Sublethal Effects Of Indoxacarb, Beta-cypermethrin And Chlorantraniliprole On Plutella Xylostella (L.)(Lepidoptera:Plutellidae)

The diamondback moth (DBM), Plutella xylostella is a worldwide pest of cruciferous vegetables. There are huge economic losses annually due to the damage of DBM. Currently, traditional chemical pesticides have been considered as the main method to control DBM. As insecticides were applied, in addition to the lethal effects, sublethal effects would be found in the survived individuals because they are exposed to different dose of insecticides or the concentration is diluted with the passing of time. Indoxacarb, beta-cypermethrin and chlorantraniliprole are the main insecticides used to control DBM currently. In this paper, sublethal effects of indoxacarb, beta-cypermethrin and chlorantraniliprole on DBM is investigated under laboratory conditions. We study the sublethal effects on the growth, development, fecundity and sex pheromone system communication of DBM. We hope the results would help to provide a theoretical basis for proper application of the three pesticides and achieving the purpose of controlling it with reducing the application of insecticides. The results are as follows:1. The acute toxicity experiment of indoxacarb, beta-cypermethrin and chlorantraniliprole to the second instar of DBM shows that the population of DBM is more sensitive to indoxacarb and chlorantraniliprole than beta-cypermethrin.2. We studied the sublethal effects of the three insecticides on the DBM.The results show that the developmental duration of3rd and4th instar in indoxacarb and chlorantraniliprole groups were significantly shorter than the control group, it could be hormoligosis. But we don’t find the phenomenon in beta-cypermethrin-treated group. The results also show that the low concentrations of indoxacarb, beta-cypermethrin and chlorantraniliprole could decrease fecundity on the parents of DBM.3. After treated by the three insecticides on the parent of DBM, we studied the sublethal effects on the offspring of the treated DBM. The results show that the growth and development, fecundity and the population growth were restrained in all treated groups when the DBM is treated by higher concentrations, such as LC30and LC50.4. In terms of sex pheromone communication system, the sum of sex pheromone and the titers of Z11-16:Ald, Z11-16:OH and Z11-16:OAc of sex pheromone in female were decreased in the treated groups. But there is no significant difference in mating choice between the treated female and healthy female.In summary, we discover that indoxacarb, beta-cypermethrin and chlorantraniliprole could restrain the growth and development, fecundity and the population growth of DBM. In the practical control of DBM, the sublethal effects should be considered.