Artichoke gall on Oak

The gall wasp Andricus foecundatrix is responsible for this artichoke or hop gall, an enlarged bud on oak. Inside this there is an inner hard gall that drops out in late summer. The single larva overwinters inside this, whilst the scaly outer gall persists on the tree.

Artichoke Gall, Andricus foecundatrix, Button Oak, 17th September 2014

 

Aceria longisetosus mite gall on birch

These felt-like erinea containing mites were found on the upperside of birch leaves in Shelfheld Coppice. The gall mite Aceria longisetosus is responsible. When young they are bright red and conspicuous. Similar erinea, but formed by a different species of gall mite, can be found on beech leaves. The mites spend the winter in crevices in the tree bark or in the buds.

Aceria longisetosus mite galls on birch, Shelfheld Coppice, 15th June 2013

Aceria longisetosus erinea on birch, Sheldheld Coppice, 15th June 2013

 

Neuroterus quercusbaccarum Currant Galls on oak catkins

These berry-like galls are commonly seen on oak male catkins. A tiny chalcid gall wasp, Neuroterus quercusbaccarum, lays her eggs on the developing oak buds in early spring. From these galls males and females hatch out and these females lay their eggs on oak leaves in the summer giving rise to Common Spangle Galls later in the year which produce the asexual generation. Two generations in one year!

Currant Galls on male oak catkins housing developing Neuroterus quercusbaccarum gall wasps, 7th June 2013

Midge Gall Macrodiplosis pustularis

Whilst in Cleobury Coppice on 5th September 2012, we found a number of galls on the oak trees, including this one. The tip of the leaf gall was turned down and had browned even though the leaf was still green. It was empty and the single larva which had spent the summer inside the gall, had presumably dropped out to pupate on the ground.