Pollen wafting from bioengineered corn to traditional varieties may be undermining the fight to keep pests from evolving resistance to pesticides, according to a new study.
Farmers who plant Bt corn, which is genetically engineered to make an insecticide produced by the bacterium Bacillus thuringiensis, by law must plant non-Bt corn nearby, explains Bruce Tabashnik of the University of Arizona in Tucson. By harboring susceptible pests, those non-Bt rows of corn, called a refuge, are supposed to slow down a pest population's tendency to develop resistance to the Bt pesticide.
Tests show, however, that pollen from the Bt corn drifts over into the refuge and creates Bt-laced kernels in the ears of otherwise non-Bt plants, say Tabashnik and Charles Chilcutt of Texas A&M University in Corpus Christi. The rules for refuges may need revising, the researchers say in the May 18 Proceedings of the National Academy of Sciences.