The release of 574,850 male and femaleLaspeyresia pomonella(L.) (sterilized with 40 krad of gamma irradiation) into a 20-acre apple orchard near Yakima, Washington, provided comparative field data concerning the effects of season and of type trap (pheromone and light) on catches of codling moths. The 15-watt blacklight, six-watt blacklight, eight-watt bactericidal lamp, and six-watt Argon lamps in light traps were 25.4, 17.7, 14.7, and 0.94 percent as effective, respectively, as pheromone (sex) traps baited with 10 virgin females. The average correlation between the native population and subsequent entries within the orchard was 0.72. An expected infestation of 6.96 percent in 1,554,100 apples was limited to 0.51 percent (92 percent reduction) by release of the sterile codling moths.