Biotech Updates

Rotation to Reduce Glyphosate-Resistant Weeds

September 15, 2011

As an offshoot of the Respect the RotationTM field day conducted in July in 2010, growers in the United States are urged to conduct management practices to reduce the development of glyphosate resistance in weeds. "Glyphosate-resistant materials costs soybean growers an added $11.50 per acre," said Jason Norsworthy, associate professor of weed science at the University of Arkansas and a key member of the Weed Science Society of America (WSSA) who is working with the Environmental Protection Agency to develop guidelines for proper resistance management practices. "Glyphosate-resistant Palmer pigweed costs cotton growers $19.45 per acre. Resistance is impacting land values, conservation tillage and more. The system, the way it is currently set up, is not sustainable," he added.

To come up with a rotation scheme that would limit build up of resistance against glyphosate, Bayer CropScience labeled all herbicides mode of action for easy identification. "If growers can see the numbering system associated with various chemistries and easily identify what mode of action they're applying, they can better identify opportunities for herbicide rotation" said Andy Hurst, product manager for Bayer CropScience. "Without that knowledge, it is easy to apply the same mode of action over and over, encouraging the development of resistance."

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