Tuesday 6 August 2019

Knopper galls

Volunteer Andy Farquar copped this Knopper Gall on an oak near post 3.  These galls overwhelm the acorns, as the photo plainly shows, with a growth  that looks a bit like a pine cone when it changes from its green beginnings to a brown maturity. 


I went up a couple of days later to find that it is a bumper year for these galls.  They are on lots of our oak trees.


They are produced by the tree in response to a female gall wasp laying her egg where the acorn is set to develop.  Hard luck, little acorn.  

Knopper galls arrived in the UK in the 1960s and the media tried a panic story that all the acorns would be neutralised and we would have no new oak trees.  This proved to be a ridiculous over-reaction and the knopper gall has taken its place in our wild world without causing a crisis in oak fertility.

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