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Sticker of Beet armyworm
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Beet armyworm

Spodoptera exigua
Eats: PlantsMothsGardens and meadows6 legs

The beet armyworm is a small brown and grey moth. Its caterpillars are very hungry and eat lots of farm plants, so farmers know them well. They can munch a small plant until no leaves are left.

Lives in
First from Asia, now almost all over the world where crops grow
Wingspan
2.6 to 3.2 cm (1 to 1.3 in)
Top speed
about 13 km/h (8.1 mph)
Flying, estimate
Can it hurt you?
Harmless
Harmless to people. It is only a problem for farmers and gardeners.
What does it eat?
Its caterpillars eat leaves, buds and fruits of many plants, like beans, peas, beets, lettuce, potatoes, tomatoes and cotton.
For real!Photo of Beet armyworm
Picture by Dumi. CC BY-SA 3.0, via Wikimedia Commons.

How big is it?

How wide are its wings?

Beet armyworm wings about 3.2 cm tip to tip (1.3 in)A grain of rice about 6 mm (0.24 in)A toy building brick about 3.2 cm (1.3 in)A crayon about 9 cm (3.5 in)
wings as wide as 5 grains of rice in a rowcould fly across a whole football pitch in 29 seconds

How big is Beet armyworm compared to YOU?

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

How fast is it?

cool stuff

Fun facts

1

Small caterpillars eat the soft middle of a leaf and leave only a thin see-through skin and the veins.

2

Bigger caterpillars bore holes straight into a head of lettuce.

3

As the young caterpillars crawl, they leave silk threads that cover leaves with a silvery film.

4

It cannot stand the cold, so in cold places it dies in winter and new moths fly back in spring.

5

It reached North America around 1876, when it was found in Oregon.

you asked

Most asked questions about Beet armyworm

?What does a beet armyworm eat?

Its caterpillars eat many crops, like beets, beans, lettuce, tomatoes and cotton.

?Is the beet armyworm dangerous?

Not to people. It only harms plants and crops.

?Why is it called armyworm?

Its caterpillars come in big numbers and eat their way through crops, like a marching army.

For bug experts

Scientific name
Spodoptera exigua
Named by
Hübner, 1808
Group
Moths
Family
Noctuidae
Classification
Insecta > Lepidoptera > Noctuidae
Lives on
Asia, Europe, North America, South America, Africa, Australia and Oceania
Also known as
Small mottled willow moth, Asparagus fern caterpillar

Where the facts come from

  1. Beet armyworm (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 Dumi. CC BY-SA 3.0, 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.

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