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- protection reaction, when leaves and leaflets bend slightly to avoid additional water loss (Fig.
Can a tomato plant recover from leaf curl?
We have gotten many calls recently reporting sightings of leaf curling on tomatoes. In late spring and early summer, we notice that the majority of the leaf curling is caused by physiological factors that, in general, do not directly affect tomato yield and fruit quality.
- Although leaf curling can be caused by a number of factors, including disease, insect, herbicide, environmental stress, etc., we have found that the majority of leaf curling is caused by physiological factors in late spring and early summer.
- Tomatoes are susceptible to developing curled leaves under the same conditions that are responsible for the condition in other types of vegetables.
In late spring and early summer, plants that are actively growing and developing fruit have a high demand for water. Under hot and dry conditions, plants respond by rolling the leaves to reduce the surface area exposed to high radiation. Lower leaves on a tomato plant are often affected first, they may recover if environmental stresses are reduced.
- But with some varieties, leaf curling may occur on most leaves of a plant and last for the entire season.
- As we mentioned earlier, leaf curling itself due to the environmental stresses is not a significant concern, but if the stress condition continues, it may eventually lead to blossom end rot fruit and decreased yield.
There is a great variation among tomato varieties in terms of whether observation of leaf curling suggest the plant is suffering water stress that may eventually affect yield and quality. But as leaf curling is rather easy to spot, it would be a good idea to inspect developing fruit for probable blossom end rot if significant leaf curling is discovered.
Excessive nitrogen can also cause leaf curling, and the rolled leaves are often thicker and become dark green. The disease is typically noted on excessively trimmed tomato plants and plants that lose growth tips. In Figure 1, the tomato plant was pruned and trellised to be grown with two main leader system.
One area of the plant developed substantial leaf curl because the growth point of this part of the plant was mistakenly removed. As long as there are other growing points remaining, the plant can recover, and the leaf curling will only be a temporary observation.
Figure 1. One part of the tomato plant shows leaf curling because of the loss of a growing point. Except for the edges of the leaves which are rolled up, the leaves normally seem normal for the above-mentioned leaf curling scenarios. On the other hand, herbicide damage might be a cause for concern if the leaves that are curling up are severely misshapen or twisted.
In Figure 2., leaf curling is likely caused by a hormone-type herbicide damage (such as 2,4-D and dicamba) (such as 2,4-D and dicamba). The symptom was more pronounced on top of the plants, where new growth occurs. Tomato plants are particularly vulnerable to herbicide harm.
Depending on the level of the injury, some plants may not be able to recover. There is no way to reverse the effects of herbicide damage. Figure 2. Tomato leaf curling which is likely caused by a hormone-type herbicide damage. The rolling of tomato leaves can also be caused by damage from insects or diseases.
Your Tomato Leaves are Curling What Does it Mean and What Causes It?
Other symptoms such as mosaic, chlorosis or the signs of the insect itself may accompany with the leaf curling symptom. If you suspect the leaf curling was caused by these biotic factors. Samples should be sent to Plant and Pest Diagnostic Laboratory for pest identification before taking actions.
