The Department of Agriculture has detected the ash disease, Chalara at five sites across Northern Ireland.
Experts identified the disease in imported young saplings at five sites in Co Down and Co Antrim. The authorities have issued notices to owners requiring owners of the plantations to destroy around 5,000 affected ash saplings and associated plant debris.
The experts are continuing to investigate a number of sites under the surveillance programme. The Northern Ireland Minister for Agricultural and Rural Development Michelle O'Neill said that the officials of the Department of Agriculture have been alerted about the disease.
He said, "Legislation was introduced north and south last month banning the import and movement of ash plants for planting from infected areas. However, we must remain vigilant as this disease still poses a very serious threat. I would appeal for a responsible approach over the coming season. I encourage all stakeholders to be alert for signs of this disease and report findings."
The disease was detected among imported saplings in a plantation in Co Leitrim during the previous month. Experts believe that the source of the outbreak is an exporter of saplings on mainland Europe.