There is a relatively common set of protocols whether surveys for pine wood nematode are being carried out in an area without PWN or in an area already known to have the nematode.
However, the emphasis is slightly different, reflected in the standardised protocols from the EU
that form the basis for survey.
Underpinning both scenarios, the presence of symptomatic trees is a common basis for sampling efforts but, in areas not known to have the nematode, this is part of a risk-based approach rather than a statistically designed random survey protocol which would require massive survey efforts to detect very low levels of infestation (see Økland, B., Skarpaas, O., Schroeder, M., Magnusson, C., Lindelöw, Å. and Thunes, K.(2010), Is Eradication of the Pinewood Nematode (Bursaphelenchus xylophilus) Likely? An Evaluation of Current Contingency Plans. Risk Analysis, 30: 1424–1439).