Oak Spangle galls

Galls smother the undersides of oak leaves this September in and around Charlton Down and further afield. The oaks in the Nature Reserve and in the grounds on the south side of Greenwood House are affected. The galls are common and I have often seen them in other years too. The exact shape is dictated by the type of wasp that has laid its eggs in the leaf. The ones like small rough brown discs with a raised centre are Spangle Galls made by the Cynipid wasp Neuroterus quercusbaccarum. The small round golden galls with a depressed centre, a donut-shape of silk threads, are made by the wasp Neuroterus nimismalis. Some leaves have both species of gall.

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