George Jacob's picture


Observed: 28th August 2012 By: George Jacob

Several oaks in this vicinity have grossly abnormal acorns. The acorn has not formed and is replaced with a malformed, green fleshy growth. On one oak there are some normally formed acorns. The leaves from this tree show what I presume is a viral disease.

Species interactions

No interactions present.

Species with which Andricus quercuscalicis interacts


Anastasia1986's picture

Hi, I found trees, in and

Hi, I found trees, in and around the field we rent for our horses, with the same deformed acorns. I have never seen it before, and found this page via Google. The owner is a bit concerned about the health of the trees now!

Stacey Brassington

Jonathan's picture

The trees will be fine. This

The trees will be fine. This gall only affects the acorns and is caused by a tiny wasp (quite harmless to humans).

University of Edinburgh and Biodiversity Observatory (OU)