Introducing genetically engineered (GE) crops two decades ago was supposed to reduce the amount of chemicals sprayed on farm fields. It turns out the exact opposite is true.

A new academic study shows farmers are using more pesticides since the adoption of GM plants because of an increase of “superweeds” and hard-to-kill insects.

Charles Benbrook, a research professor at the Center for Sustaining Agriculture and Natural Resources at Washington State University, found that overall pesticide use went up by 404 million pounds from 1996, when the first GE herbicide-tolerant crops were rolled out, to 2011. Herbicide use increased by 527 million pounds while insecticide use decreased by 123 million pounds.

Benbrook said more than two dozen weed species have become resistant to the GE crops, causing farmers to ramp up their spraying. Most of the increase has been caused by is the spread of weeds that are resistant to glyphosate, an herbicide created in 1970 and marketed by Monsanto as Roundup. It is the most commonly used agricultural herbicide in the United States.

“Things are getting worse, fast,” Benbrook told Reuters. “In order to deal with rapidly spreading resistant weeds, farmers are being forced to expand use of older, higher-risk herbicides.”

-Noel Brinkerhoff, David Wallechinsky

To Learn More:

Pesticide Use Ramping Up as GMO Crop Technology Backfires: Study (by Carey Gillam, Reuters)

Impacts of Genetically Engineered Crops on Pesticide Use in the U.S.—The First Sixteen Years (by Charles M. Benbrook, Environmental Sciences Europe) (pdf)

 Corn Cartel Battles other Farmers over Dow Herbicide (by Noel Brinkerhoff, AllGov)

Dramatic Increase in Weed-Killer Use in U.S. (by Noel Brinkerhoff, AllGov)