Sudden Oak Death
WNARS Project members would like to make all collectors aware that a disease called Sudden Oak Death (SOD) affects Rhododendron. As you travel in the Pacific Northwest, you should take precautions to prevent the spread of this fungus disease.

Damage from SOD in Rhododendron, Vaccinium ovatum and Arbutus menziesii typically involves leaf spotting, cankers on small branches and stems, and/or stem dieback.

Disease Movement
Researchers are studying how SOD spreads. The pathogen has been isolated from host debris (e.g., firewood and leaves), nursery stock, soil, stream water and rain-splash. Human movement of infested host materials is considered the most likely means of long distance spread. Infested soil and rain-splash may contribute to local and/or tree to tree spread of the disease. Animals, insects and birds as other possible vectors for this disease.

Our native oaks, tanoaks, huckleberries, and rhododendrons can best be protected by preventing further introductions of the disease.

  • Do not transport potentially infected plant materials (flowers or cuttings) from diseased areas in California or Oregon.
  • Do not export potentially infected plant materials to other collectors.
  • If you visit suspect areas, wash your vehicle and shoes before traveling to disease-free areas. If you take your dog plant hunting with you, be sure to clean your pet's feet.
  • If you see a host plant with symptoms like SOD, report it to the relevant Dept. of Agriculture or Dept. of Forestry immediately.

    Infected Leaf

    Links for more information
    WSU SOD Website
    Oregon Info