Electroantennogram and oviposition responses of Epiphyas postvittana (Lepidoptera: Tortricidae) to plant volatiles

Electroantennogram (EAG) responses of male and female Epiphyas postvittana (lightbrown apple moth) were recorded to plant volatiles delivered from either filter paper or a gas chromatograph. Males showed significantly higher EAG responses than females with both methods (P < 0.001). Responsiveness to compounds was significantly correlated between sexes and between methods (P < 0.01). Pairs of moths were caged with access to filter paper treated with plant volatiles, and untreated filter paper, for oviposition. The number of females ovipositing, the number of eggs laid, and the proportion of total eggs laid on the treated paper were recorded to determine the attractancy or repellency of the compounds. Eugenol, geraniol, and citral deterred oviposition, whereas hexanal, linalool, nonanol, octanol, and nonanal were attractants. The proportion of females laying eggs was reduced in the presence of citral, nonanol, octanol, and n-decyl aldehyde. The number of fertile eggs laid per female was reduced by 10 of the 14 compounds tested. EAG was a poor predictor of oviposition attractancy or repellency. Stimulation with fresh plant foliage produced significantly higher EAGs in eight host plants, compared to eight non-hosts (P < 0.001).