Blight is a common problem for tomato growers, and sometimes the weather just doesn't cooperate. It is best to use good practices, thinning your tomatoes, removing diseased leaves, and watering at the base of the plants to prevent excess moisture on the leaves. But sometimes that just isn't enough. Copper Sulfate is the thing I turn to when nothing else is working and the weather is getting the best of my tomatoes. This is a one pound bottle of copper sulfate dust.
I'm sorry, but we can't ship copper fungicide to California or Alaska.