The gall midge Iteomyia major causes galls to form on the leaves of some willows such as Grey Willow and Goat Willow. These take the form of a coalesced group of 2 to 10 hard, round pustules incorporating the midrib and side veins, containing larvae which are white when young but later orange or red.

The sawfly Euura bridgmanii causes similar galls on sallows, but not associated with the midrib

Smaller galls are caused by Iteomyia capreae,  Several mites also cause galls on sallows.

Gall Adult

Where the host plants (sallows) are found.

Whenever the host willows are in leaf.

Widespread and fairly frequent in Britain.

Frequent in Leicestershire and Rutland