1
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
Published by
North Carolina Cooperative Extension
College of Agriculture and Life Sciences
North Carolina State University
The North Carolina Peanut Growers Association provided financial support for publishing 2016 Peanut Information.
© 2016 North Carolina State University
2016
Information
PEANUT23
Contents
EXTENSION PERSONNEL WORKING WITH PEANUTS..........................................4
1. SITUATION AND OUTLOOK...................................................................................5
2. PEANUT SEED......................................................................................................19
3. PEANUT PRODUCTION PRACTICES..................................................................22
4. PEANUT WEED MANAGEMENT..........................................................................48
5. PEANUT INSECT AND MITE MANAGEMENT.....................................................87
6. PEANUT DISEASE MANAGEMENT...................................................................108
7. PLANTING, HARVESTING, AND CURING PEANUTS.......................................148
8. GUIDELINES FOR THE NORTH CAROLINA
PEANUT PRODUCTION CONTEST......................................................................164
9. COMPATIBILITY OF AGROCHEMICALS APPLIED TO PEANUT.....................1694
EXTENSION PERSONNEL WORKING WITH PEANUTS
County Extension personnel with peanut responsibilities as of January 1, 2016:
County
Name
City
Telephone
Beaufort
Rod Gurganus
Washington
(252) 946-0111
Bertie
Jarette Hurry
Windsor
(252) 794-5317
Bladen
Becky Spearman
Elizabethtown
(910) 862-4591
Chowan
Matthew Leary
Edenton
(252) 482-6585
Columbus
Michael Shaw
Whiteville
(910) 640-6605
Craven-Carteret
Mike Carroll
New Bern
(252) 633-1477
Cumberland
Kenny Bailey
Fayetteville
(910) 321-6875
Duplin
Vacant
Kenansville
(910) 296-2143
Edgecombe
Art Bradley
Tarboro
(252) 641-7815
Gates
Paul Smith
Gatesville
(252) 357-1400
Greene
Roy Thagard
Snow Hill
(252) 747-5831
Halifax
Arthur Whitehead
Halifax
(252) 583-5161
Harnett
Brian Parrish
Lillington
(910) 893-7530
Hertford
Mitch Smith
Winton
(252) 358-7822
Johnston
Tim Britton
Smithfield
(919) 989-5380
Jones–Lenoir
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
Paul Smith
Hertford
(252) 426-5428
Pitt
Lance Grimes
Greenville
(252) 902-1702
Robeson
Mac Malloy
Lumberton
(910) 671-3276
Sampson
Della King
Clinton
(910) 592-7161
Scotland
Randy Wood
Laurinburg
(910) 277-2422
Washington
Anna-Beth Stewart
Plymouth
(252) 793-2163
Wayne
Tyler Whaley
Goldsboro
(919) 731-1520
Wilson
Norman Harrell
Wilson
(252) 237-0111
NC State University Extension specialists with peanut responsibilities as of January 1, 2016 and directors of peanut grower organizations:
Rick BrandenburgInsects, NC State University(919) 515-8876Blake BrownEconomics, NC State University(919) 515-4536Gary BullenEconomics, NC State University(919) 515-6095David JordanAgronomy & Weeds, NC State University(919) 515-4068Gary RobersonEngineering, NC State University(919) 515-6715Barbara ShewDiseases, NC State University(919) 515-6984Bob SutterN.C. Peanut Growers Association Inc.(252) 459-5060Dell CottonPeanut Growers Cooperative Marketing Association(757) 562-41035
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 estimated at 6.322 billion pounds in 2015, according to the USDA October Crop Report, up from 5.19 billion in 2014. Harvested acres increased from 1.322 million in 2014 to 1.582 million in 2015. Yield per acre in 2015 was estimated at 3,997 pounds, up from 3,923 in 2014.
In North Carolina, harvested acreage as reported by USDA decreased from 93,000 acres in 2014 to an estimated 89,000 acres in 2015. Yields in North Carolina were down from an average yield of 4,320 pounds per acre in 2014 to an average of 4,000 pounds per acre in 2015. The USDA October crop report placed North Carolina production at 356 million pounds in 2015, down from 401.8 million pounds in 2014.
The Price Loss Coverage (PLC) provisions for peanuts under the 2014 Farm Bill are the primary drivers for increased acreage of peanuts. With the reference price for peanuts of $535 per ton well above the cost of production in the runner areas, farmers with peanut and generic base overwhelmingly chose the Price Loss Coverage option. PLC payment rate for peanuts equals the difference between the reference price of $535 per ton of PLC yield and the greater of the national marketing year average (MYA) price or loan rate of $355 per ton. Payments are on 85% of base acres and are reduced by 7.2% for sequestration. For the 2014 crop, it appears the MYA price will be $440 per ton giving a payment rate of $95 per ton of PLC yield. Accounting for payment for 85% of base acres and the 7.2% sequestration reduction gives a payment per ton of PLC yield on base acres of about $75. Payments are supposed to be made in October of the crop marketing year following the year of planting. As of writing, the payments for the 2014 crop had not been received. Farmers were not required to plant peanut base acres to receive this payment but were required to plant generic acres in order to receive the PLC payments. Further complicating this scenario is that a farm’s PLC payments by commodity were prorated by the proportions of generic base planted to various program crops.
Generic base acres for a farm were based on the farm’s 2013 cotton base acres. At the national level, 2013 cotton base acres were 15.9 million acres. Cotton 2013 base acres in Georgia were 1.46 million acres and 849 thousand acres in North Carolina. Given this situation, peanut planted acres are not limited by generic base acres. But the PLC provisions for peanuts give strong incentives to farmers, particularly in runner 6
areas, to maximize peanut planted acres on generic base acres. Limiting factors on planting peanuts are then capacity in terms of investment in specialized peanut equipment and farm program payment limitations. Payments for peanuts have a separate payment limitation of $125,000 per legal entity. This gives farmers incentives to maximize the number of legal entities allowed by USDA Farm Service Agency and to fully utilize current production capacity for peanuts to maximize generic base planted in peanuts.
For the 2015 crop, the MYA price will likely be close to or below $400 per ton. If this is the case, then the PLC payment rate could be $135 per ton of PLC yield. Payment on 85% of base and the 7.2% sequestration reduction imply payments per ton of base yield of over $105 for the 2015 crop. As a result of expected further increases in production and lower market prices, peanut buyers have little incentive to forward contract peanuts. While some contracts may be given for Virginia type peanuts, most of the crop will not likely be under contract, and market prices of Virginias will be well below traditional Virginia type peanut prices of $500 or more per ton. With market prices for Virginia type peanuts falling toward $400 per ton, even with a PLC payment of around $100 per ton of PLC base yield, VC producers are not likely to increase production. However, peanut acres in runner areas, such as Georgia, may increase again in 2016.
Not surprisingly, stocks of peanuts are rising. Peanut stocks in commercial storage as of July 31, 2015 were 2.1 billion pounds, up from 1.86 billion pounds a year earlier at the end of the 2013 crop marketing year. Given the increase in 2015 production, stocks will increase further for the 2015 crop marketing year. Lower peanut prices will stimulate increased use but not enough to offset increased production. Peanut butter use for August 2014 through July 2015 increased to 1.303 billion pounds from 1.218 billion pounds for the previous year. 7
B. PEANUT PRODUCTION BUDGETS
S. Gary Bullen
Extension Economist—Agricultural and Resource Economics
David Jordan
Peanut Specialist—Crop Science
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 gypsum is assumed to be $51.51 per ton; less expensive sources are available, although transportation costs can be significant.
