Tomato Disease With Black & Curled Leaves

Mosaic Virus

• Tobacco mosaic virus is transmitted to your tomatoes when they are exposed to tobacco plants or products. Something as minor as a cigarette smoker touching a leaf can transmit the virus, which then spreads throughout your garden. Symptoms are a mosaic light-to-dark mottling and a signature crinkling of the leaves. The fruit also takes on a burned appearance inside.

Herbicides

• Certain growth regulating herbicides, such as 2, 4-D, causes leaves to curl and discolor, although they do not usually darken. Prevent herbicide injury by adjusting your spray so that it does not drift onto nearby tomato plants. If the injury is not too severe, most plants eventually recover, although fruit may show some malformation.

Physiological Leaf Roll

• Irregular water supply and pruning stress cause leaf curl on tomato plants. The leaves remain green, but roll tightly inward until they form straws. Leaf roll does not harm or affect either the plant or fruit production, and usually corrects itself without treatment.

Other Causes

• Many bacterial and fungal diseases cause black spots, lesions or cankers on tomato leaves. Some also cause the leaves to curl, wilt or drop altogether. Among these are bacterial speck, early blight, target spot, bacterial canker and tomato spotted wilt virus. Rotating tomato crops and preventing soil and water from splashing on the leaves during watering helps prevent these diseases.