Risk assessment of Bursaphelenchus xylophilus for Finland
A detailed risk assessment on the potential of Bursaphelenchus xylophilus (EPPO A1 quarantine pest) to be introduced and to establish in Finland has been presented in a dissertation by Jyrki Tomminen of the University of Helsinki. In his evaluation of the risk of introduction he identified at least three means by which B. xylophilus could disperse from contaminated wood products into Finnish forests:
"1."escaped" contaminated wood chips or green lumber could come into physical contact with the wood of dead trees, such as logs or cut stumps, and such contact may result in the successful transmission of the nematodes;
2. green imported wood may harbour living vector beetles of different life stages which could well complete their life cycles in Finland and leave the wood with nematodes in their tracheae;
3."escaped" nematode-contaminated wood chips may end up trapping native vector insect adults that happen to be flying in places were chips are being handled and processed. As a result these insects could then spread the nematodes in the forest."
Concerning establishment potential in Finland he concluded that even if the rate of reproduction of B. xylophilus may be lower in Finland than in most of North America, due to climatic differences, there is no doubt that the nematode could survive in the country and that it could be vectored (although possibly less efficiently) by Finnish Monochamus spp.
Sources
Tomminen, J. (1993) An assessment of the pinewood nematode and related species in wood products and their potential risk to Finnish forests.
Dissertation at the University of Helsinki, Department of Applied Zoology, Report No. 18, 1993