Electrophysiological and behavioral responses of brown marmorated stink bug (Hemiptera: Pentatomidae) to hazelnut plant volatiles

Plant-produced volatiles have been explored as tools for monitoring and managing Halyomorpha halys (Stål), a highly polyphagous pest of orchard and field crops, with hosts such as apple and peach considered as sources of attractants and nonhost essential oils tested as repellents. To identify olfactory stimuli with behavioral relevance to H. halys, volatile organic compounds were collected from hazelnut (Corylus avellana (L.)) trees, a preferred H. halys host, via stir bar sorptive extraction. Extracts were identified by gas chromatography and mass spectroscopy. The physiological effects of 15 host plant volatiles (HPVs) were measured on antennae of H. halys using electroantennographic detection. Halyomorpha halys behavioral responses to the HPVs that elicited consistent antennal responses were assessed In Y-tube olfactometer bioassays, formic acid repelled adult males in a concentration-dependent manner, while trans-2-heptenal produced no clear behavioral effect. Formic acid and trans-2-heptenal both reduced H. halys attraction to hazelnut samples in subsequent single- and dual-choice arena bioassays, with the greatest and longest lasting repellence caused by the highest tested concentration of formic acid. Field experiments indicated no effect of experimental lures containing hazelnut volatiles on H. halys trap captures. The implications of these results for the development of HPV-based strategies for managing H. halys are discussed.