Walnut Blisters

Gardening types with an eye for trees, or more accurately those who know when they see something that isn’t right, might spot something a little peculiar on route from our car park to the mansion/gallery of Compton Verney. For, situated near the beautiful ornamental sphinx/Adam bridge is a mature Walnut tree with a difference.

Many of the leaves this year are deformed with a condition commonly known as Walnut Blister Mite. As the image shows, the blisters form randomly across the foliage, the underside of which feature fine white or lightly coloured hairs. Not too problematic on further investigation it seems, for the fruiting quality/quantity is said to be unaffected, but the blisters will change colour later to be more noticeable.

Tiny mites called Eriophyes erineus, or Phytotus tristriatus is the cause of the blister, which sucks sap from the underside of the leaf causing the reaction we can all see. Control or intervention isn’t necessary. If you want to take a closer look, the foliage overhangs the footpath on approach to the bridge.