Based on anecdotal reports of lower than expected performance of pyrethroid insecticides, we have conducted bioassays to test the susceptibility of WBC larvae to the active ingredient bifenthrin (Figure 3). Results from 2016-2017 indicate that populations of WBC from problem and non-problem sites across Nebraska do not differ significantly from one another in their susceptibility to bifenthrin; however, all sites from Nebraska are less susceptible than a population from Ontario, Canada, where pyrethroids are rarely used.

In insecticide efficacy trials, products with diamides or indoxacarb as active ingredients performed better than pyrethroids alone. The details of these efficacy trials will be presented and discussed.

Research on the biology of WBC while feeding on different diets has shown that WBC are able to complete development on Bt Cry1F corn, although they develop slower than larvae feeding on non-Bt corn. The implications that these results have on IPM and resistance management will be discussed.

Resources for Additional Information

Webinar from Plant Management Network on Western Bean Cutworm: Pest Status and IPM Options with Julie Peterson, extension entomology at the university’s West Central Research and Development Center at North Platte.