Bug FAQManchester Treble-bar Moth
Carsia sororiata · Order: Lepidoptera · Family: Geometridae
Also called: Manchester Treble-Bar
The Manchester Treble-bar Moth has a wingspan of about 20 to 30 mm and its forewings are slate-grey to white-grey with two wide, light-brown to black-brown crosslines. The caterpillars feed on several Vaccinium species and on Rubus arcticus, and their eggs start whitish-yellow before turning deeper yellow.
Source: Wikipedia
How to recognize it
Forewings are slate-grey to white-grey with two wide, light-brown to black-brown crosslines.
Source: Wikipedia
Size
Wingspan ranges from 20 to 30 mm.
Source: Wikipedia
Life cycle
Eggs are initially whitish-yellow and later become deeper yellow. Caterpillars are stout, deep brown-red on the back with fine black-red lines and a bright yellow side stripe that bears red spots; the underside is pale green-yellow with a darker central line.
Source: Wikipedia
When you see it
Adults are on the wing from July through August.
Source: Wikipedia
Where it is found in the US
Recorded in 4 of 51 states and DC. Most records: Alaska, New Hampshire, Minnesota, Michigan.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
When are adult Manchester Treble-bar Moths active?
Adults fly during July and August.
Source: Wikipedia
What do the larvae eat?
The caterpillars feed on various Vaccinium species and on Rubus arcticus.
Source: Wikipedia
What do the moth’s forewings look like?
The forewings are slate-grey to white-grey with two wide, light-brown to black-brown crosslines.
Source: Wikipedia
Same family (Geometridae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Carsia_sororiata
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-29 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-29.