Field evaluations of novel chloronicotinyls and insect growth regulators against the greenhouse whitefly on strawberry

Abstract

The efficacy of two novel chloronicotinyls and two novel insect growth regulators against the greenhouse whitefly [Trialeurodes vaporariorum (Westwood)] on summer-planted strawberries was evaluated in field experiments. Imidacloprid applied in soil 3 weeks after planting decreased whitefly adult numbers by 58% to 90%, first and second instars by 78% to 93% up to 56 days postapplication, and third and fourth instars by 42% to 86% up to 77 days postapplication, whereas thiamethoxam applied similarly reduced adults by 58% to 80%, first and second instars by 78% to 93% up to 6 weeks posttreatment, and third and fourth instars by 48% to 80% up to 10 weeks after initial application, compared to nontreated controls. Imidacloprid applied in soil immediately prior to planting further suppressed numbers of whiteflies by 71% to 83% (adults), 58% to 74% (first and second instars), and 52% to 74% (third and fourth instars), in comparison with the same compound applied through drip irrigation lines 4 weeks after planting. Buprofezin and pyriproxifen applied 6 weeks after planting reduced numbers of adult whiteflies by 25% to 81% and 40% to 73%, respectively; first and second instars by 61% to 92% and 51% to 100%, respectively; and third and fourth instars by 45% to 100% and 37% to 87%, respectively, on most sampling dates up to 7 weeks postapplication. The potential roles of these insecticides in integrated greenhouse whitefly management programs are discussed.