sycamore trees
 

Hi all,
We've been away for a few days with the relllies in Disley. Whilst there we
went for walks round Lyme Park and the goyt valley etc, and noticed that all
the sycamores had black spots on their leaves. The spots are about 6-8mm
Dia.

We came home to Dorset this morning and "our" sycamores haven't got these
spots. Any ideas?

Incidentally, whilst there we saw Japanese knotweed for the first time.
Pretty, since it's in flower now, but scary nonetheless.

TIA
Steve