Confused males—and effective control of cabbage looper—resulted from the uniform placement of synthetic sex pheromone stations spaced about 100 m apart in field tests. The synthetic sex pheromone of the cabbage looper, Trichoplusia ni (Hübner) (Noctuidae) was continuously evaporated from uniformly spaced sources in a field at a rate of about 1 mg per hectare per night. Males of this species were almost completely prevented from locating pheromone-releasing females. This male inhibition technique offers considerable promise for the control of insect pest populations.