It causes wilting, black-brown discolouration and loss of the leaves. Lesions or necrotic spots appear on the bark and enlarge to form perennial cankers. There is wilting of shoots and branches, causing crown dieback. Ultimately it can lead to tree death, with mortality more common in saplings.
This disease is currently spreading across Europe. In the UK it was identified in a shipment of ash trees from the Netherlands to a nursery in Buckinghamshire in February 2012, the trees were destroyed. Then in June it was found in young ash trees planted in a car park in Leicestershire, the origins of this are still under investigation.
So far the disease has not been located in the UK in the wild, but plant nursery and tree-care sectors are being urged to check the health of any recently obtained/planted ash trees.
Suspected cases can be reported to the Forestry Commission or the Food & Environment Research Agency at the following addresses:
- Forest Research Tree Health Diagnostic and Advisory Service;
tel: 01420 23000; e-mail: firstname.lastname@example.org;
- Forestry Commission Plant Health Service;
tel: 0131 314 6414; e-mail: email@example.com;
- Fera Plant Health and Seeds Inspectorate;
tel: 01904 465625; e-mail: firstname.lastname@example.org.
The Forestry Commission’s Forest Research agency is preparing a risk assessment which will provide the necessary evidence to inform future action against this disease. There is also a ‘pest alert’ factsheet on the disease available from the Forestry Commission website.
Kay Haw, Assistant Conservation Adviser