Spots on tomato leaves in a greenhouse: white - what to do if they appear on tomatoes

Vegetable growing » Tomatoes

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Kira Stoletova

White spots on tomato leaves are an alarm bell for a gardener. If you notice white spots on tomatoes, this is a symptom of one of the rather serious diseases. The main causes of many diseases of cultivated plants are improper care or pest invasion. The first step is to figure out what you did wrong.

Cause of white spots on tomato leaves

Diseases causing white plaque

Suitable conditions for ripening tomatoes are dry, warm weather. Not many regions have such a climate, so tomatoes often get sick. Infection mainly occurs through soil or seeds that have not undergone the necessary treatment. Common diseases of tomato seedlings, characterized by the appearance of white spots, are:

Septoria;
Cladosporiosis;
Mosaic;
Powdery mildew.

Fungal and viral diseases actively affect plants in conditions of high humidity levels and elevated temperatures.

One of these diseases is septoria, which is easily identified by white spots with a gray coating and a dark edging. Due to its characteristic color, the second name is white spotting. Septoria blight grows rapidly and affects not only the leaves, but also the petioles, stems, and fruits.

Cladosporiosis poses a greater danger to greenhouse tomatoes than to ground tomatoes, like septoria. Spots with a white coating on top are light olive in color and brown on the reverse side of the leaf. If there is not enough light and excessive humidity in the greenhouse, then the chances of fungus developing are high.

Another dangerous viral infection of greenhouse and ground tomatoes is called mosaic. The unusual color of leaves affected by this virus resembles a spotted mosaic of white, light green and dark areas.

Powdery mildew occurs due to excessive watering during hot periods. Characteristic are white spots with a gray coating on the back of the leaf, and a light yellow tint on the front surface. Unfortunately, the advanced stage of viral and fungal diseases leads to the death of the entire batch.

Regular inspection of seedlings will help identify white spots on tomatoes and take action.

White rot

This insidious disease is also caused by fungal spores. Unlike those described above, favorable conditions for it are high humidity and low air temperature. Most often it appears during spring frosts and is very common even in greenhouse conditions.

White rot

Externally it is characterized by a white coating covering the stem and lower leaves. The disease progresses rapidly and turns a healthy plant into rotting remains in a matter of days. At the first signs of white rot, it is necessary to spray with a solution of potassium permanganate or copper sulfate.

The main rule of prevention is regular ventilation and thinning of plantings. This is especially true for small greenhouses, where the fungus spreads instantly. It is also important to maintain a comfortable temperature regime, avoiding sudden changes. But how to dilute Trichopolum for spraying tomatoes, and how much this product can help, is indicated in this article.

White rot most often affects the stem and the back of the lower leaves.

Sunburn

It happens when seedlings cultivated indoors or in greenhouses looked richly green. But as soon as she was taken outside or planted in the garden, she suddenly began to turn pale. Pale spots spread shapelessly all over the foliage. Such lesions mainly occur on the upper leaves. All foliage may lose its color, and only the shoots of the plant will remain in their natural shade. These are real sunburns.

Remember! This happens if the seedlings are not hardened off enough or if the foliage for some reason was covered with drops of water.

Whitened tomato leaves look aesthetically unsightly, but this is not fatal to the plant itself if the damage is insignificant. As a rule, tomatoes return to normal, without any harm to health

bush. Their tomatoes only need to be fed with mineral fertilizers and growth stimulants.

If the seedling is completely discolored, then it is better to dispose of it. It can and will live, but most likely it will not bear fruit. Since it is the green mass of the plant that leads the process of photosynthesis, its disruption leads to slow development of the crop.

To avoid such damage, it is necessary to harden the seedlings for two weeks before planting in open ground. The first days, take them out only in the morning and evening for a few hours, then by the end of the second week you can leave them for the whole day. Plant seedlings either in the evening, when the sun is not so active or on a cloudy day.

Non-communicable diseases

Spots on tomato seedlings often form due to violation of maintenance conditions or errors in agricultural technology. Usually, when the problem is eliminated, the tomatoes return to normal.

