Cinara occidentalis and Cinara abietis

Photo by Luisa Santamaria, OSU.

Signs & Symptoms

Photo by Chal Landgren, OSU.

C. abietis (Giant conifer aphid)

  • Easily visible
  • Found feeding on the upper stems of trees, causing stunted terminals and needle yellowing
  • Typically attended by ants
  • Typically congregating in large colonies

C. occidentalis

  • More difficult to find because they spread out
  • Often feed on 1-year-old foliage on branches; as damage progresses, foliage may yellow and appear shiny from honeydew
  • Ants seldom present

Where to Look

Photo by Chal Landgren, OSU.

  • Randomly in the field
  • Black “soot” in leaders
  • Areas with yellow jackets

Similar Symptoms As

  • Other aphids


  • C. abietis (Giant conifer aphid) can feed throughout the year; damage may be evident any time of year. Scout for aphids in the internodal openings along the upper leaders.
  • C. occidentalis attracts wasps and yellow jackets in the summer as the honeydew becomes more prolific. Look for damaged foliage and black soot on the ground throughout the year. These aphids are harder to spot and are dispersed along branches.

Management Options

  • C. abietis (Giant conifer aphid): Control using localized treatments, including crushing colonies by hand.
  • C. occidentalis: Control early to avoid significant foliage damage. Use labeled insecticides for spot treatments to protect populations of natural predators.

Host Susceptibility

host susceptibility graph

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

Management Calendar

  • Look for stunting of terminals (C. abetis); soot on lower branches and off-color (C. occidentalis): All year round
  • Look for overwintering eggs: February through Mid-April
  • Look for adults: Mid-April through Mid-November
  • Spray insecticide (if needed): May through July