Abstract: The tea grey geometrid Ectropis grisescens Warren is a devastating chewing pest in tea plantations throughout China, and interfering with the sex pheromone recognition communication between female and male moths becomes an effective method to manage this insect pest. In the present study, the sublethal dose of broflanilide was used to treat adult E. grisescens. The results of wind tunnel tests reveal that the broflanilide-treated male adults showed a declined percentage of the behavioral responses, including excitation, oriented flight, and source contact. However, the corresponding durations of behavioral responses in male moths were significantly increased. Further studies using electrophysiological assays demonstrate that the electroantennogram responses of broflanilide-treated male moths to the sex pheromone of Z3,Z6,Z9-18:H at 0.01 mg·mL^-1 were decreased by 54.57%. Besides, when female moths were treated with a sublethal dose of broflanilide, the gas chromatography-mass spectrometry (GC-MS) analyses demonstrates that the major sex pheromone components, Z3,Z6,Z9-18:H and Z3,epo6,Z9-18:H, in the female pheromone gland were decreased by 21.76% and 34.71% respectively compared with the control. This result reveals the suppression of sex pheromone biosynthesis in broflanilide-treated female moths. Further study by qRT-PCR analysis reveals that a cytochrome P450 monooxygenase of Egri-CYP340BD1 enriched in pheromone gland was significantly up-regulated in broflanilide-treated female moths. Taken together, this study demonstrates that broflanilide treatment would manipulate the courtship of this insect pest, and the results would contribute to the design of insect-behavior-modifying technology in novel pest management.

Key words: Ectropis grisescens, broflanilide, sex pheromone recognition, behavior modification