The growing problem with weeds that have become resistant to the most common herbicide used by American corn, soybean and cotton farmers has gotten so serious that new strategies are needed to combat them, according to David Mortensen.
Mortensen should know. The professor of weed ecology in the College of Agricultural Sciences has spent his career researching weeds that affect agricultural production, sustainable ways to control them, and the relationships between crops, native and invasive weeds, and pollinators.No further comments are really needed
"During the period since the introduction of glyphosate-resistant crops, the number of weedy plant species that have evolved resistance to glyphosate has increased dramatically, from zero in 1995 to 19 in June of 2010," Mortensen said.
In the summer of 2009, glyphosate-resistant weeds were reported on as many as 14,262 sites on up to 5.4 million acres, and the most recent summary indicates 30,000 sites infested on up to 11.4 million acres, according to Mortensen. In a period of three years, the number of reported sites infested by glyphosate-resistant weeds has increased nine fold, while the maximum infested acreage increased nearly fivefold.