Weeds

New data published in the recent issue of the journal Environmental Sciences Europe finds that U.S. farmers are using significantly more applications of toxic pesticides than in 1996 when pesticide intensive genetically modified crops were first widely introduced, reports Reuters.

Genetically engineered crops have directly correlated to the rise in pesticides like glyphosate, marketed by Monsanto as Roundup. An increase of more than 527 million pounds of pesticides has been used since 1996, but they’re becoming less effective, according to study author, Charles Benbrook, research professor at the Center for Sustaining Agriculture and Natural Resources at Washington State University.

According to Benbrook, both herbicide tolerant crops and insect protected crops were intended to make killing pests and weeds easier for farmers. But “superweeds” and resistant pests have led farmers to use higher doses and more frequent applications of pesticides over the years. Already, more than two-dozen types of weeds have become resistant to Monsanto’s Roundup. The increasing resistance is requiring farmers to increase their use of herbicides by as much as 25 percent annually, says Benbrook. According to Reuters, “the annual increase in the herbicides required to deal with tougher-to-control weeds on cropland planted to genetically modified crops has grown from 1.5 million pounds in 1999 to about 90 million pounds in 2011.”

Initially, use of insecticides dropped between 1996 and 2011—by nearly 30 percent. But numbers are now rising, according to Benbrook, “The relatively recent emergence and spread of insect populations resistant to the Bt toxins expressed in Bt corn and cotton has started to increase insecticide use, and will continue to do so.”

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Image: Ian Sane