual Yield Difference (lb/acre) Yield Difference (%) Range of Yield Difference (%) 61 1997-2011 +106 +2.9 -16.1 to +27.536 Table 3-24. Advisory Index for Determining the Risk of Peanut Yield in Reduced-Tillage Systems Being Lower Than Yield in Conventional-Tillage Systems Soil series Roanoke and Craven…40 Goldsboro and Lynchburg…20 Norfolk…10 Conetoe and Wanda…0 Pod loss on finer-textured soils, such as those on the Roanoke and Craven series, is often greater than on coarser-textured soils, such as Conetoe and Wanda series, regardless of tillage system. Difficulty in digging can increase when these soils become hard in the fall if rainfall is limited. Soil series Your score: ________ Tillage intensity No tillage into flat ground…40 points Strip tillage into flat ground…10 points Strip tillage into stale seedbeds…0 points Peanut response to reduced tillage systems is invariable correlated with the degree of tillage. Efficient digging can be difficult when peanuts are planted in flat ground in reduced tillage systems. While fields may appear to be flat and uniformly level, often fields are more rugged than they appear, and setting up the digger to match unforeseen contours in the field can be difficult. Strip tillage into flat ground is a better alternative than no tillage into flat ground, although digging peanuts planted on flat ground can be more challenging regardless of the tillage system. Strip tillage into preformed beds often results in yields approaching those of conventional tillage. Tillage intensity Your score: _______ Risk of yield being lower in reduced tillage than in conventional tillage: 40 or Less—Low Risk 40 to 50—Moderate Risk 60 or More—High Risk Total Index Value Your score: _______ PLANTING Varieties grown in North Carolina generally require 142 to 160 days to reach full maturity depending upon soil moisture and temperature. Early plantings usually give higher yield, more mature pods, and permit earlier harvesting. However, planting date can affect disease and insect development (see Chapters 5 and 6). Less damage from thrips and lower incidence of tomato spotted wilt virus have been associated with later plantings. Peanut yields are often the highest when peanuts are planted in early to mid-May. However, in some years peanuts planted later can yield quite well. Conditions in the fall, especially night temperatures, can have a great impact on yield when they prevent peanut pods from reaching optimum maturity. Response of the 37 early maturing cultivar CHAMPS and the later maturing cultivar Perry planted on three dates and dug at four times were compared in trials during 2009-2011 (Table 3-25). With higher peanut prices anticipated in spring 2012, some growers are considering planting peanut after wheat. This approach can be risky. In one study over three years, lower yield was noted when comparing June 8 plantings to May 5 or May 22 (Table 3-25). If contract prices approach $850/ton, the lower yield due to delayed planting would translate into an economic loss of $363/acre compared with earlier plantings. Lower yield from later plantings is most likely associated with insufficient heat unit accumulation. Also, growers may experience difficulty harvesting due to wet conditions and freeze damage. A cool period in late September limiting further pod maturation could also adversely affect yield and quality. Freeze damage is catastrophic, especially at projected high prices for peanuts. Results also demonstrate that planting the early maturating variety CHAMPS compared with Perry does not compensate for late planting. Based on results from these trials, double cropping wheat and peanut is discouraged. Growers may have to plant in early June because of adverse weather conditions in May or because of other unforeseen circumstances, but planning to plant in June after wheat poses considerable risk. Cost of production for peanut approaches 5 times that of soybean making soybean the more appropriate double crop legume. Table 3-25. Peanut yield response based on planting date, digging date when planted in early June, and variety selection when planted in early June Treatment Factor Yield (lb/acre) Planting date (pooled over 2 varieties, 4 digging dates, and 3 years) May 5 3869 May 22 3836 June 8 2992 ($363/acre less at $0.43/lb compared with the May 22 planting date) Digging date influence when planted June 8 (pooled over 2 varieties, 4 planting dates, and 3 years) September 8 1826 September 20 2748 October 7 3745 October 20 3649 (continued)38 Table 3-25. Peanut yield response based on planting date, digging date when planted in early June, and variety selection when planted in early June (continued) Comparison of Perry (latest maturing variety) with CHAMPS (earliest maturing variety) when planted June 8 (pooled over 4 digging dates and 3 years) CHAMPS planted May 5 3764 Perry planted May 5 3973 CHAMPS planted May 22 3773 Perry planted May 22 3898 CHAMPS planted June 8 3079 Perry planted June 8 2905 Seeding Rates and Twin Rows Table 3-26 provides the conversion of seed per foot of row to pounds per acre in order to establish the desired plant population for a given variety. Germination percentage is not considered in this conversion, but it should be considered when planning planting. In the Southeast, less tomato spotted wilt virus has been associated with twin row plantings than single rows. Similar results have been observed in North Carolina. Higher plant populations and closer row spacings often result in less virus. Seeding peanuts in narrow rows or at extremely high seeding rates has not increased yield over twin row plantings that establish a plant population of 5 plants per foot of row (sum of both twin rows). Although higher seeding rates are needed and higher rates of in-furrow insecticide and inoculant are required, twin rows tend to produce a greater taproot crop rather than a limb crop. This can improve uniformity of harvested peanuts, and in a dry season when peanut vines do not lap, can result in higher yields. One of the detriments of twin row plantings, especially with the higher plant populations, is excessive vine growth, which can make digging more difficult. Table 3-26. Approximate Pounds of Peanut Seed Required per Acre to Provide 3, 4, and 5 Seeds per Foot of Row on 36-inch Rows Variety Seed/lb Pounds Per Acre (36-Inch Rows) 3 Seeds/ft 4 Seeds/ft 5 Seeds/ft Bailey 600 72 95 120 Brantley 500 87 116 145 CHAMPS 535 76 102 127 Gregory 450 97 129 161 (continued)39 Table 3-26. Approximate Pounds of Peanut Seed Required per Acre to Provide 3, 4, and 5 Seeds per Foot of Row on 36-inch Rows (continued) NC-V 11 625 70 93 116 Perry 525 83 111 138 Phillips 545 78 105 135 Sugg 575 76 101 126 VA 98R 575 76 101 126 Florida Fancy 525 83 111 138 Georgia 08V 550 79 107 136 Florida 07* 650 64 87 110 Georgia Green* 850 52 68 85 *Denotes runner market types. All other varieties are Virginia market types. IRRIGATION Having adequate water available throughout the peanut life cycle is important for optimal plant growth and development. Drought or flood can have tremendously negative impacts on peanut yields and quality. Likewise, pest infestation and severity of damage from these pests is influenced by available water, either in the form of rainfall or irrigation. Understanding how environmental conditions, and in particular irrigation, affect pest complexes is important in developing appropriate management strategies. Although less than 20 percent of North Carolina peanut acreage is irrigated, irrigation is a powerful production tool. Irrigation minimizes risk and enhances consistency of yield. Additionally, irrigation improves consistency of pesticide performance and in many ways the predictability of pest complexes. The major production and pest management practices employed in North Carolina peanut production are listed in Table 3-27, with brief comments on how irrigation or ample rainfall affect efforts to manage pests or supply peanuts with adequate nutrition. Research supported by the North Carolina Peanut Growers