I have different varieties of
I have different varieties of squash growing. I kept my summer separated from my winter. I check them daily ad they are growing some vey nice produce. We've been eating squash a lot lately. I too once noticed the powdery mildew growing on my zucchini. I try not to use any herbicides or chemicals because we have free range poultry on the farm. One tip that I read about and used is to use milk. Get a spray bottle and mix milk with water in the ratio of 1 part milk to nine parts water. Spray the leaves of your plants until the liquid begins to drip once or twice from the leaves. I don't have a particular time to say to do this but I do it in early morning once a week and it seems to have saved my squash from an inevitable fate. It worked. The source also said to use on cucumbers and tomatoes or anything else that may be susceptible to powdery mildew. Hope you have the same success as I did.