Current information on the peanut outlook and situation, budgets, farm management, and more is available at the North Carolina State University Department of Agricultural and Resource Economics website: www.ag-econ.ncsu.edu.8
Table 1-1. Estimated Costs and Returns Per Acre of RUNNER STRIP-TILL Peanuts, 2016—3,800-Pound Yield, 4-Row Equipment
Item
Quantity and Unit
Price or Cost per Unit ($)
Total per Acre ($)
Your Farm
1. GROSS RECEIPTS
Peanuts
3,800 lb
0.20
760.00
Total Receipts
760.00
2. VARIABLE COSTS*
Seed
110.00 lb
.088
96.80
Inoculant
1.00 acre
6.00
6.00
Fertilizer
Nitrogen
15.00 lb
0.63
9.45
Phosphate
30.00 lb
0.60
18.00
Potash
90.00 lb
0.42
37.80
Manganese
3.00 lb
0.35
1.05
Boron
2.50 lb
3.13
7.83
Lime (prorated)
0.50 ton
47.50
23.75
Gypsum
0.60 ton
58.70
35.22
Herbicides
1.00 acre
51.79
51.79
Insecticides
1.00 acre
37.37
37.37
Fungicides
1.00 acre
83.02
83.02
Scouting
1.00 acre
8.00
8.00
Hauling
1.90 ton
12.00
22.75
Drying & Cleaning
1.90 ton
45.00
85.33
State Check-off Fee
1.90 ton
3.00
5.69
National Assessment
$760.00
0.01
7.60
Crop Insurance
1.00 acre
30.00
30.00
Tractor/Machinery
1.00 acre
59.86
59.86
Labor
3.78 hours
10.23
38.67
Interest on Operating Capital
$253.31
5.30%
13.30
Total Variable Costs
679.28
3. INCOME ABOVE VARIABLE COSTS
80.72
4. FIXED COSTS
Tractor/Machinery
1.00 acre
133.91
133.91
Total Fixed Costs
133.91
5. TOTAL COSTS
813.19
6. NET RETURNS TO LAND, RISK, & MANAGEMENT
-53.19
Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, or land rent.9
Table 1-2. Estimated Costs and Returns Per Acre of RUNNER CONVENTIONAL-TILL Peanuts. 2016—3,800-Pound Yield, 4-Row Equipment
Item
Quantity and Unit
Price or Cost per Unit ($)
Total per Acre ($)
Your Farm
1. GROSS RECEIPTS
Peanuts
3,800 lb
0.20
760.00
Total Receipts
760.00
2. VARIABLE COSTS
Seed
110.00 lb
0.88
96.80
Inoculant
1.00 acre
6.00
6.00
Fertilizer
Nitrogen
15.00 lb
0.63
9.45
Phosphate
30.00 lb
0.60
18.00
Potash
90.00 lb
0.42
37.80
Boron
2.50 lb
3.13
7.83
Manganese
3.00 lb
0.35
1.05
Lime (prorated)
0.50 ton
47.50
23.75
Gypsum
0.60 ton
58.70
35.22
Herbicides
1.00 acre
38.80
38.80
Insecticides
1.00 acre
37.22
37.22
Fungicides
1.00 acre
82.87
82.87
Scouting
1.00 acre
8.00
8.00
Hauling
1.90 ton
12.00
22.75
Drying & Cleaning
1.90 ton
45.00
85.33
State Check-off Fee
1.90 ton
3.00
5.69
National Assessment
$760.00
0.01
7.60
Crop Insurance
1.00 acre
30.00
30.00
Tractor/Machinery
1.00 acre
63.14
63.14
Labor
3.76 hour
10.23
40.10
Interest on Operating Capital
$249.02
5.30%
13.07
Total Variable Costs
670.48
3. INCOME ABOVE VARIABLE COSTS
89.52
4. FIXED COSTS
Tractor/Machinery
1.00 acre
131.17
131.17
Total Fixed Costs
131.17
5. TOTAL COSTS
801.65
6. NET RETURNS TO LAND, RISK, & MANAGEMENT
-41.65
Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, or land rent.10
Table 1-3. Estimated Costs and Returns Per Acre of VIRGINIA STRIP-TILL Peanuts, 2016—3,800-Pound Yield, 4-Row Equipment
Item
Quantity and Unit
Price or Cost/ Unit ($)
Total per Acre ($)
Your Farm
1. GROSS RECEIPTS
Peanuts
3,800 lb
0.23
874.00
Total Receipts
874.00
2. VARIABLE COSTS
Seed
130.00 lb
0.93
120.90
Inoculant
1.00 acre
6.00
6.00
Fertilizer
Nitrogen
15.00 lb
0.63
9.45
Phosphate
30.00 lb
0.60
18.00
Potash
90.00 lb
0.42
37.80
Manganese
3.00 lb
0.35
1.05
Boron
2.50 lb
3.13
7.83
Lime (prorated)
0.50 ton
47.50
23.75
Gypsum
0.60 ton
58.70
35.22
Herbicides
1.00 acre
51.79
51.79
Insecticides
1.00 acre
37.37
37.37
Fungicides
1.00 acre
83.02
83.02
Scouting
1.00 acre
8.00
8.00
Hauling
1.90 ton
12.00
22.75
Drying & Cleaning
1.90 ton
45.00
85.33
State Check-off Fee
1.90 ton
3.00
5.69
National Assessment
$874.00
0.01
8.74
Crop Insurance
1.00 acre
30.00
30.00
Tractor/Machinery
1.00 acre
59.86
59.86
Labor
3.78 hours
10.23
38.67
Interest on Operating Capital
$269.36
5.30%
14.14
Total Variable Costs
705.36
3. INCOME ABOVE VARIABLE COSTS
168.64
4. FIXED COSTS
Tractor/Machinery
1.00 acre
135.74
135.74
Total Fixed Costs
135.74
5. TOTAL COSTS
841.10
6. NET RETURNS TO LAND, RISK, & MANAGEMENT
$32.90
Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, and land rent.11
Table 1-4. Estimated Costs and Returns Per Acre of VIRGINIA CONVENTIONAL-TILL Peanuts, 2016—3,800-Pound Yield, 4-Row Equipment
Item
Quantity and Unit
Price or Cost per Unit ($)
Total per Acre ($)
Your Farm
1. GROSS RECEIPTS
Peanuts
3800 lb
0.23
874.00
Total Receipts
874.00
2. VARIABLE COSTS
Seed
130.00 lb
0.93
120.90
Inoculant
1.00 acre
6.00
6.00
Fertilizer
Nitrogen
15.00 lb
0.63
9.45
Phosphate
30.00 lb
0.60
18.00
Potash
90.00 lb
0.42
37.80
Manganese
3.00 lb
0.35
1.05
Boron
2.50 lb
3.13
7.83
Lime (prorated)
0.50 ton
47.50
23.75
Gypsum
0.60 ton
58.70
35.22
Herbicides
1.00 acre
38.80
38.80
Insecticides
1.00 acre
37.22
37.22
Fungicides
1.00 acre
82.87
82.87
Scouting
1.00 acre
8.00
8.00
Hauling
1.90 ton
12.00
22.75
Drying & Cleaning
1.90 ton
45.00
85.33
State Check-off Fee
1.90 ton
3.00
5.69
National Assessment
$874.00
0.01
8.74
Crop Insurance
1.00 acre
30.00
30.00
Tractor/Machinery
1.00 acre
63.14
63.14
Labor
3.92 hour
10.23
40.10
Interest on Operating Capital
$261.07
5.30%
13.71
Total Variable Costs
696.36
3. INCOME ABOVE VARIABLE COSTS
177.64
4. FIXED COSTS
Tractor/Machinery
1.00 acre
132.99
132.99
Total Fixed Costs
132.99
5. TOTAL COSTS
829.35
6. NET RETURNS TO LAND, RISK, & MANAGEMENT
$44.65
Please note: This budget is for planning purposes only. It does not include sprays for Sclerotinia blight, fumigation for CBR, and land rent.12
Table 1-5. Return to Land, Overhead, and Management for Peanut at Various Yields and Costs of Production for Peanut
Peanut Yield (pounds/acre)
Net Return ($/acre) at $600/ton Potential Contract Price
Total Cost ($/acre)
750
800
850
900
950
1000
Net Return ($/acre)
3000 (1.5 tons)
150
100
50
0
-50
-100
3500 (1.75 tons)
300
250
200
150
100
50
4000 (2 tons)
450
400
350
300
250
200
4500 (2.25 tons)
600
550
500
450
400
350
5000 (2.5 tons)
750
700
650
600
550
500
Peanut Yield (pounds/acre)
