How to Fix It
What it looks like:
After the plants begin to develop tomatoes, the lower leaves break out in yellow spots. Within the yellow spots, dark gray centers with dark borders appear. Black dots appear in the center of the spots. Foliage dies and falls off.
What causes it:
A fungus called Septoria lycopersici thatinfects foliage.
What to do about it:
Avoid watering tomatoes from the top, as the spray can force the spores developing on the leaves back into the soil and continue the disease cycle.