Isolation, identification, and synthesis of the sex pheromone of the tobacco budworm

The sex attractant of adult tobacco budworms, Heliothis virescens (F.) was isolated from ether washes of "calling" females and verified as active by field cage bioassays. The components of the pheromone were identified as (Z)-11-hexadecenal and (Z)-9-tetradecenal by spectroscopic and microdegradative methods. The two components are inactive when tested separately, but when they are mixed in the ratio in which they occur in female washes (16:1, respectively), the synthesized mixture is equivalent to the natural one in attracting males in large cages. In field tests, 53 μg of synthesized mixture was competitive with four live females.