ABSTRACT The red flour weevil, Tribolium castaneum Herbst, is one the major pests of stored products. Adult pests and larvae of this pest causes economic damage through releasing toxic substances into flour. Larvae shells and adult pests affect the quality of the flour. The effectiveness of spinosad and diatomaceous earth insecticides on adult og this pests was studied. The amount of LC50 diatomaceous earth with silico-sec® formulation for adult insects of the red flour weevil and Spinosad insecticide was estimated to be 2.34 g/m2 and 76.11 mg/l , respectively After 14 days, the mortality rate was 100%.The results showed that a mixing of diatomaceous earth and Spinosad an increase in the efficacy of the mixture in causing loss. In addition, with increasing time of exposure and dose mortality rate increases.
