Aceria tenuis


Aceria tenuis is a gall mite that causes phyllanthy on Cock’s-foot (Dactylis glomerata) and various other grasses. The mites live in the length grooves of the grass leaves; on grasses with smooth leaves they are much less numerous. At high densities rolling and withering of the leaves does occur, also growth disturbance, malformations and discolouration of the inflorescence.

Identification difficulty


Recording advice

When recording the gall caused by Aceria tenuis please provide a photograph in support of your record and in the comments name the host species.


The galls may occur wherever the host grass species are found.

When to see it

Summer and autumn.

UK Status

True status in Britain is difficult to determine due to lack of records.

VC55 Status

Rarely recorded in Leicestershire and Rutland.

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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