Development of an improved attractive lure for the pine shoot beetle, Tomicus piniperda (Coleoptera: Scolytidae).

1) The pine shoot beetle, Tomicus piniperda (L.) (Coleoptera: Scolytidae), is an exotic pest of pine, Pinus spp., and was first discovered in North America in 1992. 2) Although primary attraction to host volatiles has been clearly demonstrated for T. piniperda, the existence and role of secondary attraction to insect-produced pheromones have been widely debated. 3) Currently, commercial lures for T. piniperda include only the host volatiles α-pinene in North America and α-pinene, terpinolene and (+)-3-carene in Europe. Several potential pheromone candidates have been identified for T. piniperda. 4) We tested various combinations of host volatiles and pheromone candidates in Michigan, U.S.A., and Ontario, Canada, to determine an optimal blend. 5) Attraction of T. piniperda was significantly increased when trans-verbenol(95% pure, 3.2% cis-verbenol content) was added with or without myrtenol to α-pinene or to blends of α-pinene and other kairomones and pheromone candidates. 6) Our results, together with other research demonstrating that trans-verbenol is produced by T. piniperda, support the designation of trans-verbenol as a pheromone for T. piniperda. A simple operational lure consisting of α-pinene and trans-verbenol is recommended for optimal attraction of T. piniperda.