Sex Pheromone Composition of the Diamondback Moth, Plutella xylost el la (L) in Korea

The mating behavior of the diamondback moth (DBM), Plutella xylostella, was actively observed from 2 h post-scotophase and maintained up to 2 h post-photophase. The pheromone glands of DBM populations in Korea were extracted with hexane and gas Chromatograph (GC) analysis showed that three major components of sex pheromone, (Z)-ll-hexadecenal (Z11-16: A1), (Z)-l 1-hexadecenyl acetate (Zll-16: Ac) and (Z)-l 1-hexadecenyl alcohol (Zll-16: OH), were identified at the ratio of 8:3:2. To contrast, Zl l-16: OH was not detected from Solid Phase Microextraction for the sex pheromone emitted during the scotophase. Both Z11-16-.A1 and Zll-16: Ac elicited the antennal response of male DBM in GC- electroantennographic detection and electroantennogram (EAG) assay. EAG assay revealed that the ratio of major components, Z11-16: A1 and Zll-16: Ac, in the blend of 5: 5 and 7: 3 strongly attracted DBM male adults. The minor components, 0.5% of Z11-16.-OH or 5 to 10% of (Z)-9-tetradecenyl acetate (Z9-14: Ac) also elicited the EAG response when mixed with major components blends at the ratio of 10:10 between Zll-16: Ac and Zl 1-16: A1, suggesting these components affect the activity of major components of sex pheromone.