ELECTROANTENNOGRAM AND OVIPOSITION RESPONSES OF EPIPHYAS-POSTVITTANA (LEPIDOPTERA, TORTRICIDAE) TO PLANT VOLATILES

Electroantennogram (EAG) responses of male and female Epiphyas postvit tana (lightbrown apple moth) were recorded to plant volatiles delivere d from either filter paper or a gas chromatograph. Males showed signif icantly higher EAG responses than females with both methods (P < 0.001 ). Responsiveness to compounds was significantly correlated between se xes and between methods (P < 0.01). Pairs of moths were caged with acc ess 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 pa per were recorded to determine the attractancy or repellency of the co mpounds. Eugenol, geraniol, and citral deterred oviposition, whereas h exanal, linalool, nonanol, octanol, and nonanal were attractants. The proportion of females laying eggs was reduced in the presence of citra l, 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).