Effects of sex and mating status on olfactory responses of Cydia pomonella to host plant volatiles

The codling moth, Cydia pomonella, is a major global invasive pest and a priority quarantine pest in China, primarily damaging pome fruits such as apples and pears. In recent years, with the expanding invasion range of C. pomonella in China, the management pressure for prevention and control in non-infested areas has intensified. This study aims to screen and verify the role of host plant volatiles in the olfactory recognition of adult C. pomonella, providing a theoretical basis for the development of plant-derived attractants.

Electroantennography (EAG) was employed to measure the EAG responses of virgin and mated male and female adults to 27 host plant volatiles.

Among the 27 tested compounds, ethyl 2,4-decadienoate (pear ester), octanal, and nonanal elicited relative EAG response values significantly higher than the control (CK). The sensitivity of adults to these compounds varied significantly according to sex and mating status. Concentration gradient experiments demonstrated that, within a certain range, relative EAG response values increased in a dose-dependent manner with increasing compound concentration. Specifically, pear ester elicited significant EAG responses in females at a concentration of 1 ng/μL, while males reached significant levels at 10 ng/μL. Octanal and nonanal elicited responses significantly higher than CK in both sexes at 1 μg/μL. Additionally, (E,E)-α-farnesene exhibited significant relative EAG response values at 10 μg/μL.

All 27 screened plant volatiles elicited EAG responses in C. pomonella adults to varying degrees. Olfactory sensitivity was jointly influenced by sex, mating status, and compound concentration. Notably, pear ester, octanal, nonanal, and (E,E)-α-farnesene elicited significant EAG responses in adult C. pomonella, indicating their potential as candidate compounds for the development of plant-derived attractants or repellents against this pest.