Horse-Chestnut Leaf-Miner INVADES Britain

6 Jun

The Horse-Chestnut Leaf-Miner (Camararia ohridella) is invading Britain and I need your help. This tiny moth lays its eggs on the Horse-Chestnut leaf and the caterpillar eats the leaf from the inside.

I am looking into the geographic distribution of this moth as a part of my MSc research project.

I need everyone reading this in the UK to go out on Saturday the 25th June 2011 and look at their nearest White-flowering Horse-Chestnut tree (the most commonly found).

Take a look at one of the middle ‘fingers’ (leaflets) of 10 individual Horse-Chestnut leaves and count the ‘mines’, these will look like little brown circles or lines (shown below). When held up to the light they are easier to see. IF THERE ARE NO MINES PLEASE ALSO LET ME KNOW AS THIS IS ALSO IMPORTANT.

Horse-Chestnut leaf

Single 'finger' (leaflet)

Single larger mine



















Please record this number (10 leaflets from every tree you find) and send them to me with the location (post code, or map reference) of the tree.

Please enter your results in to the online survey found at:

THANK YOU FOR YOUR HELP and happy hunting.


17 Responses to “Horse-Chestnut Leaf-Miner INVADES Britain”

  1. Martin June 8, 2011 at 6:37 pm #

    Hi Laura

    Are you aware of this:

    • leafminer June 9, 2011 at 3:51 pm #

      Thank you for letting me know, I have a few similar maps that will definitely support this project. I am hoping to get a little more information about the trees (location in relation to other horse-chestnut trees, leaf litter and population density) which I hope should give a more detailed picture of the distribution. Thank you again for your comment.


  2. Keith Palmer June 9, 2011 at 6:27 am #

    Will do this on 25th June. I know this leaf miner well and will be glad to help in the survey,
    Keith Palmer

    • leafminer June 9, 2011 at 3:48 pm #

      Thank you so much for this, your help is very much appreciated.


  3. Steve J. McWilliam June 9, 2011 at 9:10 am #

    How do we send you teh information you require ?? There is no e-mail addres (or any other contact information) !!!!

    Steve J. McWilliam

    • leafminer June 9, 2011 at 3:47 pm #

      Hi, I have now got an online survey up and running, there is now a link to this from the site. Thanks for your comment.


  4. Barry June 9, 2011 at 9:23 am #

    Laura – good project, but can I suggest that you show examples of how to recognise the mine rather than the superficially similar leaf spotting caused by fungi, etc.. Otherwise your results are likely to be badly affected by incorrect observations.
    Good luck

    • leafminer June 9, 2011 at 3:46 pm #

      Great advice, thank you for this, the site is a bit of a work in progress so any advice is very much appreciated.


  5. Richard Gabb June 9, 2011 at 6:39 pm #

    I have by far the best garden ‘conker’ tree in our 2K square and will certainly look on the 25th. Steve Hind (Poynton,Cheshire) who lives nearby will also advise as he has previously told me the Leaf Mine is in my tree.

    • leafminer June 10, 2011 at 10:08 am #

      That is great thank you so much.

  6. Jen June 11, 2011 at 11:14 am #

    Just to let you know that I have shared this on the North Wales Wildlife Trust Facebook page, so hope you will get some help from there. Jen

  7. Blotchcy June 24, 2011 at 1:42 pm #

    Good study! It is difficult to determine number of mines in an already brown leaf. I suggest count the number of mines/spots on the underside and the area (proportion 1/2, 3/4) of the leaf already brown on the top side. Whole trees are already severely burnt in South Bucks.

  8. Ed Kendrick June 27, 2011 at 11:58 am #

    The first article in the June 2011 issue of British Wildlife that came through my letterbox this morning is “The Horse-chestnut Leaf-miner and its parasitoids”by Michael Pocock et al.

    • leafminer June 27, 2011 at 12:08 pm #

      Great, should be a good read, I will have a look at it.

  9. Tim July 10, 2011 at 6:19 pm #

    I wonder how many people know that the Horse Chestnut is also an invasive species? It was introduced to Britain in the 16th Century.

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