Acalitus rudis
Acalitus rudis is a gall mite that causes galls to form on the leaves of Birch (Betula species). The gall is an erineum between the veins of the leaf. It is usually on the underside of the leaf, with or without a bulge on the other side. The hairs are quite long, white or yellowish when young, later a deep red brown.
Other mites can cause an erineum (hairy patch) to form on birch leaves
Gall 
Adult
Where the host Birch species are found.
Whenever Birch is in leaf.
This is the commonest erineum on Birch, but it remains difficult to determine the exact status in Britain due to lack of records.
Status in Leicestershire and Rutland not known.
Peter Smith
Cropston garden
22 August 2017
Erineum galls on Birch - between veins
Peter Smith
Cropston garden
30 June 2018
Galls on silver birch
Peter Smith
Cropston garden
30 June 2018
Galls on silver birch
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Species profile
- Species group:
- Mites, Ticks & Pseudoscorpions
- Kingdom:
- Animalia
- Order:
- Trombidiformes
- Family:
- Eriophyidae
- Records on NatureSpot:
- 13
- First record:
- 07/07/2016 (Grimes, Martin)
- Last record:
- 03/06/2022 (McLoughlin, Margaret)
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