Yellowing of tomato leaves: symptoms, causes, control

Yellowing of tomato leaves is a symptom that indicates the presence of a problem affecting the health of the tomato plant. In this article on your website, World of Plants, we review the possible causes and appropriate solutions.

Causes of yellowing of tomato leaves

There are many possible causes for tomato tree yellowing, including:

1. Diseases and pests

Diseases and pests are common causes of yellowing of tomato leaves, as follows:

• Fungal diseases: Fungal diseases often affect the leaves of the tomato tree and cause them to yellow, and it is rare for them to affect the fruits. Among the most prominent fungal diseases that cause the yellowing of the tomato tree are: Early blight, late blight, and Fusarium wilt.
• Viral diseases: Many viral diseases lead to yellowing of tomato tree leaves, such as: Tomato mosaic, single line virus, tomato leaf curl, and other viral diseases transmitted between tomato trees by insects.

2. Pests

A large number of pests destroy tomato trees and cause them to yellow, such as: Aphids, spider mites, whiteflies, etc.

3. Nutritional deficiency

Tomato plants need a lot of nutrients during their growth period in order to grow properly. If they lack nutrients, especially nitrogen, the leaves of the tomato tree begin to yellow and fall. As nitrogen is the primary nutrient for tomato tree leaves, sometimes their yellowing is the result of a deficiency in iron or magnesium, and the yellowing appears more in young leaves.

4. Over-watering

Tomato trees need an ideal percentage of moisture in their soil, when the soil moisture is moderate. It is neither saturated with water nor very dry, and tomato trees become yellow if they encounter excessive irrigation, according to the following:

• Excessive watering of tomato plants, especially those grown in agricultural beds, will make the soil saturated with water, and thus the roots will not be able to breathe, leading to a lack of oxygen and the death of the plant tissues, and eventually the roots of the tomato tree rot, and its leaves become yellow.
• The fungi that cause root rot may be dormant in the soil, and excessive watering activates them.
• Planting a tomato tree in poorly drained soil exacerbates irrigation problems.
• Compacted soil

Not loosening the soil before planting tomato trees makes the soil compact and anaerobic, and this may be okay for some plants and trees, but for tomato trees it is a big problem. It causes problems with root growth in the soil, which in turn causes a lack of nutrients that reach the plant, making it suffer from a lack of food, and causing its leaves to yellow.

How to treat yellowing of tomato leaves

Tomato tree yellowing is treated in one of the following ways, depending on the cause of the yellowing.

1. Treatment of diseases

If diseases are the reason behind the yellowing of tomato leaves, then the disease affecting the tomato tree must be diagnosed and then treated, according to the following instructions:

• Fungal diseases: They are treated using fungicides containing chlorothalonil, leaving sufficient spaces between tomato trees to promote air circulation.
• Viral diseases: Unfortunately, there is no chemical treatment for viral diseases, but to prevent their spread, infected trees are eliminated, new disease-resistant varieties are planted, and they are well cared for.
• Pests: The best solution for treating pests is to use horticultural oil and insecticidal soap.

2. Fertilizing tomato trees

First, you must check the level of nutrients in the soil. To find out the nutrients that tomato trees need, this is done by conducting a soil examination, and when you know the nutrients that tomato trees need, they are provided with them using fertilizers. Tomato trees must also be provided with nitrogen, magnesium, and iron constantly, while making sure to give them plenty of water after fertilizing them. .

3. Solve problems of over-watering

If excessive watering is the cause of the yellowing of tomato leaves, then it must be treated to treat the yellowing of tomato leaves, according to the following instructions:

• Stop watering tomato trees immediately, and check the soil after two days to ensure it is dry, by examining the soil by hand.
• Remove all wilted and drooping branches and leaves from the tomato tree; To help the plant maintain its energy and recover from the effects of excessive watering, make sure to use sterile tools when pruning the plant.
• The tomato plant is taken out of the soil, and the soil is placed on layers of newspaper. To absorb excess moisture, the roots of tomato plants are placed on layers of newspaper to dry.
• The roots must be pruned if they are exposed to rot, and any rotten roots must be eliminated.
• The tomato tree should be replanted in another part of the garden and in new soil with good drainage and good aeration.
• Magnesium sulfate (Epsom salt)

Epsom salt contains high levels of sulfur and magnesium, and helps plants carry out the process of photosynthesis. Epsom salt helps treat yellowing of tomato tree leaves only if it is caused by a deficiency in magnesium. It is used by adding a tablespoon of Epsom salt to 4.5 liters of water. Then spray it on the leaves of the tomato tree when it blooms.

How to prevent a tomato tree from yellowing

To prevent yellowing of tomato leaves, the following is done:

• It is recommended to give tomato trees at least 6 hours of sunlight per day.
• Tomato trees must be watered in the appropriate amounts, which differs whether you plant them in the garden or in beds.
• A tomato tree generally needs 2.5-5 cm of water per week, and trees grown in containers need more water because of the heat stored in the containers.
• It is best to water tomato trees once a day in the morning.
• It is preferable to add coffee bean to the soil to enhance nitrogen production.
• Fungicides must be used constantly on tomato trees; To avoid infection with diseases that cause yellowing.
• It is recommended to plant disease-resistant varieties of tomato trees.
• A layer of mulch should be spread around tomato trees. To avoid exposing tomato trees to excessive watering.
• A space of at least 60 cm must be left between tomato trees. To promote air circulation between them.
• Make sure to plow and loosen the soil before planting a tomato tree in it.

Tomato tree care tips

The most important tips for taking care of a tomato tree and preventing yellowing of tomato leaves are:

• It is recommended to give seedlings plenty of space to branch out and spread well.
• Small and weak seedlings should be discarded; To give the larger ones a better chance of growing.
• Operating fans on tomato trees grown indoors; To give it a good air flow.
• It is preferable to cover the planting soil in a black or red plastic bag two weeks before planting tomatoes in it. To warm the soil.
• The lower leaves should be removed from the bottom of the stem; To avoid the spread of diseases in the tomato tree.
• It is recommended to prune tomato trees regularly. To allow the sun to reach all parts of the plant.

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References

What are the causes of tomato tree yellowing and its treatment? – daleel al nabatat
Yellowing and wrinkling of tomato leaves: symptoms, and how to combat it - modernagritec