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Peanut Weed Control in the Southeast - An Overview. Eric P. Prostko, W. Carroll Johnson, III, Nathan Smith (GA) Barry J. Brecke and Jay Ferrell (FL) John Everest and C. Dale Monks (AL). 2004 U.S. Peanut Production Acres Planted - %. 1,386,000 Acres Planted in US
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Peanut Weed Control in the Southeast - An Overview Eric P. Prostko, W. Carroll Johnson, III, Nathan Smith (GA) Barry J. Brecke and Jay Ferrell (FL) John Everest and C. Dale Monks (AL)
2004 U.S. Peanut ProductionAcres Planted - % 1,386,000 Acres Planted in US 910,000 Acres harvested in SE (66%) Source: USDA June 2004
The EnemiesTop 10 Most Troublesome Weeds (1-5) 1 2 SWSS 5 3 4 SWSS
The EnemiesTop 10 Most Troublesome Weeds (6-10) 8 7 6 SWSS 9 10 10 SWSS
Significant Changes That Have Occurred • twin rows • strip tillage • herbicide incorporation • decrease in older soil applied herbicides • increase in newer herbicides • cultivation • weed shifts
Increases in Twin Row Production • Earlier canopy closure • increased yield and grade • decrease in TSWV • better weed control? • GA (50-60%)
Trends in Peanut Weed ControlStrip-Tillage Production Source: UGA Peanut Production Surveys
Weed Control ChallengesStrip-Tillage Peanuts • yellow herbicide application method • increased problems with …. • Florida pusley • Texas panicum • bermudagrass • more work is needed in this area
Florida Pusley • Why??? • No DNA used • lack of activation • tie up on residue • untimely POST’s • the R word? • extreme measures • Prowl, Sonalan, Dual Magnum, Strongarm, and Valor • Gramoxone Max
Herbicide IncorporationMechanical or Irrigation or * Equally as effective * Center-pivot irrigation is $2-7/A cheaper!
Trends in Peanut Weed ControlSonalan or Prowl????? Source: UGA Peanut Production Surveys
Trends in Peanut Weed ControlSoil-Applied Herbicides - I Source: UGA Peanut Production Surveys
Trends in Peanut Weed ControlSoil-Applied Herbicides - II Source: UGA Peanut Production Surveys
Trends in Peanut Weed ControlSoil-Applied Herbicides - III Source: UGA Peanut Production Surveys
Trends in Peanut Weed ControlPostemergence Herbicides - I Source: UGA Peanut Production Surveys
Trends in Peanut Weed ControlPostemergence Herbicides - II Source: UGA Peanut Production Surveys
What herbicides do the top peanut growers use? • 2003 GA Peanut Achievement Club • 16 Farms • average farm size • 454 acres • average yield • 5141 lbs/A • Top 5 herbicides used • Sonalan = 94% • Cadre = 81% • Gramoxone Max = 56% • 2,4-DB = 50% • Valor, Basagran = 37%
What happened to mechanical cultivation? • has been on the decline • fuel prices • better herbicides • twin rows • strip tillage • time • disease management • FL beggarweed germination Peanut Cultivation in GA Source: UGA Extension Agent Surveys
New or Emerging Weed Problems • Weed shifts resulting from …….. • changes in tillage practices • changes in herbicide use patterns • Some we know a lot about, some we don’t
Tropical Spiderwort • row spacing * twins vs. singles • residuals *Dual Magnum • POST’s * Gramoxone Max * Cadre * Basagran * Pursuit * Strongarm
Tropical spiderwortHow bad is it????? Grady County, GA
Groundcherry cutleaf • 3 common species • cutleaf (annual) • smooth (perennial) • clammy (perennial) • little information is known • cutleaf control • Dual/Outlook • Strongarm/Valor? • Ultra Blazer SWSS SWSS
Hophornbeam copperleaf • western counties • more on roadsides • easily controlled with Strongarm, Valor, and Ultra Blazer
Eclipta • Does well in wet, cool conditions • should not be a problem in peanuts • soil-applied • Strongarm, Valor, Spartan • postemergence • Basagran. Blazer, Storm
Carpetweed • Not very competitive? • Soil-applied • Prowl, Sonalan, Dual, Strongarm, Spartan • postemergence • from Grichar • 2,4-DB (58%) • Cadre (80%) • Storm (95%) • Basagran (33%) • Blazer (100%) SWSS SWSS
Purple Moonflower • Limited data • paraquat + Storm • Ultra Blazer • Cadre (?????) SWSS
Pink Purslane • Limited data • soil-applied • Sonalan, Prowl, Dual, Valor • postemergence • paraquat + Storm or Basagran • Basagran, Blazer, Storm, 2,4-DB
Spurges • Several species • hyssop, spotted, prostrate, nodding • limited data • Valor • Ultra Blazer • Storm
Yield Losses Caused By Roundup Weather Max Applied to Virginia Peanuts @ 30 DAP. Source: Adapted from B. Robinson, NCSU (3 years of data)
Where are we headed? • make do with what we got • only 1 herbicide in pipeline (Cobra) • 17 active ingredients • new uses for older products • combinations • reduced rates
University of Georgia Extension Weed Science (gaweed.com)