A new multistate research initiative led by Michigan State University (MSU) is aiming to combat the growing threat of herbicide-resistant weeds in U.S. soybean fields. Funded through the Soy Checkoff program by the United Soybean Board, the project will develop advanced diagnostic tools, improve management strategies, and train the next generation of weed scientists to protect soybean production.
Herbicide-resistant weeds have become a major challenge for growers, with resistance increasingly observed across multiple species due to the overreliance on a limited number of chemical treatments. Economic losses are substantial, with previous studies estimating that resistant weeds cost U.S. soybean farmers over $2 billion annually. Since 2020, twelve new herbicide-resistant weed populations have been identified in soybean fields nationwide.
The project, known as HERMON (Herbicide Resistance Monitoring Network), brings together a team of experts from MSU, Kansas State, Mississippi State, Penn State, Purdue, Texas A&M AgriLife Research, University of Arkansas, University of Illinois, University of Missouri, and University of Wisconsin. Its primary goal is to develop rapid resistance detection tools, expand diagnostic capacity, and provide actionable guidance directly to soybean producers.
MSU researchers will establish standardized greenhouse-based diagnostic protocols for resistance detection, positioning MSU as a northern hub for key weeds such as waterhemp, ragweed, and marestail. Mississippi State and Arkansas will serve as southern hubs for grasses and Palmer amaranth, respectively, allowing coordinated monitoring across all soybean-growing regions. These hubs will share reference seed and novel cases of resistance to ensure consistent, reliable testing and reporting for farmers.
Other partners are focusing on developing rapid testing for both known and emerging resistance mechanisms. Special attention is being given to resistance against soil-applied residual herbicides, which are deployed before weeds emerge, and foliar herbicides, which target weeds already present in the field. Understanding resistance patterns across both herbicide types is critical for effective long-term management.
The project also includes a strong extension and education component, led by Kansas State, to disseminate findings and support grower decision-making. Activities will include online seminars, farmer meetings, panel discussions, and instructional materials that cover resistance identification, diagnostics, and management strategies.
