Toxicity of Acetone to Stored-product Insects

In laboratory experiments the toxicity of acetone was investigated against four species of stored-product insects. In empty-space trials, estimates of the lethal concentrations of acetone (LC, ۷۲-h exposure) for ۵۰% mortality against adults of the lesser grain borer, Rhizopertha dominica (F.), red flour beetle, Tribolium castaneum (Herbst), rice weevil, Si-tophilus oryzae (L.) and eggs of the angoumois grain moth, Sitotroga cerealella (L.) were ۳۳.۶۴, ۴۱.۰۵, ۴۳.۹۰ and ۴۶.۱۱ µl/liter, respectively. At the LC۹۵ level, the order of sensitiv-ity was rated to be: R. dominica adults > S. oryzae adults > T. castaneum adults > S. ce-realella eggs. Penetration tests revealed that acetone vapour could penetrate into the wheat mass and kill concealed insects in interkernel spaces. Comparison of LC۵۰ values between empty-space tests and penetration experiments (after ۷۲-h exposure) indicated that the increase in penetration toxicity was ۸.۵۲- and ۸.۰۹- fold for R. dominica and T. castaneum, respectively. A similar trend was observed at the LC۹۵ level. In the hidden in-festation trial, the acetone vapour destroyed all the developmental stages of S. oryzae con-cealed inside the wheat kernels and resulted in a complete control with a concentration of ۳۲۰ µl/liter for ۸ weeks after the exposure. Based on the data collected in this study, ace-tone should be considered as a potential compound for empty space fumigations. How-ever, due to its sorption characteristics and the application of high doses, acetone may have only limited use as a fumigant under practical conditions.

Keywords:

Wheat , Acetone , Fumigation , Stored-product insect