Quick Facts…
- Pine wilt is a lethal disease caused by a native nematode (Bursaphelenchus xylophilus), vectored to trees by a wood borer insect–the pine sawyer beetle (Monochamus spp.).
- Native pines are not susceptible to this pathogen.
- High summer temperatures are required for the nematode to develop in the beetle and within infested trees.
- It can be prevented by timely sanitation and chemical injections.
This disease affects mostly non-native pines, including Austrian, Japanese black, Japanese red, Scotch and Virginia. Some native pines have also been reported as hosts, but are seldom killed by the disease. Older, weaker trees are more prone to injury and may die within 30-90 days of the onset of symptoms.
What causes pine wilt disease?
Small worms called nematodes multiple in the tree’s branches, causing tree decline. As the trees begin to die, they are attacked by insects known as sawyers. These beetles emerge in spring to feed on the developing tree. They attack weakened trees, thus transmitting the harmful pine wilt nematode.
Solutions and Treatments
Trees killed by the pine wilt nematode should be removed and disposed of by chipping, burning or de-barking. It is important to remove diseased trees in the winter or early spring before growth resumes and nematode is spread to healthy trees. Maintain trees in healthy condition by proper watering and fertilizing. Also, when planting pine trees, choose types that are adapted to your area.