Sublethal effects of chlorfenapyr on the life table parameters, nutritional physiology and enzymatic properties of Bradysia odoriphaga (Diptera: Sciaridae)

Bradysia odoriphaga (Diptera: Sciaridae) is the major pest affecting Chinese chive production. Chlorfenapyr is a halogenated pyrrole-based pro-insecticide that is currently used to control insects and mites on a variety of crops. In the present study, fourth-instar larvae of B. odoriphaga were exposed to chlorfenapyr at LC 1 , LC 20 and LC 50 concentrations. The developmental duration of the treated larvae was not significantly different, but fecundity was significantly increased in the LC 1 and LC 20 treatment groups compared with the control group. The population parameters of the LC 1 treatment group were increased significantly, whereas those of the LC 50 treatment group were reduced significantly compared with the control. The food consumption by larvae and pupal weight were significantly increased under the LC 1 treatment and decreased under the LC 50 treatment compared with the control. Moreover, chlorfenapyr decreased the lipid , carbohydrate and trehalose contents significantly, whereas the total protein content was increased compared with the control. Additionally, the activities of protease, lipase and trehalase were significantly decreased. Chlorfenapyr treatment for 24 h also induced the activities of glutathione S-transferase (GST), carboxylesterase (CarE) and O -demethylation. The results of this study suggest that low lethal concentrations of chlorfenapyr can affect oviposition , population development, the activities of digestion and detoxification enzymes , and nutrient accumulation in B. odoriphaga . This study provides valuable information for the assessment and rational application of chlorfenapyr for effective control of this pest.