Sublethal effects of some biorational pesticides on population growth parameters of cabbage aphid, Brevicoryne brassicae

The cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae), is an important pest of canola that can considerably limit crop production through direct or indirect damage. In this study, the effects of Azadirachtin, Tondexir, Palizin, and Thiamethoxam, common insecticides used in managing the cabbage aphid, were investigated on the population growth parameters of this pest. Based on the results, the LC50 values for Thiamethoxam, Palizin, Azadirachtin, and Tondexir were 0.19, 0.63, 1.00, and 3.82 g/L, respectively. Moreover, LC30 concentrations of Thiamethoxam, Palizin, Azadirachtin, and Tondexir were 0.11, 0.10, 0.41, and 1.68 g/L, respectively, applied in the sublethal studies. The cabbage aphids reared on the plants treated with these insecticides had lower longevity, fecundity, and reproductive period than the control treatment. The intrinsic rate of increase (rm), finite rate of increase (λ), net reproductive rate (R0), and generation time (T) were lower on Thiamethoxam treatment. Tondexir and Palizin treatments had lower values than Azadirachtin. However, there was no significant difference between the Tondexir and Palizin treatments. The population treated by Azadirachtin had the highest values of growth parameters. According to the results and available information in the context of risk assessment of the studied insecticides, this research recommends the application of Thiamethoxam in the integrated pest management of cabbage aphid.