Pale rolled leaves turning purple or red on Ash (Fraxinus excelsior) indicate the presence of the very common psyllid Psyllopsis fraxini. Galls develop early in the summer when nymphs hatching from over-wintered eggs feed on the leaves. Adult insects leave the gall just before the autumn leaf-fall to lay their eggs on dormnat buds.
There are three very similar species of gall which are difficult to identify, thus this is only representitive of the species. Psyllopsis fraxini is the commonest of all the species.
Class Insecta (Insects)
Order Hemiptera (True Bugs)
Family Psyllidae (Jumping Plant Lice)
Species Psyllopsis fraxini (Linnaeus, 1758)
Photos: Local wood, South Staffordshire 29th June 2021. © Peter Hillman