RODALE NEWS, EMMAUS, PA—Sneezing more than you used to? It may have something to do with the proliferation of genetically engineered (GE) crops. Farmers now plant 941 million acres of genetically engineered crops, many of which are designed to withstand heavy applications of the herbicide glyphosate used in the weed killer Roundup. However, a new report from the nonprofit Organic Center finds that all that biotech engineering means more glyphosate is being used to combat weeds, such as ragweed and other allergenic plants, that are becoming resistant to the chemical.
THE DETAILS: Herbicide-tolerant crops include soybeans, corn, and cotton that are engineered to resist weed-killing chemicals. The report states that nearly all herbicide-tolerant crops planted today are "Roundup Ready," meaning they resist the effects of the glyphosate-based herbicide Roundup, made by the company Monsanto (which also produces most of the GE seeds on the market today). It also looked at "Bt crops," cotton and corn bred to contain a natural bacterium Bacillus thuringiensis that kills some types of insects.
Researchers at The Organic Center used U.S. Department of Agriculture surveys on herbicide, insecticide, and fungicide use from the last 13 years (the period since genetically engineered crops were first planted), as well as pesticide information collected from Monsanto. Herbicide-tolerant crops accounted for 72 percent of all the "trait acres" (acres with a crop containing one GE trait) planted with genetically engineered seeds between 1996 and 2008, they found. While the Bt crops led to a consistent year-over-year reduction in insecticide use, herbicide-tolerant cotton boosted herbicide use by significant amounts. In 2007, cotton farmers were using 200 percent more Roundup on their crops than they were in 1996, at an average annual increase of 18 percent, while soybean farmers were using 98 percent more (a 10 percent annual increase) and corn farmers 39 percent more (a 5 percent annual increase; herbicide-tolerant corn was adopted more slowly than other GE crops). At the same time, researchers noted, farmers who were growing conventional (not genetically engineered) soybeans and corn saw downward trends in the amounts of herbicides needed, using 26 percent fewer pounds of pesticides than farmers of genetically engineered crops.