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Trends in Peanut Weed Control

Dr. Eric P. Prostko
Extension Weed Specialist
University of Georgia
Tifton, GA

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TABLE OF CONTENTS

Trends In Peanut Weed Control Trends in Peanut Weed Control: Topics for Discussion Trends in Peanut Weed Control: Topics for Discussion Trends in Peanut Weed Control: Strip-Tillage Production Strip-Tillage Weed Control Trends in Peanut Weed Control: Topics for Discussion Trends in Peanut Weed Control: Herbicide Incorporation Herbicide Incorporation Trends in Peanut Weed Control: Topics for Discussion Trends in Peanut Weed Control: Mechanical Cultivation Why has mechanical cultivation declined? Trends in Peanut Weed Control: Topics for Discussion Trends in Peanut Weed Control: Soil-Applied Herbicides - I Trends in Peanut Weed Control: Soil-Applied Herbicides - II Trends in Peanut Weed Control: Postemergence Herbicides - I Trends in Peanut Weed Control: Postemergence Herbicides - II Trends in Peanut Weed Control: Topics for Discussion What about reduced rates? Reduced Rates: Do they work??? The Response of Weeds to Various Cadre Rates in Georgia The Response of Weeds to Various Cadre Rates in Georgia Hophornbeam Copperleaf Control: Randolph County, GA - 2001 Weed control in peanuts with reduced rates of Strongarm and Valor, 2002. Reduced rates can work if ... What kind of grower might consider using reduced rates? Trends in Peanut Weed Control: Topics for Discussion Trends in Peanut Weed Control: Tank-Mixes Herbicide/Fungicide Tank-Mixes Trends in Peanut Weed Control: Topics for Discussion Trends in Peanut Weed Control: Weed Shifts Tropical spiderwort: Commelina benghalensis Tropical spiderwort: How bad is it????? Trends in Peanut Weed Control: Topics for Discussion Herbicide Resistance: Around the World Herbicide Resistance: Southeast Glyphosate Resistance: They said it was unlikely! Biotechnology Varieties Planted in the US in 2002 Herbicide Resistant Weeds: Strategies for Control/Prevention Trends in Peanut Weed Control: Topics for Discussion Trends in Peanut Weed Control: R & D The Peanut Weed Control Toolbox The Future? My Predictions UGA Extension Weed Science

