Aceria nervisequa is a mite that galls the leaves of Beech. The galls normally take the form of pink tufts of hairs (erineum) between the veins on the underside of the leaf, but sometimes they appear as white erineum which run along the veins on the upper surface of the leaf.

Other species of mites can cause an erineum (hairy patch) to form on beech leaves

Gall Adult

On Beech leaves.

Summer.

Widespread and fairly frequent in Britain, but under recorded.

Fairly frequent in Leicestershire and Rutland.