Inhibition Effect of Non-Host Plant Volatile Extracts on Reproductive Behaviors in the Diamondback Moth IPlutella xylostella/I

Essential oils (EOs) from many non-host plants have been reported to have insecticidal and antifeeding activities to larvae and oviposition deterrent effects on the female moths of Plutella xylostella. However, their effect on sex pheromone communication during mate location has been less studied. Here, we studied the antennal response of both adult sexes to seven non-host plant EOs and their inhibition effect on the sex pheromone orientation of males and the oviposition of female moths. The results demonstrated that 10 mg of calamus (Acorus gramineus) and citronella (Cymbopogon citratus) EOs reduced the attraction of synthetic sex pheromones to male moths up to 72% and 66% in a sensitive way. The calamus EO also decreased the egg-laying number of female moths on host plants, with the highest inhibition rate of 100%. These findings contribute to a better understanding of the roles of volatile plant secondary metabolites in modulating reproductive-related behaviors, and exploit EOs and plant resources that can be used for the behavioral control of P. xylostella. The pest management of Plutella xylostella, the global pest of cruciferous plants, is primarily dependent upon continued applications of insecticides, which has led to severe insecticide resistance and a series of ecological concerns. The essential oils (EOs) of non-host plants are considered to have a high application potential in pest behavioral control. In P. xylostella, the insecticidal properties, antifeeding activities, and oviposition inhibition effects of many EOs have been studied in larvae and female moths. However, less focus has been placed on the inhibitory effect on sex pheromone communication during courtship, which is vital for the reproduction of the offspring. In this study, by combining electrophysiological studies, laboratory behavioral assays, and field traps, we demonstrated that non-host plant EOs significantly inhibited the reproductive behaviors of both sexes. Notably, the calamus (Acorus gramineus) EO inhibited the preference of male moths for synthetic sex pheromone blends and reduced the egg-laying number of female moths on host plants, with the highest inhibition rates of 72% and 100%, respectively, suggesting a great application prospect of calamus and its EO on the behavioral control strategies of P. xylostella.