You are absolutely right that it is much easier to grow organically in
the drier west and I was going to point that out in my post, but
figured the reply would be that the OP was from the east where it is a
lot tougher to combat disease - probably it's a lot harder to grow
good vinifera grapes in general. I would think there are some people
doing it successfully, however.

Interesting about the oxyclean. Perhaps you should consider Oxidate
www.biosafesystems.com another organic fungicide I forgot about. Don't
know if it's registered for grapes but at least it is a registered
pesticide unlike oxyclean. It's widely used in the greenhouse industry
for a variety of disease problems.

As far as the milk for powdery mildew, I have seen the original
research on this and it did work in cucurbits. Don't know if anyone has
tested it on grapes.