Efficacy and Persistence of Spinetoram Against Three Stored Product Insect Pests

Abstract

The efficacy and the residual toxicity of spinetoram insecticide were evaluated in the laboratory at 26 ± 2°C and 60 ± 5RH against the adults of three insect species of stored products i.e., the rice weevil Sitophilus oryzae (L.), the lesser grain borer Rhizopertha dominica (F.) and the red flour beetle Tribolium castaneum (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. dominica adults were the most sensitive species, a complete mortality was achieved at 10ppm of spinetoram after 7days, followed by S. oryzae adults, 100.00% mortality was obtained after 14days of exposure, but T. castaneum adults,10ppm of spinetoram was not sufficient to achieve complete kill for the adults of T. castaneum even after the longest exposure periods (14days).Meanwhile, complete reduction in F1-progeny of R. dominica was observed at the three highest used concentrations(10, 5 and 2.5ppm) while, the reduction in F1progeny of S. oryzae and T. castaneum were 96.5 and 73.1% at the highest concentration (10ppm), respectively.The residual toxicity results of 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 to 2 months for T. castaneum and 3 months for S. oryzae and R. dominica then reduced gradually with the increase of the storage period. The residual effect was high against R. dominica adults and extended to 6 months with lowest reduction rate in mortality (27.8%).

The Combined Efficacy of Malathion and Spinetoram against Three Stored Product Insects

“…Results indicated that, the adults of R. dominica were highly susceptible to spinetoram than the two tested insects. The obtained results are in harmony with the findings of other investigators At hanassiou andKavallieratos, 2014 andNasr, 2015).…”