Attraction of the cerambycid beetles Tetropium gabrieli, T. castaneum and T. fuscum to pheromones and host tree volatiles

Tetropium gabrieli is native to the European Alps where it breeds in European larch and may be an important pest during drought periods by killing trees. It has spread to larch plantations in several European countries including Sweden. In trapping studies conducted in Sweden, we tested whether T. gabrieli was attracted to E-fuscumol, E,Z-fuscumol, E,Z-fuscumol acetate and the host volatile combination of alpha-pinene plus ethanol. We also compared its response with those of the native congeners, T. fuscum and T. castaneum. All three Tetropium species were caught in significantly higher numbers in traps baited with E-fuscumol plus host volatiles than in traps baited with host volatiles alone or in unbaited traps. There was no difference in catch of any Tetropium species between traps baited with E-fuscumol plus host volatiles versus traps baited with E,Z-fuscumol plus host volatiles, but the latter treatment caught more T. fuscum and T. castaneum than did E,Z-fuscumol acetate plus host volatiles. The addition of E-fuscumol to host volatile-baited traps significantly reduced mean catch of T. gabrieli, significantly increased mean catch of T. castaneum, and had no significant effect on catch of T. fuscum. Mean catch of all three species was significantly greater in traps baited with E-fuscumol alone than in traps baited with host volatiles alone. All three species were caught from May to August. The median date of captures was about 2 weeks earlier for T. fuscum compared with the other two species.