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, si-tophilus 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 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 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 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 320 µl/liter for 8 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.