Electrophysiological and Behavioural Responses of Banana Pseudostem Weevil, Odoiporus longicollis Olivier (Coleoptera:Curculionidae) to Aggregation Pheromone, 2-Methyl-4- Heptanol and Host Plant Kairomones

Laboratory bioassays were conducted using an electroantennogram (EAG) and Y-tube olfactometer to study the electrophysiological and olfactory responses of banana pseudostem weevil (BSW), Odoiporus longicollis to its aggregation pheromone, 2-methyl-4- heptanol (2M4H) and host plant extract (HPE). The aggregation pheromone and HPE from highly susceptible cultivar Nendran were tested individually and in combination to ascertain the synergistic effect of HPE on 2M4H to the BSW. The peripheral response of antennae to the 2M4H + HPE combination elicited significantly strong amplitude of 4.089 ± 0.043 mV in males in comparison to females over the aggregation pheromone and HPE individually. Dose-dependent responses indicated difference between sexes and concentrations. Behavioural assay using Y-tube demonstrated that both sexes responded to host volatiles, and that males were more sensitive than females. Similarly, both the sexes responded most strongly (64.21% ± 3.91% of males and 55.47% ± 3.06% of females) to the odour sources comprising pheromone with host plant volatiles. Addition of HPE to 2M4H significantly increased EAG activity and also the attraction as indicated in the Y-tube behavioural bioassay; thus, the blend forms a good attractant. The present study provides information useful in developing pheromonebased lure in conjunction with HPE for monitoring and mass-trapping of O. longicollis.