IDENTIFICATION OF SEX-PHEROMONE COMPONENTS OF NETTLE CATERPILLAR, SETOTHOSEA-ASIGNA

Gas chromatographic-electroantennographic detection (GC-EAD) analyses of female nettle caterpillar, Setothosea asigna, pheromone gland extra cts revealed seven antennally active compounds. Based on their retenti on indices on three fused silica columns (DB-5, DB-23, and DB-210), th ese compounds were hypothesized and, through comparative GC, GC-EAD an d GC-mass spectrometry with authentic standards, confirmed to be Delta 10-undecenal, dodecanal, (E)-9-dodecenal (E9-12:Ald), (Z)-9-dodecenal , (E)-9-dodecen-1-ol, (E)-9,11-dodecadienal (E9,11-12: Ald), and (E)-9 ,11-dodecadienol. E9-12:Ald and E9,11-12:Ald were most abundant in fem ale S, asigna pheromone extracts. In field trapping experiments in Pal embang, Indonesia, synthetic E9-12:Ald and E9,11-12:Ald at a 1:1 ratio , but not singly, attracted S. asigna males. Attractiveness of these t wo aldehydes could not be enhanced further through the addition of the ir corresponding alcohols and/or other aldehydic candidate pheromone c omponents. Use of E9-12:Ald and E9,11-12:Ald for pheromone-based monit oring of S. asigna populations will require lure formulations that min imize pheromone degradation by ultraviolet radiation and atmospheric o xidation.