Knopper Oak Gall Wasp - Andricus quercuscalicis

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.

Adult Gall

On Pendunculate Oak.

May to July.

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.

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

Common in Leicestershire and Rutland.