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Herbicide Resistance: Toward an Understanding of Resistance Development and the Impact of Herbicide-Resistant Crops

Published online by Cambridge University Press:  20 January 2017

William K. Vencill*
Department of Crop and Soil Sciences, University of Georgia, 3111 Miller Plant Science Building, 120 Carlton Street, Athens, GA 30502
Robert L. Nichols
Cotton Incorporated, 6399 Weston Parkway, Cary, NC 27513
Theodore M. Webster
Crop Protection and Management Research Unit, USDA–Agricultural Research Service, Tifton, GA 31794
John K. Soteres
Department of Scientific Affairs, Monsanto Company, 800 N. Lindburgh Boulevard, St. Louis, MO 63167
Carol Mallory-Smith
Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
Nilda R. Burgos
Department of Crop, Soil, and Environmental Sciences, University of Arkansas, 1366 West Atheimer Drive, Fayetteville, AR 72704
William G. Johnson
Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907-1155
Marilyn R. McClelland
Department of Crop, Soil, and Environmental Sciences, University of Arkansas, 1366 West Atheimer Drive, Fayetteville, AR 72704
Corresponding author's E-mail:
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Development of herbicide-resistant crops has resulted in significant changes to agronomic practices, one of which is the adoption of effective, simple, low-risk, crop-production systems with less dependency on tillage and lower energy requirements. Overall, the changes have had a positive environmental effect by reducing soil erosion, the fuel use for tillage, and the number of herbicides with groundwater advisories as well as a slight reduction in the overall environmental impact quotient of herbicide use. However, herbicides exert a high selection pressure on weed populations, and density and diversity of weed communities change over time in response to herbicides and other control practices imposed on them. Repeated and intensive use of herbicides with the same mechanisms of action (MOA; the mechanism in the plant that the herbicide detrimentally affects so that the plant succumbs to the herbicide; e.g., inhibition of an enzyme that is vital to plant growth or the inability of a plant to metabolize the herbicide before it has done damage) can rapidly select for shifts to tolerant, difficult-to-control weeds and the evolution of herbicide-resistant weeds, especially in the absence of the concurrent use of herbicides with different mechanisms of action or the use of mechanical or cultural practices or both.

Weed Biology and Ecology
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