Abstract
Male adults of Spodoptera litura were released at fixed points and captured in a pheromone trap. By comparing the experimental results with those obtained from a simulation model for the male's attraction process, the active space of the sex pheromone of S. litura was estimated. The maximum range downwind of the active space for one virgin female was estimated as about 80m for wind velocity of 0.50m/sec. This distance decreased with an increase in wind velocity above 0.50m/sec, and decreased greatly with decrease in wind velocity below 0.50m/sec. The reason for the decreased range at low wind velocities was as a result of a deposition effect of the pheromone. Thus, in a windless greenhouse, the active space was limited to a small area close to the attractant. The active space increased proportionally with an increase in the emission rate of the pheromone. It was revealed that the active space was determined by one of two components of litlure (a synthetic sex pheromone of S. litura), viz., cis-9, trans-11-tetradeca-dienyl acetate.
