Phaeocryptopus gaeumannii

Photo courtesy of USDA Forest Service - North Central Research Station Archive, USDA Forest Service,

Signs & Symptoms

Photo by Gary Chastagner, Washington State University.

  • Parallel rows of tiny, black fruiting bodies on the underside of older needles
  • Yellowing or mottling of infected needles
  • Loss of interior needles; thin appearance of trees

Where to Look

Photo by Chal Landgren, OSU.

  • Areas with poor air movement
  • Field edges near Douglas-fir timber

Similar Symptoms As

Photo by Ralph Byther, Washington State University.

  • Rhabdocline needle cast
  • Cooley spruce gall adelgid
  • Environmental stresses
  • Nutrient imbalances
  • Winter burn
  • Drought damage


  • Using a hand lens, look for parallel bands of tiny, black structures (0.1 mm) arising from the stomates on the undersides of affected needles.
  • Start scouting when trees enter their third growing season, beginning in May.
  • Look at older needles in the lower part of the tree.
  • Pay particular attention to trees that appear off-color or thin.

Management Options

  • Improve air circulation in fields.
  • Spray protective fungicides (if needed) between bud break and 3.8 cm of new growth.
  • Plant alternative tree species.
  • Avoid planting field edges near timber.
  • Remove and destroy heavily infected trees prior to bud break.

Host Susceptibility

host susceptibility graph

  • Medium susceptibility: Douglas-fir only

Management Calendar

  • Look for older needles turning yellow, as well as fungal structures: Mid-February through Mid-July
  • Check underside of needles for black fruiting bodies: March through Mid-May
  • Use fungicides to protect new growth: May through Mid-June