Net Return ($/acre) at $535/ton Reference Price Over Potential Contract Price
Total Cost ($/acre)
750
800
850
900
950
1000
Net Return ($/acre)
3000 (1.5 tons)
53
3
-47
-97
-147
-197
3500 (1.75 tons)
186
136
86
36
-14
-64
4000 (2 tons)
320
270
220
170
120
70
4500 (2.25 tons)
454
404
354
304
254
204
5000 (2.5 tons)
588
538
488
438
388
338
Peanut Yield (pounds/acre)
Net Return ($/acre) at $470/ton Loan Rate Plus Payment Rate
Total Cost ($/acre)
750
800
850
900
950
1000
Net Return ($/acre)
3000 (1.5 tons)
-45
-95
-145
-195
-245
-295
3500 (1.75 tons)
73
23
-27
-77
-127
-177
4000 (2 tons)
190
140
90
40
-10
-60
4500 (2.25 tons)
308
258
208
158
108
58
5000 (2.5 tons)
425
375
325
275
225
175
Continued on the next page.13
Table 1-5. Return to Land, Overhead, and Management for Peanut at Various Yields and Costs of Production for Peanut (continued)
Peanut Yield (pounds/acre)
Net Return ($/acre) at $405/ton Estimated Average World Price
Total Cost ($/acre)
750
800
850
900
950
1000
Net Return ($/acre)
3000 (1.5 tons)
-143
-193
-243
-293
-343
-393
3500 (1.75 tons)
-41
-91
-141
-198
-241
-291
4000 (2 tons)
60
10
-40
-90
-140
-190
4500 (2.25 tons)
161
111
61
11
-39
-89
5000 (2.5 tons)
263
213
163
113
63
13
Peanut Yield (pounds/acre)
Net Return ($/acre) at $355/ton Loan Rate
Total Cost ($/acre)
750
800
850
900
950
1000
Net Return ($/acre)
3000 (1.5 tons)
-218
-268
-318
-368
-418
-468
3500 (1.75 tons)
-129
-179
-229
-279
-329
-379
4000 (2 tons)
-40
-90
-140
-190
-240
-290
4500 (2.25 tons)
49
-1
-51
-101
-151
-201
5000 (2.5 tons)
138
88
-12
-62
-112
-16214
Table 1-6. Return to Land, Overhead, and Management for Peanut at Various Yields and Costs of Production for Corn
Corn Yield (bushels/acre)
Net Return ($/acre) at $3/bushel Price
Total Cost ($/acre)
400
450
500
550
600
Net Return ($/acre)
60
-220
-270
-320
-370
-420
90
-130
-180
-230
-280
-330
120
-40
-90
-140
-190
-240
150
50
0
-50
-100
-150
180
140
90
40
-10
-60
Corn Yield (bushels/acre)
Net Return ($/acre) at $5/bushel Price
Total Cost ($/acre)
400
450
500
550
600
Net Return ($/acre)
60
-100
-150
-200
-250
-300
90
50
0
-50
-100
-150
120
200
150
100
50
0
150
350
300
250
200
150
180
500
450
400
350
300
Corn Yield (bushels/acre)
Net Return ($/acre) at $7/bushel Price
Total Cost ($/acre)
400
450
500
550
600
Net Return ($/acre)
60
20
-30
-80
-130
-180
90
230
180
130
80
30
120
440
390
340
290
240
150
650
600
550
500
450
180
860
810
760
710
66015
Table 1-7. Return to Land, Overhead, and Management for Peanut at Various Yields and Costs of Production for Grain Sorghum
Grain Sorghum Yield (bushels/acre)
Net Return ($/acre) at $2.55/bushel Price
Total Cost ($/acre)
350
400
450
500
550
Net Return ($/acre)
60
-197
-247
-297
-347
-397
90
-121
-171
-221
-271
-321
120
-44
-94
-144
-194
-244
150
33
-17
-67
-117
-167
180
109
159
209
259
309
Grain Sorghum Yield (bushels/acre)
Net Return ($/acre) at $4.25/bushel Price
Total Cost ($/acre)
350
400
450
500
550
Net Return ($/acre)
60
-95
-145
-195
-215
-265
90
33
-17
-67
-117
-167
120
160
110
60
10
-40
150
288
238
188
138
88
180
415
365
315
265
215
Grain Sorghum Yield (bushels/acre)
Net Return ($/acre) at $6.15/bushel Price
Total Cost ($/acre)
350
400
450
500
550
Net Return ($/acre)
60
19
-31
-81
-131
-181
90
204
154
104
54
4
120
388
338
288
238
188
150
573
523
473
423
373
180
757
707
657
607
55716
Table 1-8. Return to Land, Overhead, and Management for Peanut at Various Yields and Costs of Production for Cotton
Cotton Yield
(pounds lint/acre)
Net Return ($/acre) at $0.60/pound Price
Total Cost ($/acre)
500
550
600
650
700
Net Return ($/acre)
300
-320
-370
-420
-470
-520
600
-140
-190
-240
-290
-340
900
40
-10
-60
-110
-160
1200
220
170
120
70
20
1500
400
350
300
250
200
Cotton Yield
(pounds lint/acre)
Net Return ($/acre) at $0.80/pound Price
Total Cost ($/acre)
500
550
600
650
700
Net Return ($/acre)
300
-260
-310
-360
-410
-460
600
-20
-70
-120
-170
-220
900
220
170
120
70
20
1200
460
410
360
310
260
1500
700
650
600
550
500
Cotton Yield
(pounds lint/acre)
Net Return ($/acre) at $1.00/pound Price
Total Cost ($/acre)
500
550
600
650
700
Net Return ($/acre)
300
-200
-250
-300
-350
-400
600
100
50
0
-50
-100
900
400
350
300
250
200
1200
700
650
600
550
500
1500
1000
950
900
850
80017
Table 1-9. Return to Land, Overhead, and Management for Peanut at Various Yields and Costs of Production for Soybean
Soybean Yield (bushels/acre)
Net Return ($/acre) at $6/bushel Price
Total Cost ($/acre)
160
190
220
250
280
Net Return ($/acre)
20
-40
-70
-100
-130
-160
30
20
-10
-40
-70
-100
40
80
50
20
-10
-40
50
140
110
80
50
20
60
200
170
140
110
80
Soybean Yield (bushels/acre)
Net Return ($/acre) at $10/bushel Price
Total Cost ($/acre)
160
190
220
250
280
Net Return ($/acre)
20
40
10
-20
-50
-80
30
140
110
80
50
20
40
240
210
180
150
120
50
340
310
280
250
220
60
440
410
380
350
320
Soybean Yield (bushels/acre)
Net Return ($/acre) at $14/bushel Price
Total Cost ($/acre)
160
190
220
250
280
Net Return ($/acre)
20
120
90
60
30
0
30
260
230
200
170
140
40
400
370
340
310
280
50
540
510
480
450
420
60
680
650
620
590
56018
Table 1-10. Return to Land, Overhead, and Management for Peanut at Various Yields and Costs of Production for Wheat
Wheat Yield
(bushels/acre)
Net Return ($/acre) at $3/bushel Price
Total Cost ($/acre)
250
300
350
400
450
Net Return ($/acre)
50
-100
-150
-200
-250
-300
65
-55
-105
-155
-205
-255
80
-10
-60
-110
-160
-210
95
35
-15
-65
-115
-165
110
80
30
-20
-70
-120
Wheat Yield
(bushels/acre)
Net Return ($/acre) at $5/bushel Price
Total Cost ($/acre)
250
300
350
400
450
Net Return ($/acre)
50
0
-50
-100
-150
-200
65
75
25
-25
-75
-125
80
150
100
50
0
-50
95
225
175
125
75
25
110
300
250
200
150
100
Wheat Yield
(bushels/acre)
Net Return ($/acre) at $7/bushel Price
Total Cost ($/acre)
250
300
350
400
450
Net Return ($/acre)
50
100
50
0
-50
-100
65
205
155
105
55
5
80
310
260
210
160
110
95
415
365
315
265
215
110
520
