Artichoke Gall Wasp - Andricus foecundatrix

Andricus foecundatrix causes  galls in English Oak and Sessile Oak.

The agamic (asexual) galls are most often recorded.  They are large artichoke galls formed in oak buds -  much enlarged (up to 30mm long) and covered with overlapping bud scales.  There is a cavity inside containing the the inner gall which is ejected in late summer, leaving the old galls to persist with the bud scales opened out and brown. 

The sexual generation of galls are in the catkins and are small and covered in long white hairs.

Agamic gall Sexual gall Adult

If recording sexual gall, provide photo

Anywhere that the host trees grow.

Common and widespread in much of Britain where the host trees are present.

Common in Leicestershire and Rutland.

http://hedgerowmobile.com/Andricusfecundator.html