Ash dieback is a disease of ash trees caused by a fungus called Chalara fraxinea and can affect trees of any age and the symptoms are:
- Black blotches at the base of leaves before they begin to wilt
- Legions or spots on the bark of stems and branches
- The whole tree with show signs of shoots and branches dying back
If you recognise any of these symptoms do not attempt to treat the tree yourself, report it immediately to either Fera Plant Health and Seeds Inspectorate (PHSI) or the Forestry Commission.
It is important to note that Chalara fraxinea does not affect mountain ash (Sorbus aucuparia)
Take a look at this video from The Food and Environment Research Agency about the Life Cycle of Chalara fraxinea and Symptoms to look out for.