Attraction of cabbage stem flea beetle (Psylliodes chrysocephala) to host plant odors

BACKGROUND
Oilseed rape (OSR, Brassica napus) faces substantial yield losses in Europe due to the cabbage stem flea beetle (CSFB, Psylliodes chrysocephala). Synthetic insecticide use is constrained by resistance and environmental concerns, necessitating innovative pest control strategies. Understanding CSFB host plant selection, particularly through volatile organic compounds (VOCs), is essential for developing sustainable and efficient methods. This study investigated the olfactory response of CSFB in their pre-aestivation stage to plant VOCs.

RESULTS
Olfactometer bioassays showed that female CSFB were attracted to VOCs from mechanically damaged OSR plants (BBCH 10 and BBCH 14), while undamaged OSR plants elicited no response. Damaged seedlings of Sinapis alba and Brassica rapa were not attractive. When testing individual isothiocyanates, again only female CSFB showed a positive response in the olfactometer bioassays, while no response was found for two green leaf volatiles.

CONCLUSION
This research provides insights into the olfactory behavior of CSFB and, to our knowledge, is the first to show behavioral responses of adult CSFB towards host plant volatiles in olfactometer tests. Interestingly, only females responded to VOCs, suggesting sexual dimorphism in olfactory sensitivity during this life stage. These findings may help to lay the groundwork for further studies aimed at improving pest management strategies in OSR cultivation. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.