470
420
370
32019
2. PEANUT SEED
David Jordan
Extension Specialist—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,
• 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,20
• 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 six 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, 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 market type varieties and their level of protection.21
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, or 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.
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
Yes
Sullivan
Yes
Only with permission
Yes
Wynne
Yes
Only with permission
Yes22
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. In recent years yields have increased significantly with several records set since 2011. Several factors have contributed to high yields and include improved genetics, production of peanut on soils that are adapted to peanut production, long rotations that minimize impact of disease, availability of plant protection products for virtually all pests, and skills of famers and their support staff that manage peanut extremely well. In North Carolina weather conditions can have a major impact on yield given only 15% of acreage is irrigated. But given good weather conditions, average yields of two tons per acre are now common in North Carolina.
STAND ESTABLISHMENT
Soil temperatures need to be above 65°F 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 seven days for smaller-seeded varieties like Bailey and in 10 days for larger-seeded varieties like Wynne.
Peanuts should not be planted until the soil temperature at a 4-inch depth is 65°F or above at noon for three 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. This generally means setting the planter to deliver five seeds per foot of row. 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 differing maturity dates will permit efficient use of limited harvesting and curing capacities. Planting varieties with 23
different genetic pedigrees reduces the risk of crop failure because of adverse weather or unexpected disease epidemics. In recent years the variety Bailey has become the dominant variety in North Carolina because of its high yield potential and disease resistance. There is concern that heavy reliance on this variety will increase risk that is often minimized by planting a group of varieties on each farm.
The selection of a variety should be based on more than one year’s data. Performance of our most popular peanut varieties from reports prepared by Dr. Tom Isleib (peanut breeder at NC State University) and Dr. Maria Balota’s PVQE (Peanut Variety and Quality Evaluation) program is presented in Tables 3-1 and 3-2, respectively. Yield data from research stations and by David Jordan and Dewayne Johnson (North Carolina Cooperative Extension) are presented in Table 3-3. Varietal characteristics are listed in Table 3-4. Disease reaction of varieties can be found in Chapter 6, “Peanut Disease Management.”
Table 3-1. Pod Yield and Market Grade Characteristics of Bailey and Sugg Compared with Other Commercially Available Virginia Market Type Varieties
Variety
% Fancy
% ELK
% SMK
Meat Content (%)
Yield
(lb/acre)
Bailey
84
42
65
72
4,650
Sugg
87
45
64
72
4,378
Gregory
92
48
63
69
4,299
CHAMPS
86
40
64
71
4,378
Sullivan
85
44
64
71
4,415
Wynne
90
44
62
70
4,381
Spain
91
42
54
67
4,030
Georgia 08V
88
49
64
74
4,571*Data are from Isleib et al. (March 2014) and are pooled over 20 tests over five years except Spain (only 7 tests).
Table 3-2. 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
(lb/acre)
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
Sugg
84
49
66
75
5,230*Data are from Balota et al. (PVQE Director) from 2009 – 2013.24
Table 3-3. Comparison of Yield from Commercially Available Varieties Planted in Mid-May During 2012 (Lewiston) or 2013 (Rocky Mount). Yield in Pounds Per Acre.
Name
2012
2013
Sept. 28
Oct. 17
Highest of Dig Dates
Sept. 27
Oct. 18
Highest of Dig Dates
Spain
5,688
6,137
6,137
5,428
5,501
5,501
CHAMPS
5,270
5,986
5,986
6,161
5,146
6,161
Sugg
5,234
6,186
6,186
5,831
5,462
5,831
Perry
4,993
6,046
6,046
6,125
5,200
6,125
Bailey
5,075
5,932
5,932
6,627
5,765
6,627
VARIETY CHARACTERISTICS
Bailey is a 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 stem rot. Seed size for Bailey is small compared with all other Virginia market types.
CHAMPS is a large-seeded peanut that matures slightly earlier than other varieties. 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. 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.
Sugg is a 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.
Spain is a large-seeded Virginia market type peanut that has high yield potential under irrigation. Pod size is similar to or larger than Gregory. Spain matures later than all other Virginia market types. Spain is an exclusive variety available only through Birdsong Peanut Company.
Sullivan is a large-seeded Virginia market type that possess the high-oleic trait and offers some resistance to some of the key diseases found in peanut in North Carolina. This variety does not have excessive vine growth like Bailey and has yielded well in many trials. Pod size is larger than Bailey but not as large as Gregory or Wynne.25
Wynne is a large-seeded Virginia market type possessing the high-oleic trait like Sullivan and offers some resistance to some of the key diseases. Pod size is larger than all Virginia market types except Gregory.
Table 3-4. Varietal Characteristics
Factors
Bailey
CHAMPS
Gregory
Sugg
Sullivan
Wynne
Growth habit
(R = runner; SR = semi-runner)
SR
R
R
SR
R
SR
Heat unit requirement
2,590
2,550
2,650
2,630
2,630
2,700
Comparative days to optimum maturity
+2
0
+6
+4
+4
+8
Seed per pound
600
535
450
575
575
450
Need for calcium
(M = moderate; H = high)
M
M
H
M
M
H
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.
