부산대학교 도서관

The broad-spectrum insecticides greatly influence the control of cotton aphids; however, due to frequent chemicalcontrol, Aphis gossypii (Hemiptera: Aphididae) has developed resistance against several classes of syntheticinsecticides. In this study, we explored the sub-lethal effects of imidacloprid and pirimicarb, two commonly usedinsecticides for aphid control, on a parasitoid wasp, Lysiphlebus fabarum (Marshall) (Braconidae: Aphidiinae),when simultaneously used to control melon aphid on cucumber plants, as part of a comprehensive study forintegrated pest management. Bioassays of imidacloprid and pirimicarb were performed to calculate LC50 withthird instars of A. gossypii. The LC50 of these insecticides (110.55 and 250.89 μg/lit, respectively) were used toexpose the wasp larvae, pupae, and adult parasitoids on a cucumber leaf. The percent mortality, percent adultemergence, and sex ratio were calculated during each exposure test. Moreover, the body size, egg load, andmature egg size of wasps surviving the insecticide treatments, as well as the sex ratio of the second generationwas evaluated. Regardless of the host aphid mortality, none of the insecticides caused mortality of larval stage ofthe parasitoid. The insecticide application on pupal stage revealed that the percentage of mortality, sex ratio,body size, and egg load of surviving wasps, as well as the sex ratio of their offspring was adversely affected byimidacloprid, but not by pirimicarb. The present study suggests pirimicarb as a preferred insecticide, with lessharmful effects on the fitness components of L. fabarum, for integrated pest management of cotton aphids.