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

Peanut Weed Management UpdateEric P. Prostko

Extension Weed SpecialistDepartment of Crop & Soil Sciences

The University of GeorgiaTifton

Extension Agent Training - March 2006

2005 ALS-Resistant Pigweed Survey60 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



– 1 location = 2%– Jefferson County

• 50-59% survival– 1 location = 2%– Laurens County

Herbicide Programs for ALS-Resistant Pigweed Management in Peanut

Preplant incorporated Preemergence

Cracking or early postemergence(Palmer < 2 in.)

Postemergence (Palmer < 3 in.)

Prowl or Sonalan Gramoxone + Basagran +Dual Magnum or Outlook

Cobra or Ultra Blazer

Prowl or Sonalan Valor Cobra or Ultra Blazer

Prowl or Sonalan Valor +Dual Magnum or Outlook

Cobra or Ultra Blazer

*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, 2005. (@ 250C or 770F)

0

20

40

60

80

100

Untreated

C-30 DAP

C-45 DAP

DB-75 DAP

DB-95 DAP

Herbicide

Ger

min

atio

n -

%

Tifton Dawson

Averaged over 3 varieties (GA Green, C-99R, GA-01R); Cadre @ 1.44 oz/A; 2,4-DB @ 1.1 pt/A

Research Questions?




Classic Effects on Peanut Yield– 2005 Classic @ 0.5 ozs/A + Activator 90 @ 0.25% v/v

3850 3690 3758 3875

0

800

1600

2400

3200

4000

Untreated 60 72 89

Application Date (DAC)

lbs/

A

Planted: May 2AP-3Twin rowConventional tillage3 seed/ftPhorate6’ X 100’ plots, 3 repsWeed-free

P = 0.5931

Research Questions?




Peanut Yield Response to Delayed Prowl Timings - 2004

32963109 3120 3201

28113153

0

1000

2000

3000

4000

2 7 8 9 10

Untreat

ed

DAP

lbs/

A

P = 0.198Averaged over two formulations (Prowl and Prowl H2O applied at 1.00 lb ai/A)

Peanut Yield Response to Prowl EC Timings - 2005

36994022 4169

36544088

3816

0

1000

2000

3000

4000

5000

DAP

lbs/

A

1.0 lb ai/ALSD 0.05 = 397LSD 0.10 = 326

Peanut Yield Response to Prowl H2O Timings - 2005

42354470

3765 3772 38454125

0

1000

2000

3000

4000

5000

DAP

lbs/

A

1.0 lb ai/ALSD 0.05 = 397LSD 0.10 = 326

* *

Research Questions?



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?

Cadre @ 1.44 ozs/AHeadline @ 9 ozs/ADual Magnum @ 1.33 pts/AAMS @ 1 lb/ACOC @ 1 qt/A

Research Questions?




Do you need Gramoxone?

PE-07-05July 18, 2005 (69 DAP)Ponder Farm

Untreated Gramoxone Max @ 8 ozs/A+ Pledge @ 8 ozs/A + NIS

@ 0.25% v/v (15 DAP)Fb Cadre @ 1 oz/A + COC

@ 1% v/v (28 DAP)

Cadre @ 1 oz/A + COC @ 1% v/v (28 DAP)

Gramoxone + Cadre - 2005Treatment Test 1 - Tifton

(lbs/A)

Test 2- Attaplugus

(lbs/A)

Untreated 374 e 1474 c

Gramoxone + Basagran fb

Cadre

2170 bc

(+958)

2736 a

(+501)

Cadre 1212 de 2235 b

P = 0.10

Gramoxone Inteon @ 12 ozs/A + Basagran @ 8 ozs/A + NIS @ 0.25% v/v = $7.08/A + $4.00/A = $11.08/A$11.08/$0.1775 = 62.4 lbs of peanuts

Research Questions?




Eclipta

Eclipta Control in Peanut

Strongarm @ 0.45 ozs/ANIS @ 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 Strongarm @ 0.30 ozs/A + NIS @ 0.25% v/v

6 DATBefore

19 DATLanier County2005

Research Questions?




Cobra Effects on Peanut Yield – 2005 Cobra @ 12.5 ozs/A + Herbimax @ 1% v/v

3795 37663580

3025

35653883

0

800

1600

2400

3200

4000

15 30 43 58 74 Untreated

Application Date (DAP)

Yiel

d (lb

s/A)

Planted: May 5GA GreenTwin rowConventional tillage3 seed/ftPhorateNo ClassicWeed-free

a aab

bc

aba

Research Questions?




What does 2,4-D do to peanut yield?

-45-36-27-18-909

18273645

15 DAE 30 DAE 45 DAE

Time of Application

Yie

ld L

oss

or G

ain

(%)

2 ozs 4 ozs 8 ozs 12 ozs

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%)

www.gaweed.com

Documents

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