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ARS Home » Midwest Area » Urbana, Illinois » Global Change and Photosynthesis Research » Research » Publications at this Location » Publication #306840
Title: Managing the evolution of herbicide resistance

Author
item Evans, Jeffrey
item TRANEL, PATRICK - University Of Illinois
item HAGER, AARON - University Of Illinois
item SCHUTTE, BRIAN - New Mexico State University
item WU, CHENXI - University Of Illinois
item CHATHAM, LAURA - University Of Illinois
item Davis, Adam

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2015
Publication Date: 5/11/2015
Citation: Evans, J.A., Tranel, P.J., Hager, A.G., Schutte, B.R., Wu, C., Chatham, L., Davis, A.S. 2015. Managing the evolution of herbicide resistance. Pest Management Science. DOI: 10.1002/ps.4009.

Interpretive Summary: Efforts to combat the evolution and spread of herbicide resistant (HR) weeds by using different herbicides over time have largely been ineffective. Farmers need science-based guidance to prevent this serious problem from becoming worse. We focused on identifying risk factors for glyphosate-resistance (GR) in common waterhemp, which has become a major agricultural weed over the past decade. We constructed and analyzed a database of GR waterhemp frequency, field attribute, weed community, and management data from 105 central Illinois grain farms, including over 500 site-years of herbicide application records. Presence and relative abundance of GR waterhemp were greatest in fields with frequent glyphosate applications, high annual rates of herbicide mode of action (MOA) turnover, and fewer MOA per field per year. These findings were supported by statistical models showing that combining multiple herbicide MOA at the time of application through tank mixing offers the greatest protection against GR waterhemp, while cycling MOA over time offers no defense and may actually increase GR traits within fields. Tactics such as herbicide tank mixing may temporarily delay GR waterhemp or other HR weed traits, but they are unlikely to prevent them. Long-term, cost-effective, environmentally sound weed management will require truly diversified management practices that challenge weeds with multiple stresses to create disruptive, rather than directional, selection on weed populations.

Technical Abstract: Herbicide-resistant (HR) weeds are widespread threats to the sustainability, productivity, and profitability of many cropping systems. Efforts to combat their spread through herbicide rotation schedules have been marginally effective at best. Despite the scope of the problem, we lack sound empirical data on factors that reduce HR weed presence and abundance in agricultural landscapes. We focused on identifying drivers of glyphosate-resistance (GR) in Amaranthus tuberculatus (common waterhemp), which has become a major agricultural weed over the past decade. We constructed and analyzed a database of GR A. tuberculatus frequency, field attribute, weed community, and management data from 105 central Illinois grain farms, including over 500 site-years of herbicide application records. Classification and regression tree analyses indicated that GR trait presence and relative abundance were greatest in fields with frequent glyphosate applications, high annual rates of herbicide mode of action (MOA) turnover, and fewer MOA per field per year. These findings were supported by generalized linear mixed models showing that combining herbicide MOA at the time of application through tank mixing affords the greatest protection against GR A. tuberculatus, while cycling MOA over time offers no defense and may actually enrich GR traits within fields. Measures such as herbicide tank mixing may temporarily delay GR A. tuberculatus or other HR weed traits, but they are unlikely to prevent them. Long-term, cost-effective, environmentally sound weed management will require truly diversified management practices that challenge weeds with multiple stresses to create disruptive, rather than directional, selection on weed populations.