Sadly, I had discovered some mildew on my cantelope and squash a couple weeks ago. Long hard storm rains, followed by high heat and humidity cause a lot of mold and mildew problems in the garden. Especially in the south where the conditions always seems right.
After close examination of my tomato plants, I was concerned I had caught the fateful blight again this year... it is running rampant across the country again right now, a repeat of 2009. I did some research, started Thursday, looking for a positive conclusion (took longer then I thought as I threw my nephew a birthday party here on Friday, and my husband surprised me with a birthday party as well on Saturday... so I cleaned a lot inbetween and not so much garden time). As of this morning I've determined my plants have Powdery Mildew from the squash's mildew.
I almost ripped the plants out when I saw the rotting tomatoes and leaves! ARGH!! But I composed myself and I sprayed some neem oil mixture I use on my orchard trees. If I don't see any clearing up in the next few days I will switch over to the 1/4 milk and 3/4 water solution I was suggested for mildew as well. I will treat them for the entire season.... then in the fall I will 'solar' sanitize the soil. I wish I new to do that last year.
Here's some solarization advice, I will be doing this at the end of the season, really only good for warm climates I think: http://www.waynesthisandthat.com/solarization.htm