Toxicity of Pesticides in Protein Bait to Bactrocera dorsalis

Application of protein bait adding high-efficiency and low-toxicity pesticides is an important approach controlling fruit flies in the world. Under laboratory conditions, the contact and stomach toxicity of several pesticides to Bactrocera dorsalis were tested for screening the pesticides of high-efficiency, low toxicity and good proten bait compatibility. The results of contact toxicity showed that spinosad was the best due to its lowest LC₅₀ of 72.33 mg·L^-1. The contact toxicity of other four pesticides in order was avermectins, malathion, ethiprole and chlorfenapyr. The results of stomach toxicity showed that avermectins and spinosad were better than those of other three pesticides, of which the LC₅₀ were 13.99 and 15.76 mg·L^-1 respectively, and 95% confidence interval range were 11.72-16.97 and 13.09-19.23 mg·L^-1 respectively. The effect of other three pesticides in order was chlorfenapyr, ethiprole and malathion. The bioassay results showed that the attractant effect of hydrolyzed protein dropped in various degrees after adding pesticides. The attractant rate of protein bait adding spinosad was 55.83%, only a decrease by 4.17% compared to hydrolyzed protein stock solution, which was the best among the five tested pesticides.