Peanut Weed Management Update Eric P. Prostko Extension Weed Specialist Department of Crop & Soil Sciences The University of Georgia Tifton Extension Agent Training - March 2006

2005 ALS-Resistant Pigweed Survey 60 locations, 21 counties As of March 1, 2006 Preliminary data 1573 plants treated 1395 plants survived (89%) ≥ 90% survival –30 locations = 50% 80-89% survival –23 locations = 38% 70-79% survival –5 locations = 8% 60-69% survival –1 location = 2% –Jefferson County 50-59% survival –1 location = 2% –Laurens County

Herbicide Programs for ALS-Resistant Pigweed Management in Peanut *Generic formulations of Dual Magnum and Outlook are available.

Research Questions? Do herbicides influence peanut seed germination? How does Classic effect AP-3? Can I put Prowl over-the-top of emerged peanuts? Herbicide/fungicide tank-mixes? Do I really need Gramoxone? How about eclipta? Does Cobra reduce peanut yields? What does 2,4-D do to peanut yields?

Herbicide Effects on Peanut Seed Germination, C or 77 0 F) Averaged over 3 varieties (GA Green, C-99R, GA-01R); 1.44 oz/A; 1.1 pt/A

Research Questions? Do herbicides influence peanut seed germination? How does Classic effect AP-3? Can I put Prowl over-the-top of emerged peanuts? Herbicide/fungicide tank-mixes? Do I really need Gramoxone? How about eclipta? Does Cobra reduce peanut yields? What does 2,4-D do to peanut yields?

Classic Effects on Peanut Yield– ozs/A + Activator 0.25% v/v Planted: May 2 AP-3 Twin row Conventional tillage 3 seed/ft Phorate 6’ X 100’ plots, 3 reps Weed-free P =

Research Questions? Do herbicides influence peanut seed germination? How does Classic effect AP-3? Can I put Prowl over-the-top of emerged peanuts? Herbicide/fungicide tank-mixes? Do I really need Gramoxone? How about eclipta? Does Cobra reduce peanut yields? What does 2,4-D do to peanut yields?

Peanut Yield Response to Delayed Prowl Timings P = Averaged over two formulations (Prowl and Prowl H 2 O applied at 1.00 lb ai/A)

Peanut Yield Response to Prowl EC Timings lb ai/A LSD 0.05 = 397 LSD 0.10 = 326

Peanut Yield Response to Prowl H 2 O Timings lb ai/A LSD 0.05 = 397 LSD 0.10 = 326 * *

Research Questions? Do herbicides influence peanut seed germination? How does Classic effect AP-3? Can I put Prowl over-the-top of emerged peanuts? Herbicide/fungicide tank-mixes? (handout) Do I really need Gramoxone? How about eclipta? Does Cobra reduce peanut yields? What does 2,4-D do to peanut yields?

ozs/A 9 ozs/A Dual 1.33 pts/A 1 lb/A 1 qt/A

Research Questions? Do herbicides influence peanut seed germination? How does Classic effect AP-3? Can I put Prowl over-the-top of emerged peanuts? Herbicide/fungicide tank-mixes? Do I really need Gramoxone? How about eclipta? Does Cobra reduce peanut yields? What does 2,4-D do to peanut yields?

Do you need Gramoxone? PE July 18, 2005 (69 DAP) Ponder Farm Untreated Gramoxone 8 ozs/A + 8 ozs/A % v/v (15 DAP) Fb 1 oz/A + 1% v/v (28 DAP) 1 oz/A + 1% v/v (28 DAP)

Gramoxone + Cadre TreatmentTest 1 - Tifton (lbs/A) Test 2- Attaplugus (lbs/A) Untreated374 e1474 c Gramoxone + Basagran fb Cadre 2170 bc (+958) 2736 a (+501) Cadre1212 de2235 b P = 0.10 Gramoxone 12 ozs/A + 8 ozs/A % v/v = $7.08/A + $4.00/A = $11.08/A $11.08/$ = 62.4 lbs of peanuts

Research Questions? Do herbicides influence peanut seed germination? How does Classic effect AP-3? Can I put Prowl over-the-top of emerged peanuts? Herbicide/fungicide tank-mixes? Do I really need Gramoxone? How about eclipta? Does Cobra reduce peanut yields? What does 2,4-D do to peanut yields?

Eclipta

Eclipta Control in Peanut 0.45 ozs/A 0.25% v/v 20 DAT Untreated

What weeds does Strongarm control POST? common ragweed common cocklebur horseweed bristly starbur morningglory wild radish eclipta tropical spiderwort Label –TSW suppression –up to 30 DAC –NIS –18 month cotton rotation

Common Ragweed Treated with 0.30 ozs/A % v/v 6 DATBefore 19 DAT Lanier County 2005

Research Questions? Do herbicides influence peanut seed germination? How does Classic effect AP-3? Can I put Prowl over-the-top of emerged peanuts? Herbicide/fungicide tank-mixes? Do I really need Gramoxone? How about eclipta? Does Cobra reduce peanut yields? What does 2,4-D do to peanut yields?

Cobra Effects on Peanut Yield – ozs/A + 1% v/v Planted: May 5 GA Green Twin row Conventional tillage 3 seed/ft Phorate No Classic Weed-free aa ab bc ab a

Research Questions? Do herbicides influence peanut seed germination? How does Classic effect AP-3? Can I put Prowl over-the-top of emerged peanuts? Herbicide/fungicide tank-mixes? Do I really need Gramoxone? How about eclipta? Does Cobra reduce peanut yields? What does 2,4-D do to peanut yields?

What does 2,4-D do to peanut yield? Ponder Farm 2005 GA Green

How do the top growers control weeds? 2005 Peanut Achievement Club 21 farms 4356 lbs/A State average was only 2870 lbs/A Weed Control Tactics –Conventional tillage 76% use bottom plow –Twin rows (71%) –Sonalan (81%) –Strongarm or Valor 38% vs. 43% –Cadre (76%)