Answer: There are a number of diseases that could cause blight like symptoms. You might try some extremely disease resistant varieties such as Big Beef or Super Tasty or Celebrity. Rotating the plantings and adding copious amounts of organic matter such as compost to the soil can also help. If you have a diseased plant, remove it and put it in the trash where it can't serve as a source of reinfection. At the end of the season, clean up and remove and destroy all tomato plant debris for the same reason. You mgiht also want to check with your county extension to identify exactly which disease is causing you the problems, then you may be able to take steps specifically against that particular one.
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