sounds like they are drowning from all the rain. you might want to dig a drainage ditch to the side of your garden to help remove some of the water saturation. Some people will install a drainage pipe where excess will seep into the pipe and away from the plants. Are the fruit splitting?

I just started posting on GardenWeb and saw your note. Sounds like bacterial wilt. I just had it happen to one of my very promising Evergreen plants, which was sitting at the end of a row. We've had lots of rain and tropical type weather here in NYC recently, and reading about this syndrome indicates the weather is a factor, but that the bacteria do reside in the soil. As hard as it was to do, I took out the plant and also dug around to get as much root matter as possible out of the ground as it can linger for years. Hope you are doing OK with your garden.