We tested two formulations of verbenone for efficacy in protecting ponderosa pine trees from attack by the red turpentine beetle, Dendroctonus valens LeConte: (1) polyethylene bubblecaps filled with 800 mg of neat verbenone, and (2) a sprayable water suspension of microencapsulated verbenone. We baited artificial trees (cardboard cylinders coupled with Lindgren pheromone traps) with host kairomones and the verbenone formulations. Efficacy was measured by numbers of beetles captured in baited traps. Both release systems significantly reduced trap catch, and there was no significant difference between them. Both systems have promise for use in forest stands, depending on management objectives and land use. Verbenone was an interruptant for some nontarget insects, especially Coleoptera, and none were consistently attracted to verbenone. We report on verbenone as an interruptant to host attraction in the red turpentine beetle, and also on the efficacy of a microencapsulated scolytid semiochemical.