American dagger moth

(Acronicta americana)

American dagger moth
Photo by Alfredo Colon
  Hodges #


Conservation Status
  IUCN Red List

not listed


NNR - Unranked


not listed


Dagger Moths (genus Acronicta) is a large genus with about 150 species worldwide, more than 73 species in North America north of Mexico. At least 28 species have been reported in Minnesota. The common name refers to a black, dagger-like dash on the forewings of many of the species. Most are gray with darker gray markings, and are difficult to identify.

American dagger moth is the largest dagger moth in eastern United States. The adult is 11 16 to 1½ (27 to 38 mm) long and has a wingspan of 2 to 2 9 16 (50 to 65 mm). It is found in deciduous woodlands and forests across the United States and southern Canada. It is common and sometimes abundant east of the Great Plains, common in Minnesota.

The forewings are pale gray or brownish-gray. There is a circular spot in the median area (orbicular spot) and a kidney-shaped spot at the end of the discal cell (reniform spot). The orbicular spot is a thin dark circle. The reniform spot has a thin dark outline. It is dark in the center, pale toward the edges. There is no claviform spot. There are faint gray, basal, antemedial (AM), median, and postmedial (PM) lines. The basal, AM, and PM lines are doubled, two thin dark lines with a wider pale area between. The median line is usually complete between the reniform spot and the leading edge of the wing (costal margin). The PM line is strongly jagged and the pale middle is lighter than the background color of the wing. There is only a single thin, black, dagger-like dash. It passes through the PM line in the anal area. There is no subterminal line. The terminal line consists of a series of conspicuous black spots between the veins.

The hindwing on the male is light tannish-gray. There is an indistinct gray discal spot, a gray PM line, gray shading in the submarginal area, and dark gray spots representing a terminal line. The fringe is white. On the female the hindwing is dark grayish-brown, the PM line is less distinct, and the fringe is tannish-white.

The late stage (instar) caterpillar is pale green and large, up to 23 16 (55 mm) long. It is densely covered with long, white or pale yellow, hair-like outgrowths (setae). The earlier instar caterpillar is darker yellow. There is a pair of long, erect, black lashes in the subdorsal area of the first and third abdominal segment, and a single, thicker lash in the middle of the eighth segment. The lashes are tight groups of bristle-like setae. They will break off and embed in the skin of predators or of human handlers. They contain a toxin which causes stinging and burning and can develop into a rash. Mature caterpillars are found from July to October.




Total Length: 11 16 to 1½ (27 to 38 mm)

Wingspan: 2 to 29 16 (50 to 65 mm)


Similar Species


Deciduous woodlands and forests




One generation per year in Minnesota: April to September




Adults are active at night and will come to lights.

To avoid detection by predators, the larva will sometimes clip off a partially eaten leaf, letting it fall to the ground.


Life Cycle


Pupa overwinter.


Larva Hosts


Many woody plants, including alder, ash, basswood, birch, blue beech, boxelder, elm, hazel, hickory, horse chestnut, maple, oak, poplar, walnut, and willow.


Adult Food




Distribution Map



21, 24, 27, 29, 30, 71, 75.







Lepidoptera (butterflies and moths)  




  Parvorder Heteroneura  
  No Rank Ditrysia  
  No Rank Obtectomera  


Noctuoidea (noctuid moths)  


Noctuidae (owlet moths)  









Common Names


American dagger

American dagger moth









Costal margin

The leading edge of the forewing of insects.



The developmental stage of arthropods between each molt; in insects, the developmental stage of the larvae or nymph


Orbicular spot

A circular spot or outline in the outer median area near the antemedial line on the forewing of many moths.


Reniform spot

A kidney-shaped spot or outline in the outer median area near the postmedial line on the forewing of many moths.



A stiff, hair-like process on the outer surface of an organism. In Lepidoptera: A usually rigid bristle- or hair-like outgrowth used to sense touch. In mosses: The stalk supporting a spore-bearing capsule and supplying it with nutrients. Plural: setae.






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Alfredo Colon

    American dagger moth   American dagger moth  





American Dagger Moth Caterpillar
Andree Reno Sanborn
  American Dagger Moth Caterpillar  

Acronicta americana

The moth can be seen at




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Other Videos
  American Dagger Moth Caterpillar - Acronicta americana
Walt Reven Jr

Jul 4, 2018

Walt Reven
P.O. Box 8481
Fayetteville, AR 72703

Also please click the like button, it helps my channel and dont forget to subscribe.

Showed a pic of this caterpillar on instagram(link in my bio area) but thought I would do a video as I have now found one again this year. I present to you the American Dagger Moth Caterpillar - Acronicta americana. Very awesome and unique thing!

WARNING though DO NOT attempt to do what I did here unless you understand that the hairs on these guys can really irritate your skin if you poke or rub them and cause an allergic reaction in some people, they are brightly colored for a reason!

My Amazon Wishlist:

  Stung By The Dagger Moth Catterpilar, ouch Full Video
Great Outdoors

Apr 11, 2019

The Dagger Moth Caterpillar is a species of caterpillar that is commonly confused with the puss caterpillar. There certainly are many similarities and they are both venomous. The dagger moth caterpillar is not a threat to your life however it can cause skin irritation. Especially if you have sensitive skin. We will experience this first hand as we discover more about this amazing species. this is the full video with the release and the effects one day after the sting.

You could be in my next video

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  The American Dagger Moth Caterpillar - Acronicta americana
The Dro

Sep 12, 2015

This dagger moth caterpillar turns into a medium sized moth with a wingspan of 2.0 to 2.6 inches. The American dagger moth can be spotted around April to September and the Caterpillars can be seen from months July to October. If you see one of these guys be sure not to pick it up with your bare hands because as the hairs move around on your skin they will break and release toxins into your pores thus leaving behind a large red welt that may possibly ruin your next couple days!

I was working on my resin necklaces that I custom make for people and we found this little guy crawling around our house. I already had gloves on that I wear while working with the resin so I was able to pick him up and take some video of him before releasing him outside in our back yard.

  poisonous american dagger moth caterpillar yellow and black fuzzy acronicta americana
! Funny Cute Animal Videos

Oct 12, 2013

Poisonous caterpillar video | The American dagger moth caterpillar




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  Alfredo Colon
Summer 2018

Location: Woodbury, Minnesota

American dagger moth  






Created: 10/9/2019

Last Updated:

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