Verbenone significantly reduced catches ofIps latidens(LeConte),I. pini(Say), andDendroctonus ponderosaeHopkins in multiple-funnel traps, baited with aggregation pheromones, in stands of lodgepole pine in southern British Columbia. Interruption of attraction was dose dependent for all three species. There were no significant differences in attraction between the sexes. Variation in successful use of verbenone in protecting pine stands partially may be explained by the dose-dependent variation in responses.