Posted: 21/08/2014 at 14:02
I think it could still be downey mildew. The leaves go a bit yellow, the flowers drop off, then the leaves, all quite quickly. There is a fine white powdery mould under the leaves, but it's not very noticeable. Busy Lizzies actually like water but so does the disease. If that's it then they need throwing away, in bags, not on the compost.