Adjusting Herbicide Programs to Emerging Weed Problems in Peanut

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Adjusting Herbicide Programs to Emerging Weed
Problems in Peanut

• Eric P. Prostko
• Extension Weed Specialist
• University of Georgia

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Why do new weed problems occur?

• reliance on herbicides
• decreases in cultivation
• ecological shifts
• herbicide resistance

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New or Unique Weed Problems in Peanuts

• tropic croton
• dayflower/spider-wort
• eclipta
• copperleaf
• spiderflower
• redweed
• ALS-resistant pigweed

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Tropic Croton (Croton glandulosus)

• 3rd most troublesome weed
• Cadre is weak
• not as competitive as other weeds
• PRE - Valor or Strongarm
• POST - Ultra Blazer
• Cadre/Blazer tank/mixes???

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Dayflower/Spiderwort (Commelina spp.)
Asiatic

• Berrien, Brooks, Grady, Thomas
• limited data
• Roundup is weak
• PRE - Dual (timing)
• POST - Basagran
• others????

spreading
spiderwort
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Tropical spiderwort, Cairo, GA, 2001
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Residual Spiderwort Control in Peanuts with
Dual Magnum, Brooks County, GA
a
b
Dual Magnum _at_ 1 pt/A Applied July 2, 2001
Rated August 1, 2001
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Eclipta (Eclipta prostrata)

• low, moist areas
• limited biology data
• PRE - Strongarm, Valor, Dual, Outlook
• POST - Basagran, Storm, Tough
• timing is critical

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Eclipta Control in Peanuts with POST Herbicides
Grichar, 1997
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Hophornbeam Copperleaf (Acalypha ostryifolia)

• Randolph, Terrell
• limited biology data
• PRE - Valor or Strongarm
• POST - Ultra Blazer, Storm

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Hophornbeam Copperleaf ControlRandolph County,
GA - 2001
Untreated
Strongarm
Valor
6 WAT
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Spiderflower (Cleome spp.)

• Laurens County
• limited data
• PRE - Pursuit
• POST - Pursuit, Cadre, Ultra Blazer (bloom stage)

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Redweed (Melochia corchorifolia)

• low, moist areas
• hard seed coat
• season long germination
• PRE - Strongarm, Valor, Zorial
• POST - Basagran, Storm, Cadre

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ALS-Resistant Palmer Pigweed

• Burke County
• 2001
• do not use Cadre, Pursuit, Classic, Strongarm
• Prowl, Sonalan, Dual, Valor, Ultra Blazer, Storm

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Summary

• Newer soil applied herbicides will help control
  some of the unique weed problems.
• Combinations of PRE and POST treatments will
  provide consistent control.
• Need more information about biology and
  competitiveness of newer weed problems in order
  to make better control decisions.

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University of Georgia
Extension Weed Science
(gaweed.com)