Identification of volatiles from Pinus silvestris attractive for Monochamus galloprovincialis using a SPME-GC/MS platform

A myriad of volatile organic compounds (VOCs) released by terrestrial vegetation plays an important role in environmental sciences. A thorough chemical identification of these species at the molecular level is essential in various fields, ranging from atmospheric chemistry to ecology of forest ecosystems. In particular, the recognition of VOCs profiles in a context of plant-insect communication is a key issue for the development of forest protection tools. This work was aimed at the development of a simple, robust and reliable method for the identification of volatiles emitted from plant materials, which can attract or deter pest insects. Specifically, volatiles emitted from the bark of Pinus sylvestris were studied, which might attract the black pine sawyer beetle Monochamus galloprovincialis-a serious pest of the tree and a vector of a parasitic nematode Bursaphelenchus xylophius. The volatiles from bark samples were collected using a solid-phase micro-extraction technique, and subsequently analysed by gas-chromatography/mass-spectrometry (GC/MS). The characterisation of the volatile fraction was based on the comparison with data in mass spectral libraries, and in most cases, with the available authentic standards. The identified compounds were screened against the available entomological data to select insect attractors. The identified components included terpenes (alpha-pinene, a dagger-3-carene, and para-cymenene), oxygenated terpenes (alpha-terpineol and verbenone), sesquiterpenes (alpha-longipinene, longifolene, E-beta-farnesene, gamma-cadinene and pentadecane), and diterpenes (manoyl oxide and (+)-pimaral). Of these, longifolene and (+)-pimaral are of particular interest as plausible attractors for the M. galloprovincialis beetle that might find application in the construction of insect bait traps.