Lethal and sub-lethal effects of insecticides on natural enemies of citrus scale pests

Laboratory trials were conducted to test theside-effects of the insecticides chlorpyrifos-methyl,buprofezin, pyriproxifen, spinosad and a narrow rangemineral oil on Aphytis melinus DeBach, Coccophaguslycimnia Walker (Hymenoptera: Aphelinidae) andLeptomastix dactylopii Howard (Hymenoptera: Encyrtidae).The effects of chlorpyrifos-methyl, spinosadand pyriproxifen were also investigated in semi-fieldconditions on L. dactylopii. Contact toxicity on adultfemale parasitoids after 24, 48 and 72 h, the effects ontheir fertility as well as the sex ratio of the progeny weremeasured. In the laboratory trials chlorpyrifos-methyland spinosad caused 100% mortality on all testedparasitoids just 24 h after the treatment. According tothe IOBC classification, the mineral oil was slightlyharmful on L. dactylopii; buprofezin was harmful on C. lycimnia, and slightly harmful on L. dactylopii andA. melinus; pyriproxifen resulted moderately harmful onC. lycimnia and slightly harmful on L. dactylopii andA. melinus. The progeny production of each L. dactylopiisurviving female treated with buprofezin was notaffected by the treatment while in the case of A. melinusit was significantly reduced. C. lycimnia females treatedwith pyriproxifen did not produce any progeny. In semifieldconditions the tested insecticides were less harmfulto L. dactylopii adults but, although none of theminfluenced the progeny production of the survivedfemales, the longevity was negatively affected.