U.S. farmers are using more hazardous pesticides to fight weeds and insects due largely to heavy adoption of genetically modified crop technologies that are sparking a rise of ‘superweeds’ and hard-to-kill insects, according to a newly released study.

Genetically engineered crops have led to an increase in overall pesticide use, by 404 million pounds from the time they were introduced in 1996 through 2011, according to the report by Charles Benbrook, a research professor at the Center for Sustaining Agriculture and Natural Resources at Washington State University.

Of that total, herbicide use increased over the 16-year period by 527 million pounds while insecticide use decreased by 123 million pounds.

Benbrook’s paper — published in the peer-reviewed journal Environmental Sciences Europe over the weekend and announced on Monday — undermines the value of both herbicide-tolerant crops and insect-protected crops, which were aimed at making it easier for farmers to kill weeds in their fields and protect crops from harmful pests, said Benbrook.

Herbicide-tolerant crops were the first genetically modified crops introduced to world, rolled out by Monsanto Co. in 1996, first in ‘Roundup Ready’ soybeans and then in corn, cotton and other crops. Roundup Ready crops are engineered through transgenic modification to tolerate dousings of […]