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.