Bug FAQMarsh and Reed Daggers
Acronicta insularis · Order: Lepidoptera · Family: Noctuidae
The marsh and reed dagger moth, also called Henry's marsh moth, belongs to the Noctuidae family. Its wingspan measures about 35 to 40 mm and adults fly from April through September. The larvae feed on cattail, knotweed, grasses, sedges, poplar and willow, and the species is found coast-to-coast across the United States and southern Canada.
Source: Wikipedia
How to recognize it
Acronicta insularis is known as the cattail caterpillar in its larval stage and Henry's marsh moth as an adult.
Source: Wikipedia
Size
The adult moth has a wingspan of roughly 35 to 40 mm.
Source: Wikipedia
Where it lives
It lives throughout the United States and the southern parts of Canada.
Source: Wikipedia
What it eats
Caterpillars eat Typha (cattail), Polygonum species, various grasses, sedges, poplar and willow.
Source: Wikipedia
Life cycle
Adults are on the wing from April to September.
Source: Wikipedia
When you see it
The flight period for adults spans the spring, summer and early fall months.
Source: Wikipedia
Where it comes from
Its native range covers the United States from coast to coast and southern Canada.
Source: Wikipedia
Lookalikes
It was formerly placed in the genus Simyra before being moved to Acronicta in 2015.
Source: Wikipedia
Where it is found in the US
Recorded in 49 of 51 states and DC. Most records: Texas, Ohio, Illinois, Massachusetts, Michigan, Wisconsin, Minnesota, New York.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What do the larvae of Marsh and Reed Daggers eat?
They feed on cattail, knotweed, grasses, sedges, poplar and willow.
Source: Wikipedia
When can I see adult Marsh and Reed Daggers?
Adults are active from April through September.
Source: Wikipedia
Where is this moth found?
It occurs coast-to-coast across the United States and in 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 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.