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Abstract
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The parasitoid Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) is one of the key natural
enemies of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Lethal and sublethal effects of imidacloprid
and buprofezin on emergence and key biological and population parameters of E. mundus
exposed during different developmental stages were studied. Doseeresponse bioassays were carried out
on adult wasps using a leaf dipping method. The emergence rates of adults were reduced significantly by
the field-recommended concentrations of the insecticides. However, the emergence rates were not
affected either by the stage of the parasitoid at the time of exposure (larval and pupal stages), and there
was no interaction between treatments and time of exposure. No significant mortality of E. mundus
adults was observed following buprofezin treatment. The LC50 of imidacloprid on adults was 4.75 ppm.
The results showed that the longevity and fecundity of E. mundus adults were reduced significantly by
the two insecticides, though the sex ratio of E. mundus offspring was not affected. Population parameters
of the parasitoid such as R0, rm and T were also significantly reduced by the insecticides. Our results
indicated that, in addition to lethal effects, sublethal effects should also be considered when these
insecticides are applied in IPM programs for this pest.
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