Is biotechnology really feeding the world and greening the environment? An examination of crop yields and pesticide use associated with genetically engineered crops

Two important questions that any agricultural crop technology needs to address are productivity, as measured by yield, and pesticide use. U.S. grain crops yields rose dramatically during the 20th century, and the adoption of genetically engineered (GE) varieties is often credited with recent yield increases. There is also a public perception that GE crops have led to reduced pesticide use. However, recent research has shown that intrinsic crop yields of engineered varieties have not increased compared with conventional varieties. Recent studies also show that the widespread planting of corn, soybeans, and a few other crops engineered to tolerate heavy applications of the herbicide glyphosate (also known as Roundup) has driven the evolution of glyphosate resistance in several common weed species. At least six important weed species have shown signs of glyphosate resistance in the U.S. over the past several years; these weeds infest several million acres and are spreading. With the appearance of resistant weeds, growers have had to apply more and different (usually more toxic) herbicides to control the pests. This presentation will consider the performance of GE crops in terms of yield, and update a 2004 analysis of USDA data documenting that pesticide use on GE crops is increasing compared with their non-engineered counterparts. Implications for the environment and public health will be discussed.