Abstract: This study aims to clarify the effects of sub-lethal concentration of chlorantraniliprole on parasitizing and reproductive ability in Trichogramma ostriniae. The characteristics of the parasitic functional response of T. ostriniae to Corcyra cephalonica (Stainton) eggs under the treatment of chlorantraniliprole were analyzed by HollingⅡ functional response model. Meanwhile, the density changes of T. ostriniae under the treatment of chlorantraniliprole were described using numerical response parameters. The results showed that the functional response fitted with HollingⅡ model and that the model parameters varied after chlorantraniliprole treatment. The successful attack rate was enhanced, and the prey handling time was extended, parasitizing efficiency was reduced from 60.46 to 56.05 and maximum parasitizing capacity was reduced from 57.21 to 44.24 eggs. The searching efficiency decreased with the increase of C. cephalonica egg density. When the density of C. cephalonica eggs was greater than 10, the influence of chlorantraniliprole on the interference of T. ostriniae weakened with the increase of C. cephalonica egg density. A density of 10 C. cephalonica eggs was the critical value for maintaining the reproduction of T. ostriniae population. In conclusion, chlorantraniliprole has a certain degree of negative impact on the parasitizing capacity, growth and development, and reproductive capacity of T. ostriniae. The results are helpful for rational and scientific use of pesticides and for coordination of chemical and biological control.

Key words: Trichogramma ostrinia, chlorantraniliprole, functional response, numerical response, searching efficiency