Factors Affecting Population Dynamics of (Lepidoptera: Noctuidae) in a Mixed Landscape with Bt Cotton and Peanut.

In North America, weather and host-plant abundance drive the population dynamics of the migratory pest The objectives of this study were to (i) estimate monthly abundance of moths in Bt cotton and peanut fields, (ii) document the effects of weather on trap catches, and (iii) determine larval hosts supporting populations from 2017 to 2019. Year-round trapping of moths was conducted in 16 commercial fields in two regions of the Florida Panhandle using delta traps. moth catches were associated with temperature, rainfall, and relative humidity. Larval hosts were determined by isotopic carbon analysis. Our results showed year-round flights in both regions across two years, with the highest and lowest moth catches occurring from July to September and November to March, respectively. There was no difference in catches between traps set on Bt cotton and peanut. In the Santa Rosa/Escambia counties, weather explained 59% of the variance in catches, with significant effects of temperature, relative humidity, and rainfall. In Jackson County, weather explained 38% of catches, with significant effects of temperature and relative humidity. Carbon isotopic data showed that feeding on C3 plants, including Bt cotton, occurred over most of the year, although feeding on C4 hosts, including Bt corn, occurred during the summer months. Hence overwintering and resident populations of in the Florida Panhandle may be continually exposed to Bt crops, increasing the risk for the evolution of resistance.