Extension Response to Contaminated 2,4-DB/Peanut Problems in 2007 Eric P. Prostko*, J. Tim Flanders, and Scott N. Brown The University of Georgia SWSS/WSSA

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 Farm August 23, 2007 (14 DAT) pt/AButoxone 1 pt/A

Contaminated Lots (> 250 ppm or 0.025%) Lot #Dicamba (%)2,4-D (%) FB (MCPA) EC (MCPA) EC EL EL EL CE

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 oz ai/A ( X)

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 oz ai/A –Normal dicamba (Banvel) rate for corn is 8 oz/A (3.08 oz ai/A) – X rate

What happened at harvest?

Table 1. Peanut Pod Numbers and Weights as Influenced by 2,4-DB formulation, Berrien County, September 14, Sample 1 ContaminatedNon-Contaminated Pods/plant100 pod weight (g)Pods/plant100 pod weight (g) Average Contaminated and Non-Contaminated samples collected from same field. 2 Average 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, Sample 1 ContaminatedNon-Contaminated Yield (lbs/A) 100 pod weight (g) Yield 2 (lbs/A) 100 pod weight (g) Average Contaminated and Non-Contaminated samples collected from same field. Plot size was 6’ X 130’. 2 Adjusted 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 was a dry year –May to September: -6.54” deficit Was yield loss due to product or dry weather?

2008 Research I just had to know for sure!!!! Small plot research Contaminated 2,4-DB 24 oz/A + 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, oz/A + 1% Peptoil P = CV = 8

Peanut Pod Weights in Response to Contaminated 2,4-DB, oz/A + 1% Peptoil P = CV = 6

100 Seed Weights in Response to Contaminated 2,4-DB, oz/A + 1% Peptoil LSD 0.10 = 7 CV = 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) 16 ozs/A Applied 30 DAPApplied 59 DAPApplied 91 DAP Photo 107 DAP