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Andricus quercuscalicis

Knopper gall

Description

The female of this small wasp lays eggs on the acorn cup in May, injecting a special liquid inside. As a result, oak forms a specific neoplasm - a very irregular, about 2 cm long, green lump - gall - in which is developed a larva. The gall as if were overgrown with the acorn cup and it sometimes word-for-word absorbs the entire acorn. The acorn stops developing normally and it loses its germinability. It can damage up to 70-80 % of harvest locally. Damaged acorns prematurely fall off. The species needs Quercus cerris (sexual generation) for its development.

Symptom

Oak forms a specific neoplasm - a very irregular, about 2 cm long, green lump - gall - in which is developed a larva.

Tree Species: Oak

Part of a plant- attacked: Fruit / Seed

Pest significance: Less harmful

Pest Category: Insects

Invasive Species: No

Present in EU: Yes

Last observations

There are a total of 24 observations of the species in the system

Andricus quercuscalicis Knopper gall
milan
Number of votes: 0
Published: 7.9.2025

Andricus quercuscalicis Knopper gall
milan
Number of votes: 0
Published: 21.8.2025

Andricus quercuscalicis Knopper gall
milan
Number of votes: 0
Published: 14.8.2025

Andricus quercuscalicis Knopper gall
milan
Number of votes: 0
Published: 14.8.2025

Andricus quercuscalicis Knopper gall
MARIE SOPHIE LAW
Number of votes: 0
Published: 19.8.2024