FAQ
How do you treat Septoria leaf spots on tomatoes?

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Can Septoria leaf spot be cured?
One year rotations of tomato plants have been shown to be effective in preventing the disease. Treating septoria leaf spot disease after it appears is achieved with fungicides.
What is the best fungicide for Septoria leaf spot?
Most fungicides registered for use on tomatoes would effectively control Septoria leaf spot. These include maneb, mancozeb, chlorothalonil, and benomyl. Captan is not effective and zineb may be difficult to purchase.
What are the symptoms of Septoria leaf spot in tomatoes?
The first symptoms appear as small, water-soaked, circular spots 1/16 to 1/8″ in diameter on the undersides of older leaves. The centers of these spots then turn gray to tan and have a dark-brown margin. The spots are distinctively circular and are often quite numerous.