Last updated on October 23rd, 2023 at 08:36 pm
Withered tomato leaves not only look unsightly, but can also be an indication of various diseases or pests. Read here when the withered leaves are a danger and what you can do about it!
Withered leaves can often be attributed to harmless causes such as the wrong location or care errors. However, there are also numerous pests and diseases that make themselves known through withered leaves. Therefore, when the foliage dries up, you should always be on the lookout for other symptoms. Only then can the cause of the withered leaves be found and appropriate countermeasures taken in time.
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Sunburn
Tomatoes prefer a location that is as sunny as possible, but it can always happen that the plants get sunburn. Especially young plants are often affected by this, as they are still particularly sensitive. If the tomatoes are sunburned, bright to white spots will also appear on the leaves. Likewise, the fruits may suffer heat damage, which is manifested by circular, shallow cracks. In the event of sunburn, immediate action is required to prevent further heat damage if possible:
- Water the plant extensively
- Place potted plants in the shade
- Shade outdoor and growing tomatoes
- Only prune gently
- Cold damage
Tomatoes are not only affected by the heat, but also by the cold. This is because the plants are extremely sensitive to cold and react accordingly to temperatures that are too low. Often cold damage occurs when night temperatures fall below 5 degrees in the spring. The tomato leaves lighten between the leaf veins and become necrotic. If the cold damage is particularly severe, the leaves also turn brown and dry out. To prevent this, it is important to protect tomatoes extensively from cold:
- especially when late frost threatens
- at night provide tomatoes with protection from the cold
- for example, with a fleece
- bring tub tomatoes indoors
Care error: lack of nutrients
Withered leaves can often also be traced back to care errors, with fertilizing in particular proving to be the cause. If the plants are fertilized too much, it can lead to a nutrient surplus and thus to withered leaves. In these cases, it is advisable to take countermeasures and change the fertilization accordingly:
Magnesium deficiency
In the case of a magnesium deficiency, the leaf areas between the leaf veins lighten and the leaves turn yellow. In the further course, the leaves turn brown and dry out. It is noticeable that the main veins remain unaffected and retain their green coloration. The magnesium deficiency can be counteracted with simple measures:
- Apply fertilizer containing magnesium
- for example Epsom salt
- Increase the pH value of the soil
- dolomitic limes are suitable for this purpose
Potassium deficiency
Potassium represents an essential nutrient for tomatoes, because it not only promotes tissue, but also has a positive effect on water balance. If the tomatoes do not receive enough potassium, the leaves evaporate more water, which causes them to slacken faster. As a result, the leaves turn brown and dry out. In this case, the plants should be fertilized with a fertilizer containing potassium, and the following fertilizers are the most suitable for this purpose:
- Wood ash
- Liquid manure
- Comfrey liquid manure
Tip: A potassium fertilizer can be made quickly and easily by dissolving some potash in water. Generally, about one liter of water is mixed with 120 grams of potash for this purpose.
Diseases
Many diseases of tomatoes are noticeable on the foliage, such as withered leaves. Some of the diseases are quite aggressive and not always allow to save the plants. However, depending on the symptoms and symptoms of the disease is worth trying to take countermeasures:
Tomato wilt
In tomato wilt, the leaves turn yellow before turning brown and eventually drying out. Another symptom of this disease is brown longitudinal stripes on the upper stems, which are also sunken. Tomato wilt also affects the fruits and “decorates” them with brown spots. What is striking here is that the spots on the tomatoes have a bright yard. Diseased tomato plants die and can not be saved. Therefore, to prevent tomato wilt from spreading further, the following procedure should be followed:
- destroy the affected plant
- do not dispose of it in the compost!
- do not grow tomatoes in the same place
- for about 4 years
Late blight and brown rot
Late blight occurs very often on tomatoes, especially if they are grown near potatoes. When the disease occurs, gray-black spots first form on the stems and leaves. As the disease progresses, the leaf tips turn brown and a white mold coating forms on the underside of the leaf. The leaves eventually rot and dry out. The disease is also noticeable on the fruits, which also show gray-green, wrinkled areas. However, late blight can be prevented:
- do not plant next to potatoes
- always water from below
- regular pruning
- in case of infestation spray copper preparation
- alternatively use a plant protection product
- for example Ortiva Special Fungus-Free
- Spoonleaf
Care errors can also lead to withered leaves, because the so-called spoon leafiness is caused, among other things, by too strong ausizen. In this case, the leaves not only curl from top to bottom, but also dry out. Spoon leafiness may be visually unattractive, but it does not usually affect the harvest. Nevertheless, to avoid spoon leafiness, the following should be taken into account:
- do not overcrop
- Moderate the nutrient density in the soil
- always dose fertilizer correctly
- Pests
Tomatoes are also popular among numerous pests, infestation of which can also lead to withering of the leaves. However, most pests can usually be successfully combated and thus save the plants.
Tomato rust mite
In case of an infestation of tomato rust mites, first the stems and individual leaf stalks turn brown. Subsequently, the leaves are also affected, which turn bronze to rusty brown. In case of a heavy infestation, the leaves subsequently curl upwards from the edge and dry out. A particularly severe infestation can lead to inedible fruits and subsequently to the death of the plant. Unfortunately, an infestation is usually only detected in the late stages, so that control is often no longer possible. However, if the tomato rust mites are detected early, the following control attempt is worthwhile:
- biological control with predatory mites
- alternatively use chemical pesticides
- dispose of plants in case of heavy infestation
- spider mites
The annoying spider mites form fine spider threads on the plants, which are visible to the naked eye. Furthermore, their sucking activity leaves quite a few bright spots on the foliage. In case of a heavy infestation, the leaves curl up, dry out and finally fall off. However, the spider mites can be successfully combated as follows:
- Canola oil
- Potash soap
- use natural enemies
- such as gall midges or predatory mites