Bug FAQMarsh Dagger
Simyra insularis · Order: Lepidoptera · Family: Noctuidae
Also called: Cattail Caterpillar Moth
The marsh dagger moth has a wingspan of about 35 to 40 mm. Adults are on the wing from April through September. It occurs coast-to-coast across the United States and southern Canada.
Source: Wikipedia
How to recognize it
The adult is called Henry's marsh moth and the larva is known as the cattail caterpillar.
Source: Wikipedia
Size
Wingspan ranges from 35 to 40 mm.
Source: Wikipedia
Where it lives
Found throughout the United States and southern Canada.
Source: Wikipedia
What it eats
Larvae feed on cattail, knotweed, various grasses, sedges, poplar and willow.
Source: Wikipedia
Life cycle
Adults are active from April to September.
Source: Wikipedia
When you see it
The flight period spans spring through early fall.
Source: Wikipedia
Where it comes from
Native to North America, from coast to coast in the US and southern Canada.
Source: Wikipedia
Where it is found in the US
Recorded in 37 of 51 states and DC. Most records: Minnesota, Ohio, Kansas, Pennsylvania, Massachusetts, California, Connecticut, New Hampshire.
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 marsh dagger moths?
Adults are on the wing from April through September.
Source: Wikipedia
What do the caterpillars eat?
The larvae feed on cattail, knotweed, grasses, sedges, poplar and willow.
Source: Wikipedia
Where is this moth found?
It occurs coast-to-coast across the United States and southern Canada.
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_insularis
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-26 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-26.