(Heterobasidion root rot), Heterobasidion annosum

Photo by Chal Landgren, OSU.

Signs & symptoms

Photo by Chal Landgren, OSU.

  • Declining leader growth
  • Dark, irregular-shaped staining in the center of cut trees
  • Dead trees near old stumps
  • Small white mounds (fungus) on the bark near ground line

Where to Look

Photo by Gary Chastagner, Washington State University.

  • Fields after multiple rotations without stump removal
  • Trees planted near stumps

Similar Symptoms As

Photo by Chal Landgren, OSU.

  • Other root and canker diseases
  • Drought

Scouting

  • Examine stumps of harvested and dead trees.

Management Options

  • Consider stump removal prior to replanting.
  • Treat freshly cut stumps of healthy trees with borax (Sporax) to prevent infection by windborne spores.
  • Plant resistant species.

Host Susceptibility

host susceptibility graph

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

Management Calendar

“management

  • Look for declining growth, yellowing, dead trees (most likely during moisture stress): Mid-April through Mid-December
  • Examine stumps at harvest season: November
  • Remove stumps: March through Mid-July
  • Treat stumps at harvest: Mid-October through Mid-December