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

Abstract

The banana pseudostem weevil (BSW), Odoiporus longicollis Olivier (Coleoptera: Curculionidae) is one of the mostdestructive pests of banana and plantains. Our laboratory bioassay studies showed that out of 50 host plants related volatilechemicals screened against BSW, only methyl jasmonate (MeJA) and 1-hexanol was electrophysiologically and behaviourallyactive. 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 resultsshowed that HPE alone elicited greater EAG response only in males suggesting that males involved predominantly in the hostplant selection. Addition of HPE to MeJA increased significantly higher EAG response in females and the response wasinsignificant in males. Similarly, the addition of HPE to 1-hexanol evoked higher response in females but decreased antennalactivity was recorded in males compared to HPE alone. The HPE showed additive effect on MeJA and 1-hexanol in their EAGresponses only in female BSW. The result also revealed that 1-hexanol+HPE blend exhibited enhanced EAG responsecompared to 1-hexanol alone in both sexes.