Association has been conducted to determine the feasibility of subsurface drip irrigation. While there are many logistical issues associated with this approach, data collected at Lewiston-Woodville in corn, cotton, and peanut are presented in Table 3-28. The amount of water delivered through this irrigation system and rainfall during that period of time are also presented. These data give a good indication of yield under growing conditions where water is not limiting relative to dryland production for these crops.40 Production or Pest Management Practice Benefits of Irrigation or Optimum Rainfall Land Preparation Helps in establishment of seedbeds, either conventional or reduced tillage. Seed Germination Ensures germination of seed when existing soil moisture is marginal for complete stand establishment. Weed Management Irrigation or adequate rainfall activates preemergence herbicides and minimizes plant stress. Less moisture stress often enhances control by postemergence herbicides and enables peanut to recover more rapidly from herbicide damage. Insect Management Important for activation of in-furrow insecticides. Improves plant growth and root establishment, which is important in absorption of in-furrow insecticides. Improves peanut recovery from early-season insect damage and insecticide phytotoxicity. Increases the likelihood of southern corn rootworm survival and subsequent damage to pods, but can protect against damage from lesser cornstalk borer. Minimizes potential damage from corn earworms and armyworms by establishment of a dense canopy that can withstand damage from feeding. Reduces the likelihood of spider mite damage by keeping spider mite populations low. Disease Management Wet conditions early in the season can favor infection of peanut by CBR, but can minimize potential for crown rot. Irrigation increases likelihood of having a favorable microclimate for development of foliar and soilborne disease. A dense canopy that is supplemented by irrigation increases humidity within the canopy and minimizes airflow, all of which favor pathogen and disease development. Symptoms associated with tomato spotted wilt of peanut are often more pronounced when peanut are growing under dry and especially hot conditions. Timely irrigation will reduce plant stress and possibly enable plants to withstand tomato spotted wilt more effectively than non-irrigated, water-stressed plants. Pod Maturation Irrigation buffers against extremes in moisture and reduces stress (heat and drought), which allows normal flower production and kernel development. Maturation is more predictable and generally earlier. Limited rainfall during reproductive growth often causes delays in maturation and establishment of “multiple crops” or “split crops” on the same plant. Sufficient rainfall is critical for complete kernel development and pod fill. Limited soil moisture during flowering can reduce pegging. Irrigation modeling programs often include soil temperature as a trigger for irrigation during pegging. Supplemental Calcium Kernels need adequate calcium to become mature and completely developed. Irrigation buffers against drought, which reduces calcium concentration in soil water and mass flow movement into developing pegs. Digging Ability to supply soil water to improve digging conditions (reduces hardness of soil), improves digging efficiency and minimizes pod loss during the digging process. Table 3-27. Impact of Irrigation on Production and Pest Management Strategies41 Table 3-28. Corn, Cotton, and Peanut Response to Subsurface Drip Irrigation from 2001–2011 at Lewiston-Woodville Crop Year Water Delivered (June through August for corn or June through September for other crops) in Inches Crop Yield (peanut in lb/A, cotton in lb lint/A, corn in bu/A) Percent increase in yield due to irrigation Rainfall Rainfall plus Subsurface Drip Nonirrigated Irrigated % Peanut 2001 8.6 13.8 2,350 3,400 * 31 Peanut 2002 13.0 18.5 2,024 2,956 * 32 Peanut 2003 19.6 24.8 3,017 3,210 6 Peanut 2004 20.0 25.0 2,660 2,830 6 Peanut1 2010 9.3 21.9 2,537 3,875* 34 Peanut1 2011 19.9 39.1 3,436 4,016* 14 Cotton 2001 8.6 13.8 804 1,018 * 21 Cotton 2002 13.0 18.5 460 902 * 49 Cotton 2003 18.9 24.4 840 850 1 Cotton 2004 24.9 31.8 920 1,010 9 Cotton 2005 12.2 18.3 850 1,300 * 35 Cotton 2006 19.5 27.8 810 860 6 Cotton 2007 11.5 21.3 465 1,016 * 54 Cotton 2008 13.8 25.2 386 835 * 54 Cotton1 2011 19.9 39.1 480 802 * 40 Corn 2008 11.3 21.9 96 146 * 34 Corn 2009 12.9 27.6 62 148 * 58 Corn 2010 3.6 16.8 64 155 * 59 Corn 2011 13.6 30.7 64 101* 37 1 Does not include excessive rainfall during the last few days of September (13.3 inches) during 2010 and only includes a value of 3 inches from Hurricane Irene in August 2011 (9.0 inches total) due to estimates of runoff. *Significance of p < 0.05.42 DETERMINING MATURITY Maturity affects flavor, grade, milling quality, and shelf life. Not only do mature peanuts have the quality characteristics that consumers desire; they are worth more to the producer. However, the indeterminate fruiting pattern of peanuts makes it difficult to determine when optimum maturity occurs. The fruiting pattern can vary considerably from year to year, mostly because of the weather. Therefore, each field should be checked before digging begins. The hull-scrape method, currently the most objective method, requires the use of a peanut profile board that is available at county Extension centers. The peanut profile board in Figure 3-1 was developed for runner market types grown in the southeastern United States. A version of the peanut profile board was developed for Virginia market types grown in the V-C Region (Figure 3-2). It is important to follow a specific maturity prediction method to achieve maximum dollar value for peanuts. The current chart for Virginia market type varieties is being modified to include additional information on newer varieties and adjustments of prediction curves. Heat units or growing degree days (DD) can be a means of determining maturity. One growing degree day (base 56oF) accumulates when the average daily high and low temperature is 57oF. If the average daily high and low temperatures were 76oF, then 20 growing degree days accumulate for that day. Research has shown that 2,520 to 2,770 growing degree days are needed for Virginia market types to mature if soil moisture is not limiting. Variation in heat unit accumulation for 2009-2011 is presented in Table 3-29. Pod maturation generally ceases in the fall when night temperatures are in the mid- to high 40s for two nights in a row. Even though day temperatures may increase considerably, the plant seldom recovers from these cooler night temperatures. In 2011 at Lewiston-Woodville, low temperatures ranged from 44 to 47 oF from October 1-4 and essentially eliminated any further maturation of pods. 43 Table 3-29. Average Heat Unit Accumulation per Day (DD56) from May 1 through November 1 at Lewiston-Woodville for various categories Dates Average for the Interval Described 2009 2010 2011 May 16 to June 15 17.8 19.1 20.7 June 16 to July 15 20.1 24.5 25.2 July 16 to August 15 22.9 26.3 28.0 August 16 to September 15 18.5 20.9 21.3 September 16 to October 15 11.9 14.4 11.1 October 16 to November 1 7.1 9.3 1.3 Table 3-30. Yield (lb/acre) of the Variety Gregory Planted May 5, 2003, or May 10, 2004, at Lewiston-Woodville 2003 2004 Digging Date Yield Digging Date Yield September 14 3,150 September 13 2,910 September 23 3,110 September 17 4,920 September 30 4,210 September 24 3,890 October 6 4,950 October 1 3,530 October 13 4,440 October 8 1,860 October 20 3,360 October 15 1,290 Pod yields in 2003 and 2004 demonstrate that heat units play a major role in determining optimum maturity (Table 3-30). Optimum yield across the six digging dates occurred when approximately 2,650 DD were accumulated. This number of heat units occurred 20 days earlier in 2004 compared with 2003, and highest pod yield also occurred 15 days earlier in 2004 compared with 2003. Adequate rainfall during both years allowed plant and pod development to continue at a predictable rate, but heat unit accumulation will be a poor indicator of peanut maturity at some locations and in some years, especially when rainfall is limited or stress during the season causes delays in growth and development. Based on results from studies evaluating the influence of digging dates on six varieties grown at several locations in North Carolina, growers can lose between 4 and 19 pounds pod yield per acre per day by digging too soon (data not shown). A typical response of peanut to digging date can be seen for the variety Gregory (Table 3-31). 