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