2022
Establishing an herbicide resistance monitoring program for PA Soybean Growers
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Contributor/Checkoff:
Pennsylvania Soybean Promotion Board
Category:
Sustainable Production
Keywords:
AgricultureCrop protectionHerbicide
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Caio Brunharo , Pennsylvania State University
Co-Principal Investigators:
Project Code:
PSB-R2022-02
Contributing Organization (Checkoff):
Pennsylvania Soybean Promotion Board
$10,181
Institution Funded:
Pennsylvania State University
$10,181
Brief Project Summary:

The long-term goal of this project is to establish a herbicide resistance monitoring program to provide timely detection of resistant weeds for Pennsylvania soybean famers. The monitoring program is based at Penn State University and, in the long-term, will provide quick tests for soybean farmers in Pennsylvania to submit weed samples for herbicide resistance diagnosis. The first step towards this goal, is to conduct a statewide survey to characterize the predominance of herbicide resistance in Pennsylvania, by sampling populations of Palmer amaranth, waterhemp, common, marestail and Italian ryegrass, and screening for resistance to common herbicides.

Key Benefactors:
farmers, agronomists, extension agents

Information And Results
Project Deliverables

We observed that resistance to glyphosate, ALS inhibitors (e.g., Pursuit), and atrazine in waterhemp is widespread, but not in all populations. A single population displayed resistance to 2,4-D and dicamba. We also observed that products containing flumioxazin (e.g., Valor), fomesafen (e.g., Reflex), glufosinate (e.g., Liberty), and tiafenacil (Reviton) are still efficient. Populations of Italian ryegrass displayed resistance to fluazifop (e.g., Fusilade) and glyphosate. All marestail populations were resistant to glyphosate and chlorimuron (e.g., Classic), but were controlled by atrazine, 2,4-D, glufosinate, and dicamba.

Final Project Results

Updated December 31, 2023:
Establishing an herbicide resistance monitoring program for Pennsylvania soybean growers

View uploaded report PDF file

We observed that resistance to glyphosate, ALS inhibitors (e.g., Pursuit), and atrazine in waterhemp is widespread in Pennsylvania, but not in all populations. A single population displayed resistance to 2,4-D and dicamba. We also observed that products containing flumioxazin (e.g., Valor), fomesafen (e.g., Reflex), glufosinate (e.g., Liberty), and tiafenacil (Reviton) are still efficient. Populations of Italian ryegrass displayed resistance to fluazifop (e.g., Fusilade) and glyphosate. All marestail populations were resistant to glyphosate and chlorimuron (e.g., Classic), but were controlled by atrazine, 2,4-D, glufosinate, and dicamba. Given weed populations displayed distinct resistance patterns, growers could benefit from a system for quick herbicide resistance diagnosis. In 2023, we considerably expanded our sample size to obtain a better representation of the state of herbicide resistance in PA. Future work will test those populations against key soybean herbicides.

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.