44 Figure 3-1 The traditional profile board shown below was developed for runner market type production in the Southeastern United States Figure 3-2. The peanut profile board shown below was developed for Virginia market types.45 Although market grade characteristics often remain high when peanuts are dug later in the fall, yield is often lower due to pod shed. A balance between digging too soon and digging before frost or inclement weather needs to be reached to maximize yield and quality. At harvest, growers should follow the weather forecast closely and not dig peanuts when freezing temperatures are expected. It is also important to have adequate harvesting and curing equipment so that the peanut crop can be handled within a reasonable period of time. At least 3 days, and in many cases more than 3 days, are needed between the time of digging and frost to allow sufficient drying to prevent freeze damage. Digging and harvest capacity for growers is important to consider. The speed at which growers can plant peanuts is not the same as the time it takes to dig, combine, dry, and haul peanuts. Most crops require a one-step process to harvest, while peanuts require two stages. Soil conditions during digging must be ideal to effectively remove peanuts from the soil and invert vines. Growers need to realistically determine the amount of time these operations will require. With respect to digging, it is estimated that with four-row equipment and six-row equipment, 30 and 40 acres can be dug per day if growers dig for 10 hours a day driving at 3 mph. A six-row self-propelled combine can harvest 20 acres in a day driving at 1.5 mph, while four- and six-row pull-type combines can haravest 15 to 20 acres in a day, respectively. Table 3-31. Average from 13 Trials for Heat Unit Accumulation, Days from Emergence, Yield, and Grade of the Variety Gregory Planted from 2003 – 2010 at Lewiston-Woodville Days after Emergence Heat Unit Accumulation Yield (lb/acre) Yield (% of max) Extra Large (%) Total Sound Mature (%) 122 2559 3800 85 49 53 129 2674 4414 99 53 57 140 2826 4466 100 56 62 146 2886 4285 96 58 64 154 2944 3564 80 60 64 Demand for runner market type peanuts had declined in North Carolina, but new farm legislation and the federal peanut program has rekindled interest in production of runner market types in the Virginia-Carolina region. Part of this interest relates to market demand, while an appealing aspect of growing runners is potential 46 savings in productions costs relative to Virginia market type peanuts (approximately 80 to 100 pounds of seed for runners versus 115 to 160 pounds of seed for Virginia market types and lower requirements for supplemental calcium by runner market types). Yield of runner market types were compared at two locations during 2010 (Lewiston and Whiteville). The highest yield of the two digging dates is included in Table 3-32. These varieties performed as well as the Virginia types. Table 3-32. Yield of Runner Market Types at Lewiston-Woodville and Whiteville in 2010. Yield (lb/acre) reflects the highest yield of two digging dates for each variety. Variety Lewiston-Woodville Whiteville Georgia Green 4.815 3,769 Georgia 06G 4,712 4,065 Georgia Greener 4,740 4,561 Georgia 07W 4,954 4,799 Georgia 09B 5,418 4,005 Tifguard 5,359 4,374 Florida 07 5,199 4,374 AP-4 5,396 4,725 CULTURAL PRACTICES AND TOMATO SPOTTED WILT VIRUS Tomato spotted wilt virus can be a problem in North Carolina with no control practices available after peanuts have been planted. Planting peanuts in reduced tillage systems (no till or strip till), seeding peanuts at higher rates (establishing 4 or more plants per row foot in single rows), planting twin rows, applying Thimet or Phorate in furrow, delaying planting until late May, planting tolerant varieties, and maintaining good soil fertility can lessen the impact of tomato spotted wilt on peanut growth and yield. However, each of these cultural practices presents a range of risks and benefits. A tomato spotted wilt virus advisory, AG-638, Managing Tomato Spotted Wilt Virus in Peanuts in North Carolina and Virginia, was initially prepared in 2003 with an updated version of the advisory provided in Chapter 5. PLANT GROWTH REGULATORS Apogee (prohexadione calcium) is registered for use in peanuts. Research has demonstrated that Apogee improves row definition, which can lead to increased efficiency in the digging and inversion process. Apogee should be applied when 50 percent of vines from adjacent rows are touching. Sequential applications (7.2 ounces per acre fol47 lowed by 7.2 ounces per acre) spaced two to three weeks apart are generally needed. Include crop oil concentrate and nitrogen solution (UAN) with Apogee. Depending upon growing conditions, soil fertility, frequency of rainfall and irrigation, and variety selection, row visibility obtained in mid-August may not be sufficient through digging. Research suggests that in addition to increased row visibility, Apogee minimizes pod shed and pod loss during digging and harvesting operations. Work conducted in cooperation with Dr. Gary Roberson in 2009-2011 compared benefits of Apogee with precision digging, and results are presented in Table 3-33. A more comprehensive data set for performance of Apogee is provided in Table 3-34. Some environmental conditions and subsequent vine growth were not excessive in some of the trials in this data set suggesting that the yield difference may be underestimated. Investment in guidance systems for digging can be expensive. However, these systems have been very effective in minimizing challenges in digging, especically when vine growth is excessive and/or tractor operators are fatigued. Apogee can improve row visibility but may not minimize operator fatigue. Guidance systems will not affect pod retention in a manner similar to Apogee. Table 3-33. Peanut Yield (lb/acre) as Influenced by Application of Apogee and Precision Digging Location and Year Steering Apogee Applications Manual Auto-steer None Two Lewiston-Woodville, 2009 4,818 5,181 5,104 5,392 Lewiston-Woodville, 2010 2,818 2,644 2,694 2,768 Rocky Mount, 2010 2,628 3,111 2,881 2,816 Rocky Mount, 2011 4,125 4,710 4,555 4,370 Average 3,619 3,912 3,809 3,836 Table 3-34. Peanut Yield (lb/acre) Following Application of Plant Growth Regulators and Fertilizers Item Parameter No. of Trials 103 No. of Varieties or Lines 12 Years 1997–2011 Not Treated 4,065 Treated 4,169 Difference 10448 4. WEED MANAGEMENT IN PEANUTS David L. Jordan Extension Specialist— Crop Science Effective weed management is essential for profitable peanut production. Peanuts are not very competitive with weeds and thus require higher levels of weed control than most other agronomic crops to avoid yield losses. Weeds may also decrease digging efficiency, so effective late-season weed control can minimize losses during harvest. A weed management program in peanuts consists of good weed control in rotational crops; cultivation, if needed; establishment of a satisfactory stand and growing a competitive crop; and proper selection and use of herbicides. CROP ROTATION Rotate peanuts with corn or cotton to help manage various pests, including weeds. Crop rotation allows use of different herbicides on the same field in different years. Crop and herbicide rotation, along with good weed control in the rotational crops, helps prevent the buildup of problem weeds and helps keep the overall weed population at lower levels. Crop rotation will