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ARS Home » Midwest Area » Urbana, Illinois » Global Change and Photosynthesis Research » Research » Publications at this Location » Publication #317573
Title: Crop advisor perceptions of giant ragweed distribution, herbicide-resistance, and management in the Corn Belt

Author
item REGNIER, E - The Ohio State University
item HARRISON, K - The Ohio State University
item LOUX, M - The Ohio State University
item HOLLOMAN, C - The Ohio State University
item VENKATESH, R - The Ohio State University
item Davis, Adam
item TAYLOR, R - The Ohio State University

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/22/2015
Publication Date: 4/24/2016
Citation: Regnier, E.E., Harrison, K., Loux, M.M., Holloman, C., Venkatesh, R., Davis, A.S., Taylor, R. 2016. Crop advisor perceptions of giant ragweed distribution, herbicide-resistance, and management in the Corn Belt. Weed Science. 64:361-377.

Interpretive Summary: Understanding the underlying causes of weed problems can help in developing proactive management strategies. Giant ragweed has been increasing as a major weed of row crops in North America. We surveyed Certified Crop Advisors in the north central U.S. corn belt to aid mapping of herbicide resistant and sensitive populations of giant ragweed in this region. Giant ragweed was reported as one of the most difficult weeds to manage in 190 counties, most of which were located in Minnesota, Wisconsin, Iowa, Illinois, Indiana, and Ohio. In most counties outside this area, giant ragweed was reported to appear in crop fields more recently and only within the last five years in some counties (e.g., northern Wisconsin), indicating that it is spreading outward from the east-central area of the corn belt. Giant ragweed populations with resistance to glyphosate or ALS herbicides were reported by 58% of respondents, and populations resistant to both herbicide modes of action were reported by 44% of respondents. Crop production factors associated with more severe giant ragweed problems included reduced tillage, continuous soybean production, and multiple application herbicide management programs. Ecological factors included the presence of giant ragweed in non-crop edge habitats, a prolonged emergence period, and the presence of the common nightcrawler in crop fields. Changing the production practices conducive to giant ragweed establishment in reduced tillage systems and managing giant ragweed in non-crop areas may help to slow its spread and support effective long-term management of this species.

Technical Abstract: Giant ragweed has been increasing as a major weed of row crops in North America. We conducted a web-based survey of Certified Crop Advisors in the Corn Belt to determine the current distribution of giant ragweed, the distribution of herbicide resistant populations, and management and ecological factors associated with herbicide resistance. The survey response indicated that giant ragweed was one of the most difficult weeds to manage in 190 counties, most of which were located in Minnesota, Wisconsin, Iowa, Illinois, Indiana, and Ohio. Giant ragweed was reported to appear in crop fields 20 years ago or longer in western Ohio, most of Indiana, northern Illinois, southern Wisconsin, southeastern Minnesota, and eastern Iowa. In most counties outside this area, giant ragweed was reported to appear in crop fields more recently and only within the last five years in some counties (e.g., northern Wisconsin), indicating that it is spreading outward from the east-central area of the Corn Belt. Fifty-eight percent or more of all respondents reported the presence of ALS- or glyphosate-resistant populations in corn or soybean fields their county, and 44% or more reported ALS- and glyphosate multiple-resistant populations. Crop production factors associated with acreage infested by giant ragweed, difficulty of managing giant ragweed, and/or presence of herbicide-resistant giant ragweed populations included reduced tillage, continuous soybean production, and multiple application herbicide management programs; ecological factors included the presence of giant ragweed in non-crop edge habitats, a prolonged emergence period, and the presence of the common nightcrawler (Lumbricus terrestris L.) in crop fields. Results suggest that changing production practices conducive to giant ragweed establishment in reduced tillage systems and managing giant ragweed in non-crop areas could reduce giant ragweed populations and slow its spread in the Corn Belt.