Need help identifying a problem I am having with my tomatoes. Last week this was on just one plant. today it is on all of them and the first one is almost dead. I have sprayed with liquid sevin but I think it may be fungal or bacterial. any suggestions and solutions would be greatly appreciated.

this is my second year of square foot gardening. The original beds were made with mostly store bought materials. This year I expanded my bed using a lot of compost made from oak leaves, grass and vegetable scraps from the kitchen. Plants are in a 4 foot by 8 foot area in a checkerboard pattern. We have had a good bit of rain over the last two weeks.
thanks