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Cause of Tomato Leaf Curl

Symptoms / Characteristics: The rolling or curling of tomato leaves can be a symptom of environmental stress, herbicide damage or viral infection.

Physiological leaf roll may be associated with environmental stresses such as excess moisture, excess nitrogen, and transplant shock. Leaf roll may also be related to moisture conservation during periods of extreme heat and drought. Improper cultural practices such as severe pruning and root damage during cultivation can also cause leaf roll symptoms. Physiological leaf roll involves an initial upward cupping of the leaves, followed by an inward roll. In severe cases, the leaves roll up until the leaflets overlap. Symptomatic leaves become thickened and leathery. Symptoms typically appear first in lower leaves but may spread to the entire plant, depending on the severity of the condition. Leaf roll is more commonly associated with staking varieties of tomato, such as "Early Girl" and "Big Boy", rather than bush types. In most cases, the condition is temporary and will have little or no affect on plant growth or fruit production.