Volatiles from host plant brinjal attract the brinjal Fruit and Shoot Borer -Leucinodes orbonalis Guenee

Abstract

Blinjal Fruit and Shoot Borer- Leucinodes orbo11alis Guenee is a major insect pest on brinjal- Sola11u111 111elo11ge11a 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 consti tuents and attractant effects of the volatiles extracted from different parts of the host plant brinjal on the behavior of ad ult L. orbo11alis. 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 exU'acted 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 specuomeuy analysis of volatiles indicated that brinjal plant produces volatile seconda1y metabolites, which include 2,2' -(Ethane-l ,2-diylbis(oxy))bis(ethane-2,1-diyl) di benzoate (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.