A disease which blocks the water transport system in plants, ash dieback is devastating for ash species.
It is caused by a fungus called Hymenoscyphus fraxineus, and is spread by fungal spores in the wind.
It was first discovered in Europe in 1992, and in the UK in 2012.
- Blackening and wilting of leaves and shoots in infected trees between July and September.
- Dark lesions can show on the bark of the tree. They are often elongated-diamond shape and typically spread upwards and downwards from the joint.
- Dieback in the crown of the tree.