Ash Dieback disease

Ash dieback is a serious disease of ash trees caused by the fungus Hymenoscyphus fraxineus (It used to be called Chalara fraxinea). The disease causes leaf loss and crown dieback in affected trees and can lead to the death of the tree.

Recently detected in the UK and Ireland

The disease is increasingly being found in countries across continental Europe, but until recently had not been detected in the UK or Ireland.

Further information on the disease and symptoms can be found on
Information on Ash Dieback (Forestry Commission website)
A copy of the Forest Research Rapid Assessment on the disease is available at Forest Research Rapid Assessment

Current Situation in Northern Ireland

Ninety three premises have been confirmed positive for the fungus Hymenoscyphus fraxineus. Ninety of these are recently planted sites in all six counties, with an additional three findings in nursery/retail/trade situations.

Current outbreak map
Current outbreak map

The plants are all linked to imports. Ongoing action is being taken to destroy the saplings and debris. Survey work is continuing.


Legislation is now in force to prevent the introduction and spread of Ash Dieback here through plants, seeds and wood.

Ash Plants and Seeds for Planting

Ash Wood and Bark


There are things you can do to prevent pests and diseases spreading from site to site.

For advice on working in forests/woods, see attached Biosecurity Guidance

For visitors to the countryside, see link below on tree health and biosecurity
Tree Health Biosecurity Poster
For review on biocide and disinfectant treatment on Ash dieback, see
Efficacy of biocides and disinfectants on chalara fraxinea (AFBI website)

Questions and Answers

Answers to some frequently asked questions on the disease and the current legislation are available at

Stakeholder Meetings

DARD Minister Michelle O’Neill met with industry stakeholders on 31 October 2012 to update them on the disease and seek their views on possible further measures required to help prevent the introduction of Ash Dieback.

The Minister also held a further meeting with a range of stakeholders on 11 December 2012 to update them on the handling of Ash Dieback disease.

On January 24 2013, a stakeholder event aimed specifically at Councils, Arborists and Woodland Agents took place at Greenmount College. Presentations for the event are available at

A further stakeholder event was held on the 25th April 2013, presentations for this event are available below


Reporting Suspect Symptoms

We would also urge professionals engaged in the plant trade, and those involved in tree planting and management to be vigilant for any signs of the disease, particularly in young trees.
For more information and photos on what to look out for, click on the link below

If you are concerned about symptoms in ash you manage please contact DARD on 0300 200 7847 or email You can also report suspect symptoms using a smartphone. Go to and complete the form.

and a video showing symptoms is available below

Signs of the disease include:

  • diseased saplings typically display dead tops and/ or side shoots at the base of dead side shoots, lesions can often be found on the subtending branch or stem
  • lesions which girdle the branch or stem can cause wilting of the foliage above
  • mature trees affected by the disease initially display dieback of the shoots and twigs at the periphery of their crowns. Dense clumps of foliage may be seen further back on branches where recovery shoots are produced

More useful links