Language selection


Ceanothus silk moth

Ceanothus silk moth -
  • Latin name: Hyalophora euryalis (Walker)
  • French name:
  • Order: Lepidoptera
  • Family: Saturniidae


British Columbia

This species occurs throughout southern British Columbia; it also occurs south to California.


Needle, Twig

Damage, symptoms and biology

The ceanothus silk moth is a relatively uncommon innocuous solitary defoliator.

Mature larva up to 90 mm long. Head, green with with two black spots on vertices (not prepupal larva). Body yellowish green (penultimate instar), bluish green (final instar) to bluish (prepupal); subdorsal row of orange to red tubercles each tipped with black spines; supra- and subspiracular rows of blue tubercles each tipped with black spines.

This species overwinters as a pupa in a sac-like cocoon attached to a twig. Adults emerge May to June and lay 250-350 eggs either singly or in small groups on host foliage. Larvae are present June to August and pupation occurs in August.

Canadian Forest Service Publications

Ceanothus silk moth

Diet and feeding behaviour

  • Phyllophagous : Feeds on the leaves of plants.
    • Free-living defoliator: Feeds on and moves about freely on foliage.
Information on host(s)

The principal coniferous hosts of the ceanothus silk moth are Douglas-fir and grand fir; other hosts include alder, willow, birch, ceanothus and manzanita.

Main host(s)

Alaska paper birch, alders, balsam willow, Bebb willow, birch, black willow, blueleaf birch, cherry birch, common bearberry, Douglas-fir, dwarf birch, European black alder, European white birch, feltleaf willow, golden weeping willow, grand fir, green alder, grey birch, hazel alder, heartleaf willow, hooker willow, hybrid white willow, Kenai birch, laurel willow, littletree willow, low birch, Mackenzie willow, meadow willow, mountain alder, mountain paper birch, New Jersey tea, Pacific willow, peachleaf willow, pussy willow, red alder, Rocky Mountain Douglas-fir, sandbar willow, satiny willow, Scouler willow, shining willow, Siberian alder, Sitka alder, Sitka willow, speckled alder, violet willow, water birch, white birch, white birch, yellow birch


Page details

Date modified: