What is a cure or treatment for tomato leaf curl?

Avoid leaf curl through destruction of the plant, careful application of herbicides, or proper watering habits. There is no cure for leaves that are already curled.

Leaf curl can be of the physiological, viral or herbicidal variety. Physiological leaf curl generally occurs when growing conditions are not optimal; avoid this kind of leaf curl by properly watering and fertilizing the plant. Viral leaf curl cannot be treated; destroy affected plants to avoid further infection of healthy plants. Plants that receive a high dose of herbicides can experience leaf curl, which is best avoided by using more caution during the application of herbicides in the future.