Abstract

Flonicamid (N-cyanomethyl-4-trifluoromethylnicotinamide) is a novel systemic insecticide that shows high insecticidal toxicity against sap-sucking pests. However, little is known about the sublethal effects of flonicamid on melon aphid, Aphis gossypii Glover, a serious insect pest of many vegetables. Herein, the toxicity of flonicamid to A. gossypii was determined using the leaf-dipping method, and the sublethal effects of this insecticide on biological traits of A. gossypii were evaluated using age-stage, two-sex life table method. The results showed that the LC 50 value of flonicamid to A. gossypii adults was 7.177 mg L −1 . The sublethal (LC 5 ) and low lethal (LC 15 ) concentrations of flonicamid reduced the fecundity of the F 0 generation aphids. Moreover, the intrinsic rate of increase ( r ) and finite rate of increase ( λ ) of F 1 generation were also significantly decreased in the flonicamid treatment groups, while the mean generation time ( T ) of the F 1 generation was significantly prolonged compared to the control. In addition, the expression levels of juvenile hormone epoxide hydrolase ( JHEH ), vitellogenin ( Vg ), and ultraspiracle protein ( USP ) significantly increased in surviving adult aphids that were exposed to LC 5 and LC 15 of flonicamid in the F 0 generation. The data demonstrate that sublethal and low lethal concentrations of flonicamid could suppress the growth of A. gossypii , and the differential expression of development- and reproduction-related genes might be involved in the sublethal effects of flonicamid on A. gossypii .