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Rethinking Refuges? Drifting pollen may bring earlier pest resistance to bioengineered crops

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.

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