Cottonwool Gall Wasp - Andricus quercusramuli


Andricus quercusramuli is a cynipid wasp that causes galls to form on the catkins of English Oak and Sessile Oak. Cottonwool galls are the sexual generation of Andricus quercusramuli (the asexual generation is a bud gall on oak).

Identification difficulty

Adult Gall


On English Oak and Sessile Oak.

When to see it

Galls from spring (cottonwool galls) to late summer (bud galls).

Life History

The spherical mass of white hairs hides up to 20 gall chambers, each about 2mm dia. and occupied by one larva. These mature and emerge in late June and following mating, the females then cause the alternate asexual generation galls in oak buds.

UK Status

Occasional in England, though probably under recorded.

VC55 Status

Scarce in Leicestershire and Rutland where there are only a handful of records.

be our species champion

Leicestershire & Rutland Map


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

UK Map