Leaf Mine

4.088 BF36a. Ectoedemia heringella (Mariani, 1939)

On 5^th May 2020 Jamie O’Neill posted images on Insects & Invertebrates Ireland Facebook page of an abundant leaf miner that he found on Evergreen Oak in Phoenix Park, Dublin. He putatively identified them as E. heringella. This was quickly confirmed by Stuart Dunlop and Dave Allen (DA) who also confirmed it, after consultation with Ken Bond, as “New to Ireland”. A few weeks later Philip Strickland contacted DA with images of the same species from the same locality but taken on 13th February 2017! The mines are persistent so can be found in any month of the year. The species has obviously been established here for a number of years but remained undetected. If it follows the same pattern as in GB, where it was first found close to Kew Gardens in London, then it will certainly colonise other parts of Ireland.

Cameraria ohridella was first confirmed in Ireland in south Dublin during 2013. In recent weeks, (June & July 2014) as well as throughout Dublin, mines and adults have been noticed in Belfast, Cavan, Louth and Wicklow and while many searches of trees have been negative it is likely to be more widespread than the current distribution map indicates.

As I write this the 2 maps above are the same. The map on left will stay fixed as a snapshot of what is known on 1st Aug 2014, the right map will update when further sightings are confirmed.

We would like you to look for mines of this species in your area on Horse Chestnut trees (Conker Tree) While fresh mines are distinctive, the old mines are brown as is leaf blotch, a fungal disease which can be found, sometimes very extensively on practically all Horse Chestnut trees. For the inexperienced this blotch can be easily interpreted as mines. If in doubt it is probably blotch

If you feel you have a definite sighting of a mine, forward a photo via Ask an Expert
If we can confirm we will add your sighting to the map.

The following 3 photos, courtesy of Dave Allen indicate of what to look out for. the fresh mines are pale and obvious. Part of the mine is usually a darker blotch and frass and a caterpillar may be visible. The mines may join together and many caterpillars may be visible together. The most likely location on tree is low, usually within reach and often near the trunk. The caterpillar pupates inside the mine. The 2nd photo shows an exit case. These are often seen sticking out of the leaf. If it has fallen out then a hole is left. The 3rd photo shows many mines in a leaf.

Further information

Ukmoths
British Leafminers

Cameraria ohridella has a very recent history having been first observed in Macedonia in 1984. It was first observed in Britain in 2002
See wikipedia for more info