Curling or rolling of tomato leaves may be caused by various factors, including environmental stresses, viral infection, and herbicide damage. To determine which factor is the culprit, it pays to take a close look at the plant(s). Which leaves are rolling – old leaves, new leaves, or all leaves? What direction do the leaves roll – upward or downward? Are any other parts of the plant, including fruit, that are exhibiting symptoms?
Physiological Leaf Roll
Tomato foliage on the lower portion of the plant is exhibiting physiological leaf roll.
Joey Williamson, HGIC Clemson University
Excessive moisture and nitrogen, insufficient phosphorus, heat, drought, severe pruning, root damage from tilling or hoeing, early planting and transplant shock are some of the cultural and environmental factors that can cause physiological leaf roll in tomatoes. Initial symptoms are usually apparent in the lower leaves with an upward cupping of leaflets followed by an inward lengthwise rolling of the leaflets toward the mid-vein. The affected leaves tend to become thickened and have a leathery texture, but retain a normal, healthy green color. Over time, all of the leaves on the plant may be affected.
Interestingly, vine tomato (indeterminate) varieties tend to exhibit physiological leaf roll more often than bush tomato (determinate) varieties. While this condition can occur at any time of the growing season, it usually occurs as spring weather shifts to summer. The good news is that the condition has minimal impact on tomato fruit production and plant growth. To lessen the chance of physiological tomato leaf roll, apply the following cultural techniques:
- Choose determinate growing tomato cultivars.
- Properly harden off tomato seedlings before planting them in the garden.
- Transplant tomatoes once the weather has warmed sufficiently.
- Maintain a consistent moisture level in the soil by mulching around the plants.
- Avoid over-fertilization with nitrogen.
- Apply sufficient phosphorus as based on a recent soil test report.
- Avoid excessive plant pruning or root damage during cultivation by tilling or hoeing.
- Site tomato plants in the garden to receive late afternoon shade, which is the hottest time of day.
Viral Infections
The tomato is infected with Tomato yellow leaf curl virus and shows the symptoms of cupped, pale green foliage.
David B. Langston, University of Georgia, United States
Some viral infections also cause leaf rolling in tomatoes. When tomato plants are infected with Tomato yellow leaf curl virus (transmitted by whiteflies), new leaves become cupped and pale green in color. In addition, the entire plant may exhibit stunted growth, yellowing leaf edges, purplish veins on the undersides of leaves, and decline of fruit production. A second virus, Tomato mosaic virus, causes rolling of leaves, but other symptoms, including mottled-coloring of leaves, small leaflets, and internal browning of infected fruit, distinguish it from physiological or herbicide-induced leaf roll.
There is no treatment for virus-infected plants. Removal and destruction of plants is recommended. Since weeds often act as hosts to the viruses, controlling weeds around the garden can reduce virus transmission by insects. As some viruses are transmitted mechanically on garden tools, it also helps to disinfect any tools, such as pruners, that were used on diseased plants.
Herbicide Damage
These tomato plants were exhibiting damage from exposure to 2,4-D herbicide drift from nearby spraying.
Joey Williamson, HGIC Clemson University
When tomato plants are exposed to the 2,4-D herbicides, typical symptoms include downward rolling of leaves and twisted growth. In addition, stems may turn white and split, and the fruit may become deformed. Depending on the level of exposure, the plant may or may not survive.
Herbicide injury cannot be reversed, but if the plant is not killed, new growth may be normal. Always be very careful when spraying an herbicide, as it may drift much further than anticipated.
To learn more about growing healthy tomatoes, as well as common tomato diseases and insect pests, see: HGIC 1323, Tomato; HGIC 2217, Tomato Diseases and HGIC 2218, Tomato Insects.
Pesticides are updated annually. Last updates were done on 7/21 by Joey Williamson.
Originally published 05/08
If this document didn’t answer your questions, please contact HGIC at hgic@clemson.edu or 1-888-656-9988.
FAQs
Excessive moisture and nitrogen, insufficient phosphorus, heat, drought, severe pruning, root damage from tilling or hoeing, early planting and transplant shock are some of the cultural and environmental factors that can cause physiological leaf roll in tomatoes.
Can overwatering cause tomato leaves to curl? ›
Over-watering.
