Olfactory and electrophysiological response of cucumber moth Diaphania indica (Saunders)n(Lepidoptera, Crambidae) to different plants

Abstract

The behavioural response of adults and larvae of cucumber moth, Diaphania indica (Saunders) (Lepidoptera, Crambidae), a serious pest of cucurbitaceous crops was evaluated on different cucurbitaceous and non-cucurbitaceous plants through olfactometer bioassay. The volatile organic compounds (VOCs) present in these plants were identified by gas chromatography-mass spectrometry. Further, electrophysiological response of D. indica to plant extracts and synthetic volatiles were recorded by electroantennographic detection. Larvae had the highest olfactory response to wild coccinia followed by bitter gourd, coccinia and cucumber. In GC-MS analysis, á-linolenic acid, palmitic acid and dotriacontane were identified as common components in leaf extracts, whereas, benzaldehyde was the major component in headspace of dried leaves. The antennae of gravid female moths were more sensitive to plant odours than unmated females and males. Gravid females showed highest response to extracts of bitter gourd and unmated females to cucumber extract. A synthetic volatile mixture of 10?L of benzaldehyde and 30?L of benzyl alcohol were found responsible for high antennal response. Significant orientation and landing response were shown by D. indica moths to a mixture of 10?L benzaldehyde (10%) and 20?L benzyl alcohol (10%). These findings suggest the above blend could be employed for the development of plant volatile based management strategies.