also help reduce the chance of developing populations of weeds that are resistant to herbicides. CULTIVATION Cultivation is an excellent way to supplement chemical weed control. One or two “non-dirting” cultivations often improve weed control. Additionally, cultivation in combination with banded herbicide applications can reduce costs. However, cultivation can damage the crop and reduce yield if not done properly. Movement of soil onto the lower branches and around the base of the plants causes physical damage and enhances development of stem and pod diseases. Deep cultivation also destroys residual herbicide barriers and brings up additional weed seeds. Cultivate when peanuts are small. Set sweeps to run flat and shallow to avoid throwing soil onto the peanut plants. WEED SCOUTING All fields, regardless of the crop being grown, should be surveyed for weeds between mid-August and the first killing frost. Record the weed 49 species present, and note the general level of infestation of each species (light, moderate, or heavy). Weeds present in the fall will be the ones most likely to be problems the following year. Knowing what problems to expect allows you to better plan a weed management program for the following crop. Scout peanut fields weekly from planting through mid-July to determine if or when postemergence herbicide treatment is needed. Proper weed identification is necessary because species respond differently to various herbicides. Contact your county Extension center for aid in weed identification. Timely application of postemergence herbicides is critical for effective control. Cultivation may be more appropriate if herbicide-resistant biotypes increase in prevalence. WebHADSS (Herbicide Application Decision Support System), a computer-based program designed to assist in making decisions pertaining to postemergence herbicide applications, is available online through North Carolina Cooperative Extension (http://www.webhadss.ncsu.edu/). Weed density, predicted crop value, predicted weed-free crop yield, herbicide and application costs, and herbicide efficacy are used to develop a ranking of the economics of herbicide options for a specific weed complex. This approach does not consider the long-term effect of weed seed production if weeds are not controlled. The patchiness of weeds in each field and the time needed to scout fields are limitations to this approach. However, this decision support system is beneficial in explaining herbicide options. Listed below is the competitive index value assigned to weeds typically found in North Carolina peanut fields (Table 4-1). Cocklebur, with a ranking of 10, is considered the most competitive weed in peanut. Table 4-1. Competitive Indices for Weeds in Peanut* Weed Rank Weed Rank Common cocklebur 10.0 Fall panicum 1.8 Jimsonweed 5.8 Florida pusley 1.5 Common lambsquarters 5.2 Tropic croton 1.2 Smartweed 4.7 Dayflower 1.2 Redroot pigweed 4.0 Common purslane 1.2 Common ragweed 3.8 Prickly sida 1.2 Sicklepod 3.6 Horsenettle 1.1 Pitted morningglory 3.6 Yellow nutsedge 0.3 Entireleaf morningglory 3.2 Purple nutsedge 0.2 Velvetleaf 3.0 Goosegrass 0.2 Broadleaf signalgrass 1.8 Crabgrass 0.2 Eclipta 1.8 *10 = most competitive weed.50 The combined effect of interference by the weed complex is used to predict yield loss in the WebHADSS program. For example, a weed complex containing two Palmer amaranth, two crabgrass, and two eclipta per 100 square feet (33 feet of row with rows spaced 3 feet apart) would reduce peanut yield by 21 percent, based on a projected weed-free yield of 4,000 pounds per acre (Table 4-2). Using WebHADSS and given a crop value of $750 per ton, adequate growing conditions (good soil moisture for satisfactory herbicide performance), and large size weeds (at least 4 inches tall), WebHADSS would provide the suggestions in Table 4-3 with various economic returns. In this example, peanuts were planted May 10 and emerged May 17. The field was scouted June 4 and herbicide sprayed soon thereafter. Although issues relative to accuracy and time required for weed scouting do exist, the WebHADSS program does allow a relatively quick and clear comparison of herbicide options while taking herbicide efficacy, herbicide cost, and economic return from that investment into account. Table 4-2. Potential Yield and Economic Losses if Weeds Are Not Controlled as Compared to Weed-Free Peanuts* Weed species Population Yield Loss (lb per acre) Yield Loss (% of weed-free yield) Economic Loss ($ per acre) Palmer amaranth 2 320 8.0 88 Crabgrass 2 16 0.4 4 Eclipta 2 216 5.4 79 Total Estimated Loss − 552 13.8 152 *Anticipated yield of 4,000 pounds per acre and crop value of $750 per ton farmer stock peanuts. Table 4-3. Ranking of Selected Herbicide Options Considering Efficacy and Economics* Herbicide Rate per Acre** Gain by Applying Herbicide ($ per acre) Cost of Weed Control ($ per acre) Cobra + Cadre 12.5 oz + 4 oz 127 34 Cobra + 2,4-DB 12.5 oz + 16 oz 110 21 Cobra + Clethodim 12.5 oz + 8 oz 122 29 *Herbicide options other than these were listed. Includes adjuvant and application costs. **Abbreviation: oz, ounces.51 COMMENTS ON PEANUT HERBICIDES Preplant Burndown Herbicides Glyphosate (various formulations) and Gramoxone INTEON are relatively nonselective herbicides that control many of the winter weeds present in reduced tillage fields (Table 4-4). Harmony Extra and 2,4-D (various formulations) can also be applied. Harmony Extra can be applied no closer to planting than 45 days before planting. 2,4-D should be applied at least 30 days before planting. Preplant Incorporated, Preemergence, and Postemergence Herbicices Numerous herbicides are labeled for use in peanuts (Tables 4-5, 4-6, 4-7). Timely application of the appropriate herbicide at the correct rate is essential for successful weed control in peanuts. Additional information on feeding restrictions of peanut hay (Table 4-8), suggested rain-free period to maintain control (Table 4-9), and rotation restrictions on herbicide use (Table 4-10) are provided. Reduced Rates of Herbicides When crop prices are low, producers are looking for ways to reduce production costs. One possibility is to reduce the application rate of herbicides. Under certain environmental conditions and with certain weed species or weed complexes, specific herbicides can be applied below the manufacturer’s suggested use rate without sacrificing weed control. However, growers are cautioned that herbicides applied at reduced rates often do not control weeds adequately when environmental conditions (soil moisture in particular) do not favor herbicide activity. Applying herbicides at reduced rates to large weeds or weeds that are “hardened” often results in poor control as well. Weeds can also be more difficult to control if they were injured by herbicide with previous treatment. Using reduced rates will require that growers apply herbicides in a more timely manner and when weeds are not stressed. Regardless of the previously mentioned factors relative to reduced rates, manufacturers of herbicides will not back up their products when they are applied below the suggested use rate. Liability falls exclusively to the grower.52 COMPATIBILITY OF AGRICHEMICALS Table 4-4. Weed Responses to Herbicides Applied Prior to Peanut Planting in Reduced Tillage Systems1,3 Species Gramoxone SL Glyphosate 2,4-D Glyphosate + Harmony Extra Glyphosate + 2,4-D Glyphosate + Valor SX2 Bluegrass GE E N E E E Buttercup E E G E E E Chickweed E E P E E E Curly dock NP E F E FG G Geranium GE PF PF GE F GE Henbit E E FG E E E Horseweed PF GE GE E E E Mustard FG FG GE GE E E Primrose PF F E FG E G Ryegrass G E N E E E Small grains GE E N E E E Swinecress P FG F GE G E 1Gramoxone SL can be applied after peanut emergence; see notes in Table 4-7. Glyphosate (various formations) can be applied at or before ground cracking. 2,4-D (various formulations) should be applied 3 or more weeks before planting. Harmony Extra cannot be applied closer than 45 days prior to planting. See specific product labels for tank mixtures with these herbicides. 