What to look for: White-mold encircled gray spots on leaves and gray or brown lesions on stems. Eventually the fruit exhibits dark, greasy-looking lesions (yuck) and the plants blacken, wilt and die. Since I don't have any (knock on wood) I looked around and found this picture on Illinois Fruit and Vegetable News Website. (click here) Itt
What to do: Affected plants must be tightly sealed in plastic bags and put in the trash. They should never be composted or allowed to linger on the ground.
Preventative: For organic gardens the paper suggests products with fixed copper but states it's the least effective against blight. for non organic it suggests looking for products that contain maneb, mancozeb or chlorothalonil.