Electrophysiological responses of banana pseudostem weevil, Odoiporus longicollis Olivier (Coleoptera: Curculionidae) to methyl jasmonate, 1-hexanol and host plant extract

Abstract

The banana pseudostem weevil (BSW), Odoiporus longicollis Olivier (Coleoptera: Curculionidae) is one of the most destructive pests of banana and plantains. Our laboratory bioassay studies showed that out of 50 host plants related volatile chemicals screened against BSW, only methyl jasmonate (MeJA) and 1-hexanol was electrophysiologically and behaviourally active. Here, we investigated the influence of host plant extract (HPE) on two semiochemicals, namely methyl jasmonate (MeJA) and 1-hexanol, both independently and in combination, in the electroantennogram (EAG) response in BSW. The results showed that HPE alone elicited greater EAG response only in males suggesting that males involved predominantly in the host plant selection. Addition of HPE to MeJA increased significantly higher EAG response in females and the response was insignificant in males. Similarly, the addition of HPE to 1-hexanol evoked higher response in females but decreased antennal activity was recorded in males compared to HPE alone. The HPE showed additive effect on MeJA and 1-hexanol in their EAG responses only in female BSW. The result also revealed that 1 hexanol+HPE blend exhibited enhanced EAG response compared to 1-hexanol alone in both sexes.