SELECTING AND MANAGING SOIL RESOURCES
Peanuts are best adapted to well-drained, sandy loam soils, such as Norfolk, Orangeburg, and Goldsboro sandy loam soils. 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. 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 same field. Research shows that long rotations are best for maintaining peanut yields and quality. Benefits and potential problems associated with crops typically found within 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 and cotton. 26
In recent years, there has been interest in crop yields, especially grains, when transitioning out of traditional peanut rotations. Results indicate that corn, cotton, soybeans, and wheat are not affected by rotation to the extent that peanuts are affected. Peanut was planted in these trials during 2013, and results indicate that the effects of rotation on peanut noted earlier are minimized when peanut is not included in the field for six years. 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. 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. Cotton yield did not differ during 2012 when compared to planting after tall fescue or agronomic crops. Peanut yield during 2013 was higher following tall fescue. In other research peanut yield following grain sorghum was similar to that of peanut following corn or cotton. Sweet potato is a good rotation crop for peanut, while some decreases in peanut yield have been observed when peanut follows sage. Growers should plant corn, cotton, or grain sorghum for at least one year following sage before planting peanut.
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 3-5. 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 land plaster) can reduce peanut yield when soil pH in the pegging zone is relatively low (Table 3-6). 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 27
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 3-5. Crop Response to Soil pH
Approximate Soil pH
Percentage of Yield at Lower pH Values Compared with Yield at pH 5.9
Corn
Cotton
Peanut
Soybean
Wheat
Grain Sorghum
4.3
26
24
55
45
41
78
4.9
76
57
62
62
72
83
5.4
99
89
83
90
100
94
5.9
100
100
100
100
100
100
Years
2
2
3
2
2
2
Table 3-6. Peanut Response to Gypsum Rate at Three Soil pH Values
Relative Gypsum Rate
Soil pH
5.0
5.5
6.0
0
1,920
2,720
2,900
0.5X
1,930
2,690
3,320
1.0X
2,110
2,190
3,250Data are pooled over three 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. 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 3-7 are from multiple locations and years and give an indication of the possible response of peanuts to inoculant applied as a liquid or granular in the seed furrow. These data demonstrate that while peanut response to rotation is often predictable, 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. Generally, a peanut plant with 15 nodules by 40 days after emergence has adequate nodulation. Oftentimes foliar symptoms of nitrogen deficiency will be apparent by this time if 28
nodulation is not effective. Later in the season the plant will need many more nodules, more than 100, for optimum growth, development, and yield. If fewer than 15 nodules are noted 40 days after emergence, especially if peanut foliage is yellow, growers should consider application of ammonium sulfate.
Table 3-7. Peanut Yield Response in Fields without a History of Peanuts versus Fields with Frequent Plantings of Peanuts (1999–2014)
Inoculant Use
New Peanut Fields
Fields with a Recent History of Peanuts
No inoculant
3,507
4,256
Inoculant
5,072
4,454
Difference
1,565
198
Number of Trials
35
35
Years
1999–2014
1999–2014
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. Delivering granular or in-furrow sprays above seed placement also will compromise effectiveness of systemic insecticides and fungicides.
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. 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 90 to 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 (Table 3-8). Economic return on investment of inoculant and various rates of ammonium sulfate are also compared in Table 3-8 at a peanut price of $560/ton and fertilizer cost of $0.29/pound ammonium sulfate. While a rate of 90 pounds of nitrogen is the most economically effective, in some trials 120 pounds of nitrogen were needed when late-season rainfall was excessive. Lower rates also may be effective but perform inconsistently. Research also suggests that ammonium sulfate is a more effective source than ammonium nitrate. Split applications may be more efficient than a single application. 29
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 3-8. Peanut Response to Ammonium Sulfate in New Ground with Observable Nitrogen Deficiency in Leaves. Data are pooled over 10 experiments from 2007–2014. Ammonium sulfate cost of $0.29/lb and peanut price of $0.28/lb ($560/ton).
Ammonium Sulfate Rate
Actual Nitrogen Rate
Ammonium Sulfate or Inoculant Cost
Actual Peanut Yield
Peanut Yield above No-Inoculant and No-Ammonium Sulfate Control
Economic Return above Inoculant or Ammonium Sulfate Cost
lb/acre
lb/acre
$/acre
lb/acre
lb/acre
$/acre
0
0
0
3,161
–
–
285
60
83
3,867
692
111
428
90
124
4,163
991
154
571
120
166
4,225
1,061
131
714
150
207
4,261
1,094
99
Inoculant
0
8
4,335
1,261
345
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 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.30
Calcium
Perhaps the most critical element in the production of large-seeded Virginia market type peanuts is calcium. Lack of calcium uptake by peanuts causes “pops” and is often reflected as 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 to the peg and pod and developing kernels. 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 for 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.
Gypsum 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 3-9.
Table 3-9. 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 North Carolina Department of Agriculture and Consumer Services.
**Buckshot is considered a lime by-product material and not a gypsum product.31
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 3-9. 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 3-9. Data from twelve trials (Table 3-10) indicate that gypsum at rates below those recommended in Table 3-9 can, in some cases, be effective.
Table 3-10. Pod Yield Following Application of Gypsum at 0.5 and 1 Times (X) the Recommended Use Rate for Virginia Market Types.
Pod Yield (lb/acre)
No. of Trials
Pod Yield (lb/acre)
No Gypsum
0.5X
Gypsum
1.0X
Gypsum
Actual yield
12
3,970
4,510
4,590
Increase in yield over no-gypsum control
—
—
540
620
In some years, for example 2013, excessive rainfall occurred during June and July after gypsum had been applied. If rainfall exceeding 5 inches occurs over a short period of time within a few weeks after gypsum is applied, growers should consider applying a rate of 0.5X the normal use rate to make sure sufficient calcium is in soil during the entire period of reproductive growth. Likewise, if growers cannot get into fields to apply gypsum on time due to wet soils, gypsum still needs to be applied even if application is delayed until early to mid-August. While liquid calcium products are available, they are not a substitute for gypsum.32
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 to 2005 at two locations, during each year, indicated that a rate of gypsum 1.5 times the recommended rate did not increase pod yield over the normal use rate in most experiments. 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 3-9.
In recent years runner market type varieties referred to as “jumbo runners” have become more popular. These varieties, such as Georgia 06G, 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 3-9).
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 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 pound elemental boron per acre is provided in Table 3-11. Similarly, the amount of formulated manganese product needed to supply 1.0 pound of manganese per acre or two applications of 0.5 pounds of manganese spaced 10 to 14 days apart is provided in Table 3-12. Lower rates of 33
boron or manganese are often applied for “maintenance.” Growers should make sure the product they purchase supplies the amount of boron or manganese the plant needs.
Table 3-11. 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 3-12. 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.
Step 1. Figure the weight of manganese per gallon by multiplying the percentage 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 per acre desired = 1.2 gal 8% manganese product per acre
0.84 lb manganese per gal34
LAND PREPARATION
Historically, peanut growers have planted into conventionally prepared seedbeds to obtain a smooth, uniform, residue-free seedbed for planting. The effectiveness of burial of old crop residue and weed seed in the long-term suppression of soilborne diseases and short-term suppression of some weed problems was noted when the moldboard plow was used. However, only 7% of acres were treated this way, based on a 2009 survey in North Carolina (Table 3-13), in part because newer plant protection products are very effective. There is also 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 3-13.
