Stalker

Something is stalking and killing horse chestnut trees.
We have lost two big trees in the last couple of years and i am worried that something destructive has entered the metabolism of this beautiful big tree.
Maybe it's the strange summer or age or just the fact that it is in an exposed place but I am very concerned as there is something decidedly insidious out there.
Apparently there is disease coming into the country that rapidly kills chestnuts.
If anyone can shed some light on this please tell me.