Semiochemicals for the mountain pine beetle, Dendroctonusponderosae (Coleoptera: Scolytidae), in British Columbia: baited-tree studies

Abstract

Lodgepole pines, Pinuscontorta var. latifolia Engelm., in three interior British Columbia locations were baited with six monoterpenes alone or combined, and various combinations of the beetle-produced volatiles trans-verbenol, exo-brevicomin, and 3-caren-10-ol. Trees baited with trans-verbenol, exo brevicomin, and the monoterpene 3-carene sustained higher attack densities by the mountain pine beetle, Dendroctonusponderosae Hopkins, and were surrounded by more attacked trees than trees baited with trans-verbenol and 3-carene or unbaited controls. Myrcene was apparently the best of six monoterpenes as a synergist for trans-verbenol. 3-Caren-10-ol appeared to have some activity in an early test but did not prove to be an attractive pheromone in extensive studies. In a 17-ha portion of an infestation, treatment of 99 trees with 3-carene and trans-verbenol apparently caused a higher attack rate, resulting in 56.4% of the available green trees being attacked, as opposed to 22.3% of the available trees in the 14-ha unbaited area. These data as well as the high attack rates associated with trees which also had an exo-brevicomin bait suggest that semiochemicals could be used to contain D. ponderosae infestations and to attract beetles to lethal trap trees.