PestControlBasics
Menu

Identify

Treat

Local

About

Promylea lunigerella

Promylea lunigerella[4]

Promylea lunigerella is a small gray moth of the coastal conifer forest from British Columbia and Washington south to California, with records from Colorado. It has no common name. Its green caterpillar, marked with a broad yellow stripe low on each side, feeds singly on the needles of grand fir, amabilis fir, Douglas-fir and western hemlock in May and June. Natural Resources Canada classes it as a common but innocuous defoliator, and the USDA manual calls it little known.[1][2]

Group
Insect
Order
Lepidoptera
Family
Pyralidae
US records
4 states
Sources
4 cited
Updated
2026-11-10
Promylea lunigerella moth, a pale gray pyralid moth with its wings folded tent-like, at rest on a dark surface
Promylea lunigerella moth, a pale gray pyralid moth with its wings folded tent-like, at rest on a dark surface. Photo: Ben Keen, public domain (CC0), via iNaturalist
On this page
  1. Identification
  2. Look-alikes
  3. Where it lives
  4. Biology
  5. Damage and signs
  6. Health risk
  7. Control
  8. Related profiles
  9. Common questions
  10. Sources

How to identify it

  • The full-grown caterpillar is up to 20 mm long and green, with a yellowish-green back and a broad yellow stripe below the spiracles. The head is light green with dark mottling.[1]
  • The moth's forewings are gray or brownish gray and span 20 to 24 mm. Adults fly from July to early August.[2][1]
  • Caterpillars are found feeding in the open on conifer foliage from May to mid-June, one to a site.[1]

Look-alikes

Look-alikeHow to tell them apart
Dioryctria pseudotsugellaDioryctria pseudotsugella is another innocuous pyralid defoliator on the same Douglas-fir and fir foliage in British Columbia, but its caterpillar is brown with a rusty back and creamy stripes rather than green, and it feeds from May to July.[3][1]

Where it lives

It occurs throughout south coastal British Columbia and south to California; the USDA manual records it from coastal British Columbia and Washington and from California and Colorado.[1][2]

US map: public records from 4 states since 1990 (GBIF).

Biology and life cycle

Grand fir is the principal host and amabilis fir the second; Douglas-fir and western hemlock are also main hosts, with red alder, Sitka spruce, western redcedar and white spruce as secondary hosts. The USDA manual lists grand fir, Douglas-fir, western hemlock and other conifers.[1][2]

The moth appears to overwinter in the egg stage. Caterpillars are present from May to mid-June, pupation takes place from June to July, and the adults emerge from July to early August.[1]

It is a free-living solitary defoliator, feeding on and moving about the foliage in the open.[1][2]

Damage and signs

  • Natural Resources Canada classes it as a common innocuous solitary defoliator, and the USDA manual records no damage beyond calling it a little-known defoliator of conifers.[1][2]

Health risk

The sources treat it only as a conifer foliage feeder and mention no effect on people.[1][2]

Control

Prevention

No control is needed: the insect is rated innocuous. A green, yellow-striped caterpillar found on grand fir or Douglas-fir needles in late spring can be left where it is.[1]

Common questions

Is Promylea lunigerella a pest?
No. Natural Resources Canada classes it as a common innocuous solitary defoliator of grand fir and other conifers, and the USDA manual records no damage.[1][2]
When and where would I find the caterpillar?
From May to mid-June on the foliage of grand fir, amabilis fir, Douglas-fir or western hemlock on the Pacific coast, feeding singly in the open.[1]
What does the moth look like?
A gray or brownish-gray moth with a wingspread of 20 to 24 mm, on the wing from July to early August.[2][1]

Sources

  1. Natural Resources Canada, Canadian Forest Service, “Promylea lunigerella Ragonot, Trees, insects and diseases of Canada's forests.” tidcf.nrcan.gc.ca/en/insects/factsheet/11598 (accessed 2026-11-10)
  2. USDA Forest Service, “Western Forest Insects, Miscellaneous Publication 1339 (R. L. Furniss and V. M. Carolin, November 1977; scanned copy).” archive.org/details/CAT78702369 (accessed 2026-11-10)
  3. Natural Resources Canada, Canadian Forest Service, “Dioryctria moth (Dioryctria pseudotsugella), Trees, insects and diseases of Canada's forests.” tidcf.nrcan.gc.ca/en/insects/factsheet/11444 (accessed 2026-11-10)
  4. iNaturalist, “Promylea lunigerella taxon page (order and family).” www.inaturalist.org/taxa/477707 (accessed 2026-11-10)

Updated 2026-11-10. Built from sourced records. Spot an error? Tell us.