Extension Response to Contaminated 2,4-DB/Peanut

Problems in 2007

Eric P. Prostko*, J. Tim Flanders, and Scott N. BrownThe University of Georgia

SWSS/WSSA - 2009

The Players

• UGA

– Eric Prostko

• County Extension Agents

– Scott Brown – Colquitt

– Tim Flanders – Berrien

• Dealers

– Joe Dixon – Berrien

• Growers

– At least 48

• Industry

– Jim Shue (NuFarm)

– J.W. Christiansen (Aceto)

• Private Consultant

– Tim Adcock (Diligene Technologies)

• GA Department of Agriculture

2,4-DB in Peanuts

• One of the most commonly used herbicides

• 50% of acres

• 1-3 applications/year

• From 2 WAP until 30 DBH

• Annual morningglory, sicklepod, pigweed (?)

Typical 2,4-DB Injury Symptoms

2007 Symptomology

Berrien County – Dixon FarmAugust 23, 2007 (14 DAT)

2005 2,4-DB @ 1 pt/A Butoxone 175 @ 1 pt/A

Contaminated Lots(> 250 ppm or 0.025%)

Lot # Dicamba (%) 2,4-D (%)

FB-01 0 0.294

0.091 (MCPA)

EC-16 0.170 0.110

0.079 (MCPA)

EC-16 0.198 0.104

EL-31 0 0.011

EL-31 0 0.010

EL-31 0 0.012

CE-04 0 0.006

What will 2,4-D and dicamba do to peanuts????

• Research in GA conducted over the past few years would suggest that 2 oz/A (0.778 oz ai/A) of 2,4-D would not cause many problems.– If contaminated product was applied at

24 oz/A then 2,4-D rate would only be 0.025-0.071 oz ai/A (0.03-0.09X)

What will 2,4-D and dicamba do to peanuts????• No data exists for peanut response to

dicamba.– Peanuts are more sensitive to dicamba

than 2,4-D.– Dicamba rate was equivalent to 0.041-

0.048 oz ai/A – Normal dicamba (Banvel) rate for corn

is 8 oz/A (3.08 oz ai/A)– 0.013-0.016X rate

What happened at harvest?

Table 1. Peanut Pod Numbers and Weights as Influenced by 2,4-DB formulation, Berrien County, September 14, 2007.

Sample1

Contaminated Non-Contaminated

Pods/plant 100 pod weight (g) Pods/plant 100 pod weight (g)

1 31.5 144.6 28.3 153.1

2 32.1 162.5 39.1 168.6

3 29.3 169.4 25.5 159.0

Average 31.0 158.8 31.0 160.2

1Contaminated and Non-Contaminated samples collected from same field.2Average of 10 plants.

Table 2. Peanut yield (cv. Georgia Green) as influenced by 2,4-DB formulation, P.H. Danforth Farm, Berrien County, October 12, 2007.

Sample1

Contaminated Non-Contaminated

Yield (lbs/A)

100 pod weight (g)

Yield2

(lbs/A)100 pod

weight (g)

1 4667 187.6 4619 184.1

2 4581 204.4 4849 155.4

3 4424 184.9 4302 155.8

Average 4557 192.3 4590 165.1

1Contaminated and Non-Contaminated samples collected from same field. Plot size was 6’ X 130’. 2Adjusted to 10% moisture.

Berrien County, 2007

What did the company do?

• Hired consultant to manage complaints• Information request form was mailed to all

growers• Monies were distributed based upon

comparison of 2007 yields to historical yields• Growers were happy and I was curious.• 2007 was a dry year

– May to September: -6.54” deficit

• Was yield loss due to product or dry weather?

2008 ResearchI just had to know for sure!!!!

• Small plot research

• Contaminated 2,4-DB

• 24 oz/A + COC @ 1%

• Applied at various stages (28, 45, 62, 78, 91, and 105 DAP)

• Irrigated peanuts

• Weed-free

• Twin-row

• AP-3

• Visual observations

• yield

Peanut Yield Response to Contaminated 2,4-DB, 2008

47234505

43624612

5014 5037

4588 47235002

4827

0

1000

2000

3000

4000

5000

6000

Time of Application (DAP)

Yie

ld (lb

s/A

) >

24 oz/A +1% Peptoil

P = 0.2142CV = 8

Peanut Pod Weights in Response to Contaminated 2,4-DB, 2008

161167

159

177

163 161 163 161172

165

0

50

100

150

200

Time of Application (DAP)

100

pods

(gra

ms)

.

24 oz/A +1% Peptoil

P = 0.3239CV = 6

100 Seed Weights in Response to Contaminated 2,4-DB, 2008

67 6762 60

68 68 6772

67

78

0

20

40

60

80

100

Time of Application (DAP)

gra

ms

.

24 oz/A +1% Peptoil

LSD 0.10 = 7CV = 9

Why is this important?

• Peanut response to dicamba

– Dicamba resistant crops are in the pipeline

– More contamination/drift problems are likely

• Dicamba/peanut tolerance studies were conducted in 7 locations in 2008 across peanut belt

Peanut Response to Clarity (dicamba) 4SC @ 16 ozs/A

Applied 30 DAP Applied 59 DAP Applied 91 DAP

Photo 107 DAP

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