jscarb's picture

Growth on Oak leaf

Observed: 27th August 2013 By: jscarbjscarb’s reputation in Invertebratesjscarb’s reputation in Invertebrates

What's causing the growths on the underside of these oak leaves?

Species interactions

No interactions present.

Species with which Cherry Gall (Cynips quercusfolii) interacts


Amadan's picture

Two types of galls

For the price of one!
The smaller spangle galls are caused by Neuroterus quercusbaccarum, which is a cynipid wasp, the same family as the Apple Gall one.
It's quite pissoble you'd have found Knopper Galls on the acorns as well - they seem quite prevelent on the good acorn crop this year.

darob57's picture

Common spangle galls yes, but...

...the large rounded gall looks more like a cherry gall, caused by Cynips quercusfolii.
Oak apples have long since disappeared by August.
Cherry galls usually form on the underside of the leaves and can be coloured green and/or red, later turning brown.