Crop Biotech Update

Herbicide Resistance Predates GM Crops, Says Weed Scientists

July 20, 2016

Herbicide resistance has been blamed to glyphosate use in genetically engineered crops. However, the Weed Science Society of America (WSSA) reports that herbicide resistance predates genetically engineered crops by 40 years. According to a WSSA press release, while 2016 marks only the 20th anniversary of glyphosate resistant crops, 2017 will mark the 60th anniversary of the first reported herbicide resistant weeds.

The first known case of herbicide resistance was reported in 1957 when a spreading dayflower in Hawaii was found to be resistant to a synthetic auxin herbicide. The same year, a wild carrot in Ontario, Canada was found to be resistant to some of the same synthetic auxin herbicides. Since then, 250 species of weeds have evolved resistance to 160 different herbicides that span 23 of the 26 known herbicide mechanisms of action, and they are found in 86 crops in 66 countries.

Research shows that resistant weeds evolve when a single approach to weed management is used repeatedly to the exclusion of other chemical and cultural controls – making a diverse, integrated approach to weed management the first line of defense. Many growers have successfully fought resistance by adopting a broader range of controls.

For more details, read the press release at the WSSA website.