Weed Resistance to Herbicides May Undermine Benefits of GM Crops

U.S. farmers who have switched to genetically engineered crops have made increased profits and reduced short-term damage to the environment, but reliance on weedkillers associated with the new crops could undermine the environmental benefits, according to a new study.

More than 80 percent of the soy, corn, and cotton grown in the U.S. is now genetically engineered to resist pests or the popular herbicide, Roundup, according to the report by the National Academy of Sciences.

But nine species of weeds have evolved resistance to glyphosate, a main component of Roundup.

Increased resistance may force farmers to use more toxic herbicides or engage in plowing practices that cause soil damage.

“We’ve got a significant weed-resistance problem,” said David Ervin, lead author of the report and professor of environmental management and economics at Portland State University. “That’s an issue that’s not going to go away. And it has to be dealt with, as it could jeopardize the usefulness of the technology down the road.”

The report suggests that farmers must adopt more diverse management practices, including a rotation of herbicides and improved mechanical weed-control practices.

Article appearing courtesy Yale Environment 360.

photo: cwalker 71