| Stored grain insect pests have traditionally been controlled with insecticides. However, inherent with their use over the last 30 years, problems of insecticide resistance have occurred. Additionally, concerns over toxic residues and environmental contamination have arisen. Thus, alternative management tactics, especially using entomopathogens such as Bacillus thuringiensis (Bt), have gained support. Bt has been shown to control several moth species in stored commodities however, only one Bt based product has been registered for use against them. Attempts to find effective Bt isolates for the control of stored grain beetle pests have not been successful. Thus, the objective of this research was to find novel Bt isolates to manage stored grain insect pests.;An array of Bt isolates were screened against the maize weevil, lesser grain borer, red flour beetle, sawtoothed grain beetle, and the flour mill beetle. In general none of the Bt isolates screened caused significant mortality of any of these beetles.;Transgenic (Bt) plants are relatively new tools in insect pest management systems and transgenic grain has not been examined for activity against stored grain insect pests. A study was conducted to quantify the effects of several hybrids/isolines on Indian meal moth (IMM) and Angoumois grain moth (AGM). At least two transgenic hybrids/isolines caused significant reduction in adult emergence and fecundity of both moth species. It is believed that transgenic plants (grain) will contribute to insect pest management in stored grain.;Seven novel Bt isolates were examined for activity against IMM and AGM in diet assays. Six and 5 of them caused significant mortality of IMM and AGM larvae, respectively. Based on LD50 values and probit slopes, two isolates were found to be most effective and merit further consideration for development. Finally, a field experiment was conducted to examine the effectiveness of three Bt products for controlling IMM and AGM populations in stored shelled corn. They were found to significantly reduce moth populations during peak moth activity. |
