Pest profile

Giant Conifer Aphids

Cinara species · Hemiptera: Aphididae[3]

Giant conifer aphids are large, brownish-black aphids that cluster on fir and pine branches and produce copious honeydew that attracts yellowjackets.[1]

Colony of large, dark giant conifer aphids packed together on a conifer branch
Colony of large, dark giant conifer aphids packed together on a conifer branch. (c) Toby, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • They're large for aphids, 0.13 to 0.2 inch long, and brownish black.[1]
  • They gather in big colonies on branches, especially on the undersides.[1]
  • Aphids that drop onto foliage or decks below can look somewhat like spiders.[1]

Look-alikes

Look-alikeHow to tell them apart
Other aphidsMost landscape aphids are only 1/16 to 1/8 inch long and tend to match the color of their host plant.[2]

Where it lives

The PNW Insect Management Handbook covers them on firs and pines in Pacific Northwest landscapes.[1]

US map: public records from 40 states since 1990 (GBIF).

Biology and life cycle

Eggs overwinter on needles and bark; large black stem mothers hatch in early spring and give birth to live young.[1]

Colonies build among the needles and under larger branches, and there may be several generations through summer.[1]

Damage and signs

  • Feeding can turn needles yellow and make them drop early, defoliating branches.[1]
  • Copious honeydew attracts yellowjackets and other wasps, and black sooty mold growing on it blocks light to the needles.[1]

Health risk

They feed on trees; the PNW Insect Management Handbook mentions no risk to people, though their honeydew draws yellowjackets.[1]

Control

Prevention

Check early in the season, when aphids are fewer; a dark plate under the branches shows spatters of honeydew from the first activity.[2]

Avoid heavy nitrogen fertilizer and heavy watering, which produce the succulent growth aphids favor.[2]

Traps and physical control

Wash aphids off with a strong stream of water or wipe them off by hand.[2]

Biological control

Lady beetles, syrphid fly larvae, green lacewings and parasitoid wasps attack aphids; avoid broad-spectrum sprays that kill them.[2]

Common questions

What are the big dark bugs clustered under my fir branches?
Likely giant conifer aphids, which form large colonies on branch undersides.[1]
Why are so many yellowjackets around my pine tree?
Giant conifer aphids produce copious honeydew that attracts yellowjackets and other wasps.[1]

Sources

  1. Pacific Northwest Pest Management Handbooks (OSU, WSU, University of Idaho), “Fir (Abies): Giant conifer aphid (Insect Management Handbook).” pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/fir-abies-giant-conifer-aphid (accessed 2026-10-06)
  2. Pacific Northwest Pest Management Handbooks (OSU, WSU, University of Idaho), “Landscape pests: Aphid (Insect Management Handbook).” pnwhandbooks.org/insect/hort/landscape/common/landscape-aphid (accessed 2026-10-06)
  3. iNaturalist, “Cinara taxon page (order and family).” www.inaturalist.org/taxa/199407 (accessed 2026-10-06)

Updated 2026-10-14. Built from sourced records. Spot an error? Tell us.