Table 3-13. Percentage of Farmers Using Certain Tillage Practices on at Least a
Portion of Their Farms
Tillage
1998
2004
2009
2014
Disk
90
78
71
75
Chisel
25
23
27
12
Moldboard plow
58
17
7
5
Field cultivate
75
55
42
44
Rip and bed
49
39
40
55
Bed
44
35
32
25
Reduced tillage
10
23
41
20
There is concern about stratification of nutrients in reduced-tillage systems. For example, repeated applications of potassium in reduced-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 the 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 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 3-14.35
Table 3-14. Peanut Yield Response to Tillage Practices in North Carolina,1999–2013. A positive value indicates that yield of peanut in conventional tillage exceeded yield of peanut in reduced tillage.
No. of Trials
Years
Actual Yield Difference
(lb/acre)
Yield Difference (%)
Range of
Yield Difference (%)
65
1997–2013
+132
+3.4
-16.1 to +27.5
Table 3-15. 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 points
Goldsboro and Lynchburg…20 points
Norfolk…10 points
Conetoe and Wanda…0 points
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…35 points
Strip tillage into flat ground…10 points
Strip tillage into stale seedbeds…0 points
Peanut response to reduced-tillage systems is invariably correlated with the degree of tillage. Efficient digging can be difficult when peanuts are planted in flat ground in reduced-tillage systems. Although 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:
35 or Less—Low Risk
40 to 50—Moderate Risk
60 or more—High risk
Total index value
Your score: 36
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 demonstrated that wheat, cereal (cover crop), rye, oats, and triticale can serve equally well as wheat when used as a cover crop 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 3-15). 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 systems, primarily because of the digging requirement. The risk advisory index has been modified from the initial version. A positive value indicates that yield was higher in conventional tillage than in reduced tillage.
PLANTING
Varieties grown in North Carolina can require as many as 160 days for full pod maturity, depending upon soil moisture and temperature. Along with yield and market grades, 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 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.
Data for the variety Bailey during 2013, 2014, and 2015 exposed to three planting dates when peanut was dug at optimum maturity based on pod mesocarp color are provided in Table 3-16. Yield was notably lower when peanut was planted in early May compared with mid-May or late-May plantings. During 2014, when peanut was dug at optimum maturity, yield was highest (5,682 or 5,660 pounds per acre) with early and mid-May planting compared with late May (5,289 pounds per acre).
Table 3-16. Yield (lb/acre) of the Variety Bailey as Influenced by Planting Dates at Lewiston-Woodville during 2013, 2014, and 2015.
Planting Date
2013
2014
2015
May 3–4
5,157
5,228
4,921
May 16–19
6,423
4,838
6,495
May 28
6,875
4,131
4,61237
Seeding Rates and Twin Rows
Table 3-17 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.
Table 3-17. 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
CHAMPS
535
76
102
127
Gregory
450
97
129
161
Sugg
575
76
101
126
Florida 07*
650
64
87
110
Georgia 06G*
650
64
87
110
Sullivan
575
76
101
126
Wynne
450
97
129
161
*Denotes runner market types. All other varieties are Virginia market types.
In the Southeast, less tomato spotted wilt virus has been associated with twin row plantings than with single rows. Similar results have been observed in North Carolina. Higher plant populations and closer row spacings often result in fewer symptoms of virus. Pod yield of peanut in twin rows was higher than yield of single rows by 235 pounds per acre (Table 3-18). 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 five 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, this 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 3-18. Peanut Yield Response to Twin Row Planting
Planting Pattern
Pod Yield (pounds/acre)
Single Rows
3,760
Twin Rows
3,995
Difference
235
Number of Trials
2038
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% 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 3-19, 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 indicate that this approach to irrigation is feasible. As expected, corn yield was affected more than cotton or peanut yield by irrigation. Peanut yield was maintained more effectively than cotton in dry years without irrigation. These data give a good indication of yield under growing conditions where water is not limiting relative to dry-land production for these crops.
Table 3-19. Impact of Irrigation on Production and Pest Management Strategies
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.
Table 3-19. Impact of Irrigation continues on the next page.39
Table 3-19. Impact of Irrigation on Production and Pest Management Strategies
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 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 peanuts 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 nonirrigated, 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.
DETERMINING MATURITY
Maturity affects flavor, grade, milling quality, and shelf life. Not only do mature peanuts have the quality characteristics that the consumer desires; they are also 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.40
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.41
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.
Heat units, or growing degree days (DD), can be a means of determining maturity. One growing degree day (base 56°F) accumulates when the average daily high and low temperature is 57°F. If the average daily high and low temperatures were 76°F, 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 to 2015 is presented in Table 3-20. 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°F from October 1 to 4 and essentially eliminated any further maturation of pods. During 2012 at this location, daily lows of 46°F were noted on two consecutive days (September 24 and 25). Temperature was between 42 and 45°F on four consecutive days from October 11 to October 14, 2012. However, during 2012 temperature and heat units in early October increased considerably compared with other years, allowing peanut to continue maturing.
Table 3-20. Average Heat Unit Accumulation per Day (DD56) from May 16 through November 1 at Lewiston-Woodville for Various Categories
Time period
Average for the Interval Described
2009
2010
2011
2012
2013
2014
2015
May 16–June 15
17.8
19.1
20.7
15.4
17.6
15.9
19.5
June 16–July 15
20.1
24.5
25.2
23.0
21.2
22.5
25.5
July 16–August 15
22.9
26.3
28.0
24.8
22.4
18.9
23.5
August 16–September 15
18.5
20.9
21.3
20.2
20.9
20.0
23.5
September 16–October 15
11.9
14.4
11.1
20.3
10.6
11.1
12.8
October 16–November 1
7.1
9.3
1.3
4.5
3.8
2.9
2.8
Pod yields from 2012 to 2014 for the variety Bailey are presented over six digging dates starting in early September and occurring on intervals of approximately one week (Figure 3-3). While yields increased as digging was delayed during 2012 and 2013 well into October, a more typical yield curve for digging trials was observed in 2014. Many peanut fields had a very "tight" maturity profile during 2014 compared 42
with previous years. Although this characteristic can increase yield and market grades, if digging is delayed past the optimum window, yield can decrease more rapidly. A typical response of peanut to digging date can also be seen for the variety Gregory and includes both yield and key market grade factors (Figure 3-4).
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 three days, and in many cases more than three days, are needed between the time of digging and frost to allow sufficient drying to prevent freeze damage.
Digging and harvest capacity for growers are important to consider. The speed at which growers can plant peanuts is not the same as the time and labor 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 with no interruptions. 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 harvest 15 to 20 acres in a day, respectively. Weather conditions can have a tremendous impact on the number of hours peanut can be dug and combined in a given day, and the estimates provided here relative to time represent a best-case scenario.
As stated previously, both planting and digging date can have an impact on peanut yield and quality. Disease can have an impact on peanut response to digging date. Results with Dr. Barbara Shew from research conducted with the variety Gregory over six years demonstrate the value of digging peanut at optimum maturity (October 15 and controlling foliar disease (five-spray fungicide program) (Table 3-21). Yield increased by 400 to 550 lb/acre over the three digging intervals (September 20 to October 15).
Digging very early resulted in lower yields even when disease was controlled. The balance between pod loss from disease and immature peanut resulted in no 43
0 10 20 30 40 50 60 70 80 90 100 128 135 146 153 160 Yield ELK TSMK Digging Date (days after planting) Percent of Maximum Yield
Figure 3-4. Pod yield (lb/acre) and percentages of extra large kernels (ELK) and total sound mature kernels (TSMK) for the variety Gregory to digging date. Data are from 18 trials during 2003 – 2013.
