Susceptibility status of different life stages of Tribolium castaneum Herbst (Col: Tenebrionidae) to spinosad.

Red flour beetle, Tribolium castaneum, is one the most important and worldwide pest of stored-products. To evaluate the susceptibility of different life stages of this pest we used a commercial formulation of biorational insecticide, Spinosad, Tracer against adults, young and old larvae and pupae using topical application bioassay method. Mortality was recorded after exclusion of pupae and 24, 48 and 72 h posttreatment for the other life stages. Spinosad did not cause pupal mortality. Comparison of LD50 values of different life stages of T. castaneum at 48 h exposure-time revealed that, young larvae and adults were more susceptible to spinosad than the old larvae. Overlapping of 95% CL revealed similarity of susceptibility of young larvae and adult insects to spinosad. Due to compatibility of spinosad with environment, this compound could be considered as a useful tool in the control of the pest in question.