Leaf Miners

I have seen the browning leaves on Horse Chestnuts before and just thought it was the normal aging process, perhaps accelerated by the hot weather.  Recently, I was told it was a fungus,  but I now know better.
My Blip shows the characteristic damage caused by the Horse Chestnut Leaf Miner. The larvae of this tiny moth mine within the leaves, creating distinctive brown blotches that can cover much of the leaf. While they can cause significant browning and premature leaf fall, it generally does not cause long-term damage to the tree's health, which is good news. 
Apparently, if you hold the leaves up to the light you can see the tiny caterpillars or the pupae. Checking that will be one of tomorrow's jobs.