Efficacy of verbenone in reducing lodgepole pine infestation by mountain pine beetles in Idaho

Abstract

Verbenone, a bark beetle antiaggregative pheromone, was deployed in lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) stands in the Sawtooth National Forest, Idaho, U.S.A., to test its efficacy in reducing tree losses to mountain pine beetle (Dendroctonusponderosae Hopkins). Treatments tested were verbenone, mountain pine beetle tree bait, verbenone plus mountain pine beetle tree bait, and a control. Each treatment was applied individually to 1-ha blocks and replicated four times. Treatment effects were measured by percentage of infested (i.e., mass-attacked) lodgepole pine. ANOVA showed a significant treatment effect (P < 0.005). Blocks treated with mountain pine beetle tree baits had significantly (P < 0.002) higher average percentages of infested trees (24.4%), whereas no significant difference occurred in percentages of infested trees among the other three treatments. Average percentages of infested trees were 0.9% for verbenone, 7.4% for verbenone plus mountain pine beetle tree bait, and 3.3% for the control. A 2.3-fold reduction in infested trees occurred when verbenone was applied to blocks treated with mountain pine beetle tree baits.