Past studies have shown that sex pheromone communication in the cabbage looper moth, Trichoplusia ni (Hübner) can be disrupted by permeating the air the with synthetic pheromone of this species, looplure ( cis -7-dodecenyl acetate), (Berger 1966, Gaston et al. 1967, et al. 1967, 1972). Successful disruption of pheromone communication between lepidopteran males and females may not be a function of the spacing between release points of synthetic pheromone, but rather may be dependent upon the amount of the chemical released into the air per unit area of land under treatment (McLaughlin et al. 1972, Shorey et al. 1972, Shorey and 1974). Thus, two different approaches can be taken in developing a pheromone-disruption technique. The devices from which the pheromone is to be evaporated(evaporation-substrates) may be placed close together (within cm apart) in the treated area, with each evaporation-substrate releasing pheromone at a low rate. On the contrary, evaporation-substrates may be spaced far apart (m or possibly km), emitting pheromone at a relatively high rate. Each approach requires different evaporation-substrate designs and different methods for distributing them. The former approach most likely requires pheromone to be impregnated into a small evaporation-substrate which releases pheromone continuously and is dispersed by aerial or other mass dispensing means. Periodic distribution of the evaporators would probably be required throughout the duration of the season. On the other hand, widely separated evaporators would require dispensers which release large nightly quantities of pheromone from fixed points in the area under treatment. Evaporators in this case could conceivably be engineered to release pheromone during only the night and function with a minimum of maintenance throughout the season.