Role of infested sawdust in the spread of Bursaphelenchus xylophilus
The pinewood nematode Bursaphelenchus xylophilus (EPPO A2 List) is the causal agent of pine wilt disease. It is spread in coniferous forests by beetles of the genus Monochamus. Long distance spread of the nematode can occur from transport of coniferous commodities such as plants for planting, round wood, sawn wood, wood chips, wood residues, bark, and wood packaging material. A recent study by Arbuzova et al. (2023) suggests that sawdust could also play a role if used near host plants (e.g. used as mulch).
In an experiment in controlled conditions, 4-year-old seedlings of Pinus sylvestris became infested with B. xylophilus when injured stems or roots were in contact with infested sawdust.
Sources
Arbuzova EN, Kulinich OA, Chalkin AA, Kozyreva NI, Gorbach VV, Ryss AY (2023) Infestation of pine (Pinus sylvestris L.) seedlings with the pinewood nematode Bursaphelenchus xylophilus Steiner and Buhrer (Nickle) through wood sawdust. Annals of Forest Science 80, 6. https://doi.org/10.1186/s13595-023-01174-y