Prediction of insecticide field efficacy and other IRM studies on whiteflies in Georgia

Whiteflies are economically important pests in the cotton and vegetable mosaic in Georgia. The use of insecticides, mainly rapid-action neurotoxic, is the current main strategy for its control. The widespread and intense use of chemicals requires quick and adequate insecticide resistance management (IRM) strategies. Laboratory bioassays were conducted to assess field insecticide efficacy for selected insecticides used to control whiteflies in Georgia. In order to quickly predict field related insecticide resistance, lab maximum (high) dose bioassays were compared to simultaneous cucurbit field trial efficacy results for multiple insecticides in the 2021 and 2022 seasons. Additionally, four insecticides were used for a high-low dosage test to evaluate in principle how the addition of one concentration of a serial dosage would refine the efficacy prediction. Results from the predictive study indicated a general positive correlation between lab survival and field counts of adult whiteflies based on the ranking of the insecticides used. Venom (dinotefuran), Sivanto Prime (flupyradifurone) and Exirel were consistently more efficient and settled the correlation basis for 24 h lab-field response. Other whitefly experiments being conducted from our lab group involves: survey of diamide and imidacloprid resistance and the effects of host plant and different locations on the dose-response curve, identification of molecular mechanisms associated with this resistance traits, and analyzing sublethal effects of Exirel and Knack (pyriproxyfen) over adults and immatures. IRM strategies for managing whitefly in affected crops in Georgia are supplemented with the results.