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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #236377
Title: Loss of glyphosate efficacy: a changing weed spectrum in Georgia cotton

Author
item Webster, Theodore
item SOSNOSKIE, L - UNVI OF GA

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/24/2009
Publication Date: 1/1/2010
Citation: Webster, T.M., Sosnoskie, L.M. 2010. Loss of glyphosate efficacy: A changing weed spectrum in Georgia cotton. Weed Science. 58:73-79.

Interpretive Summary: The introduction of glyphosate (i.e. Roundup) resistance into crops through genetic modification has revolutionized crop protection. Glyphosate, the proverbial silver bullet, is a broad spectrum herbicide with favorable environmental characteristics and effective broad-spectrum weed control. The benefits of glyphosate include improved crop protection efficiency, reduction in use of other herbicides, and have allowed growers to adopt conservation tillage practices. However, in less than a decade, the utility of glyphosate resistant crop technology is threatened by the occurrence of weed species that are tolerant or resistant to glyphosate. Factors that have contributed to this shift in weed species composition in Georgia cotton production are reviewed, along with the implications of continued overreliance on this technology. Potential scenarios for managing glyphosate resistant populations, as well as implications on the role of various sectors for dealing with this purported “tragedy of the commons” are presented. While glyphosate susceptibility in Palmer amaranth (Amaranthus palmeri) is likely lost in Georgia, and perhaps in other cotton producing states in the Southern US, there are lessons to be learned. Improved understanding of how the technology was lost will allow us to avoid repeating these mistakes with the next herbicide resistant technology.

Technical Abstract: Introduction of glyphosate resistance into crops through genetic modification has revolutionized crop protection. Glyphosate, the proverbial silver bullet, is a broad spectrum herbicide with favorable environmental characteristics and effective broad-spectrum weed control that has greatly improved crop protection efficiency. However, in less than a decade, the utility of this technology is threatened by the occurrence of glyphosate tolerant and glyphosate resistant weed species. Factors that have contributed to this shift in weed species composition in Georgia cotton production are reviewed, along with the implications of continued overreliance on this technology. Potential scenarios for managing glyphosate resistant populations, as well as implications on the role of various sectors for dealing with this purported “tragedy of the commons” are presented. While glyphosate susceptibility in Palmer amaranth (Amaranthus palmeri) is likely lost in Georgia, and perhaps in other cotton producing states in the Southern US, there are lessons to be learned. Improved understanding of how the technology was lost will allow us to avoid repeating these mistakes with the next herbicide resistant technology.