虱螨脲对小菜蛾成虫繁殖力及子代种群发展的影响

In order to investigate the sublethal activities of lufenuron to diamondback moth Plutella xylostella adults, the fecundity, egg hatchability and adult longevity were measured when adults were treated with 50 mg/L lufenuron for 24 hours by using residual film or feeding method, and its long-term effects on the progenies of P. xylostella adults were studied by constructing life tables. The results showed that, when the adults were treated with lufenuron by using the residual film method, the fecundity of treated adults and their egg hatching rate were significantly lower than those of the control by 39.09 and 19.38%, respectively. When adults were treated by using the feeding method, the fecundity of treated adults and their egg hatching rate decreased by 13.42 and 72.03%, respectively, and the lifespan of treated female adults shortened by 1.56 d. The egg hatching rate of adults fed with lufenuron was significantly lower than that of the control adults. The survival of F1 1st instar larvae, the lifespan and fecundity of F1 female adults, and the hatching rate of F1 eggs of adults fed with lufenuron were 74.29%, 5.90 d, 146.65 and 84.43%, respectively, all of which were significantly lower than those of the untreated control, resulting in a significant reduction in the population trend index. This indicates that feeding adults with lufenuron yielded a certain degree of interference effects on the development of the offspring population. In addition, reciprocal mating of adults fed with lufenuron or sugar water showed that crossing types did not affected fecundity, but significantly reduced egg hatching rate only when the crosses involved females fed with lufenuron, indicating that lufenuron affects oogenesis and embryo development of fertilized eggs but not the formation and transfer of sperms. These results indicated that lufenuron could inhibit the population growth of P. xylostella by adult feeding or contact.