Bug FAQMarbled Oak Dagger
Acronicta marmorata · Order: Lepidoptera · Family: Noctuidae
Also called: Marble Dagger, Marble Dagger Moth
The marble dagger moth belongs to the Noctuidae family and is known as Acronicta marmorata. It lives across the Pacific Northwest of North America, including places like British Columbia, Oregon and Washington. Adults appear in midsummer, typically flying from July through August depending on where they are found.
Source: Wikipedia
How to recognize it
Acronicta marmorata is the scientific name for the marble dagger moth, a member of the Noctuidae family.
Source: Wikipedia
Size
Its wingspan measures roughly 43 millimeters.
Source: Wikipedia
Where it lives
The species is common in the Pacific West of North America.
Source: Wikipedia
What it eats
Caterpillars feed on oak trees, such as white oak.
Source: Wikipedia
Life cycle
Moths are active as adults during July and August, varying with location.
Source: Wikipedia
When you see it
The flight period for adults spans midsummer months, typically July to August.
Source: Wikipedia
Where it comes from
It is native to the Pacific Northwest region, including British Columbia, Oregon and Washington.
Source: Wikipedia
Where it is found in the US
Recorded in 5 of 51 states and DC. Most records: California, Oregon, Washington, Nevada, Colorado.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada; native in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
When can I see adult marble dagger moths?
Adults are on the wing in midsummer, usually from July through August, depending on the area.
Source: Wikipedia
Same family (Noctuidae)
Ipsilon Dart MothAgrotis ipsilonDamages trees, gardens or crops
Fall Armyworm MothSpodoptera frugiperdaDamages trees, gardens or crops
Army Cutworm MothEuxoa auxiliarisDamages trees, gardens or crops
Large Yellow UnderwingNoctua pronubaDamages trees, gardens or crops
Silver ΥAutographa gamma
American DaggerAcronicta americanaCan irritate skinSources
- Wikipedia: https://en.wikipedia.org/wiki/Acronicta_marmorata
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-24.