I use the diluted bleach spray to keep it out of my garden with great success. The trick is to use it early and make sure to hit the undersides of the leaves, especially on the squash type plants. If you wait til the mildew is bad then most leaves with bad infections will dry up and die from the bleach spray but that is true of almost any disease that is allowed to get too bad. If you decide you want to try it start out with the milder solution first and make sure to spray very late in the day or very very early.
Here is a link to a good thread on using the bleach spray.
http://tomatoville.com/showthread.ph...t=bleach+spray
It also works on most bacterial and fungal diseases of almost any plant in the garden and has no affect on beneficials or pests for that matter. If done correctly it can be a big benefit. Another useful product is a copper spray which is better as a preventative than as a curative.
Bill