Bug FAQPorcelain Gray
Protoboarmia porcelaria · Order: Lepidoptera · Family: Geometridae
Also called: Porcelain Gray Moth
Source: Wikipedia
Porcelain Gray moths have a wingspan of about 27 to 30 mm and show brown-gray wings with curved crosslines, one of which often has a tiny tooth-like notch. Adults appear from May through September across eastern and north-western North America, while the larvae feed on balsam fir, red spruce, tamarack, white spruce and related trees.
Source: Wikipedia
How to recognize it
The forewings are brown-gray with several curved crosslines, and at least one line has a small tooth-like dentation. A black blotch occurs near the postmedian area and a discal spot is present where the antemedian line meets the costa. The hindwing usually has a central discal mark.
Source: Wikipedia
Size
Adults have a wingspan ranging from 27 to 30 mm.
Source: Wikipedia
Where it lives
They are found throughout North America, especially in the eastern and northwestern regions.
Source: Wikipedia
What it eats
Larvae are leaf-eaters that mainly feed on balsam fir, red spruce, tamarack and white spruce, but they will also use other hosts.
Source: Wikipedia
Life cycle
In the north there is one generation per year, while farther south two generations may occur. The larvae spend the winter in their second-last instar stage.
Source: Wikipedia
When you see it
Adult moths are on the wing from May through September.
Source: Wikipedia
Where it comes from
Their native range covers the same eastern and northwestern parts of North America.
Source: Wikipedia
Where it is found in the US
Recorded in 44 of 51 states and DC. Most records: Pennsylvania, Massachusetts, New York, Alabama, North Carolina, Michigan, Vermont, Connecticut.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in United States; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
Do Porcelain Gray larvae damage trees?
Yes, the caterpillars feed on the foliage of fir and spruce trees and can cause defoliation.
Source: Wikipedia
When can I see adult Porcelain Gray moths?
Adults are active from late spring into early fall, roughly May to September.
Source: Wikipedia
Same family (Geometridae)
Willow BeautyPeribatodes rhomboidaria
Pale BeautyCampaea perlataDamages trees, gardens or crops
Large Lace-border MothScopula limboundataDamages trees, gardens or crops
Riband WaveIdaea aversata
Yellow Shell MothCamptogramma bilineata
Large Maple Spanworm MothProchoerodes lineolaDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Protoboarmia_porcelaria
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.