2Valor SX can be applied prior to planting up to 2 days after planting. See product label for information on sprayer cleanout. 3E = excellent control, 90% or better; G = good control, 80 to 90%; F = fair control, 50 to 80%; P = poor control, 25 to 50%; N = no control, less than 25%. Compatibility is an important consideration when applying two or more products in the same tank. AG-653, Tank Mixing Chemicals Applied to Peanut: Are the Chemicals Compatible, is a comprehensive guide to agricultural compatibility. This Extension publication is available on the Web at http://www.peanut.ncsu.edu or from your local Extension Center. Consult product labels, AG-653, and your local Extension Agent for more information on agricultural chemical compatibility.53 CHEMICAL WEED CONTROL IN PEANUTS Control of witchweed is part of the State/Federal Quarantine Program. Contact the N.C. Department of Agriculture, Plant Industry Division, at 1-800-206-9333. TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks PREPLANT INCORPORATED Annual grasses and small-seeded broadleaf weeds alachlor (Intrro) 4 EC, MOA 15 2 to 3 qt 2 to 3 Incorporate no deeper than 2 in.; see label for specific instructions. Unless shallowly incorporated, Intrro is more consistently effective when applied pre-emergence. Weak on Texas panicum. Do not apply more than 4 qt of Intrro per acre per season. Before using Intrro, check with buyers to determine if there are marketing restrictions on Intrro-treated peanuts. ethalfluralin (Sonalan) 3 EC, MOA 3 1.5 to 2 pt 0.56 to 0.75 Controls common annual grasses including Texas panicum. Use 3 pt of Prowl H2O or 2 pt of Sonalan for control of broadleaf signalgrass, Texas panicum, and fall panicum. Incorporate 3 in. deep for Texas panicum; otherwise, incorporate 2 to 3 in. deep. See labels for maximum waiting period between application and incorporation. Immediate incorporation is best. Dual Magnum or Outlook may be tank mixed with Prowl or Sonalan to suppress yellow nutsedge. pendimethalin (Prowl H2O) 3.8, MOA 3 1.5 to 3 pt 0.71 to 1.4354 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual grasses, small-seeded broadleaf weeds, and nutsedge dimethenamid (Outlook) 6.0 L, MOA 15 16 to 21 fl oz 0.75 to 1 Apply and incorporate in top 2 in. of soil within 14 days of planting. Use high rate of Dual Magnum or Outlook for yellow nutsedge and broadleaf signalgrass. Not effective on purple nutsedge. Weak on Texas panicum. May be tank mixed with Prowl or Sonalan. metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC 1 to 1.33 pt 0.95 to 1.27 1 to 1.33 Broadleaf weeds and suppression of nutsedge diclosulam (Strongarm) 84 WDG, MOA 2 0.45 oz 0.024 Effective on common cocklebur, morningglory, common ragweed, eclipta, and common lambsquarters. Suppresses yellow and purple nutsedge. Does not control sicklepod. More effective when applied in combination with Dual Magnum, Outlook, Prowl H2O, Sonalan, or Stalwart. See label for rotation restrictions, especially corn. Growers are cautioned that Strongarm applied at rates exceeding 0.45 oz per acre can injure cotton the following year on soils with a shallow hardpan (less than 10 inches) and/or loam soils. Cotton grown under early season stress resulting from conditions such as excessively cool, wet, dry, or crusted soils may be particularly susceptible to carryover of Strongarm. Some weed species have developed resistance to Strongarm.55 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual grasses, broadleaf weeds, and suppression of nutsedge diclosulam (Strongarm) 84 WDG, MOA 2 + pendimethalin (Prowl H2O) 3.8, MOA 3 or ethalfluralin (Sonalan) 3 EC, MOA 3 or metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC or dimethenamid (Outlook) 6.0 L, MOA 15 0.45 oz + 1.5 to 3 pt or 1.5 to 2 pt or 1 to 1.33 pt or 16 to 21 fl oz 0.024 + 0.71 to 1.43 or 0.56 to 0.75 or 0.95 to 1.27 1 to 1.33 or 0.75 to 1 Effective on annual grasses, common cocklebur, common ragweed, eclipta, morningglory, and common lambsquarters. Suppresses purple and yellow nutsedge. Does not control sicklepod. See Strongarm label for rotation restrictions.56 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks PPI FOLLOWED BY PRE Annual grasses, broadleaf weeds, and suppression of nutsedge pendimethalin (Prowl H2O) 3.8, MOA 3 or ethalfluralin (Sonalan) 3 EC, MOA 3 or metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC or dimethenamid (Outlook) 6.0 L, MOA 15 followed by diclosulam (Strongarm) 84 WDG, MOA 2 or flumioxazin (Valor SX) 51 WDG, MOA 14 1.5 to 3 pt or 1.5 to 2 pt or 1 to 1.33 pt or 16 to 24 fl oz 0.45 oz or 2 oz 0.71 to 1.43 or 0.56 to 0.75 or 0.95 to 1.27 1 to 1.33 or 0.75 to 1 0.024 or 0.063 Controls most broadleaf weeds. Will not control sicklepod and is marginal on certain large-seeded broadleaf weeds. Do not incorporate Valor. Valor SX should be applied to the soil surface immediately after planting. Significant injury can occur if Valor is incorporated or applied 3 or more days after planting. Significant injury from Valor SX was noted in 2001, 2004, and 2006, and 2009 even when applied according to label recommendations. However, injury is generally transient and does not affect yield. Cotton grown under early season stress from conditions like excessively cool, wet, or crusted soils may be particularly susceptible to carryover of Strongarm. Some weed species have developed resistance to Strongarm.57 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks SPLIT APPLICATION (PPI + POST) Most broadleaf weeds and nutsedge imazethapyr (Pursuit) 2 AS, MOA 2 2 + 2 oz 0.031 + 0.031 Effective on most common broadleaf weeds and yellow and purple nutsedge. Does not control eclipta, lambsquarters, ragweed, or croton. Pursuit will usually control seedling johnsongrass and foxtails. For control of other annual grasses, Pursuit may be tank mixed with Dual Magnum, Outlook, Prowl H2O, or Sonalan and incorporated. See label for incorporation directions and rotational restrictions. Some weed species have developed resistance to Pursuit. Research in N.C. has generally shown more effective control of a broader spectrum of weeds with split applications of half of the Pursuit applied preplant incorporated followed by the other half applied early postemergence. PREEMERGENCE Annual grasses and small-seeded broadleaf weeds alachlor (Intrro) 4 EC, MOA 15 2 to 3 qt 2 to 3 Apply as soon after planting as possible. All three herbicides are weak on Texas panicum. Before using Intrro, check with buyers to determine if there are marketing restrictions on Intrro-treated peanuts. dimethenamid (Outlook) 6.0 L, MOA 15 16 to 21 fl oz 0.75 to 1 metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC 1 to 1.33 pt 0.95 to 1.27 1 to 1.33 Broadleaf weeds flumioxazin (Valor SX) 51 WDG, MOA 14 2 oz 0.063 Apply within 2 days after planting. Significant injury can occur if Valor SX is incorporated or applied 3 or more days after seeding. Controls carpetweed, common lambsquarters, Florida pusley, nightshade, pigweeds, prickly sida, and spotted spurge. Does not control sicklepod, yellow and purple nutsedge, or annual grasses. Significant injury from Valor SX was noted in 2001, 2004, and 2006, even when applied according to label recommendations. However, injury is generally transient and does not affect yield. Injury may occur if excessive and forceful rainfall occurs when peanut is emerging. Peanut recovers from injury by midseason in most instances. See product label for comments on sprayer cleanup.58 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual grasses, broadleaf weeds, and suppression of nutsedge flumioxazin (Valor SX) 51 WDG, MOA 14 + metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC or dimethenamid (Outlook) 6.0 L, MOA 15 2 oz + to 1.33 pt or 16 to 21 fl oz 0.063 + 0.95 to 1.27 1 to 1.33 or 0.75 to 1 Apply within 2 days after planting. Significant injury can occur if applied 3 or more days after planting. This combination does not control sicklepod but will control annual grasses (except Texas panicum) and