ELECTROANTENNOGRAM, WIND-TUNNEL AND HELD RESPONSES OF MALE MEDITERRANEAN CORN-BORER, SESAMIA NONAGRIOIDES, TO SEVERAL BLENDS OF ITS SEX-PHEROMONE COMPONENTS

The electrophysiological and behavioural responses of male Sesamia non agrioides Lefebvre (Lepidoptera: Noctuidae) to several synthetic blend s of its sex pheromone components were investigated. Electroantennogra m (EAG) recordings showed the greatest response to a 77:8:10:5 blend o f the four compounds found in the female glands: (Z)-11-hexadecen-1-yl acetate, (Z)-11-hexadecen-1-ol, (Z)-11-hexadecenal and dodecyl acetat e. A logistic equation was fitted to the dose-response data and differ ences in relative EAG responses were analysed by deriving five paramet ers of this equation. Flight responses of males were also evaluated in a wind tunnel where the proposed blend (77:8:10:5) also elicited the best response. Field tests confirmed the laboratory findings as the 77 :8:10:5 blend captured more S. nonagrioides males than other pheromone mixtures and showed more selectivity for male S. nonagrioides over ot her noctuid species, Discestra trifolii Rottenberg and Lacanobia olera cea L., but not for Mythimna unipuncta Haworth, a species with a sex p heromone composition almost identical to that of S. nonagrioides.