I get it, too on my pumpkins and gourds. I am still researching this problem myself. So far, I try to cut off any dead leaves on the vines and any tendrils that have turned brown. I try not to water too late in the evenings, either, which is getting harder to do w/ the evening getting so much shorter all the time! Only thing I have found that sort of works is to get a powerful spray bottle, and mix up a solution of powdered milk and water, and a couple of good drops of dish deterg. I dilute the powdered milk mix pretty well -- 9 to 1 is usually recommended. Spray liberally about mid afternoon when sun is out. Spray after it rains. I know it won't help w/ the leaves that have it the worst, but I believe it does help keep the newer growth and healthier leaves healthy! I think there are a few other effective ways but not sure myself! I am reading some things about copper right now. I don't know about that.

Thanks Lizbeth, I think it is too late for my plants this year and I have so many other problems with bugs. But thought I would figure out that battle for next year.