Knopper Oak Gall Wasp - Andricus quercuscalicis

Alternative names
Knopper Oak Gall

A Cynipid  gall wasp that causes a gall to form on the acorns of various oaks. The gall is seen more often than the adult wasp.

Identification difficulty

Adult Gall


On Pendunculate Oak.

When to see it

May to July.

Life History

Knopper Galls develop as a chemically induced distortion of growing acorns on Pendunculate Oak trees, caused by cynipid gall wasp Andricus quercuscalicis which lays eggs within buds using the ovipositor.

UK Status

A recent introduction to the British Isles, first arriving in the 1960s and now found throughout England, Wales and as far north as Scotland.

VC55 Status

Common in Leicestershire and Rutland.

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Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map