will suppress yellow nutsedge. Significant injury from Valor was noted in 2001, 2004, and 2006, even when applied according to label recommendations. However, injury is generally transient and does not affect yield. Injury may occur if excessive and forceful rainfall occurs when peanut is emerging. Peanut recovers from injury by midseason in most instances. See product label for comments on sprayer cleanup. Broadleaf weeds and suppression of nutsedge diclosulam (Strongarm) 84 WDG, MOA 2 0.45 oz 0.024 Effective on common cocklebur, morningglory, common ragweed, eclipta, and common lambsquarters. Suppresses yellow and purple nutsedge. Does not control sicklepod. More effective when applied in combination with Dual Magnum, Outlook, Prowl H2O, Sonalan, or Stalwart. See label for rotation restrictions, especially corn. Growers are cautioned that Strongarm applied at rates exceeding 0.45 oz per acre can injure cotton the following year on soils with a shallow hardpan (less than 10 inches) and/or loam soils. Cotton grown under early season stress resulting from conditions such as excessively cool, wet, dry, or crusted soils may be particularly susceptible to carryover of Strongarm. Some weed species have developed resistance to Strongarm.59 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks sulfentrazone, MOA 14 + carfentrazone, MOA 14 (Spartan Charge) 0.35 + 3.15F 3 to 5 fl oz 0.07 + 0.12 Do not apply Spartan Charge after peanuts crack soil. Application immediately after planting is advised. See Spartan Charge label for specific rates based on soil texture and organic matter content. See product label for comments on application with other herbicides. Rotation restrictions for planting cotton following Spartan Charge at recommended rates for peanuts are 12 months. Annual grasses, broadleaf weeds, and suppression of nutsedge diclosulam (Strongarm) 84 WDG, MOA 2 + metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC or dimethenamid (Outlook) 6.0 L, MOA 15 0.45 oz + 1 to 1.33 pt or 16 to 21 fl oz 0.024 + 0.95 to 1.27 1 to 1.33 or 0.75 to 1 Effective on annual grasses, common cocklebur, common ragweed, eclipta, morningglory, and common lambsquarters. Suppresses purple and yellow nutsedge. Does not control sicklepod. See label for rotation restrictions. Some weed species have developed resistance to Strongarm. Cotton grown under early season stress, such as excessively cool, wet, or dry weather, or crusted soils may be particularly susceptible to carryover of Strongarm. Most annual broadleaf weeds and nutsedge imazethapyr (Pursuit) 2 AS, MOA 2 4 oz 0.063 Effective on most common broadleaf weeds and yellow and purple nutsedge. Does not control ragweed, eclipta, lambsquarters, or croton. Pursuit may be tank mixed with Dual Magnum, Intrro, Outlook, or Stalwart for annual grass control. See label for rotational restrictions. Some weed species have developed resistance to Pursuit. Research in N.C. has generally shown more effective control of a broader spectrum of weeds with split applications of half of the Pursuit applied preplant incorporated followed by the other half applied early postemergence.60 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks CRACKING STAGE Emerged annual grasses and broadleaf weeds paraquat, MOA 22 (Firestorm or Parazone) 3.0 SL (Gramoxone SL) 2.5 L 5.4 fl oz 8 fl oz 0.13 Apply at ground cracking for control of small emerged annual grasses and broadleaf weeds. May be tank mixed with Dual Magnum, Outlook, or Stalwart for residual control. Tank mix may cause severe injury to emerged peanuts. Add 1 pt nonionic surfactant per 100 gal spray solution. Follow all safety precautions on label. May also be tank mixed with Pursuit for residual control of nutsedge and broadleaf weeds. Applying Basagran at 0.5 pt per acre will reduce injury. Additional residual control of annual grasses and certain small-seeded broadleaf weeds alachlor (Intrro) 4 EC, MOA 15 2 to 3 qt 2 to 3 Use as a supplement to preplant or preemergence herbicides to provide additional residual control of annual grasses and certain small-seeded broadleaf weeds such as pigweed and eclipta. This treatment will not control emerged grasses or broadleaf weeds. Do not apply more than 4 qt Intrro, 21 oz Outlook, or 2.6 pt Dual Magnum or Stalwart per acre per season. Before using Intrro, check with buyers to determine if there are marketing restrictions on Intrro-treated peanuts. dimethenamid (Outlook) 6.0 L, MOA 15 16 to 21 fl oz 0.75 to 1 metolachlor, MOA 15 (Dual Magnum) 7.62 EC (Stalwart) 8 EC 1 to 1.33 pt 0.95 to 1.27 1 to 1.33 Most annual broadleaf weeds and nutsedge imazethapyr (Pursuit) 2 AS, MOA 2 4 oz 0.063 Effective on most common broadleaf weeds and yellow and purple nutsedge. Does not control ragweed, eclipta, lambsquarters, or croton. If weeds are emerged, add surfactant or crop oil according to label directions. See label for rotational restrictions. Pursuit may be tank mixed with paraquat. Some weed species have developed resistance to Pursuit. Research in N.C. has generally shown more effective control of a broader spectrum of weeds with split applications of half of the Pursuit applied preplant incorporated followed by the other half applied early postemergence. Some emerged broadleaf weeds and suppression of eclipta and yellow nutsedge diclosulam (Strongarm) 84 WDG, MOA 2 0.45 oz 0.024 Strongarm can be applied through the cracking stage. Add 1 qt nonionic surfactant per 100 gal. The spectrum of weeds controlled is much narrower when Strongarm is applied to emerged weeds. Strongarm will not control emerged common lambsquarters or pigweeds but will control common ragweed and morningglories. Strongarm will suppress yellow nutsedge and eclipta. See product labels for information on mixing Strongarm with other herbicides. Some weed species have developed resistance to Strongarm.61 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks POSTEMERGENCE Annual broadleaf weeds acifluorfen (Ultra Blazer) 2L, MOA 14 1 to 1.5 pt 0.25 to 0.38 Apply when weeds are small and actively growing. Use minimum of 20 GPA and high pressure (40 to 60 psi). See label for species controlled, maximum weed size to treat, and addition of surfactant. Do not apply more than 2 pt postemergence per acre per season. May make sequential applications of 1 pt per acre followed by 1 pt per acre. Allow at least 15 days between sequential applications. acifluorfen (Ultra Blazer) 2L, MOA 14 + 2,4-DB (Butyrac 200) 2 L, MOA 4 1 to 1.5 pt + 16 fl oz 0.25 to 0.38 + 0.25 Addition of 2,4-DB to Ultra Blazer improves the control of certain weeds when weed size exceeds that specified on the Ultra Blazer label. See above comments on Ultra Blazer. See label for suggestions on use of surfactant or crop oil. Apply when peanuts are at least 2 weeks old and before pod filling begins. Make only one application per year. Other trade names for 2,4-DB may be available. bentazon, MOA 6 (Basagran) 4 L, MOA 6 1.5 to 2 pt 0.75 to 1 Apply when weeds are small and actively growing. Use minimum of 20 GPA and high pressure (40 to 60 psi). See label for addition of oil concentrate, species controlled, and maximum weed size to treat. Basagran may also be applied at 1 pt per acre for control of cocklebur, jimsonweed, and smartweed 4 in. or less. Do not apply more than 4 pt of Basagran per acre per season. Peanuts normally are very tolerant of Basagran. However, injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow. bentazon, MOA 6 (Basagran) 4 L, MOA 6 + acifluorfen (Ultra Blazer) 2 L, MOA 14 1 to 2 pt + 1 to 1.5 pt 0.5 to 1 + 0.25 to 0.38 See above comments for Basagran and Ultra Blazer. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants. Peanuts normally are very tolerant of Basagran. However, injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow.62 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual broadleaf weeds (continued) bentazon, MOA 6 + acifluorfen, MOA 14 (Storm) 4 L 1.5 pt 0.5 + 0.25 Apply when weeds are small and actively growing. