Tag: oak apple

August 10th – Oak galls continue to fascinate, and on this tree in Victoria Park, Darlaston, there’s quite a display of knopper galls, the first I’ve seen this year.

Like other oak parasites, the knopper wasp lays eggs in it’s host, secreted in a chemical that corrupts the cellular DNA of the host plant matter causing the gall too grow. In this case, the target is the acorn itself, and on this tree, one can see some acorns blighted by two such galls.

As with others, the egg hatches and ithe wasp larva eats the gall and grows safe in it’s corrupted acorn, before boring it’s way out when mature.

Also on this tree, the more conventional wasp gall – the common ‘oak apple’ of folklore, a spherical gall grown the same way.

These galls don’t harm the host, but do reduce the functional acorn crop. I’d love to know just why the oak is targeted so particularly with the and not so much other trees…

August 18th – The poor acorns are really hampered this year – the gall wasps really seem to have affected them. These seem very like knopper galls, which are caused by the wasp injecting a chemical encased egg into the acorn bud when it’s forming. The chemical causes the acorn to mutate, and inside, the wasp larvae hates and feeds.

There are now a good few healthy acorns, though, so perhaps it’s not as bad as I feared, but I do wonder why it just seems to be oaks that are tortured so.