Establishment Risks for Invasive Species

In North America, the native pinewood nematode (PWN), Bursaphelenchus xylophilus, kills exotic pines. When inadvertently introduced to Japan and other Asian countries, PWN became a destructive pest of pines. The PWN has been intercepted in pine shipments from North America to Europe, where there is concern that it may also kill pines and other conifers. To protect their forests from the PWN and other pests, the European Union and other countries now regulate the import of all coniferous chips, sawn wood, and logs. Several species of Bursaphelenchus have a phoretic relationship with Monochamus spp., which carry them to recently felled logs and dead or dying conifers, particularly pines. As a result, species of Monochamus, Bursaphelenchus, or both may be found in chips, unseasoned lumber, and logs. During the past decade, procedures to disinfest transported unprocessed wood have been investigated. These mitigation measures include prevention, host selection, and treatment by fumigation, irradiation, chemical dips, and elevated temperatures.