Leaves might yellow and wither, or they could curl. Tomatoes like humid conditions, but they don't like being soaked. Check for signs of oedema – lumps and nodules on leaves and stems – a sure sign you're over-watering, and reduce as necessary.
How do you treat tomato leaf curl disease? ›
Once infected with the virus, there are no treatments against the infection. Control the whitefly population to avoid the infection with the virus. Insecticides of the family of the pyrethroids used as soil drenches or spray during the seedling stage can reduce the population of whiteflies.
What disease causes tomato leaves to curl? ›
Problem: Tomato Viruses
6 Whiteflies transmit tomato yellow leaf curl virus. New leaves become cupped and turn pale green. The leaf edges turn yellow, and the undersides of the leaves may turn purplish. The plant's entire growth is stunted, and fruit production is poor.
What do overwatered tomato leaves look like? ›
Curling Leaves
Downward-curled leaves may result from overwatering, indicating root stress that can harm plant growth and fruit production. Curling tomato leaves can induce panic in tomato growers, but the problem is more common than you may think.
Will too much fertilizer make tomato leaves curl? ›
Excessive nitrogen fertilization will also cause tomato leaves to curl. Excessive nitrogen will have another side effect, as it can favor the growth of new leaves and shoots at the expense of setting fruit. In some cases, heavy pruning or damage to roots may also cause leaf curl.
Why are my tomato leaves curling and twisting? ›
Heat and low moisture can cause the edges of the tomato leaves to die back, then twist and curl. Hot dry weather may also cause a symptom called physiological leaf roll. This is a self- defense response, where leaves and leaflets curl slightly to prevent further water loss (Fig. 6).
Will curled tomato leaves uncurl? ›
Leaf curl brought on by tough growing conditions usually resolves when the conditions improve. Don't expect long-term effects. A short battle with leaf curl "does not significantly reduce plant growth or yield," says Nair.
Can tomatoes recover from leaf curl? ›
Tomato leaves cup inwards and can appear leathery. Affected leaves will still retain their green color. Usually, plants recover from physiological leaf roll and environmental stress with proper cultural practices, so the fruit yield should not be affected.
What does the tomato leaf curl virus look like? ›
On tomatoes, the primary symptoms of TYLCV are interveinal and marginal chlorosis of young leaves (Figure 2), an overall crumpled appearance of the leaves, and upward and downward leaf-curling. Plants infected with TYLCV will also be stunted in height (Figure 3), and appear bushy due to shortened internode length.
Tomato leaf curl disease is not transmitted in seed, soil or from plant to plant by handling. It is harboured in infected host plants, some of which may be hosts that do not show symptoms.
Why are my tomato leaves curling under grow light? ›
The most likely cause of tomato leaf curl up is usually excessive heat and or light energy. There are two specific instances in which this is a common occurrence: Outdoor growing during the summer in hotter climates. Indoor growing when young plants are exposed to intense grow lights for the first time.
What is the cause of leaf curling? ›
Leaf margins curling down, yellowing – overwatering. Leaf margins curling upwards – heat or wind stress. Leaf curling mainly in new growth and in deformed ways – often a disease or insect pest. Middle or old leaves curling and have patchy yellowing but green veins – Magnesium deficiency.
Is leaf curl of tomato caused by fungus? ›
There are various factors that can cause curling or rolling of tomato leaves. These factors can be environmental stresses, fungal, bacterial, or viral infections, insects, herbicide damage, overfertilizing, and excess or insufficient water. These factors trigger physiological problems that manifest this condition.
Why are my tomato plant leaves curling under grow light? ›
Check For Sucking Pests On Your Leaves
When you're dealing with tomato plant leaves curling up, it generally means they are shocked or dehydrated. If you don't believe the issue to be related to your environment - heat or humidity - it could be related to pests.
Why are the leaves of my plant curling? ›
The most common causes of indoor leaves curling upward are too little water, low humidity, insufficient light, or high temperatures. Verify the plant's soil is not dry. Increase watering frequency, mist leaves, move to brighter indirect light, and keep away from heat vents.
What causes yellowing and curling of the leaves of tomato plants? ›
Broad mites and viruses in tomatoes
The toxins they inject into the leaves make them distort and curl. Tomato plants also can be affected by hundreds of viruses, but the most common one associated with yellow and curling leaves is the tomato yellow leaf curl virus.
