Current and emerging threats to Ireland’s trees from diseases and pests.

  • Alistair McCracken Agri-Food, Sustainable Agri-Food Science Division, Agri-Food and Biosciences Institute, 18A Newforge Lane, Belfast BT9 5PX, Northern Ireland, UK.
Keywords: Phytophthora ramorum, P. lateralis, P. pseudosyringae, Chalara fraxinea, Global plant trade, Phytosanitary measures, Pseudomonas syringae pv. aesculi, Dothistroma septosporum.


Over the past decade the number of new pests and diseases detected in the United Kingdom and Ireland has increased significantly, particularly on trees and woody ornamentals. Whilst there has been a wide range of pests and diseases affecting woody hosts, those caused by members of the genus Phytophthora have been very damaging and widespread. These include P. ramorum on larch and rhododendron, P. lateralis affecting Lawson cypress, P. kernoviae on beech (Fagus sylvatica L.) and P. pseudosyringae infecting Nothofagus and bilberry species. Other recently introduced pathogens are responsible for causing the diseases red band needle blight (Dothistroma septosporum), ash dieback (Chalara fraxinea); and horse chestnut bleeding canker (Pseudomonas syringae pv. aesculi). A number of invertebrate pests also pose significant threats to Ireland’s trees including, oak processionary moth (Thaumetopoea processionea), pine processionary moth (Thaumetopoea pityocampa), horse chestnut leaf miner (Cameraria ohridella), Asian longhorn beetle (Anoplophora glabripennis), and pine wilt nematode (Bursaphelenchus xylophilus). A number of factors have contributed to this increase. In recent years there has been an upsurge in the global trade of plants, which are being moved more rapidly from country to country. Small changes in temperature or weather patterns, due to climate change, can enable organisms to become established in areas where previously they would have struggled to survive. Often phytosanitary regulations and how they are applied are not as robust as they might be. Furthermore there is a general lack of understanding in the general public of the importance of being vigilant in keeping pests and diseases out of the country. In Ireland there is a better chance of remaining free ofmany pests and diseases not currently found on the island.
How to Cite
McCracken, A. (2013) “Current and emerging threats to Ireland’s trees from diseases and pests.”, Irish Forestry, pp. 18-35. Available at: (Accessed: 26February2024).