2020
Two Approaches for Palmer Amaranth Control: We Need Multiple Approaches
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Contributor/Checkoff:
Delaware Soybean Board
Category:
Sustainable Production
Keywords:
AgricultureCrop protectionHerbicide
Parent Project:
Two Approaches for Palmer Amaranth Control: We Need Multiple Approaches
Lead Principal Investigator:
Mark VanGessel, University of Delaware
Co-Principal Investigators:
Project Code:
Contributing Organization (Checkoff):
Delaware Soybean Board
$13,838
Leveraged Funding (Non-Checkoff):
Based on results from last year, I am part of a project seeking funding from USDA-NIFA Crop Protection Pest Management program. Proposals are in the review process
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Institution Funded:
University of Delaware
$13,838
Brief Project Summary:

The noxious weed Palmer amaranth can put up a good fight, as it competes with row crops for nutrients, sunlight and space, causing yield reductions. This research project aims to improve control of this weed and glyphosate-resistant horseweed in no-till fields through cereal rye cover crop management and herbicide applications. Trials compare cereal rye terminated four weeks prior to soybean planting, two weeks before planting, terminated the same day as soybean planting and planting greed for weed suppression. After cover crop termination, postemergence herbicide applications alone and in combination with a residual herbicide will work together to control the weed.

Key Benefactors:
farmers, agronomists, Extension agents

Information And Results
Final Project Results

Updated May 17, 2021:
Final Report for 2020 Delaware Soybean Board Funding

View uploaded report Word file

When treating large Palmer amaranth plants, a single herbicide application is unlikely to provide acceptable control or eliminate seed production. While two applications is not desirable, no one herbicide consistently provide excellent control and prevented seed production. Avoid the temptation to add additional products with the postemergence application, since they have not provided additional control. Effective Palmer amaranth management should focus on timely postemergence applications while Palmer amaranth plants are small and most susceptible to herbicides. This timing is typically 3 to 4 weeks after soybean planting.

When using cereal rye to improve weed control, terminating as close to planting as possible often improves overall control. While cereal rye can improve weed control, it often is not sufficient to provide season long control and should be used in combination with other effective weed management options, notably timely herbicide applications

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.