Comparison of volatile organic compounds from uninfested and Monochamus alternatus Hope infested Pinus massoniana Lamb.

Monochamus alternatus is a destructive stem‐boring herbivore of Pinus massoniana , and the principal vector of pine wood nematode. To investigate the impacts of boring by M. alternatus larvae on the emission of volatile organic compounds (VOCs) from their host trees, the VOCs from uninfested and M. alternatus larvae infested P. massoniana trees were observed using a gas chromatograph–mass spectrometer. We detected 12, 9, 18 and 14 volatile organic compounds from infested xylem, infested phloem, uninfested xylem and uninfested phloem, respectively. In P. massoniana xylem, the boring of M. alternatus larvae induced cyclosativene, and inhibited 4‐carene, humulene, styrene, α‐phellandrene, β‐myrcene, β‐phellandrene and γ‐terpinene. The relative amounts of camphene, copacamphene, longicyclene, longifolene, tricyclene and α‐longipinene were significantly increased, and the relative amounts of α‐pinene and β‐pinene were significantly decreased by the boring behaviors of M. alternatus larvae. In P. massoniana phloem, the boring of M. alternatus larvae induced 2‐bornanone, copacamphene, longicyclene and α‐longipinene, and inhibited 2‐carene, 4‐carene, styrene, α‐phellandrene, β‐myrcene, β‐phellandrene, β‐pinene, γ‐terpinene and ο‐cymene. The relative amounts of camphene, caryophyllene and longifolene were significantly increased by the boring behaviors of M. alternatus larvae. The results indicate that the boring behaviors of M. alternatus larvae changed both the sorts and contents of the VOCs from P. massoniana trees.