Sex pheromone components of corn stalk borerSesamia nonagriodes (Lef.) isolation, identification, and field tests.

Z-11-Hexadecenyl acetate (Z11-16∶OAc), dodecyl acetate (12∶OAc),Z-11-hexadecenal (Z11-16∶Aid), andZ-11-hexadecenol (Z11- 16∶OH), were found in pheromone gland extracts of femaleSesamia nonagriodes (Lef.) [Lepidoptera: Noctuidae]. These four components were also present in airborne volatiles collected from calling virgin females in a 65∶18∶8∶9 ratio. Hexadecyl acetate (16∶OAc) was also detected but found to be inactive. The identification was based on multicolumn GC analysis, mass spectrometry, and field activity.Z11-16∶OAc is the major sex pheromone component; the addition of the secondary components individually decreased male captures. The blend of the four synthetic components in 69∶15∶8∶8 ratio was highly attractive to males; 200 μg per trap was the most effective concentration in field tests.