Acalitus brevitarsus

Alternative names
Eriophyes brevitarsus

Acalitus brevitarsus is a mite that causes blister like galls to form on the leaves of Alder. Like many mite galls, the leaf is made to grow clusters of hairs, called erineum, among which the mites live. On the underside of the leaf these galls have a shiny pale brown appearance. The galls are seen more often than the mite.

Identification difficulty

Adult Gall


Wherever Alder is found.

When to see it

The galls are to be found when Alder is in leaf. They usually appear in June and reach full size in September or October.

UK Status

Widespread, but under recorded in Britain.

VC55 Status

Status in Leicestershire and Rutland not known.

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Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map