Cherry Gall Wasp - Cynips quercusfolii

Cynips quercusfolii is a small black gall wasp.  Agamic galls are cherry galls on the leaves of some species of oak. The galls are large and succulent, 15 to 25 mm in diameter, smoother on Quercus robur or more warty on Quercus petraea; yellow-green suffused with pink or red, and later dark red then brown with a thick walled chamber. They persist on fallen leaves over winter.

The sexual gall is on buds, and is ovoid and with a velvety surface.

The agamic cherry galls are a similar size to the common marble gall (Andricus kollari) but these form from buds, not on a leaf. 

There are several similar bud galls on oak

Agamic (cherry) gall sexual gall  Adult

Around oaks.

Galls appear towards autumn.

Its larvae cause cherry galls to form on the leaves of some species of oak (see above).

Widespread in Britain.

Status in Leicestershire and Rutland not known.