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants. These rates of bentazon and acifluorfen may not provide consistent control of lambsquarters, prickly sida, and spurred anoda. Do not apply more than 3 pt of Storm per season. Peanuts normally are very tolerant of Storm. However, injury is occasionally noted when Basagran, one of the components of Storm, is applied to peanuts treated with Di-Syston in-furrow. bentazon, MOA 6 + acifluorfen, MOA 14 (Storm) 4 L + 2,4-DB (Butyrac 200) 2 L, MOA 4 1.5 pt + 8 to 16 fl oz 0.5 + 0.25 + 0.125 to 0.25 Adding 2,4-DB will improve control of larger morningglory, cocklebur, common ragweed, pigweed, jimsonweed, and citron. Add surfactant or crop oil according to label directions. Make only one appli-cation per year. Apply when peanuts are at least 2 weeks old. Do not apply after pod filling begins. See comments for Storm alone. Peanuts normally are very tolerant of Storm. However, injury is occasionally noted when bentazon, MOA 6, one of the components of Storm, is applied to peanuts treated with Di-Syston in-furrow. Other trade names for 2,4-DB may be available. bentazon, MOA 6 (Basagran) 4 L, MOA 6 + 2,4-DB (Butyrac 200) 2 L, MOA 4 1 to 2 pt + 8 fl oz 0.75 to 1 + 0.125 Addition of 2,4-DB to Basagran improves control of morningglories. See above comments for Basagran. Add surfactant or crop oil according to label directions. Do not make more than two applications per year. Apply when peanuts are at least 2 weeks old and not within 45 days of harvest. Peanuts normally are very tolerant of Basagran. However, injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow. Other trade names for 2,4-DB may be available. imazapic (Cadre or Impose) 2 AS, MOA 2 4 oz 0.063 Controls most broadleaf weeds except ragweed, croton, lambsquarters, and eclipta. Apply before weeds exceed 2 to 4 in.; see label for specific weed sizes to treat. Add nonionic surfactant at 1 qt per 100 gal or crop oil concentrate at 1 qt per acre. A soil-applied grass control herbicide should be used. However, Cadre and Impose will usually control escaped broadleaf signalgrass, fall panicum, and Texas panicum. See label for rotational restrictions. Some weed species have developed resistance to Cadre and Impose.63 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual broadleaf weeds (continued) imazethapyr (Pursuit) 2 AS, MOA 2 4 oz 0.063 Effective on most common broadleaf weeds and yellow and purple nutsedge. Does not control eclipta, lambsquarters, ragweed, or croton. Apply when weeds are 3 in. tall or less. Add surfactant or crop oil according to label directions. See label for rotational restrictions. Pursuit may be tank mixed with Basagran, Ultra Blazer, paraquat formulations, and 2,4-DB. Some weed species have developed resistance to Pursuit. Research in N.C. has generally shown more effective control of a broader spectrum of weeds with split applications of half of the Pursuit applied preplant incorporated followed by the other half applied early postemergence. 2,4-DB (Butyrac 200) 2 L, MOA 4 1 pt 0.2 to 0.25 Effective on cocklebur and morningglory; pitted morningglory may be only partially controlled. Best results achieved when applied to small weeds. May use two applications per year. Do not apply within 45 days before harvest. Other trade names for 2,4-DB may be available. lactofen (Cobra) 2 EC, MOA 14 12.5 fl oz 0.2 Apply after peanuts have at least six true leaves. Apply to actively growing peanut. Controls most annual broadleaf weeds. Use minimum of 10 GPA and high pressure (40 to 60 psi). See label for species controlled and maximum weed size to treat. Add nonionic surfactant at 1 qt per 100 gal or crop oil concentrate or methylated seed oil at 1 to 2 pt per acre. See label on when to use various adjuvants. Allow at least 14 days between applications. Can be tank mixed with Basagran, Pursuit, Cadre, Impose, 2,4-DB, and/or Select. lactofen (Cobra) 2 EC, MOA 14 + bentazon, MOA 6 (Basagran) 4 L, MOA 6 12.5 fl oz + 1.5 to 2 pt 0.2 + 0.75 to 1 See above comments for Cobra and Basagran. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants.64 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual broadleaf weeds (continued) lactofen (Cobra) 2 EC, MOA 14 + bentazon, MOA 6 (Basagran) 4 L, MOA 6 + 2.4-DB (Butyrac 200) 2 L, MOA 4 12.5 fl oz + 1.5 to 2 pt + 8 to 16 fl oz 0.2 + 0.75 to 1 + 0.125 to 0.25 Adding 2,4-DB will improve control of larger morningglory, cocklebur, common ragweed, jimsonweed, and citron. See above comments for Cobra, Basagran, and 2,4-DB. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants. Other trade names for 2,4-DB may be available. lactofen (Cobra) 2 EC, MOA 14 + imazapic (Cadre or Impose) 2 AS, MOA 2 12.5 fl oz + 4 oz 0.2 + 0.063 See above comments for Cobra and Cadre and Impose. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants. Some weed species have developed resistance to Cadre and Impose. lactofen (Cobra) 2 EC, MOA 14 + imazethapyr (Pursuit) 2 AS, MOA 2 12.5 fl oz + 4 oz 0.2 + 0.063 See above comments for Cobra and Pursuit. See labels for weeds controlled, maximum weed size to treat, and use of adjuvants. Some weed species have developed resistance to Pursuit. Annual grasses and broadleaf weeds paraquat, MOA 22 (Firestorm or Parazone) 3.0 SL (Gramoxone SL) 2.5 L 5.4 fl oz 8 fl oz 0.13 See label for weeds controlled and maximum weed size to treat; best results if weeds 1 in. or less. A postemergence application may be made following an at-crack application. Do not make more than two applications per season, do not apply later than 28 days after ground cracking, and do not apply to peanuts under stress, including damage from thrips feeding. Add 1 pt of nonionic surfactant per 100 gal of spray solution. Will cause foliar burn on peanuts, but the crop recovers and yield not affected. Follow all safety precautions on label. Do not apply to peanuts showing symptoms of thrips damage.65 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual grasses and broadleaf weeds (continued) paraquat, MOA 22 (Firestorm or Parazone) 3.0 SL (Gramoxone SL) 2.5 L + bentazon, MOA 6 (Basagran) 4 L, MOA 6 5.4 fl oz 8 fl oz + 0.5 to 1.5 pt 0.13 + 0.25 to 0.75 See previous comments for paraquat alone. Adding Basagran improves control of common ragweed, prickly sida, smartweed, lambsquarters, and cocklebur and reduces injury to peanuts from paraquat. May be applied any time from ground cracking up to 28 days after ground cracking. Add 1 pt of nonionic surfactant per 100 gal of spray solution. Peanuts normally are very tolerant of Basagran. However, severe injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow. paraquat, MOA 22 (Firestorm or Parazone) 3.0 SL (Gramoxone SL) 2.5 L + bentazon, MOA 6 + acifluorfen, MOA 14 (Storm) 4 L, 5.4 fl oz 8 fl oz + 1.5 pt 0.13 + 0.5 0.25 See previous comments for Gramoxone SL alone. Storm improves control of common ragweed, smartweed, lambsquarters, common cocklebur, tropic croton, and spurred anoda. May be applied anytime from ground cracking up to 28 days after ground cracking. Add 0.5 pt of nonionic surfactant per 100 gal of spray solution. Peanuts normally are very tolerant of Basagran. However, severe injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow. The mixture of paraquat and Storm is more injurious than these herbicides applied alone. Florida beggarweed chlorimuron (Classic) 25 DF, MOA 2 0.5 oz 0.008 Use only for control of Florida beggarweed. Apply from 60 days after crop emergence to within 45 days of harvest. Application to peanuts less than 60 days old will result in crop injury and yield reduction. Apply before Florida beggarweed has begun to bloom and before it has reached 10 in. tall. Larger beggarweed may only be suppressed. Add 1 qt of nonionic surfactant per 100 gal spray solution; do not add crop oil. May be tank mixed with 2,4-DB; see label for rates and precautions. Recommended as a salvage treatment only.66 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Yellow nutsedge bentazon, MOA 6 (Basagran) 4 L, MOA 6 1.5 to 2 pt 0.75 to 1 Apply when nutsedge is 6 to 8 in. tall. A repeat application 