George Jacob's picture

IMG_1083

Observed: 28th August 2012 By: George Jacob
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Description:

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.

Identifications
Species interactions

No interactions present.

Species with which Andricus quercuscalicis interacts

Comments

petershirley's picture

Oak galls

These are galls caused by cynipid wasps. Those on the leaves are caused by Neuroterus quercusbaccarum (agamic generation) and are known as spangle galls. Those on the acorns are caused by Andricus quercuscalicis (agamic generation), the knopper gall.

Peter Shirley