Evaluation of alternative mode of action insecticides in managing neonicotinoid-resistant Frankliniella fusca in cotton

Abstract

BackgroundFrankliniella fusca (Hinds) resistance to neonicotinoid seed treatments (NSTs) used in cotton has created a need for more diverse insecticide options targeting thrips. Alternative insecticides must protect seedlings while they are most vulnerable to F. fusca injury (emergence through five true leaves). In this study, we evaluated non-neonicotinoid foliar insecticide sprays currently registered for use on cotton against a neonicotinoid resistant F. fusca population. MethodsDuring two-seasons, we compared NSTs (imidacloprid, imidacloprid + thiodicarb, and thiamethoxam) to non-neonicotinoid foliar sprays of acephate, spinetoram, abamectin, cyantraniliprole, and cyantraniliprole + abamectin in field trials to evaluate their efficacy against a neonicotinoid resistant F. fusca population. Applications were made to both early- and full-maturity cotton varieties (Stoneville 4946GLB2 & 6448GLB2) to examine F. fusca larval establishment, plant vigor, and seed cotton yield. ResultsWith the exception of abamectin, foliar insecticide treatments consistently reduced F. fusca larval numbers and minimized true leaf damage at a level equal to or greater than NSTs. Yield was not affected by insecticide treatment. Non-neonicotinoid foliar sprays have utility in managing neonicotinoid-resistant F. fusca and should be recommended to alleviate selection pressure against NSTs in cotton and unnecessary economic losses due to ineffective NST use against resistant F. fusca populations.