Figure 3-3. Response of the variety Bailey to digging date. Peanut was planted approximately May 3 during 2012, 2013, and 2014.
0 10 20 30 40 50 60 70 80 90 100 10-Sep 17-Sep 24-Sep 1-Oct 8-Oct 15-Oct 2012 2013 2014 Digging Date Percent of Maximum Yield 44
difference in yield across digging dates. See Chapter 6 for more information on disease management in peanuts.
Table 3-21. Percent Canopy Defoliation, Pod Yield, and Percentage of Extra Large Kernels for the Variety Gregory as Influenced by the Interaction of Digging Date and Fungicide
Digging date
Fungicide program
None
2 sprays
5 sprays
Canopy defoliation (%)
September 20
22 c
9 d
3 e
October 5
38 b
15 d
3 e
October 15
57 a
41 b
4 e
Pod yield (pounds/acre)
September 20
3200 de
3,280 cd
3,540 bc
October 5
3230 d
3,290 cd
3,680 ab
October 15
2930 e
3,330 cd
3,880 a
Extra large kernels (%)
September 20
48 f
48 f
50 e
October 5
51 d
50 e
53 b
October 15
52 c
52 c
54 a
Means followed by the same letter are not significantly different, according to Fisher’s Protected LSD test at p < 0.05. Data are pooled over six experiments.
Adequate control of thrips continues to be very important to optimize yield in North Carolina. A trial was conducted during 2013 with the variety Bailey to determine the influence of planting date on thrips control and peanut yield with combinations of Thimet applied in the seed furrow and Orthene applied two weeks after peanut emergence. While several interactions were noted, the value of adequate thrips control is summarized in Table 3-22. While both Thimet and Orthene protected yield, the combination of both insecticides provided the greatest protection of yield. Thrips pressure was high during 2013 at this location during all of May and well into June. During 2014, results were slightly different than in 2013. The value of Orthene was less pronounced in 2014 with the in-furrow treatment the most effective approach. Thrips injury was higher in 2013 than 2014 and most likely contributed to the minor impact of Orthene on yield. Peanut did not respond to insecticide during 2015. While this was surprising, in some years peanuts are able to recover quickly from thrips feeding and yield is not reduced.
Thrips damage is generally more severe with early plantings in North Carolina due to cooler weather early in the season, which slows peanut growth and allows thrips damage to have a greater impact on plant recovery. Thrips populations can be lower when peanuts emerge from later plantings. 45
In a second trial involving planting dates at this location, the value of treating seed with fungicide was apparent relative to peanut yield at all three planting dates (Table 3-23). Yield was most likely lower due to poorer stands and less seedling vigor when seed was not treated with fungicide. Drs. Brandenburg and Shew will have more information on thrips management and seedling disease management in their respective chapters.
Table 3-23. Influence of Planting Date and Fungicide Seed Treatment on Peanut Stand and Pod Yield at Lewiston-Woodville during 2013, 2014, and 2015. Data are pooled over insecticide treatments.
Planting Date
Peanut Stand (Plants/20 ft of row)
Pod yield (lb/acre)
Fungicide Seed Treatment
Fungicide Seed Treatment
No
Yes
No
Yes
2013
May 4
56
80
2,597
4,544
May 16
55
72
4,736
5,420
May 28
71
86
5,273
6,001
2014
May 4
21
52
3,937
4,860
May 19
36
56
4,148
4,476
May 28
17
48
3,022
4,187
2015
May 4
45
95
4,024
4,535
May 19
73
102
5,703
5,803
May 28
75
83
4,912
5,503
Table 3-22. Interactions of Thimet and Orthene Spray Programs at Lewiston-Woodville during 2013, 2014, and 2015.
Insecticide
2013
2014
2015
In-furrow
Post-
emergence
Thrips Damage (Scale 0-5)
Pod Yield in lb/acre
(yield increase over nontreated control)
Thrips Damage
(Scale 0-5)
Pod Yield in lb/acre
(yield increase over nontreated control)
Thrips Damage (Scale 0-5)
Pod Yield in lb/acre
(yield increase over nontreated control)
No Thimet
No Orthene
3.3
5,232
2.3
4,741
2.6
5,238
Thimet
No Orthene
1.1
5,651 (384)
0.7
4,982 (241)
0.8
5,246 (8)
No Thimet
Orthene
1.7
5,642 (278)
1.0
4,780 (39)
1.0
5,295 (49)
Thimet
Orthene
0.5
5,878 (645)
0.4
4,972 (231)
0.3
5,278 (40)
Data are pooled over planting dates.46
RUNNER MARKET TYPES
There is some demand for runner market type peanut production in North Carolina. Part of this interest is related to market demand and sheller operations in the region. Runner production is also appealing to some growers because of potential savings in production of runners compared with Virginia market type peanuts (approximately 110 pounds of seed for runners versus 125 to 160 pounds of seed for Virginia market types and lower requirements for supplemental calcium by runner market types). Yield of runner market types often perform as well as the Virginia types.
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 four or more plants per row foot in single rows), planting twin rows, applying Thimet or Phorate in furrow, delaying planting until mid-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 and Kudos (prohexadione calcium) are registered for use in peanuts. Research has demonstrated that prohexadione calcium improves row definition, which can lead to increased efficiency in the digging and inversion process. Prohexadione calcium should be applied when 50% of vines from adjacent rows are touching. Sequential applications (7.2 ounces per acre followed by 7.2 ounces per acre) spaced two to three weeks apart are generally needed. Include crop oil concentrate and nitrogen solution (UAN) or ammonium sulfate with prohexadione calcium. 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, prohexadione calcium minimizes pod shed and pod loss during digging and harvesting operations. When pooled over 121 trials from 1997 to 2014, yield following two applications of prohexadione calcium was 96 pounds per acre higher than yield from nontreated peanut (4,223 versus 4,319 pounds per acre). 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. 47
However, in recent years with the variety Bailey, very few differences in yield with prohexadione calcium have been noted. While Apogee always improves row visibility, this characteristic has not always translated into yield increases with prohexadione calcium. The lack of yield response may be associated with excellent pod retention for Bailey, which would limit the value of prohexadione calcium in terms of yield increase.
Work conducted in cooperation with Dr. Gary Roberson in 2009 to 2011 compared benefits of Apogee with precision digging. In these studies Apogee did not affect peanut yield. However, yield increased with precision digging (Table 3-24). These data demonstrate the value of auto-steer relative to efficient peanut digging. See Chapter 7 for more details related to precision agricultural tools for peanuts. Investment in guidance systems for digging can be expensive. However, these systems have been very effective in minimizing challenges in digging, especially when vine growth is excessive, tractor operators are fatigued, and peanuts are not planted on beds. 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 3-24. Acres Required to Capture Investment Cost of Guidance System ($23,000). Data are pooled over four experiments and were conducted in cooperation with Gary Roberson.
Mode
Pod Yield
(pounds/acre)
Peanut Price ($/pound)
0.20
0.25
0.3
0.35
0.40
Manual steering
4,121
Guidance
4,574
Value of guidance
453
254
203
169
145
12748
4. PEANUT WEED MANAGEMENT
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. Finally, weeds interfere with fungicide movement into the peanut canopy, often referred to as deposition, and this can negatively affect disease control.
