Leaves of tomato seedlings turn white: causes, methods of eliminating them and preventive measures

Main reasons

If the leaves of tomato seedlings turn white, then experienced gardeners, analyzing additional symptoms, can assume:

• sunburn;
• eating disorders;
• soil salinization as a violation of agricultural technology;
• bacterial and fungal diseases, including cladosporiosis, powdery mildew, mosaic, septoria.

See also: White spots on tomato seedlings

Preventive measures

An illness or sunburn that has already manifested itself is difficult, and sometimes impossible, to cure. To prevent stains from appearing on tomatoes, you must adhere to the following rules:

1. Disinfection of seeds and soil before planting.
2. Regular disinfection of garden tools.
3. Proper crop rotation (the location of the beds should be changed every three years or more often).
4. Timely weeding.
5. Compliance with the watering regime.
6. Maintaining a constant climate in the greenhouse (temperature from +20 to 28 degrees, humidity no more than 75%).
7. Ventilation.
8. Adding necessary fertilizers to the soil.
9. No mechanical damage to the landings.

Burn

Causes of the disease

1. Seedlings grown indoors or in a glass greenhouse are more likely to get sunburn. April seedlings are especially susceptible to burns, when the sun's rays become most aggressive. The situation is aggravated by the effect of light refraction through glass.
2. The second reason is transplanting seedlings into the ground under the open sun without first preparing the seedlings for changing conditions.
3. The third reason is improper watering, in which drops of water fall on young foliage. The lens effect is triggered.

How to recognize

When burned, the top of the bushes suffers, but the lower leaves remain green and do not dry out. A characteristic feature is chaotic white, almost transparent spots concentrated in the middle of the leaf blade. The edges of the sheet look like they are burnt. The turgor of the leaves is not disturbed, and the color of the veins is also preserved.

If indoor seedlings are burned, the leaves closest to the glass are affected. In open ground, if a recently transplanted seedling is burned, the top suffers. If plants are exposed to scorching rays after pinching, damage to the entire bush, including the stem, cannot be avoided.

Important: burns cause selective whitening of the leaves of tomato seedlings.

What to do

It is impossible to restore burnt leaves, but you need to stop the process and take care of the health of the entire seedling. To do this, spray the seedlings with a solution of Epin or Zircon at the rate of 1 ml of product per 5 liters of water. Spraying is carried out twice with a break of 7 days.

In this case, the seedlings must be removed from the sun or protective screens placed near them.

Prevention

1. Growing seedlings on south-eastern windows with mandatory shading from direct sunlight.
2. Compliance with watering techniques: do not water during the day, avoid getting drops on the leaves, do not spray young seedlings.
3. Hardening off seedlings before planting in the ground. They change not only the temperature, but also the duration of natural light.
4. Stepping in cloudy weather.

What to do?

Most often, the whitened leaves from the bushes fall off over time. The plants look stubby, but this is not so scary, you just need to help them survive stress faster.

For burns

It is recommended to spray the seedlings with a solution of Zircon or Epin. 1 ml of stimulant is diluted per five liters, carefully spraying the seedlings in the morning.

The same remedies are used for burns on plants planted in the ground or in a greenhouse.

On a note! Tomatoes are planted on a cloudy day or in the late afternoon. The bushes are covered with non-woven material and tree branches from the scorching rays for several days so that they quickly adapt to new conditions.

When affected by infections

Having found out that the cause of pale foliage is pathogens, they promptly begin treatment. Chemical preparations are used, since folk remedies (infusions, decoctions) are ineffective at this stage.

When carrying out treatments, the concentration of solutions is strictly observed (according to the instructions). Highly concentrated formulations harm plants, leading to foliage burns.

On a note! Timely treatment will save the tomatoes, but the fruiting period will be shifted by 1-1.5 weeks.

Soil salinization

On highly saline soils, tomatoes grow slowly; the tomato leaves are pale green, whitish, and the stems have spots. When examining the soil, a yellow-brown coating in the form of grains is visible on the surface.

Treatment regimen: the top layer of soil is carefully removed and new soil is added. Filtered and settled water is used for irrigation.

Plant nutritional disorder

White spots or borders appear on tomatoes due to lack of nutrition or irregular feeding. What to do:

• observe the dosage of fertilizers;
• alternate root feeding and spraying;
• from the second half of the growing season, increase the dose of potassium and phosphorus supplements;
• use special formulations with microelements to feed tomatoes (Kemira, Red Giant).

Eating disorder

Causes

Whitening of the leaves of tomato seedlings is often associated with a lack of iron in the soil. Despite the fact that the need of seedlings for this element can be assessed as average, compared to nitrogen, phosphorus and potassium, glandular chlorosis is still one of the 5 main problems of white leaves on seedlings.

Ferrous chlorosis is caused by an overdose of manganese during disinfection of soil, seeds and seedlings, as well as excessive liming of the soil.

How to recognize

The lack of iron in tomato seedlings manifests itself in changes in leaf color. First, yellowness begins to spread from the stem to the tips of the leaf blades, while the edges of the leaves and veins always remain green.

