Synergistic attraction of pine sawyer Monochamus saltuarius (Coleoptera: Cerambycidae) to monochamol and α-pinene

Monochamus (Coleoptera: Cerambycidae) species are longhorn pine sawyers that serve as insect vectors of the pinewood nematode Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae), which are responsible for debilitating pine wilt disease. An aggregation pheromone, 2-(1-undecyloxy)-1-ethanol (hereafter referred to as monochamol), was shown to be effective at attracting Monochamus species. However, attraction of the pine sawyers to aggregation pheromones varied depending on semiochemicals, including host plant volatiles and kairomones. In this study, we investigated the abilities of monochamol and the host-plant volatiles α-pinene and ethanol to attract M. saltuarius in a pine forest in Cheongsong, Gyeongsangbuk-do, Korea. A total of 91 M. saltuarius (28 males and 63 females) were captured. The combination of monochamol (700 mg) with α-pinene and ethanol exhibited a synergistic effect on attracting M. saltuarius (11.0 beetles per trap), whereas monochamol alone and a mixture of α-pinene and ethanol resulted in the capture of 3.2 beetles and 3.6 beetles per trap, respectively. Our results suggest that multi-funnel traps baited with a blend of monochamol, α-pinene and ethanol are highly effective for monitoring M. saltuarius and M. alternatus in pine forests.