SLIDE CONTENTS

Trends In Peanut Weed Control Dr. Eric P. Prostko Extension Weed Specialist University of Georgia Tifton December 2002 Trends in Peanut Weed ControlTopics for Discussion tillage incorporation cultivation herbicide use reduced rates tank-mixes weed shifts resistance R & D Trends in Peanut Weed ControlTopics for Discussion tillage incorporation cultivation herbicide use reduced rates tank-mixes weed shifts resistance R & D Trends in Peanut Weed ControlStrip-Tillage Production Source: UGA Peanut Production Surveys Strip-Tillage Weed Control timing of burndown paraquat, glyphosate, 2,4-D, Valor yellow herbicides? Incorporation Florida pusley, evening primrose, Texas millet perennial weeds? Trends in Peanut Weed ControlTopics for Discussion tillage incorporation cultivation herbicide use reduced rates tank-mixes weed shifts resistance R & D Trends in Peanut Weed ControlHerbicide Incorporation Source: UGA Peanut Production Surveys Herbicide Incorporation or Equally as effective Center-pivot irrigation is $2-7/A cheaper! Trends in Peanut Weed ControlTopics for Discussion tillage incorporation cultivation herbicide use reduced rates tank-mixes weed shifts resistance R & D Trends in Peanut Weed ControlMechanical Cultivation Source: UGA Peanut Production Surveys Why has mechanical cultivation declined? disease management better herbicides time savings strip-tillage increases fuel prices Trends in Peanut Weed ControlTopics for Discussion tillage incorporation cultivation herbicide use reduced rates tank-mixes weed shifts resistance R & D 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 ControlPostemergence Herbicides - I Source: UGA Peanut Production Surveys Trends in Peanut Weed ControlPostemergence Herbicides - II Source: UGA Peanut Production Surveys Trends in Peanut Weed ControlTopics for Discussion tillage incorporation cultivation herbicide use reduced rates tank-mixes weed shifts resistance R & D What about reduced rates? not labeled but not illegal companies will not support failures not a guarantee to minimize crop rotation issues part of a total program future R&D and new products Reduced RatesDo they work??? The Response of Weeds to Various Cadre Rates in Georgia Webster et al. 1997 Applied EPOST (C-2LF) The Response of Weeds to Various Cadre Rates in Georgia Webster et al. 1997 Applied EPOST Hophornbeam Copperleaf ControlRandolph County, GA - 2001 6 WAT Untreated Strongarm (0.45 ozs/A) Valor (3 ozs/A) Strongarm 0.113 ozs + Valor 0.75 ozs/A Weed control in peanuts with reduced rates of Strongarm and Valor, 2002. Untreated Strongarm 0.45 oz/A Valor 3 oz/A Strongarm 0.113 oz/A + Valor 0.75 oz/A Attapulgus, GA 7 WAP Reduced rates can work if…….. The weed is susceptible good growing/application conditions exist the application is timely (small weeds) Full rates help to overcome variability of application due to weed size, improper sprayer calibration, environmental conditions, etc. What kind of grower might consider using reduced rates? regularly calibrates his sprayer has irrigation or can predict when it will rain gets consistent weed control at full rates understands the difference between 2” and 4” can cover his acreage in a short time period is willing to scout his field regularly is willing to accept less than 100% weed control is not a lawyer or close friends with one A grower who ……... Trends in Peanut Weed ControlTopics for Discussion tillage incorporation cultivation herbicide use reduced rates tank-mixes weed shifts resistance R & D Trends in Peanut Weed ControlTank-Mixes herbicides fungicides insecticides foliar fertilizers reductions in time and money may not be well researched or clearly labeled Herbicide/Fungicide Tank-Mixes Trends in Peanut Weed ControlTopics for Discussion tillage incorporation cultivation herbicide use reduced rates tank-mixes weed shifts resistance R & D Trends in Peanut Weed ControlWeed Shifts Top 5 Most Common Weeds in GA Peanuts Tropical spiderwortCommelina benghalensis annual or perennial seeds and rhizomes above and below ground flowers 1600 seeds/plant high soil moisture and fertility problem weed in other countries (Holm’s) Tropical spiderwortHow bad is it????? Grady County, GA 2001 Trends in Peanut Weed ControlTopics for Discussion tillage incorporation cultivation herbicide use reduced rates tank-mixes weed shifts resistance R & D Herbicide ResistanceAround the World 261 Resistant Biotypes 157 Species (95 dicots and 62 monocots) over 210,000 fields Source: Heap, I. The International Survey of Herbicide Resistant Weeds. Online. Internet. December 2, 2002 . Herbicide ResistanceSoutheast Glyphosate ResistanceThey said it was unlikely! Horseweed * DE (2000) * TN (2001) Goosegrass * Malaysia (1997) Italian Ryegrass * Chile (2001) Rigid Ryegrass * Australia (1996) * California (1998) * South Africa (2001) Weed Technology, 1997 11:189-198 Biotechnology Varieties Planted in the US in 2002 Source:USDA/NASS June 2002 Herbicide Resistant WeedsStrategies for Control/Prevention prevention is the key!!! utilize other weed control tactics (cultivation, row patterns, etc). rotate herbicides with different MOA rotate crops scout fields prevent seed production clean tillage and harvesting equipment Trends in Peanut Weed ControlTopics for Discussion tillage incorporation cultivation herbicide use reduced rates tank-mixes weed shifts resistance R & D Trends in Peanut Weed ControlR & D have had a few good years (Cadre, Select, Strongarm, Valor) peanut is a minor crop only 2 products currently in pipeline (Spartan, Cobra) Will they make it? Do we need them? The Peanut Weed Control Toolbox The Future?My Predictions limited new herbicides $25 or less on herbicides increase in reduced rates and combinations new uses for older products increases in resistance weed shifts perennials unknowns University of Georgia Extension Weed Science (gaweed.com)