Ten different populations of western corn rootworms were evaluated to determine susceptibility to the Cry3Bb Bt toxin that has been expressed in transgenic corn to control rootworm larvae. Varying concentrations of Cry3Bb were spread evenly over the surface of an artificial diet dispensed into wells of a 96-well mircotiter plate. Individual neonate larvae were transferred into each well, and both mortality and larval weight were measured 4-7 days later. Control treatments consisted of larvae exposed to untreated diet. Rootworm populations were obtained from field collections but some had been maintained in the laboratory for several generations prior to bioassay. Microbial contamination of the diet was consistently a problem and egg handling, and washing procedures were critical to minimize microbial growth on the rearing medium. Significant dose-response regressions were obtained for each population which provide a baseline of susceptibility prior to commercialization and widespread exposure to the Cry3Bb toxin.
Species 1: Coleoptera Chrysomelidae Diabrotica virgifera virgifera
Keywords: Cry3Bb
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA