Landscapes of Resistance: Describing Cotton Production Factors Driving Tobacco Thrips Neonicotinoid Resistance in the Eastern Cotton Belt

Tobacco thrips (Frankliniella fusca, Hinds) resistance to neonicotinoid insecticides has become a critical issue for cotton producers throughout the Eastern Cotton Belt. In response to this emerging resistance issue, university and industry researchers collaborated on a regional survey of resistance to imidacloprid and thiamethoxam. From 2014-2016, a diagnostic dose feeding assay (360 mg formulated insecticide per L sucrose diet) was used to screen 338 thrips populations from ten states in the Mid-South and Southeast. Then geospatial crop data was collected surrounding bioassay locations to characterize the abundance of thrips host crops (cotton, soybean) that are often treated with neonicotinoids. Survival at the diagnostic dose was then related to the spatial and temporal abundance of thrips host crops that are commonly treated with neonicotinoid seed treatments. Results show that the spatiotemporal abundance of cotton and soybean described areas where elevated thrips resistance was detected. The addition of site-wise correlation significantly improved description of thrips resistance in the surrounding landscape. Outcomes of this project highlight the importance of spatial and temporal host crop abundance for the evolution of resistance in tobacco thrips and will inform the development of more comprehensive thrips IRM plans for future technologies.