Toxicity of Acetone to Stored-product Insects

Abstract

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 LC 95 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 LC 50 values between empty-space tests and penetration experiments (after 72-h exposure) indicated that the increase in penetration t oxicity was 8.52- and 8.09- fold for R. dominica and T. castaneum, respectively. A similar trend was observed at the LC 95 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. Base d 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 fumi gant under practical conditions