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Biology and Behavior of Striacosta albicosta (Smith) (Lepidoptera: Noctuidae) and Implications for Insect Pest Management
The rapid adaptation of the western bean cutworm (WBC), Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), to current management tactics requires the development of baseline data in order to improve management approaches. In chapter two, we described developmental parameters of WBC feeding on an artificial diet under laboratory conditions. Data suggest that WBC develop mainly through seven instars and the crucial developmental period is the prepupal stage. Eggs laid by wild-mated moths showed a fertility of 75.71%, compared to 4.18% from laboratory-reared moths, indicating that laboratory conditions strongly affect fertility success. In chapter three, we described developmental parameters of immature WBC stages feeding on dry beans, non-Bt, Cry1F and Vip3A maize. For Vip3A, mortality was 100% after 24h. Larvae feeding on non-Bt maize had the highest larval survival compared to the other hosts, and Cry1F maize had higher survival than dry beans. Larvae feeding on dry beans had significantly faster total development time compared to non-Bt and Cry1F maize. In chapter four, we conducted a series of on-plant and artificial scenario experiments to determine neonate behavior when exposed to Bt. On-plant experiments indicated that the presence of Bt toxins increased plant abandonment. However, maize tissue choice experiments failed to prove that larvae could distinguish between Bt and non-Bt tissue. Video tracking trials showed an increase in mean velocity and total time spent moving in the presence of Cry1F and non-Bt tissues. In chapter five, we determined baseline LC50 data for the pyrethroid bifenthrin from WBC populations from Nebraska, Kansas, and Canada. Our data determined that Nebraska populations have lower susceptibility when compared to Canada, with no differences in susceptibility among Nebraska populations. Aerial application simulations suggested that levels of resistance estimated for bifenthrin active ingredient did not impact the efficacy of the correspondent commercial product under controlled conditions. Our results represent the first steps in understanding the complex behavior of WBC when exposed to Bt plants. Furthermore, results obtained from this research might indicate that insecticide control failures reported in Nebraska could be associated with factors other than resistance, such as application technique and environmental conditions. Data generated may assist current and future western bean cutworm resistance management programs.
Goulart Montezano, Débora, "Biology and Behavior of Striacosta albicosta (Smith) (Lepidoptera: Noctuidae) and Implications for Insect Pest Management" (2019). ETD collection for University of Nebraska - Lincoln. AAI13815120.