7 to 10 days later may be needed. Adding crop oil concentrate at 1 qt per acre will increase control. Do not apply more than 4 pt of Basagran per season. Not effective on purple nutsedge. Peanuts normally are very tolerant of bentazon. However, severe injury is occasionally noted when Basagran is applied to peanuts treated with Di-Syston in-furrow. Yellow and purple nutsedge imazapic (Cadre or Impose) 2 AS, MOA 2 4 oz 0.063 Apply postemergence when nutsedge is 4 in. or less. Add nonionic surfactant at 1 qt per 100 gal or crop oil concentrate at 1 qt per acre. See label for rotational restrictions. imazethapyr (Pursuit) 2 AS, MOA 2 4 oz 0.063 Apply before nutsedge is larger than 3 in. tall. Add surfactant at 1 qt per 100 gal or crop oil concentrate at 1 qt per acre. Do not mix with Basagran for nutsedge control. See label for rotational restrictions. A split application with half of the Pursuit applied preplant incorporated and half applied early post-emergence may be more effective than applying all of the Pursuit at one time. Annual grasses clethodim, MOA 1 (Arrow, Select, or Volunteer) 2 EC (Select MAX or TapOut) 0.97 EC 6 to 8 fl oz 9 to 16 fl oz 0.094 to 0.125 0.068 to 0.121 Apply Arrow, Poast, Poast Plus, Select 2 EC, Select MAX, TapOut, or Volunteer to actively growing grass not under drought stress. Consult labels for maximum grass size to treat. Apply in 5 to 20 GPA at 40 to 60 psi. Add 2 pt of crop oil concentrate per acre to Poast or Poast Plus. Do not cultivate within 7 days before or after application. Poast Plus is often slightly better than Poast. Add crop oil concentrate at 1 qt per acre to Arrow, Select 2 EC, Select MAX, TapOut, and Volunteer. Nonionic surfactant at 1 qt per 100 gal can be applied with Select MAX rather than crop oil concentrate. Some herbicides and fungicides can reduce the efficacy of Arrow, Select 2 EC, Select MAX, Volunteer, Poast, and Poast Plus when applied in tank mixtures. See product labels for specific instructions concerning compatibility with other chemicals. Also see AGW-653, Tank Mixing Chemicals Applied to Peanut, Are the Chemicals Compatible, which is on the Web at www.peanut.ncsu.edu and is available at your county Extension center. sethoxydim, MOA 1 (Poast) 1.5 EC (Poast Plus) 1 EC 1 pt 1.5 pt 0.1967 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Bermudagrass clethodim, MOA 1 (Arrow, Select, or Volunteer) 2 EC (Select MAX or TapOut) 0.97 EC 8 to 16 fl oz 12 to 32 fl oz 0.125 to 0.25 0.091 to 0.24 Apply to actively growing bermudagrass before runners exceed 6 in. In most cases, a second application will be needed. Make second application of 1 pt of Poast or 1.5 pt of Poast Plus per acre if regrowth occurs. Add 2 pt per acre of crop oil concentrate. Poast Plus is often slightly better than Poast. If needed, make a second application of Arrow, Select 2 EC, TapOut, or Volunteer at 8 to 16 oz per acre when regrowth is less than 6 in. Add crop oil concentrate at 1 qt per acre to Arrow, Select 2 EC, TapOut, and Volunteer. Crop oil concentrate (1 qt per acre) or nonionic surfactant (1 qt per 100 gallons) should be applied with Select MAX. See product labels for specific instructions concerning compatibility with other chemicals. Also see AGW-653, Tank Mixing Chemicals Applied to Peanut, Are the Chemicals Compatible, which is on the Web at www.peanut.ncsu.edu and available at your county Extension center. sethoxydim, MOA 1 (Poast) 1.5 EC (Poast Plus) 1 EC 1.5 pt 2.25 pt 0.28 Rhizome johnsongrass clethodim, MOA 1 (Arrow, Select, or Volunteer) 2 EC (Select MAX or TapOut) 0.97 EC 8 to 16 fl oz 12 to 32 fl oz 0.125 to 0.25 0.091 to 0.24 Apply to actively growing johnsongrass before it exceeds 25 in. tall. Add 2 pt per acre of crop oil concentrate. A second application of the same rates can be made if needed before new plants or regrowth exceeds 12 in. Apply Arrow, Select 2 EC, TapOut, or Volunteer when johnsongrass is 12 to 24 in. tall. If needed, make a second application when regrowth is 6 to 18 in. Add crop oil concentrate at 1 qt per acre to Arrow, Select 2 EC, Select MAX, TapOut, and Volunteer. Crop oil concentrate (1 qt per acre) or nonionic surfactant (1 qt per 100 gallons) should be applied with Select MAX. For specific instructions for compatibility concerns with other chemicals, see product labels and AGW-653, Tank Mixing Chemicals Applied to Peanut, Are the Chemicals Compatible, which is on the Web at www.peanut.ncsu.edu and available at your county Extension center. sethoxydim, MOA 1 (Poast) 1.5 EC (Poast Plus) 1 EC 1 pt 1.5 pt 0.1968 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Suppression of large Palmer amaranth and other pigweed species that are resistant to the ALS inhibiting herbicides Cadre, Classic, Impose, Pursuit, and Strongarm 2,4-DB (Butyrac 200 and others) 2 L, MOA 4 + lactofen (Cobra) 2 EC, MOA 14 or acifluorfen (Ultra Blazer) 2 L, MOA 14 16 oz + 12.5 oz or 1.5 pt 0.25 + 0.20 or 0.38 Suppresses and does not completely control Palmer amaranth and other pigweed species that exceed 8 inches. Suppression of weeds exceeding 12 inches will be less than suppression of smaller weeds. Do not expect suppression to exceed 60%. Applying 2,4-DB 3 to 4 days prior to Cobra or Ultra Blazer may be more effective than tank mixtures of 2,4-DB with Cobra or Ultra Blazer. Cobra is generally more effective on larger Palmer amaranth and other pigweed species than Ultra Blazer. Apply crop oil concentrate at 1% (v/v) with Cobra and Ultra Blazer. Do not apply adjuvant with 2,4-DB alone. See product labels for comments on spray volume and effects on peanut especially during pod set and pod fill. Higher spray volumes are more effective by increasing spray coverage of the contact herbicides Cobra and Ultra Blazer. Two applications of 2,4-DB spaced 10 to 14 days apart will suppress Palmer amaranth and other pigweed species. Although suppression by 2,4-DB is lower than sequential or tank mix application of 2,4-DB and Cobra or Ultra Blazer within two weeks after application, suppression by sequential applications of 2,4-DB 4 to 5 weeks after initial application is only slightly lower than suppression by sequential or tank mix applilcation of 2,4-DB and Cobra or Ultra Blazer. For more information on managing herbicide-resistant weeds in peanut, see AG-692, Managing Herbicide-Resistant Weeds in Peanuts in the United States, which is on the Web at www.peanut.ncsu.edu. 2,4-DB (Butyrac 200 and others) 2 L, MOA 4 then lactofen (Cobra) 2 EC or acifluorfen (Ultra Blazer) 2 L, MOA 14 16 oz then 12.5 oz or 1.5 pt 0.25 then 0.20 or 0.38 2,4-DB (Butyrac 200) 2 L, MOA 4 then 2,4-DB (Butyrac 200) 2 L, MOA 4 16 oz then 16 oz 0.25 then 0.25 Paraquat, MOA 22 (Gramoxone SL) 2.5L See comments See comments Apply in a roller/wiper implement. Best control achieved when at least 60% coverage of weed foliage can be achieved. Do not allow paraquat to contact peanut foliage. Mix 1 part Gramoxone SL with 1 to 1.5 parts water to prepare a 40% to 50% solution. Add nonionic surfactant at 0.25% (v/v) or 1 qt/100 gallons. Adjust roller/wiper system to apply up to 2 pt/A of the herbicide-water mixture.69 TABLE 4-5. Herbicide Information for Peanuts (continued) Weed Herbicide and Formulation Amount of Formulation Per Acre Pounds Active Ingredient Per Acre Precautions and Remarks Annual grasses and certain small-seeded broadleaf weeds dimethenamid (Outlook) 6.0 L, MOA 15 16 to 21 fl oz 0.75 to 1 Will not control emerged grasses or weeds; apply following a cultivation or appropriate postemergence herbicide if emerged grasses or broadleaf weeds are present. Benefit likely only on very sandy fields heavily infested with annual grasses that receive above normal rainfall during the first 4 to 5 weeks of the growing season. Lay-by of Dual Magnum or Outlook may also be of value in fields with a history of eclipta problems; the application must be made before eclipta emerges. Rates are on a broadcast basis; apply in an 18-in. band to row middles. The maximum use rate of Dual Magnum is 2.6 pt per acre pe |
OCLC number | 32194430 |