Acalitus 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.
Other mites may cause an erineum (hairy patch) to form on Alder leaves
Gall 
Adult
Wherever Alder is found.
The galls are to be found when Alder is in leaf. They usually appear in June and reach full size in September or October.
Widespread, but under recorded in Britain.
Status in Leicestershire and Rutland not known.
David Nicholls
Sarahs Wood
04 June 2016
galls on alder - upperside
Annie Smith
Black Brook, Hathern
08 October 2017
galls on alder - erineum underside
David Nicholls
Sarahs Wood
04 June 2016
Graham Calow
Ullesthorpe Stewardship Farm
31 August 2012
on Alder - upper leaf surface
Graham Calow
Ullesthorpe Stewardship Farm
05 September 2012
Underside of Alder leaf
David Gould
Narborough Bog
11 August 2017
on Alder
Leicestershire & Rutland Map
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Yellow squares = NBN records (all known data)
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UK Map
Species profile
- Species group:
- Mites, Ticks & Pseudoscorpions
- Kingdom:
- Animalia
- Order:
- Trombidiformes
- Family:
- Eriophyidae
- Records on NatureSpot:
- 94
- First record:
- 31/08/2012 (Calow, Graham)
- Last record:
- 21/10/2024 (Timms, Sue)
Total records by month
% of records within its species group
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Latest images
Latest records
Graham Calow
Ullesthorpe Stewardship Farm
05 September 2012
Upper surface of Alder leaf
Annie Smith
Black Brook, Hathern
08 October 2017
Alan Semper
Rutland Water path between Redshank & Grebe hides
26 September 2015
Alan Semper
Rutland Water path between Redshank & Grebe hides
26 September 2015
Peter Smith
Cropston
02 August 2015
Galls on upper side of alder leaf
Graham Calow
Huncote, Field off Thurlaston Lane
10 September 2019
gall on Alder
Peter Smith
Cropston
02 August 2015
Underside of the same leaf
Graham Calow
Ullesthorpe Stewardship Farm
31 August 2012
on Alder - underside of leaf
Graham Calow
Ullesthorpe Stewardship Farm
31 August 2012
on Alder - upper leaf surface
Graham Calow
Ullesthorpe Stewardship Farm
05 September 2012
Underside of Alder leaf