As the pathology progresses, the color of the leaves changes to beige-white. At the last stage, necrotic spots appear. Due to low mobility, iron accumulates in the lower tier of the seedling, which causes chlorosis to appear on young leaves.

To test the version of iron deficiency, an experiment is carried out: if a solution of iron sulfate is dropped onto a whitened leaf, then after a while the affected area will turn green.

What to do

Iron deficiency is corrected by treating seedlings with preparations containing this element. From ready-made forms you can use:

• iron chelate;
• ferovite;
• ferrylene.

They are diluted according to the instructions and used for spraying on the leaf.

Attention: spraying is only permissible in the evening or in cloudy weather. In the sun, drops of the solution can cause sunburn and chemical burns.

Among the folk remedies, a composition based on iron sulfate and citric acid is effective:

• 8 g of vitriol per 2 liters of water;
• 5 g of citric acid per 2 liters of water;
• mix both solutions and add another 1 liter of water to them.
• The seedlings are sprayed with this product three times with a 10-day break.

Prevention

1. Selection of balanced soil.
2. Control of the use of manganese solution in caring for tomato seedlings.
3. Liming the soil 1-2 months before sowing seeds.

Prevention

You can prevent the leaves of tomato seedlings from turning white. To do this you need:

• pick up tomato seedlings into separate containers;
• a week before planting, spray with a solution of microelements;
• prepare agrofibre to shelter seedlings from the bright sun and night coolness;
• two weeks before transplantation, carry out hardening;
• choose a day for planting, following the weather forecast;
• one day after planting, spray with Epin, Zircon or other growth stimulants.

Hardening is carried out in stages. This is especially important for tomatoes that grew under artificial light lamps. In the first days, plants are taken out only for a few hours, avoiding sunlight. After a week, the boxes with seedlings are left overnight, covered with thin insulation. You can cover it overnight until transplantation, it depends on the weather.

A week after the start of hardening, they are accustomed to the sun. First, the plants are left in diffuse sunlight, then placed in bright light for two hours. The time is increased by 2-3 hours daily.

Soil salinization

Causes

Tomatoes are not grown in acidic and salty soil. The use of low-quality water, as well as fertilizing seedlings with complexes with a high sodium content, leads to an increase in salts in the soil.

How to recognize

1. You can suspect soil salinity as the cause of the whitening of the leaves of tomato seedlings if the plates gradually acquire a light green, almost transparent tint. The stems become the same: with a general whitening, clear green spots remain on them.
2. A secondary sign of soil salinity is the formation of a white coating on top of the soil.

What to do

The only way to reduce the concentration of salts in the soil is to change the top layer of the soil mixture. For indoor seedlings, picking with a complete replacement of the substrate is acceptable. In greenhouse conditions, the top layer of soil is cut off and washed.

Prevention

1. Watering with settled or melt water.
2. Watering with water at room temperature.
3. Application of fertilizing according to the regime for tomatoes.
4. Growing seedlings in the ground after green manure or next to such plants if the seedlings are sown in a greenhouse.

White rot

This type of disease is classified as a fungal disease that affects the stems and fruits of the bush. This also applies to plants that are located in open areas and in greenhouses. Symptoms of the disease:

Methods to combat the disease

The main rule is to create completely acceptable and comfortable conditions for keeping plants. Also, if you immediately notice infected areas or particles on the bush, you must remove them immediately so that they do not infect all the tomatoes that are near them.

All leaves and branches that you cut must be treated with crushed chalk, clean coal, and also add potassium permanganate or copper sulfate. In addition, spray with Bordeaux mixture - this is an excellent method of prevention.

Cladosporiosis

Causes

The disease is caused by the fungus Cladosporium fulvum cooke, which persists on the seed coat and in the soil. The reason for its activity is a violation of the rules of agricultural technology: sowing seedlings without prior disinfection, thickening seedlings, growing seedlings in conditions of high humidity.

How to recognize

The disease spreads from bottom to top. The fungus affects old leaves with a gradual transition to the top.

The first sign is chaotic olive spots on the outside of the leaf blades. As the disease progresses, they acquire a lighter shade, gradually becoming white. On the reverse side of the leaf in an advanced stage, brown spots with a silvery coating begin to form.

Caution: Cladosporiosis spotting is similar to late blight. The main difference is the time at which the brown spots appear. In late blight, they are considered the first sign and are scattered along the edges of the leaf blade.

What to do

Seedlings can be treated only in the early stages of the disease.

1. Spraying with systemic fungicides: Bravo, Acrobat MC, Polyram, Quadris.
2. Spraying with biological fungicides: Fitosporin, Trichodermin, Alirin, Gamair.
3. Spraying with folk remedies: a solution of iodine in milk, whey, fermented herbal infusion.

Prevention

1. Application of organic fertilizers at the soil preparation stage
2. Maintaining a watering schedule.
3. Disinfection of soil and seeds.
4. Treatment of seedlings with biological fungicides in a prophylactic dose.
5. Growing in conditions of moderate humidity (up to 70%) without exceeding temperature limits.

