Effects of Bt and non-Bt corn on survival and development of larval western corn rootworm Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae)

Transgenic corn, Zea mays L., expressing genes from Bacillus thuringiensis Berliner (Bt) is widely used to control Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) in North America. Larval D. v. virgifera live in the soil and feed on corn roots, leading to crop losses. We conducted laboratory, field and greenhouse experiments to examine the effects of Bt corn (producing Cry34Ab1/35Ab1) and non-Bt corn on feeding behavior, survival and development of larval D. v. virgifera. Results from laboratory experiments indicated that larvae prefer to feed on non-Bt corn over Bt corn, and this preference for non-Bt corn was also observed in the field and greenhouse experiments. In the field experiment, the number of larvae recovered was higher from non-Bt corn than from Bt corn, and recovery decreased as distance from the infested plant increased. Larval survival at 17 days did not differ significantly among treatments(non-Bt only, Bt only, or a blend of non-Bt and Bt) in a greenhouse experiment, but larval development was hindered on Bt corn compared to either the non-Bt or the blend treatment.