Horse Chestnut Leaf-miner (Cameraria ohridella) present in Ireland

MothsIreland have posted an up-date with distribution maps on the presence of the Horse Chestnut Leaf-miner (cameraria ohridella) in Ireland. Visit:

Please download and circulate the      Species Alert poster


If you have seen this species please submit your sighting with a photo to MothsIreland via their online form.

Prior to this species being recorded in Ireland, Invasive Species Ireland undertook a risk assessment of its likely impact. It was assessed as a species with a risk of having a high impact. Download the risk assessment summary. Extract of impacts and management listed below:


  • Conservation goals: The severely defoliated trees produce smaller seeds (conkers) with a lower fitness that affects tree regeneration and seriously impairs recruitment of horse chestnut (as seen in the last endemic forests in the Balkans). Parasitism rates are low, but a single tree can host up to a million leaf‐miners. As most of the parasitoids emerge when larvae or pupae are not yet available, this may have an important impact on the native leaf‐miners.
  • Economic cost: The main cost is derived from dealing with severely damaged horse chestnut trees planted in cities and villages. Methods used to control this pest (additional leaf removal, insecticide treatment, replacement of trees) have a supplementary cost for municipalities.
  • No plant or animal health issues identified
  • No human health issues identified


  • Effective management is possible but resource intensive and/or with non target impacts and/or difficult to implement.
  • Management and control is difficult but pesticides and mechanical removal do have an effect.

An excellent account of the species has been published by The Natural History Museum, London: