Does Roundup-resistant marestail illustrate problems with reliance on GM crops and pesticides?
(February 22, 2001 –Crophchoice news) — Scientists discovered glyphosate-resistant marestail (horseweed) in three fields of Roundup Ready soybeans in Delaware. The resistant weeds may be present in other fields there, and in New Jersey and Maryland, as well. Glyphosate is the active ingredient in the herbicide Roundup, which Monsanto has engineered its Roundup Ready soybeans to resist. “It certainly looked like resistance,” University of Delaware weed scientist Mark VanGessel told Farm Chemicals magazine. “Marestail control was random throughout the field, which ruled out sprayer problems or applicator error. With almost ideal weather conditions early in 2000, we also ruled out environmental or stress factors.” Members of the agricultural community disagree about the implications of this finding. VanGessel dismissed the idea that Roundup Ready soybeans transferred their herbicide resistant genes to the marestail. “Weeds go through frequent genetic changes,” he said. “It’s random chan
