Beech Leaf Gall

Hartigiola annulipes

These galls are cylindrical formations that develop on Beech leaves as a result of the midge Hartigiola annulipes. They initially appear as flattened hemispheres on both surfaces of the leaf. Over time, they can grow to about 5mm in length, protruding like hairy columns and turning reddish-brown. Each gall contains a single white larva. Once the larva matures, the gall detaches from the leaf, leaving behind a circular hole. The larva then pupates, and adults emerge in the following spring. These adults will lay eggs on new leaves, continuing the cycle.