First time gardener, and things were going well till about a month or so
ago when I noticed that one of the two peonies planted this spring had
some white/gray substance on the leaves. It's been spreading all over
the plant. Can anyone confirm that it is Botrytis? Here are some pictures

http://home.comcast.net/~hgohel/Peony/PeonyDisease.htm

click on the thumbnails to get larger images. In one of the pictures
there's a remnant of a flower with four seed pods or something. I
didn't know if I should deadhead that part or no? Other flowers on the
plant did not leave anything like that behind.

There's another Peony next to this (not pictured) that hasn't yet got
this disease. Somehow I didn't record which plant was which, but one of
the two is 'Monsiuer Jules ...' and the other is 'Karl Rosenfeld' both
obtained from a reputed local nursery.

Anyway, what should be the treatment for this now? Should I apply
something and/or cut off everything on the plant that has the disease
(which won't leave much at this point).

Thanks for your advice,

--
Himanshu