Knopper gall wasp
Enw gwyddonol: Andricus quercuscalicis
The knopper gall wasp produces knobbly red, turning to brown, growths, or 'galls', on the acorns of Pedunculate Oak. Inside the gall, the larvae of the wasp feed on the host tissues, but cause little damage.
Species information
Ystadegau
Length of gall: up to 2.8cmStatws cadwraethol
Introduced species.