Early Blight and Septoria Leaf Spot on Tomato Plants

Early blight and Septoria leaf spot infections on tomato plants most commonly begin in the early or middle part of the growing season but can start at any time. Infections can occur anywhere and are most severe in wet and humid areas.

How to identify Early Blight

Early blight on tomato leaves (7871930010)

Photo of Early Blight by Dwight Sipler [CC BY 2.0]

Symptoms of early blight typically begin on the older, lower leaves of a tomato plant. Over time, infections spread upward to newer growth. Early blight infections appear as spots that may start out circular or irregular in shape. Spots are dark brown in color and form concentric rings, or a bullseye pattern, as they grow. The area around the infection commonly turns yellow. As infections grow, leaves may fall off. Extensive loss of foliage is common. Infections most commonly occur on leaves but can also appear on stems and fruit.

How to identify Septoria Leaf Spot

Symptoms of Septoria leaf spot also start on the older, lower leaves of a tomato plant and spread upward to newer growth. The spots start out circular but change shape as they grow and can merge with other spots. Spots typically have a dark brown edge with a lighter gray or tan center. Small dark spots, the fruiting bodies of the fungus, will appear in the gray or tan centers. As infections progress, leaves can turn yellow, then brown and finally dry and dead. Stems can also become infected but infection of fruit is rare.

How to Prevent and Control Early Blight and Septoria Leaf Spot

Follow the 12 easy steps below to enjoy a long season of sweet cherry tomatoes, colorful heirloom tomatoes, vigorous hybrid tomatoes, and richly flavored sauce tomatoes.

Late Blight on Tomato Plants

Late blight is another fungus that infects tomato plants. It spreads fast and can quickly kill all tomato plants in a garden. Once a tomato plant is infected with late blight, the entire plant should be removed and destroyed. Late blight infections first appear as small, water-soaked spots on leaves and stems that grow and turn dark brown or gray. A white downy growth may develop on the underside of infected leaves. Late blight can infect all parts of a tomato plant, including the fruit. Most of the methods for preventing early blight and Septoria leaf spot infections will also help prevent late blight infections.