Other diseases and pests of tomatoes

Whitened tomato leaves are not the only problem that can arise in a greenhouse. Infection with one or another type of disease can occur at any stage: from “birth” to fruiting. An exacerbation may also occur during the appearance of flowers, because... at this point, chemical treatment is no longer recommended.

Ash as a fertilizer for tomatoes

Why do tomato leaves curl in a greenhouse?

At such a moment, folk remedies are perfect for maintaining the health of seedlings:

Important! These drugs are not drugs for the treatment of already existing diseases, these are only preventive measures.

The main diseases to which tomatoes in greenhouses and greenhouses are susceptible:

Brown spot

Powdery mildew

Causes

The disease is caused by the fungus Leveilluia taurica. The second name for powdery mildew is white or ash.

Favorable factors for the spread of the pathogen:

• violation of the irrigation regime, constant lack of moisture in the soil;
• dense sowing without subsequent thinning of seedlings;
• excess nitrogen;
• non-compliance with crop rotation rules if seedlings are grown in a greenhouse.

How to recognize

In the first stages, powdery mildew is very similar to white rot and downy mildew. Characteristic symptoms appear as the pathology progresses.

A white powdery coating forms on the leaves. Along with it, brown balls appear on the surface of the leaf blades, and ring-shaped powdery deposits appear on the reverse side. The disease starts from the lower leaves.

What to do

To combat the fungus, seedlings are sprayed:

• folk remedies: soda-soap solution, whey solution;
• chemicals for severe damage. Optimally – Fundazol, Quadris, Topaz;
• biological preparations that are effective during fruit ripening. They use Fitosporin and Alirin.

Problems with adult seedlings

Often the leaves turn white due to disease. The disease is indicated not only by white spots, but also by other signs.

Brown spot

Happens at the beginning of fruiting. As a rule, tomatoes grown in a greenhouse suffer from the disease.

This is one of the reasons why tomato leaves turn white and dry.

The disease progresses quickly and spreads at high humidity and air temperature. The best prevention is to frequently ventilate the greenhouse and lower the humidity.

At the first signs, tomatoes should be treated with Bordeaux mixture - a solution of copper sulfate in lime milk. The procedure is repeated four times with an interval of 10 days.

White rot

This is a fungal disease that attacks stems and fruits.

The disease spreads quickly at low temperatures and high humidity.

Powdery mildew

The causative agent of the disease is the marsupial fungus.

Why do the leaves of tomato seedlings turn white? If there is a gray-white coating on the bottom and yellowness on the top, then powdery mildew is the culprit of the disease. The disease progresses with sudden changes in humidity. Tomato is very difficult to treat. It is easier to prevent the problem - during frequent rains, spray the seedlings with Zineb, an effective fungicide.

Septoria

Another name for the disease is white spotting. This is a fungal disease.

The affected parts must be cut off. The entire bush is treated with Fitosporin, a new generation biofungicide.

Source

Septoria

Causes

The disease is caused by the fungus Septoria lucopersici, which penetrates tissue cells through stomata and blocks chemical processes. Seedlings planted in the ground get sick more often. In indoor conditions, septoria is rarely diagnosed.

The reason is planting in contaminated soil and a sharp decrease in plant immunity. A favorable factor is waterlogging of the soil.

How to recognize

The main symptom of septoria is watery, round or angular spots with a diameter of 2-5 mm on the surface of the lower leaves. The pathogen is most active during tomato flowering. As the disease progresses, the spots acquire a characteristic grayish-white hue, and a brown rim forms around them.

Gradually, the spots expand, occupying more and more of the leaf plate. Black dots appear in their middle. Parts of the leaf free from septoria inclusions become yellow.

What to do

1. Treat plants with fungicides according to instructions depending on the age of the seedlings. They use Previkur, Acrobat MC, Ridomil.
2. Treatment with copper-containing preparations.
3. At the initial stages - spraying with folk remedies. An iodine-milk solution, a weak solution of manganese, and whey are recommended.

Prevention

1. Pre-sowing seed treatment.
2. Compliance with the rules of crop rotation when growing seedlings in a greenhouse.
3. Maintaining temperature conditions.
4. Spraying with biological fungicides.

Disease Prevention Measures

Why do tomato leaves curl in a greenhouse?

There are several ways to minimize problems with tomatoes. These include:

• Compliance with crop rotation - do not plant the crop in the same place as last season.
• Deep digging of the area before frost;
• The soil should be disinfected with special preparations before planting;
• Treatment of all plants on the site with natural-based preparations.

So, knowing what to do if the leaves of tomatoes in the greenhouse turn white, you can try to save the crop. Tomatoes are considered an easy crop to grow. Nevertheless, they require care, feeding, and care from the gardener. You should definitely familiarize yourself with the rules and basic care tips, then even a beginner in gardening will be lucky to reap an excellent harvest.

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