Bug FAQSmall Grey
Eudonia mercurella · Order: Lepidoptera · Family: Crambidae
Also called: Garden Grey
The small grey moth has a wingspan of about 16 to 19 mm. Its forewings are dark with mixed brown, a darker band near the edge of a pale antemedian line, and a distinct pale post-median line.
Source: Wikipedia
Size
The wingspan ranges from 16 to 19 mm (about 0.63 to 0.75 in).
Source: Wikipedia
What it eats
The larvae feed on various mosses.
Source: Wikipedia
Life cycle
Adults fly from June to August, depending on location.
Source: Wikipedia
When you see it
The flight period is June through August, varying with locality.
Source: Wikipedia
Lookalikes
It can be confused with Eudonia lacustrata, which has a broken wavy line forming a broad white spot at the wing tip. It also resembles Eudonia speideli and pale specimens of Eudonia liebmani.
Source: Wikipedia
More photos
Questions people ask
When can I see the small grey moth?
Adults are on the wing from June to August, depending on where you are.
Source: Wikipedia
How do I tell it apart from similar species?
Look for the broken wavy line that makes a broad white spot at the wing tip; that character belongs to Eudonia lacustrata, not Eudonia mercurella. It also differs from Eudonia speideli and pale Eudonia liebmani in overall wing pattern.
Source: Wikipedia
Same family (Crambidae)
Box Tree MothCydalima perspectalisDamages trees, gardens or crops
Celery Leaftier MothUdea rubigalisDamages trees, gardens or crops
Elegant Grass-veneerMicrocrambus elegans
Hawaiian Beet Webworm MothSpoladea recurvalisDamages trees, gardens or crops
Garden Grass-veneerChrysoteuchia culmellaDamages trees, gardens or crops
Bluegrass Webworm MothParapediasia teterrellusDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Eudonia_mercurella
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.