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

12:57pm, May 12, 2004

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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