Adelges Cooleyi

Alternate hosts: Picea spp. such as Colorado blue spruce and other spruces

Photo by Sandy Gardosik, Pennsylvania Dept. of Agriculture (PDA).

Signs & Symptoms

Photo by Sandy Gardosik, Pennsylvania Dept. of Agriculture (PDA).

  • Yellow spots on needles
  • Needles with bends or crooks
  • Small, white, cottony balls on the underside of needles or pepper-sized crawlers on new needles
  • Premature needle drop

Where to Look

Photo by Bryan Schildt, Pennsylvania Dept. of Agriculture (PDA).

  • Current season needles

Similar Symptoms As

  • Rhabdocline needle cast
  • Douglas-fir needle midge


  • Examine the underside of needles for overwintering nymphs that could be covered by white wax (cottony tufts).
  • Control for 2 years before harvest to have damage-free needles.

Management Options

  • Remove any mature spruce or Douglas-fir that may be a source of infestation.
  • Use sprays when the crawlers are present and before the cottony stage occurs.
  • Spot spray where problem populations are localized.
  • Note: In most cases low to moderate numbers of this pest will not require control(s).

Host Susceptibility

host susceptibility graph

  • High susceptibility: Douglas-fir

Management Calendar

  • Look for yellow spots and distortion on needles: Mid-January through Mid-November
  • Look for crawlers on new needles: April through mid-June
  • Spray insecticide (if needed) before cottony stage: May through June