Laboratory Activity of Spinosad on Non-Target Beneficial Arthropods, 1994

Abstract

Abstract This report details the results of a number of laboratory tests on spinosad as spray-dried broth (NAF-144) and an extracted 480 gms/liter SC (NAF-85) against a variety of beneficial organisms. All beneficial insects were obtained from a commercial supplier, Nature’s Control, P.O. Box 35, Medford, OR 97501. For topical, honey bee tests, the bees were confined to a petri dish and then sprayed with a hand syringe. For contact exposure, the exposure units consisted of glass tubes, 7.5 cm. long × 4 cm. in diameter. The tubes were treated by applying a uniform film to the inside of the glass tube using a fine DeVilbis sprayer. Materials were field applied to ‘Courtland’ Apples during bloom. Branches were harvested at 0, 16, 24, and 40 hours post spray. Bees were caged in the laboratory with the treated blossoms. The experiment was held at 40-50% RH and 23°C. The exposure units for Encarsia were treated by applying a uniform film to the inside of the glass tube using a fine DeVilbis sprayer. Ten newly emerged adult Encarsia formosa were aspired from the emergence chamber into each of the treated vials which were then capped with fine muslin. For Orius and Hippodamia and Lacewing exposure units were created by first treating the glass sheet by applying an even film of pesticide using a DeVilbis nozzle. After the sheet was dry, the Plexiglas sheet was placed on top of the glass sheet. 5 cm. tall rings were coated with Fluon and placed in holes drilled in the Plexiglas sheet and seated firmly against the glass creating separate exposure units. Each exposure unit was capped with muslin held in place with rubber bands. For the treated prey ingestion studies in the ladybird beetle test, squash leaves heavily infested with aphids were sprayed to run off and the treated aphids were driven off into the cage to be consumed by the beetles. Second instar, green lacewing larvae were fed tobacco budworm eggs which had been killed by freezing and treated by swirling them in formulated pesticides. For predatory mites, an even film of pesticide was applied to each leaf using a hand held syringe. After the leaves were dry, they were trimmed to an approximate diameter of 4 cm. and placed abaxial side up on agar in a petri dish. Five adult female predator mites were transferred by hand to each leaf. Tests were held under ambient laboratory conditions of approximately 23°C and 50% RH for 72 hours at which time, they were graded for mortality. LC50’s were generated using the Trimmed Spearman Karber method.