Pest profile

Pandora Moth

Coloradia pandora · Lepidoptera: Saturniidae[2]

Pandora moth caterpillars feed on the needles of ponderosa, Jeffrey and lodgepole pines and can severely defoliate them in sporadic outbreaks.[1]

Pandora moth, a large heavy-bodied moth with dark gray forewings and pinkish hind wings, on a rock
Pandora moth, a large heavy-bodied moth with dark gray forewings and pinkish hind wings, on a rock. (c) Tom Kennedy, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Adults are large, heavy-bodied, brown-gray moths with a wingspan of 2.7 to 4 inches and black wing markings.[1]
  • Caterpillars are brownish to yellowish green, spiny and about 1 inch long when grown.[1]
  • Caterpillars travel in single file to new feeding spots, and eaten needles leave stubs on the twigs.[1]

Where it lives

The PNW Insect Management Handbook calls it a sporadic pest of forest and landscape pines.[1]

US map: public records from 13 states since 1990 (GBIF).

Biology and life cycle

Moths emerge in midsummer and lay eggs on pine needles or bark; larvae feed on new foliage through summer.[1]

Larvae overwinter in clusters on the tree, feed again in spring, then drop to the soil to pupate, a stage that lasts at least a year.[1]

The larvae are considered a delicacy among tribes in areas where they occur.[1]

Damage and signs

  • Crowns of infested trees thin out, and large outbreaks can severely defoliate them.[1]

Health risk

It feeds on plants; the PNW Insect Management Handbook mentions no risk to people.[1]

Control

Prevention

Control isn't needed except in outbreak years; watch for increasing defoliation or clusters of larvae in winter.[1]

Traps and physical control

Hand-pick larvae you find, and prune out severely defoliated sections.[1]

Common questions

Do I need to spray for pandora moths?
Usually not; the PNW handbook says control isn't needed except in outbreak years.[1]
Why are caterpillars marching in a line on my pine?
Pandora moth caterpillars travel in single file when moving to new feeding areas.[1]

Sources

  1. Pacific Northwest Pest Management Handbooks (OSU, WSU, University of Idaho), “Pine (Pinus): Pandora moth (Insect Management Handbook).” pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/pine-pinus-pandora-moth (accessed 2026-10-06)
  2. iNaturalist, “Coloradia pandora taxon page (order and family).” www.inaturalist.org/taxa/179711 (accessed 2026-10-06)

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