Phytophthora spp

Photo by Chal Landgren, OSU.

Signs & Symptoms

Photo by Chal Landgren, OSU.

  • Reduced or stunted growth
  • Poor color
  • Root decay
  • Bleeding basal cankers
  • Dead branches first noticeable at the base of the tree

Where to Look

Photo by Chal Landgren, OSU.

  • Low-lying areas with poor drainage

Similar Symptoms As

Photo by Chal Landgren, OSU.

  • Other root diseases
  • Drought


  • Cut the tree and check cambium for presence of canker.
  • Dig roots and check for dark and rotten roots.
  • Look for dead trees in field.
  • Look for flagging branches.

Management Options

  • Replant with resistant species.
  • Improve field drainage (e.g., tiling, ditches).
  • Avoid sites with poorly drained soils.

Host Susceptibility

host susceptibility graph

  • High susceptibility: Fraser fir, Noble fir, Shasta fir
  • Medium susceptibility: Douglas-fir
  • Low susceptibility: Grand fir, Nordmann fir, Turkish fir

Management Calendar

  • Look for dying, yellowing trees; trees with cankers: April through Mid-September
  • Scout for especially off-color trees with dead branches and wet areas: April through Mid-September
  • Plant resistant species: February through March
  • Improve drainage: September through October