Pine wilt is often discussed as if it is a disease but it is actually the damage that results from the actions of the critter called the pine wilt nematode (Bursaphelenchus xylophilus). This tiny creature is moved from tree to tree by the pine sawyer insect. As the nematode burrows through the wood of the tree, it clogs the "pipes" of the plant restricting the movement of water and nutrients. When enough of the system has been destroyed, the entire tree dies.


One of the key symptoms of pine wilt nematode infestation is the rapid browning and death of the tree. Fortunately, this generally only happens to older, sick and declining trees under environmental stress. These are the types of trees that are attractive to the sawyers which are borer insects. Thus, they are the trees that get infected by the nematodes.

Trees that die of this problem usually exhibit a bluish stain in the heartwood of the tree. Unfortunately, this can only be discovered on a post mortem examination. The stain is not part of pine wilt but is almost always associated with it.


Scotch (Pinus sylvestris), Red (Pinus resinosa) and Japanese black (Pinus thunbergiana) pines are considered highly susceptible to the nematode. Others are either not susceptible or are rarely infested.

 

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.

Some Pines susceptible to and resistant to Pine wilt:
 
SUSCEPTIBLE PINES
  • Pinus contorta var. lotifolia - Lodgepole Pine
  • P. densiflora - Japanese Red Pine
  • P. lambertiana - Sugar Pine
  • P. monticola - Western White Pine
  • P. mugo - Mugho Pine
  • P. nigra - Austrian Pine
  • P. pinaster - Cluster Pine
  • P. radiata - Monterey Pine
  • P. sylvestris - Scotch Pine
  • P. taeda - Loblolly Pine
  • P. thunbergiana - Japanese Black Pine
  • P. virginiana - Scrub Pine
 
RESISTANT PINES
  • P. banksiana - Jack Pine
  • P. caribaeo - Cuban Pine
  • P. echinata - Shortleaf Pine
  • P. eillottii - Slash Pine
  • P. jeffreyi - Jeffrey Pine
  • P. palustris - Langleaf Pine
  • P. pungens - Table Mountain Pine
  • P. rigida - Pitch Pine
  • P. strobus - White Pine

 
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