Guidance on sampling to detect pine wood nematode Bursaphelenchus xylophilus in trees, wood and insects

The pine wood nematode Bursaphelenchus xylophilus is the causal agent of pine wilt disease. It is a quarantine pest for most countries in the world. Surveys for the occurrence of the nematode may be necessary in the framework of internationally agreed phytosanitary standards, in order to delimit infested areas or to demonstrate the absence of B. xylophilus and thus to identify pest free areas. Import inspections of wood and wood products also need sound monitoring systems. It is obvious that the quality of survey/monitoring, as well as the results of diagnosis, are strongly dependent on the sampling procedure. Although, in the literature, numerous results of surveys and monitoring are documented, sampling procedures vary and there is no scientific or statistically based sampling system published for B. xylophilus. The current paper relates background information concerning the biology of the nematode, its vector beetles and the development of pine wilt disease and the influence of these factors on sampling procedures, and attempts to define a more systematic methodology.