The response of Dendroctonus valens and Temnochila chlorodia to Ips paraconfusus pheromone components and verbenone

The red turpentine beetle, Dendroctonus valens LeConte, 1860 (Coleoptera: Curculionidae, Scolytinae), is a common bark beetle found throughout much of North America and China. In 2004, we observed that attack densities of the California fivespined ips, Ips paraconfusus Lanier, 1970 (Coleoptera: Curculionidae, Scolytinae), in logging debris were inversely related to D. valens attacks on freshly cut stumps, which led to the demonstration that components of the aggregation pheromone of I. paraconfusus inhibited the response of D. valens to attractant-baited traps. In this study, we test the response of D. valens and Temnochila chlorodia (Mannerheim, 1843) (Coleoptera: Trogositidae), a common bark beetle predator, to racemic ipsenol, racemic ipsdienol, and (-)-cis-verbenol (IPSR) in the presence and absence of two release rates of (-)-verbenone. The addition of a relatively low release rate of (-)-verbenone (4 mg/24 h) to attractant-baited traps did not affect catch and had no significant effect on the response of D. valens to IPSR. IPSR significantly reduced D. valens attraction to baited traps. The addition of high release rates of (-)-verbenone (50 mg/24 h) to IPSR significantly increased inhibition; however, the effect was not significantly different from that observed with (-)-verbenone alone (50 mg/24 h). Temnochila chlorodia was attracted to traps baited with (-)-beta-pinene, (+)-3-carene, and (+)-alpha-pinene. The addition of (-)-verbenone (50 mg/24 h) significantly increased attraction. Traps baited with IPSR caught significantly more T chlorodia than those baited with (-)-verbenone. Few other beetles were collected. We are hopeful that these results will help facilitate the development of an effective tool for protecting Pinus spp. from D. valens infestations.