Disruption of red turpentine beetle attraction to baited traps by the addition of California fivespined ips pheromone components

The red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Scolytidae), is a common bark beetle species found throughout much of North America. In California, D . valens and the California fivespined ips, Ips paraconfusus Lanier (Coleoptera: Scolytidae), are sympatric and often colonize the same tree. In an unrelated study, we observed that I . paraconfusus attack densities in logging debris were inversely related to D . valens attacks on freshly cut stumps. In this study, we test the hypothesis that allomonal inhibition occurs between these two species. Components of the aggregation pheromone of I . paraconfusus (racemic ipsenol, (+)-ipsdienol, and (–)- cis -verbenol) inhibited the response of D . valens to attractant-baited traps. Substitution of racemic ipsdienol for (+)-ipsdienol did not alter this effect. Doubling the release rate did not enhance inhibition. Racemic ipsdienol was not attractive to I . paraconfusus . Temnochila chlorodia (Mannerheim, 1843) (Coleoptera: Trogositidae), a common bark beetle predator, was attracted to the I . paraconfusus aggregation pheromone. These results could have important implications for the development of an effective semiochemical-based management tool for D . valens .