Diseases Causing Dark Venation & Rolling of Leaves in Tomatoes

Phosphorous Deficiency

• When the tomato plant receives less phosphorous than necessary, its veins turn purple. This eventually causes the entire plant to take on this characteristic. If these symptoms are spotted, the tomato plant needs more phosphorus. When the soil is too cold, generally in the early season, it is hard for the plant to consume as much phosphorus as it needs. Don't plant tomatoes too early in the season, and if it seems like the soil is cold, plastic mulch heats.

Curly Top Virus

• The Beet Leafhopper spread curly top virus from plant to plant. After feeding from one plant, this pest spreads the disease to others. The curly top virus causes the tomato's leaves to harden and roll up and damages the fruit's quality. There is no direct chemical treatment for the virus, but avoiding it is possible. Cut out any plant displaying these symptoms. Additionally, controlling insects helps stop leafhoppers from spreading the virus.

Broad Mite

• The broad mite is a tomato pest that attacks many different plants. These very small pests are less than a millimeter in length and have a yellow-to-green color. Since they are very small and hard to see, the best way to identify them is through the symptoms in the plant. The mite's saliva damages the plant as a whole in the time it uses it as a host. The veins darken, and the leaves harden and roll up. In addition, the fruit discolors and possibly becomes inedible. Miticide controls these mites.

Bacterial Canker

• The bacterium Corynebacterium michiganense causes bacterial canker. Identifying this infection is difficult. The symptoms are similar to the other two ailments and there's no way to tell if a plant has the disease except by the symptoms. On newer plants, the bacteria destroy the growth and formation. On older ones, it causes the leaves to brown and curl up. If you spot either of the symptoms, immediately cut the plant out and throw it away to avoid spread. Only plant seeds officially certified as bacteria-free.