CHALARA FRAXINEA, a fungus that attacks ash trees causing Ash Dieback Disease, is the latest invasive alien to reach our shores. Its presence was confirmed recently at a site in County Leitrim by Forestry Inspectors from the Department of Agriculture, Food and the Marine while carrying out regular monitoring.
First reported in Poland in the early 1990s, the disease spread very rapidly and is now found in most parts of mainland northern Europe. It has not been reported from elsewhere in the world and since its discovery in Europe is relatively recent the biology of the fungus is not fully understood.
What is known, and is a cause of serious concern, is that wherever it gains a foothold it causes widespread losses of ash trees. Young saplings are particularly prone to death from the disease but ash trees of any age are vulnerable to attack. Ash is one of our most common native broadleaved trees so widespread damage to the species would be likely to have serious implications for the rural landscape. Makers of hurleys from ash wood are understandably very concerned about the future of their businesses.
It is believed that the infected trees in Leitrim were imported from abroad so the first line of attack against the alien pathogenic fungus is to destroy the infected trees before the disease gets a foothold. The disease is also known to travel in firewood sourced from infected trees.
The department has called on the forest nursery trade and contractors to introduce a voluntary moratorium on imported stock from continental Europe until such time as legislation is in place banning the importation of ash saplings from areas known to have the disease.
Forest owners and others are asked to be vigilant for the disease and report any sites where there are concerns about unusual ill health in ash by email, with pictures, to firstname.lastname@example.org or by phoning 01 6072651. It is particularly important to check the health of trees less than five years old.
Symptoms to look for in ash include lesions on stems and branches leading to foliage wilt, dieback of branches and death of the top of the crown. All of these symptoms are featured on a very helpful fact sheet with coloured pictures of ash trees suffering from various different stages of the disease. The fact sheet is available at alturl.com/47yc4.