Sex pheromone of lucerne leafroller,Merophyas divulsana (Walker) (Lepidoptera: Tortricidae): Evidence for two distinct populations

When specimens of the lucerne leafroller,Merophyas divulsana, were sampled from an area with a history of crop damage, they were found to have (E)-11-tetradecenyl acetate, hexadecyl acetate, and tetradecyl acetate as principal components of the pheromone gland. A synthetic mixture of these compounds proved to be a successful lure in delta traps. On the other hand, apparently identical moths collected in areas with no history of crop damage were found to have (Z)-11-tetradecenyl acetate as the major component of the sex pheromone gland. The distribution of the two moths provides the basis for a plausible explanation of the regional pest activity reported forM. divulsana.