Bark beetles (Coleoptera: Curculionidae, Scolytinae) are important tree mortality agents in western coniferous forests. Protection of individual trees from bark beetle attack has historically involved applications of liquid formulations of contact insecticides to the tree bole using hydraulic sprayers. More recently, researchers have examined the effectiveness of injecting small quantities of systemic insecticides directly into trees, but early efforts were largely unsuccessful. In this study, we determine the efficacy of fall (16 - 18 September) injections of abamectin (Abacide™ 2Hp; Mauget Inc., Arcadia, CA) alone and combined with tebuconazole (Tebuject™ 16, Mauget Inc.) for protecting individual lodgepole pine, Pinus contorta Dougl. ex Laws., from mortality attributed to mountain pine beetle, Dendroctonus ponderosae Hopkins. Both abamectin and abamectin tebuconazole were efficacious for one field season, whereas results from a second field season were inconclusive due to insufficient beetle pressure. To our knowledge, this is the first demonstration of the successful application of a systemic insecticide for protecting P. contorta from mortality attributed to D. ponderosae.