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Leaf Mold on tomato, top side of leaf
Photo: Wayne Nishijima
Leaf Mold on tomato, underside
Photo: Wayne Nishijima
There are pale green or yellow spots on the upper surfaces of older leaves on tomato plants. The undersides of leaves have dark, olive green spots with mold. Leaves turn yellow and drop off.
Leaf mold is a fungus and is spread by the wind; high humidity and warm temperatures are contributing factors. Increased ventilation and sanitation are important if you are growing tomatoes in a greenhouse (remove affected leaves.) Fungicides effectively control Leaf mold.
Kendal Lyon, Hawaii Island Master Gardeners