It’s the best time of year for home-grown tomatoes. Your plants are loaded with fruit waiting for picking and enjoying! While harvesting the brilliant red orbs you notice some of your tomato leaves curling or rolling. What’s up with that?
Time to play detective, as tomato leaf curl can be the result of a variety of things including:
Environmental stressors – Too much or too little water or nutrients can make leaves curl. A wet spring, followed by warm weather can cause physiological leaf roll. Leaves may roll downward and become firm and leathery. Usually, the lowest leaves are affected most and the plant appears healthy otherwise. When conditions become more favorable, like more water if the plant hasn’t been getting enough or consistent watering, environmental stressors will often resolve themselves and the plant will recover.
Plant disease – Several viral infections can cause tomato leaves to curl. Curly top virus causes leaves to cup downward, become thick and brittle, and stunts plant growth. Tobacco mosaic virus results in mottled leaves that appear stringy and distorted. Tomato spotted wilt virus causes downward-cupped leaves and necrotic spots. Unfortunately, there’s no treatment for virus-infected plants, so it is best to remove and dispose of them.
Bugs – Aphids, whiteflies, thrips and other sap-sucking insects can cause leaves to curl by sucking plant juices out of the leaves. Check the undersides of leaves to look for these insects.
Visit the UC IPM website for more information about tomato pests, issues, and cultural controls.