Connecting stink bug pyrethroid resistance to landscape composition in eastern North Carolina

The arrangement of crop hosts in the landscape can affect exposure of polyphagous pests to insecticides registered in multiple crops that, in turn, lead to repeated exposure to specific modes of action. Stink bugs, a polyphagous pest complex, are intensively managed in a sequence of southern US row crop hosts (corn, cotton, soybean) throughout the growing season. The seasonal availability of these hosts creates a shifting mosaic, each with a high likelihood for insecticide exposure. In this study, we measured bifenthrin susceptibility of three common stink bug species: Chinavia hilaris (Say), Nezara viridula L., and Euschistus servus (Say) from 2022 to 2024. Populations were collected from 34 field locations in eastern North Carolina. A glass-vial bioassay procedure was used to assess the bifenthrin susceptibility. To understand how selection may occur as a function of host crop availability where bifenthrin use is common, we used a geospatial approach to connect host crop abundance over time (predictors) with observed levels of bifenthrin susceptibility (response). Results indicated that susceptibility varied among species and across populations nested within species. Susceptibility was also linked to the abundance of host crops, particularly corn. Although we did not know the true intensity of sprays deployed for stink bugs over the study extent, this approach yielded logical relationships among crop predictors where bifenthrin is used and the susceptibility of target species. Here, aspects of crop abundance provided a useful strategy to understand where intense resistance selection may occur, which can help prioritize spatially explicit insecticide resistance management efforts.