Operational Success of Verbenone Against the Mountain Pine Beetle in a Rural Community

Pouches releasing verbenone, the antiaggregation pheromone of the mountain pine beetle, were stapled to 1191 lodgepole pines throughout 95 residential properties in four subdivisions at Lac le Jeune, British Columbia, in July 2005. Postflight assessment in October in three of the subdivisions, where almost all infested trees had been removed before beetle flight, revealed new mass attacks on 3.6% of 3857 available trees 17.5 cm or greater (7 in) dbh. In a fourth subdivision where no infested trees were removed, 19.6% of 634 available trees were mass-attacked. In contrast, 17.4% of 1145 available trees were mass-attacked within 25 m (27.5 yd) wide, verbenone-treated buffer strips on public forest land adjacent to the residential properties, and 48.3% of 4975 available trees were mass-attacked on untreated control areas beyond the buffer strips. We conclude that treatment with verbenone pouches at roughly 15 m (16.5 yd) centers is a useful tool for protecting trees from attack by the mountain pine beetle provided that verbenone is used as part of a multiyear integrated pest management program that also includes disposal of all infested trees on the area to be protected before beetle flight in midsummer.