US scientists fear <i>Bt</i> maize resistance

US maize entomologists have raised concerns about corn rootworms ( Diabrotica spp) developing resistance to the Bt Cry3Bb1 toxin in genetically modified insect-resistant maize. More than 20 entomologists have written to EPA Office of Pesticide Programs director Dr Steven Bradbury about the Agency’s findings that resistance is suspected in parts of four states ( Agrow No 630, p 14). “We are troubled about the immediate implications of these observations for the durability of pyramid toxin rootworm-protected corn, as well as their potential long-term impact on corn production,” the letter states.