CROP ROTATION
Rotate peanuts with corn or cotton to help manage various pests, including weeds. Crop rotation allows the 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 can 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. Moving 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. Generally, in-season cultivation of peanuts is not recommended.
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 species present and note the general level of infestation of each species (light, moderate, or heavy). Weeds present 49
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 (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. More importantly, allowing herbicide-resistant biotypes to reproduce, especially when they are first appearing in fields, can result in a tremendous long-term problem. 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 are the competitive index values 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 weed50
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 one Palmer amaranth, five yellow nutsedge, four broadleaf signalgrass, and one sicklepod per 100 square feet (33 feet of row with rows spaced 3 feet apart) would reduce peanut yield by 16%, based on a projected weed-free yield of 4,500 pounds per acre (Table 4-2). Using WebHADSS and given a crop value of $535 per ton, adequate growing conditions (good soil moisture for satisfactory herbicide performance), and large size weeds (at least 4 inches tall), WebHADSS would provide the suggestions in Table 4-3 with various economic returns. In this example, peanuts were planted May 6 and emerged May 14. The field was scouted June 4 and herbicide sprayed soon thereafter. Although issues relative to accuracy and time required for weed scouting do exist, the WebHADSS program does allow a relatively quick and clear comparison of herbicide options while taking herbicide efficacy, herbicide cost, and economic return from that investment into account.
Table 4-2. Potential Yield and Economic Losses if Weeds Are Not Controlled as
Compared to Weed-Free Peanuts*
Weed species
Population
Yield Loss
(lb per acre)
Yield Loss
(% of weed-free yield)
Economic Loss
($ per acre)
Palmer amaranth
1
180
4.0
48
Sicklepod
1
162
3.6
43
Signalgrass
4
324
7.2
87
Yellow nutsedge
5
66
1.5
18
Total Estimated Loss
734
16.3
196*Anticipated yield of 4,500 pounds per acre and crop value of $535 per ton farmer stock peanuts.
Table 4-3. Ranking of Selected Herbicide Options Considering Efficacy and Economics*
Herbicide
Gain by Applying
Herbicide
($ per acre)
Cost of Weed
Control
($ per acre)
Paraquat
170
5.1
Cadre + 2,4-DB
144
29
Clethodim then Storm + 2,4-DB
121
33*Herbicide options other than these were listed. Includes adjuvant and application costs.51
COMMENTS ON PEANUT HERBICIDES
Preplant Burndown Herbicides
Glyphosate (various formulations) and Gramoxone SL (other formulations are available) 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 Herbicides
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.
COMPATIBILITY OF AGROCHEMICALS
Compatibility is an important consideration when applying two or more products in the same tank. See Chapter 9 for more information on agrochemical compatibility. Consult product labels, Chapter 9, and your local Extension agent for more information on agricultural chemical compatibility.52
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
1 Gramoxone 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.
2 Valor SX can be applied prior to planting up to 2 days after planting. See product label for information on sprayer cleanout.
3 E = 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%.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
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.
acetochlor
(Warrant) 3 ME, MOA 15
1.25 to 2 qt
0.94 to 1.5
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
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
PREPLANT INCORPORATED (continued)
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 and grain sorghum. 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
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
PREPLANT INCORPORATED (continued)
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
or
acetochlor (Warrant)
3 ME, 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
or
1.25 to 2 qt
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
or
0.94 to 1.5
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
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
or
acetochlor
(Warrant) 3 ME, MOA 15
followed by
diclosulam (Strongarm) 84 WDG, MOA 2
or
flumioxazin (Valor SX) 51 WDG, MOA 14
1.5 to 3 pt or
or
1.5 to 2 pt
or
1 to 1.33 pt
or
16 to 24 fl oz
or
1.25 to 2 qt
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
or
0.94 to 1.5
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 three or more days after planting. Significant injury from Valor SX was noted in 2001, 2004, 2006, 2009, and 2012, even when applied according to label recommendations. However, injury is generally transient and does not affect yield. Strongarm can carry over and injure corn and grain sorghum. 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
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
acetochlor
(Warrant) 3 ME, MOA 15
1.25 to 2 qt
0.94 to 1.558
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
PREEMERGENCE (continued)
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, 2006, 2009, and 2012, 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.
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
or
acetochlor (Warrant)
3 ME, MOA 15
2 oz
+
to 1.33 pt
or
16 to 21 fl oz
or
1.25 to 2 qt
0.063
+
0.95 to 1.27
1 to 1.33
or
0.75 to 1
or
0.94 to 1.5
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.59
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
PREEMERGENCE (continued)
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 and grain sorghum. 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.
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.60
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
PREEMERGENCE (continued)
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
or
acetochlor (Warrant)
3 ME, MOA 15
0.45 oz
+
1 to 1.33 pt
or
16 to 21 fl oz
or
1.25 to 2 qt
0.024
+
0.95 to 1.27
1 to 1.33
or
0.75 to 1
or
0.94 to 1.5
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, expecially relative to corn and grain sorghum. 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.61
Table 4-5. Herbicide Information for Peanuts
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. Add1 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
or
acetochlor
(Warrant) 3 ME, MOA 15
1 to 1.33 pt
or
1.25 to 2 qt
0.95 to 1.27
1 to 1.33
or
0.94 to 1.562
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
CRACKING STAGE (continued)
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.
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.63
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
POSTEMERGENCE (continued)
Annual broadleaf weeds
(continued)
acifluorfen
(Ultra Blazer) 2L, MOA 14
+
2,4-DB
(Butyrac 200) 2L, 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.
bentazon, MOA 6
(Basagran) 4 L, MOA 6
+
acifluorfen
(Ultra Blazer) 2L, 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. 64
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
POSTEMERGENCE (continued)
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.
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.
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.65
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
POSTEMERGENCE (continued)
Annual broadleaf weeds
(continued)
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.
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. Some weeds, especially Palmer amaranth, are resistant to Pursuit.
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.66
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
POSTEMERGENCE (continued)
Annual broadleaf weeds
(continued)
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.
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.67
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
POSTEMERGENCE (continued)
Annual broadleaf weeds
(continued)
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.
pyraflufen ethyl (ET) 2.5 EC, MOA 14
1 to 2 fl oz
0.02 to 0.04
Controls morningglories when applied alone and can improve control when mixed with paraquat and other broadleaf herbicides. Apply with nonionic surfactant at 1 quart/100 gal. Do not apply with crop oil concentrate. Can be applied up to 7 days prior to digging peanut.
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 significant thrips damage.68
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
POSTEMERGENCE (continued)
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.
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. 69
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
POSTEMERGENCE (continued)
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.
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.
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.70
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
POSTEMERGENCE (continued)
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 chapter 9 in this publication.
sethoxydim, MOA 1 (Poast) 1.5 EC
(Poast Plus) 1 EC
1 pt
1.5 pt
0.19
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 chapter 9 in this publication.
sethoxydim, MOA 1 (Poast) 1.5 EC
(Poast Plus) 1 EC
1.5 pt
2.25 pt
0.2871
Table 4-5. Herbicide Information for Peanuts
Weed
Herbicide and Formulation
Amount of Formulation Per Acre
Pounds Active Ingredient Per Acre
Precautions and Remarks
POSTEMERGENCE (continued)
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 chapter 9 in in this publication.
sethoxydim, MOA 1 (Poast) 1.5 EC
(Poast Plus) 1 EC
1 pt
1.5 pt
0.1