Blight early & late
Two of the serious diseases effecting tomato are early and late blights. The late blight is the more serious, especially in the cooler areas of the state.Early blight is very common and almost unavoidable. The fungus overwinters in the soil. Removing last years debris and soil cultivation will help lessen the number of overwintering spores of the fungus.The attached link will explain this further as well ass other preventative practices.