How to identify Chalara dieback of Ash (Chalara fraxinea)
- Leaves turn black and hang on twigs
- Dark, diamond-shaped lesions form where twigs meet the main stem
- It leads to death of twigs and branches.
- Ash trees
- Common Ash (Fraxinus excelsior) is very susceptible and young trees are particularly vulnerable.
UK status and other information:
- Currently it has a limited distribution in the UK
- Chalara fraxinea emerged as an entirely new disease in Europe in the 1990s. It has already infected a large number of Ash trees across continental Europe, with a
significant loss of trees anticipated in the next 20 years
- It was first found in Britain in 2012
- There is evidence that it has spread between countries via the plant trade and at present there is a ban on imports and movement of Ash in the UK.
Why will any findings be important?
- We need to know about the distribution and extent of Chalara dieback of Ash
- Knowing exactly where it is will help us to manage the spread of this disease.
Could be confused with:
- Other diseases that affect Ash trees, such as Ash decline. Check our information on Ash pests and diseases.
Spotted one of our Most Unwanted?
Images: leaves © Andrej Kunca, diamond shape © Forestry Commission, death of branches © Iben Thomas