Spangle gall

Description:

The spangle gall generation on the underside of the oak leaves are flat discs, with a distinct central elevation, slightly hairy, yellow-green at first and reddish later, attached by a short stalk. These galls are up to 6 mm in diameter, unilocular, unilarval with a whitish or yellow undersurface. They mature in September, detach and fall to the ground before the leaves themselves. The larva continue to develop in the fallen spangle and, protected by the leaf layer, they overwinter. Any spangle galls that remain attached to the leaves dry up and die.

Habitat:

Neuroterus quercusbaccarum is found throughout Europe, Asia Minor and North Africa, anywhere oak is present.

Notes:

Spangle galls caused by the cynipid wasp spotted on an oak leaf (Quercus robur) in Nieuwe Rande Forest in rural area of Deventer, Holland. (sources:see reference)