Rosebud Gall

Andricus gemmeus

Originally discovered in the UK in 2008 at Colchester, Essex, the galls (3-4mm in diameter) are produced by the asexual generation of the gall wasp Andricus gemmeus. They are commonly observed on oak bark during September, often appearing in clusters arising from dormant buds. The surface features cone-shaped protrusions, many of which are covered in short hairs. Initially yellowish-green, the galls transition to red and then brown as they mature. Also found on Sessile Oak.