SUPPRESSION OF BEMISIA-TABACI (HOMOPTERA, ALEYRODIDAE) INFESTATIONS IN CANTALOUPE AND COTTON WITH SPRINKLER IRRIGATION

A series of field experiments were conducted to evaluate Bemisia tabac i (Genn.) infestations in both sprinkler and furrow irrigated cantalou pe and cotton plots under conditions of intense whitefly pressure in I mperial Valley, CA. Various fungal pathogen and insecticide treatments also were compared within each irrigation regime. A consistent findin g throughout all experiments was that densities of immature whiteflies were significantly reduced in sprinkler irrigated plots. This was mos t evident in sprinkler irrigated cantaloupe plots treated with the ins ecticide imidacloprid, as plants survived whitefly infestations to pro duce marketable fruit in these plots only; Similarly, whitefly densiti es in imidacloprid- treated/sprinkler-irrigated cotton were significan tly lower than all other treatments. Spray applications of insect fung al pathogens were for the most part indistinguishable from the untreat ed control in terms of densities of whiteflies. Results from the first cantaloupe trial indicate that sprinkler irrigation on a daily schedu le resulted in consistently lower whitefly infestations compared to a biweekly schedule. Published by Elsevier Science Ltd