Pine Wilt Disease

Pine wilt is a fatal disease of pine (Pinus sp.) caused by the nematode Bursaphelenchus xylophilus. As a native organism to North America it is a primary pathogen of non-native, 2-3 needle pines. The disease is vectored by pine sawyer beetles (Monochamus sp.) as they feed on the bark and foliage of susceptible pine trees. This disease is a major concern for arborists as well as Christmas tree growers in the Midwest states, including IA, IL, MO, KS, NE, KY.

Treatment Strategy

Aracinate (formerly called Pinetect) and Mectinte are tree injection products that are used to preventively treat pines that are susceptible to pine wilt disease. Optimal results occur when these products are applied in the spring of the year prior to adult flight of the pine sawyer beetle, which vectors the nematode. Any refillable injection device that is capable of injecting pine can be used to apply these products. Rainbow distributes the Q Connect system that can be used to apply these products.

Other Treatment Practices

  • Preventive trunk and limb sprays with Bifen XTS or Tengard will control the pine sawyer beetle and other pine bark beetles.
  • Preventive applications of Xytect will control sawfly and other insects.
  • Promptly remove and burn infected trees.
  • Promptly remove and burn, chip, or bury infected trees.
  • DO NOT transport firewood or logs from infected trees.
  • Plant resistant native pines and 5-needle pines.

Tree Injection Using Mectinite

Tree Injection Using Aracinate

Expected Results

  • Mectinite will provide two years of protection from pine wilt.
  • Uptake on pines can be unpredictable and slower than on deciduous trees.
  • Uptake times may vary from a few minutes up to 60-90 minutes per tree, a 30 minute average is common.
  • Applications with Arborsystems wedgle have demonstrated negative results in KSU trials and will not be effective.

Signs of Damage

  • Field diagnosis is difficult due to the rapid death of infected trees
  • Early symptoms may be reduced vigor, fading green color, and yellowing throughout the entire tree
  • Symptoms often begin from the top of the tree progressing down
  • Trees begin to die in midsummer and can die within weeks of the initial infection, leaving brown, dead needles still attached to the branches
  • It can be helpful to scout for infection centers formed by previous infections

Trees At Risk

  • Scots Pine (Pinus sylvestris)
  • Austrian/Black Pine (Pinus nigra)
  • Aleppo Pine (Pinus halepensis)
  • Japanese Black Pine (Pinus thunbergii
  • Japanese Red Pine (Pinus densiflora)
  • Mugo Pine (Pinus mugo)
  • Pitch Pine (Pinus rigida)
  • Swiss Stone Pine (Pinus cembra)
  • Shortleaf Pine (Pinus echinata)
  • Virginia Pine (Pinus virginiana)
  • Lodgepole Pine (Pinus contorta)
  • Jack Pine (Pinus banksiana)
  • Red Pine (Pinus resinosa)
  • Loblolly Pine (Pinus taeda)
  • Monterey Pine (Pinus radiata)


USDA Forest Service

American Phytopathological Society

James, R., et. al. 2006. Prevention of pine wilt of Scots pine with systemic abamectin injections. Vol. 32, No. 5. September.

James, R. 2005. Prevention of pine wilt of Scots pine with systemic abamectin injections. M.S. Thesis, Kansas State University, Manhattan, KS.

Always refer to product label for rates and approved uses. Some images courtesy of or Wikimedia Commons. Use of the images does not imply endorsement of treatments.

A Treatment Guide is designed to help you identify common issues and management solutions. Comprehensive Treatment Guide PDFs, which include current products, application rates, and additional information, are available upon request.