Our heirloom tomatoes and their foliage are blue and beautiful. We’ve been spraying them with an organically approved fungicide for 4 weeks. We began spraying when we got word from UMass that late blight, a devastating disease of tomatoes and potatoes, was in the area. This season several organic farms in the northeast have already lost their tomato crops to late blight. No evidence of it in our fields yet. Here’s an excellent source of information on late blight for those of you who want to know more.