Pollen drift from Bacillus thuringiensis corn: Efficacy against European corn borer (Lepidoptera : Crambidae) in adjacent rows of non-Bt corn

Commercial non-Bacillus thuringiensis (Bt) corn was planted adjacent to Bt corn to determine the effects of Bt corn pollen falling on non-Bt plants fo r control of European corn borer larvae, Ostrinia nubilalis (Hubner). Field plots in Iowa and Kansas consisted of two center rows of Bt corn with eigh t rows of adjacent non-Bt corn on each side. In mid-September 1996 and 1997 , we counted European corn barer larvae and larval tunnels in the stalk and ear shank. There were no significant differences in European corn borer nu mbers across non-Bt rows and the slope of the regression line was not signi ficantly different from zero. In a single plot in Iowa, however, fewer tunn els were observed in rows of coin that were closer to Bt corn. This site wa s isolated from natural infestations and probably does not reflect a typica l field situation. Our results suggest that Bt pollen has minimal or no con trol of European corn borer larvae in adjacent rows of non-Bt corn under na tural conditions. Bt pollen drifting onto adjacent nun-Bt plants should not increase the risks related to resistance management.