Effects of Surfactants on Rainfastness of Reduced-Risk Agricultural Insecticides

Abstract

Control of pest insects in agriculture is vital to protection of food crops. This experiment examined the rainfastness provided by surfactants to certain reduced-risk insecticides designed to control fruit crop infestation by lepidopteran pest insects. Three insecticides—a s pinosyn insecticide, an avermectin insecticide, and an anthranilic diamide—were formulated with either of two binding surfactants; Damoil or NuFilm 17 and sprayed on apple trees. Leaves and fruit from the sprayed trees were exposed to either 0 or 1 inch of simulated rainfall and then placed in bioassay chambers with lepidopteran pest larvae. Two species of apple pest larvae were used: Cydia Pomenella (codling moth) and Choristoneura rosaceana (obliquebanded leafroller). Larval mortality, percent of leaves eaten, and larval entries into fruit were counted. We found only a few results that showed that either surfactant contributed significantly to the performance of the insecticides, but we also found that the insecticides tested has some inherent rainfastness. These findings may have applications in agricultural pest control, though more investigation is necessary.