Sublethal Effects Of Cyantraniliprole On Helicoverpa Assulta(Guenée)

The Helicoverpa assulta(Guenée)(Lepidoptera Noctuidae) is an oligophagous pest which major feeding Solanaceae and harm pepper and tobacco in crops. In China, this pest is found in all provinces regions, with the exception of Tibetan region. Because of the damage of H. assulta, the loss of tobacco is 5%-15% per year, individual regions could reach as more as 25%. The control of H. assulta is mainly rely on chemical control at present, but because of abuse insecticide, the resistance to some insecticide have been improved. Cyantraniliprole which developed by DUPONT recently has a unique insecticidal mechanism. The pesticide has broad-spectrum, low toxicity, high efficiency and long residual activity characteristics. What′s more, it has better systemic and high selectivity. The diet-incorporated method was used for the bioassay. And the sublethal effects of cyantraniliprole were assessed on the development and reproductive parameters of H. assulta derived from larvae that had been exposed to LC05, LC20, and LC40 of cyantraniliprole, which will help us to get a comprehensive understanding of the control effect and biological influences, and provide theoretical basis for scientific prevention and control of H. assulta. The results of my research in this paper are as follows:1. The LC50 value of cyantraniliprole on third instars of H. assulta at 120 h was 0.085 mg of active ingredient / L, and the other three sublethal concentrations LC40, LC20, LC05 were 0.068 mg AI / L, 0.040 mg AI / L and 0.020 mg AI / L, which determined from the concentration-mortality response line.2. The development time of parental larval stage tended to be prolonged in the treatment compared with the control, sometimes even extending 11 d, but the larval stage of the offspring was not affected by sublethal concentrations of cyantraniliprole. The pupation rate decreased significantly with the rising of sublethal concentrations in the parental, which in the offspring were not affected by cyantraniliprole. The LC05 and LC40 concentrations of cyantraniliprole, but not the LC20, significantly decreased the female pupal weight in parent compared to the control. The pupal weight of female in parent and pupal weight of both female and male in the offspring only significantly decreased by the highest concentration of cyantraniliprole(LC40). The proportion of adult deformity of LC40 treatment was significantly influenced by cyantraniliprole in parental and offspring. No significant difference was found in adult longevity, the rate of emergence, female ratio and pupal period among all groups.3. The experimental population life table on parent generation which are stressing in the sublethal doses cyantraniliprole was analyzed to make sure the change of population parameter. Cyantraniliprole significantly decreased the intrinsic rate of increase(rm), finite rate of increase(λ), and the rm and λ decreased gradually with the increase of dose as well as prolonged doubling time.Sublethal doses of cyantraniliprole decreased the intrinsic rate of increase by affecting larval period, pupation rate, increasement in adult deformity rate, etc, thus decrease the population of the next generation. Further work is needed to investigate the sublethal effect on field population.