| There is a fairly recent disease called bleeding disease which kills Horse Chestnuts very quickly. The symptoms are not the leaf splotches that you are seeing, but rather cankers on the trunk which exude sap that runs down and discolours the trunk. Various minor leaf diseases must be considered normal for Horse Chestnuts. The link should be helpful to you. |
Here is a link that might be useful: Horse Chestnut bleeding and other diseases
| Could you have a problem with horse chestnut leaf miner, I wonder? It's relatively new to these shores but has started to cause more problems of late - I remember reading about it in the paper last year and noticing more damage on horse chestnut leaves in my own area. |
Here is a link that might be useful: article on Cameraria ohridella (leaf miner moth)
