• Bacillus thuringiensis;
  • behavior;
  • blended refuge;
  • developmental delay;
  • feeding preference;
  • insect resistance management



The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a major agricultural pest that is managed with transgenic corn, Zea mays L., expressing genes from Bacillus thuringiensis Berliner (Bt). The effects of Bt corn producing Cry34/35Ab1 (event DAS-59122–7) and entomopathogens on the survival and development of larval D. v. virgifera were examined in laboratory, field and greenhouse experiments.


Larvae preferred non-Bt over Bt corn in a laboratory experiment, and there was higher recovery from non-Bt corn than from Bt corn in a field experiment. In a greenhouse study, survival at 17 days did not differ significantly among non-Bt corn, Bt corn and a blend of Bt and non-Bt corn, but development was delayed on Bt corn. Older larvae fed non-Bt corn had lower survival when entomopathogenic nematodes were added, but no other effects of pathogen were detected.


Bt corn producing Cry34/35Ab1 delayed larval development of D. v. virgifera and deterred feeding. In a mixture of Bt and non-Bt corn, larval development and survival were similar to non-Bt corn alone, suggesting that non-Bt plants in a blended refuge or a pure stand may produce a similar number of adult insects, and that timing of adult emergence may also be similar. © 2012 Society of Chemical Industry