Abstract :
The efficacy and the residual toxicity of spinetoram insecticide wereevaluated in the laboratory at 26 ± 2°C and 60 ± 5 RH against the adults of three insect species of stored products i.e., the rice weevil Sitophilusoryzae (L.), the lesser grain borer Rhizoperthadominica (F.) and the red flour beetle Triboliumcastaneum (Herbst.).The obtained results showed that, the toxicity of spinetoram to the adults of the three insect species was concentration and exposure period - dependent. The susceptibility of the insects varied from insect species to another.R. dominicaadults were the most sensitive species, a complete mortality was achieved at 10ppm of spinetoramafter 7days,followed by S. oryzaeadults, 100.00% mortality was obtained after14 days of exposure, but T.castaneumadults,10 ppm ofspinetoram was not sufficient to achieve complete kill for the adults of T.castaneum even after the longest exposure periods (14 days). Meanwhile, complete reduction in F1-progeny of R. dominica was observed at the three highest used concentrations(10, 5 and 2.5 ppm) while, the reduction in F1-progeny of S. oryzae and T.castaneumwere 96.5 and 73.1 % at the highest concentration (10 ppm),respectively. The residual toxicity resultsof spinetoram showed that, the initial concentration of(10ppm) gave 95.3,100.0 and 71.0 % kill for S. oryzae, R. dominica and T. castaneum, resp. mortality levels remained stable to2 months for T. castaneum and 3 monthsforS. oryzae andR. dominicathen reduced gradually with the increase of the storage period.The residual effect was high againstR. dominicaadults and extended to 6 monthswith lowest reduction rate in mortality (27.8 %).
