The effects of sublethal exposure to imidacloprid (Kendor® 18.3SL) on the biological performance of the ladybird beetle, Menochilus sexmaculatus F., the most common coccinellid beetle found feeding on aphids, were studied under ambient laboratory conditions of 27-32˚C and 50-75% RH. The corn leaf aphid, Rhopalosiphum maidis, was offered as prey. The LC50 obtained from the contact bioassay at 24 h post-treatment for the regression slope, b=1.08, indicated that imidacloprid was likely to be selective. Sublethal exposure to imidacloprid caused reduction in survival with the females reaching 50% mortality by the 24th day, while that of the control was the 36th day. Meanwhile, demographic parameters including the net reproductive rate (Ro), generation time (T), innate capacity of increase (rm) and the finite rate of increase (λ) of the treated females were markedly inferior as compared to the untreated females. The Ro value indicated that the control female was capable of producing 17.59.....

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