But many gardeners simply do not pay attention to such mistakes, and look for the reasons for the appearance of spots solely in diseases and pests. Therefore, non-infectious problems should be examined in detail.

White spots

If white spots appear on the leaves of tomato seedlings, first of all you should pay attention to whether all seedlings are affected. Often only the top plates, or those facing the window or light source, are affected.

Burn

White spots on tomato leaves can appear from sun or heat burn. The affected organs are located at the top of the tomato or on the side facing the light source.

Reasons why leaves get burned and spots appear on them:

Watering, spraying or foliar treatment of tomatoes is carried out on a sunny morning. Drops of water turn into lenses. The sun's rays leave burn spots on the leaves. When the affected areas can already be identified with the naked eye, they appear whitish. Then they become dry and die. Usually the upper leaves suffer, since they are both wet and exposed to the sun's rays. If tomato seedlings are artificially illuminated, the side facing the light will suffer.
Watering was carried out at the root, but at high temperatures, in the morning, on a sunny day. At such a time, moisture evaporates intensely, and can literally scald young leaves. Naturally, spots will appear on them before they die.
The seedlings stood in unsuitable conditions, in partial shade. Instead of spending several days gradually increasing the intensity of light on the tomatoes, the gardener immediately places the containers in direct sunlight. Here there is no need to water the leaves - burns are guaranteed. If at the same time there are drops of moisture on the seedlings, first spots will appear in their place, then holes, and the seedlings may die.
When growing tomato seedlings in a separate heated room, the thermal regime is sometimes disrupted and increases. Or ventilation is not carried out to save energy. This could end badly. Spots will not even form on the tomato leaves - they will be completely damaged.

Burns can be easily avoided if you water tomato seedlings at the roots in the afternoon. Spray or foliar fertilize tomatoes only in cloudy weather.

It is not recommended to process and water in the evening. There is a possibility that as the temperature drops, various rots will appear, which also often appear as spots on the leaves, but not white, but brown.

It is useless to treat burns that have already occurred. If the tomato is severely affected, it is thrown away. When individual leaves are damaged, you need to make a decision whether to leave them or remove them:

If the seedlings are already weak, it is better not to touch the vegetative organs. They provide at least some additional nutrition and respiration to the young plant and participate in photosynthesis. When the time comes, the leaf with the spots will dry out and fall off.
On strong, healthy tomatoes, the affected organs can be plucked off or left. Usually, if stains occupy more than half the leaf area, they must be removed. In other cases, the decision is up to the gardener.

Weak tomatoes suffer more from burns. To increase their own immunity, it is recommended to alternately spray with Epin and Zircon every 10 days. The drugs are of natural origin and increase the resistance of seedlings to negative factors.

Frostbite

Light spots on tomato leaves may appear due to frostbite. In this case, it is not at all necessary that the room temperature be below zero:

If white spots appear on the leaves in contact with the window glass, there is nothing to even think about - this is frostbite. Or, if you prefer, a cold burn.
Sometimes frostbite occurs when ventilating. The room was warm, windows or doors were opened, cold, sometimes icy, air rushed in, frosted the leaves, and whitish spots appeared on them.
For some reason, the temperature in the room where the seedlings are grown dropped for a long time below 0° C (even very young tomatoes can withstand a short-term cold snap). The nursery may die completely.

Avoiding frostbite is very easy. You need to make sure that the tomato leaves do not come into contact with the glass. It’s even better to be at least 5 cm away from him.

When ventilating, the planting boxes are covered with newspapers. Usually this is quite enough to prevent frostbite in the tomatoes.

There is no treatment for leaves affected by low temperatures. They are treated in the same way as for burns.

As a preventive measure, treatment with stimulants such as Epin or Zircon is recommended. They also increase resistance to low temperatures.

Yellow spots

Yellow spots on the leaves of tomato seedlings usually appear due to chlorosis. This is a very unpleasant disease in which the activity of photosynthesis processes decreases and the formation of chlorophyll decreases. It manifests itself in the appearance of spots or yellowing of the entire leaf. Over time, the vegetative organ dries out. A tomato can die completely, especially a young one.

