Olfactory response of pepper weevil Anthonomus eugenii (Coleoptera: Curculionidae) to Capsicum annuum volatiles

The pepper weevil Anthonomus eugenii Cano (Coleoptera: Curculionidae) is the most devastating pest of Capsicumm spp. in Mexico and other parts of the world. Recent researches have proven that this insect can detect and orientate to flowers, floral buds and immature fruits volatiles released from pepper [Capsicum annuum L. (Solanaceae)]. Therefore, in this work, we investigated the behavioral and electrophysiological responses of the pepper weevil to volatiles of Jalapeño pepper, Capsicum annuum L. In olfactometer tests including flowers, and floral buds, the males demonstrated a higher response rate 71.4% compared with female responses of 50.7%. The volatile compounds of pepper plants structures evaluated by olfactometer, as well as the immature fruits were obtained through Headspace and analyzed by gas chromatography–Mass Detection Spectrometry (GC-MSD). The most representative compounds in the structures analyzed were Cis-β-ocimene, methyl salicilate, ethyl salicilate, (3E)-4,8-dimethyl-1,3,7-nonatriene, α-pinene, linalool and guyacol. The electrophysiological responses of males and females to these volatiles from flowers were 0.67 mV and 0.51mV, respectively. Male insects revealed a higher stimuli to linalool and 2-ethyl hexen-1-ol whereas females showed no preference. The volatiles of flowers and buds play an important role in the orientation of A. eugenii, therefore the volatile compounds identified in this work could be integrated in other plant attractants reported for peppers to prepare other formulations for future studies.