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, 72-h exposure) for 50% mortality against adults of the lesser grain borer, Rhizopertha dominica (F.), red flour beetle, Tribolium castaneum (Herbst), rice weevil, Sitophilus oryzae (L.) and eggs of the angoumois grain moth, Sitotroga cerealella (L.) were 33.64, 41.05, 43.90 and 46.11 μl/liter, respectively. At the LC95 level, the order of sensitivity was rated to be: R. dominica adults > S. oryzae adults > T. castaneum adults > S. cerealella eggs. Penetration tests revealed that acetone vapour could penetrate into the wheat mass and kill concealed insects in interkernel spaces. Comparison of LC50 values between empty-space tests and penetration experiments (after 72-h exposure) indicated that the increase in penetration toxicity was 8.52- and 8.09- fold for R. dominica and T.castaneum, respectively. A similar trend was observed at the LC95 level. In the hidden infestation trial, the acetone vapour destroyed all the developmental stages of S. oryzae concealed inside the wheat kernels and resulted in a complete control with a concentration of 320 μl/liter for 8 weeks after the exposure. Based on the data collected in this study, acetone should be considered as a potential compound for empty space fumigations. However, due to its sorption characteristics and the application of high doses, acetone may have only limited use as a fumigant under practical conditions