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Sticker of Knapweed root moth
Bug card No. 2457 of 4,939

Knapweed root moth

Agapeta zoegana
Eats: PlantsMothsGardens and meadows6 legs

The knapweed root moth is a small, bright yellow moth with brown patches on its wings. Its caterpillar lives inside the roots of knapweed plants. People in America use it as a helper to stop knapweed weeds from spreading.

Lives in
Europe and Asia, and brought to the western United States
Length
1.1 cm (0.43 in)
Top speed
about 7.3 km/h (4.5 mph)
Flying, estimate
Can it hurt you?
Harmless
Harmless. It does not bite or sting.
What does it eat?
Its caterpillars tunnel through the roots of knapweed plants and eat them.
For real!Photo of Knapweed root moth
Picture by Kulac. CC BY-SA 3.0, via Wikimedia Commons.

How big is it?

How long is it?

Knapweed root moth about 1.1 cm long (0.43 in)A grain of rice about 6 mm (0.24 in)A toy building brick about 3.2 cm (1.3 in)
as long as 2 grains of rice in a rowcould fly across a whole football pitch in 52 secondsmoves 180 times its own body length every second

How big is Knapweed root moth compared to YOU?

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How fast is it?

cool stuff

Fun facts

1

A grown-up moth lives for only a few days.

2

Since the 1980s people have released it in the United States to fight knapweed weeds.

3

It only eats knapweed and has not been found to harm other plants.

4

It flies from May to August, starting at dusk, and comes to lights.

you asked

Most asked questions about Knapweed root moth

?Why was the knapweed root moth brought to America?

To help control knapweed, a weed that spreads fast. Its caterpillars eat the knapweed roots.

?How big is the knapweed root moth?

It is about 11 millimetres long.

For bug experts

Scientific name
Agapeta zoegana
Group
Moths
Family
Tortricidae
Classification
Insecta > Lepidoptera > Tortricidae
Lives on
Europe, Asia, North America
Also known as
Sulphur knapweed moth, Yellow-winged knapweed root moth

Where the facts come from

  1. Agapeta zoegana (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 Kulac. CC BY-SA 3.0, Wikimedia Commons. The sticker of this bug is drawn from this picture.

If we got something wrong, sorry, we are bug fans, not a science journal. Tell us at [email protected] and we will fix it.

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