Abstract:
Brinjal Fruit and Shoot Borer- Leucinodes orbonalis Guenee is a major insect pest on brinjal- Solanum melongena
worldwide. An effective strategy used in developing pest controlling agents is the synergism between insect
pheromones and host plant volatiles, which can increase the attraction of insect pest. The present study was
aimed at investigating the chemical constituents and attractant effects of the volatiles extracted from different
parts of the host plant brinjal on the behavior of adult L. orbonalis. Bioassay using Y-shaped olfactometer revealed
that the one-day old virgin female, gravid female and male insects respond positively to the host plant volatiles
extracted from fruits, leaves and shoots but not to that of flowers. It was shown that the gravid females were
significantly attracted to all three volatiles (p < 0.05). Bioassay using X-shaped olfactometer identified that all
three types of insects highly preferred the volatiles from fruits (p < 0.05). Gas chromatography-mass spec trometry analysis of volatiles indicated that brinjal plant produces volatile secondary metabolites, which include
2,2′
-(Ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl) dibenzoate (12.11%), 3,7-dimethylocta-1,6-dien-3-ol
(22.38%), Benzyl alcohol (22.9%) and Benzyl alcohol (27.06%) as major constituents from fruits, shoots,
leaves and flowers respectively. Responses of insects to the volatiles from host plant in the absence of visual cues
direct us to focus on the importance of host plant volatiles to locate the plant. Results of this study emphasize the
major role that host plant volatiles play in the attraction of insect pests towards the plant.
