The leaves on our Horse Chestnut are turning brown and withering; however. new growth is still progressing. Can't see any sign of insects with the exception of a group of tiny white dots on one leaf; but it resembles the damage done to birches by the birch leafminer - and there is a birch tree about 20 feet away. See photos. Any explanations or suggested treatment?
Check out the minor leaf disease fungus Guignardia aesculi. You're lucky it is not the Horse-chestnut leaf miner (Cameraria ohridella) which is currently ravaging the species across most of Europe
I know it's supposed to be only in Europe; but the photos and descriptions are a perfect match for Cameraria Ohridella.
It (fortunately!) isn't right for Cameraria - that has more evenly-sized rounded blotches with paler edges; the irregular-shaped uniformly brown blotches on yours match Guignardia much better. This is (at least over here) a very common minor fungal disease which shows up about this time of year
