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Sticker of Elm sack gall aphid
Bug card No. 1536 of 4,939

Elm sack gall aphid

Tetraneura ulmi
Eats: PlantsTrue bugs and cicadasGardens and meadows6 legs

The elm sack gall aphid is a tiny aphid that makes elm leaves grow little bags. Each bag, called a gall, looks like a smooth club or a tiny fig standing on the leaf. Inside, a baby aphid feeds and has babies of its own.

Lives in
Europe, Asia and North America, on elm trees and grass roots
Length
2 to 3 mm (0.08 to 0.12 in)
Top speed
about 0.01 km/h (0.01 mph)
On foot, estimate
Can it hurt you?
Harmless
Harmless. It cannot bite or sting people.
What does it eat?
It sucks sap from elm leaves in spring, and from the roots of grasses in summer.
For real!Photo of Elm sack gall aphid
Picture by Holger Krisp. CC BY 3.0, via Wikimedia Commons.

How big is it?

How long is it?

Elm sack gall aphid about 3 mm long (0.12 in)A grain of rice about 6 mm (0.24 in)
small enough to sit on your fingernailneeds 6 minutes to cross a dinner table

How big is Elm sack gall aphid compared to YOU?

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How fast is it?

cool stuff

Fun facts

1

Its gall is 7 to 15 millimetres tall, sitting on a little stalk on the leaf.

2

The aphids are pink, orange or purple and dusted with fine wax powder.

3

In summer they leave the galls and move to grass roots. In autumn winged ones fly back to the elms.

4

A gall starts as a tiny yellowish pimple on the top of the leaf.

you asked

Most asked questions about Elm sack gall aphid

?What are the little bags on elm leaves?

They are often galls made by the elm sack gall aphid. A tiny aphid lives inside.

?Are elm galls harmful?

They are harmless to people. They are just the aphid's little homes on the leaves.

For bug experts

Scientific name
Tetraneura ulmi
Named by
Linnaeus, 1758
Group
True bugs and cicadas
Family
Aphididae
Classification
Insecta > Hemiptera > Aphididae
Lives on
Europe, Asia, North America
Also known as
Fig gall

Where the facts come from

  1. Tetraneura ulmi (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 Holger Krisp. CC BY 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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