Electro-Physiological and Olfactometric Responses of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) and Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) to Volatiles of Trap Crops -Tagetes erecta Linnaeus and So

Abstract

Experiments were done on electro-physiological and olfactometeric responses of Helicoverpa armigera (Hiibner) and its egg parasitoid Trichogramma chilonis Ishii to leaf and floral volatiles of Tagetes erecta Linnaeus and Solanum viarum Dunal. H. armigera female moths exhibited highest mean absolute net electrophysiological response (−0,462mv) to floral volatiles of T. erecta followed by volatiles from leaves (−0.395mv), In case of olfactometric responses, T. chilonis showed maximum net response to hexane extract of T. erecta flower bud (47.5%), followed by floral and leaf volatiles. However, statistically all these cues were on par. The volatile compounds identified from leaves and flowers of T. erecta, and leaves of 5. viarum were 16, 17 and 21 in number, respectively. The compounds found common in both the trap crops were: 1, 2, benzenedicarboxylic acid, cis-a-bisabolene, eicosane, hexacosane, heptacosane, pentacosane, tetradecane and nonadecane. Among the floral volatiles, piperitenone was in the highest proportion (25.5%), followed by piperitone (5.39%), limonene (4.83%), trans- b-ocimene (3.35%), cis-epoxy-ocimene (4.83%), myrcene (1.13%) and BHT-aldehyde (0.34%). Studies revealed that both the trap crops -T. erecta and S.viarum are Trichogramma friendly.