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Sticker of Fall cankerworm
Bug card No. 0498 of 1,500

Fall cankerworm

Alsophila pometaria
Eats: PlantsMothsForests and woods6 legs

The fall cankerworm is a moth, but its mums cannot fly. Females are grey and have no wings at all, while the males have glossy brown wings with white bands. Its caterpillars are inchworms that loop along like a measuring tape.

Lives in
North America, from Nova Scotia to Alberta and south to Colorado and California
Wingspan
2.5 to 3.5 cm (0.98 to 1.4 in)
males only, females have no wings
Top speed
about 13 km/h (8.1 mph)
Flying, estimate
Can it hurt you?
Harmless
Harmless to people. Lots of caterpillars can strip the leaves off trees, though.
What does it eat?
The caterpillars munch the new spring leaves of many trees, like elm, ash, maple, oak and willow.
For real!Photo of Fall cankerworm
Picture by USDA Forest Service - Region 8 Archive, USDA Forest Service, Bugwood.org. Public domain, via Wikimedia Commons.

How big is it?

How wide are its wings?

Fall cankerworm wings about 3.5 cm tip to tip (1.4 in)A toy building brick about 3.2 cm (1.3 in)A crayon about 9 cm (3.5 in)A banana about 18 cm (7.1 in)
wings as wide as 6 grains of rice in a rowcould fly across a whole football pitch in 29 seconds

How big is Fall cankerworm compared to YOU?

Just maths in your browser. Nothing is saved or sent anywhere.

How fast is it?

cool stuff

Fun facts

1

It is called fall cankerworm because the females come out of the ground in November, in the fall.

2

The caterpillars grow to about 25 millimetres long and can be light green or dark brownish green.

3

Its eggs are smaller than 1 millimetre and laid in groups on trees.

4

Many birds eat the caterpillars, and so do some ground beetles.

5

The caterpillar turns into a moth inside a silk cocoon just under the ground.

you asked

Most asked questions about Fall cankerworm

?Why can't female fall cankerworms fly?

Female fall cankerworm moths have no wings at all. Only the males fly.

?What is an inchworm?

An inchworm is a caterpillar that moves by looping its body. Fall cankerworm caterpillars are inchworms.

?Are fall cankerworms harmful?

They are harmless to people, but many caterpillars can eat all the new leaves off a tree.

For bug experts

Scientific name
Alsophila pometaria
Named by
Harris, 1841
Group
Moths
Family
Geometridae
Classification
Insecta > Lepidoptera > Geometridae
Lives on
North America

Where the facts come from

  1. Alsophila pometaria (Wikipedia, CC BY-SA 4.0): what it looks like, where it lives, what it eats, sizes and fun facts, retold in simple words.
  2. Picture by USDA Forest Service - Region 8 Archive, USDA Forest Service, Bugwood.org. Public domain, Wikimedia Commons. The round sticker of this bug is cut from the same picture.

If we got something wrong, sorry, we are bug fans, not a science journal. Tell us at hello@bugwiki.app and we will fix it.

More from the same group: Moths

Also at home here: Forests and woods