Caging studies and insect surveys were employed to identify the agent of extensive conelet damage and abortion in a Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) seed orchard in western Oregon. Both approaches confirmed involvement of Lepesoma lecontei (Casey) in moderate to severe cone injury during the flowering stage. More than one-third of cones surveyed at the pendent stage showed some degree of injury and 19% of the injured cones were aborted. L. lecontei -damaged cones accounted for 60% of total abortion, or 6% of the potential cone crop. Economic impact of this injury at this seed orchard in 1985 was ca. $29,000. These results suggest that this poorly known species is economically important in Douglas-fir seed orchards.