Eriophyes pyri

Eriophyes pyri is a tiny mite that causes galls to form on the leaves of Rowan and Pear, and some other members of the rose family. The mite causes domed pustules with openings, on both leaf surfaces - green/yellow at first but turning brown.

Phyllocoptes sorbeus is also found on Rowan, and is similar, but has a dense whitish, pinkish or yellowish felt-like erineum on the under- or upper-side of the leaf.

Gall Adult

Good photos of both under- and upper-side of leaf are needed, showing presence of pustules with openings.  The host plant should be noted in the Comments box.

On the leaves of Rowan and Pear trees.

Galls are visible from late spring or summer until autumn.

The mites escape from the gall through pores on either side of the leaf to pass the winter in bark crevices.

Widespread and common in Britain.

Common in Leicestershire and Rutland.

Note that some authors split this species into 2 separate species, depending on host: Eriophyes pyri on Pear, and Eriophyes sorbi on Rowan.  The latest checklist from the British Plant Gall Society (2025), available on their website, lists Eriophyes pyri as a gall-causer on Pear, Rowan, Apple, and gives E sorbi as a synonym of E pyri. 

See Roskam, J.C. & Carbonnelle, S. (2023) Plant Galls of the Netherlands, Belgium and Luxembourg.  KNNV Publishing