Effect of Ethyl Alcohol and Acetone on the Toxicity of Ethion in Bioassays on Two Species of Rust Mites of Citrus1

Abstract

Replicated laboratory experiments were conducted to determine the effect that ethyl alcohol and acetone exert upon the toxicity of ethion against the citrus rust mite, Phyllocoptruta oleivora (Ashmead); and Aculops pelekassi (Keifer). In routine screening work, technical acaricides are dissolved in 4 ml of solvent and then diluted to 800 ml with distilled water into which mites are dipped. Three dosages of ethion were tested comparing this method with 2 other methods using increased concentrations of solvents. A significant reduction in mean percent mortality of both mites resulted when mites were either dipped in 10% solvent before immersion into the toxicant or were dipped into toxicant diluted with 10% solvent. Using the standard technique, mortality of mites was essentially the same as obtained in previous tests.