Nepytia freemani Munroe reached outbreak proportions in one area in north central Utah in 1965 and subsided in early 1967. The looper has a 1-year life cycle and overwinters in the egg stage. Larvae issue from eggs in mid-May, feed during the summer months, and begin pupation in late July. Adults appear in August and females lay clusters of small oval eggs on both sides of the needle. White fir is the preferred host but Douglas-fir is also fed on. Even though defoliation was extremely heavy, topkill was the only permanent damage. Starved larvae fed on ground vegetation in the understory. Parasitism was heavy but its overall effectiveness in causing the sudden population decline is unknown.