Chlorosis can be infectious; some viruses, fungi, and other microorganisms can be its causative agents. The carriers are pests. But it doesn't happen often.

Yellow spots on tomato leaves caused by non-infectious chlorosis can appear for many reasons. But most often this is a nutritional disorder - deficiency of iron, nitrogen or magnesium.

Before saving tomatoes, you need to determine which element is missing. After all, if you allow an excess of nitrogen, this in itself can lead to the death of the plant. In the best case, the seedlings will stretch out, the vegetative organs will become loose, which will open the way for infections and make it easier for pests - leaves that have lost turgor are easier to bite or puncture.

Signs of chlorosis on tomatoes caused by lack of nutrients:

Iron deficiency. Observed when the substrate is heavily limed. Starts from the top leaves. The veins remain green, the rest of the plate first turns pale, then turns yellow, and at the last stage becomes whitish.
Lack of magnesium. It is especially common when preparing the substrate yourself using sandy loam podzolic-turf soils. It begins with yellowing of the edges of tomato leaves and the area between the small veins. Sometimes they take on a different color - reddish or purple. The area near the main vein remains green. The edges and tips of the leaves bend, then the plate dies. The spread of the disease is from the lower tiers upward. It occurs on tomato seedlings only when the soil is incorrectly selected and there are no fertilizers containing microelements.
Nitrogen deficiency. It appears more often when there is a high sand content in the substrate. Yellowing starts from the veins. The rest of the leaf may remain green. Accompanied by delay and inhibition of the development and growth of tomatoes.

Chlorosis is also caused by a lack of other microelements. But this is already exotic. Nitrogen, which, by the way, is not a micro-, but a macro-element, is replenished simply. The seedlings need to be watered with any fertilizer containing nitrates.

If there is a lack of microelements, root feeding is ineffective. Plants, including tomatoes, absorb them better through the leaf.

It would be ideal to treat the seedlings with a complex of chelates. It is useful to do this at least once before transplanting into the ground and without yellowing of the leaves.

But chlorosis may have other causes:

root damage;
poor drainage;
substrate acidity is too high or low;
delay in picking - the roots do not have enough space and nutrition;
poisonous effects of sulfur dioxide.

The last point shows that the processing of the greenhouse needs to be done in the fall. The rest are a consequence of the carelessness or illiteracy of the gardeners themselves. It is recommended to urgently pick up tomatoes or transplant them into suitable soil.

There is such a cause of chlorosis as long daylight hours. Many gardeners know that it should not exceed 16 hours. But they don’t even think about the fact that tomatoes need to be given rest in one piece.

Black or brown spots

Brown or black spots on tomato seedlings are usually infectious. But sometimes they appear for the following reasons:

A grain of fertilizer, or, even worse, potassium permanganate got on the leaf.
Leaf rotting. This disease is not always caused by microorganisms. Sometimes tomatoes are simply drowned in water. This is especially dangerous if there are no holes at the bottom of the seedling containers for the drainage of excess liquid, or the substrate is too dense.
Calcium deficiency. The leaves become distorted and the edges become brown, as if scorched. It is especially common on overly acidic substrates.

What to do? Always strain fertilizers. Or at least pour it into another bowl so that all undissolved grains remain at the bottom.

Do not overwater the seedlings. Use only containers with bottom holes, or make them yourself. Plant seeds in purchased, high-quality substrate.

If the tomato leaves are already covered with weeping putrefactive spots, it is better to move the seedlings to fresh soil. Drying the soil and sprinkling it with ash will no longer help.

In case of calcium deficiency, transplantation into a new substrate is also recommended. Additionally, tomatoes are fed with Ca. It’s better to do it one sheet at a time, it will work faster.

Fungal diseases

These diseases often occur due to improper care. Water the seedlings regularly, but moderately. Do not allow the soil in the container to flood.

If the sprouts are located too close to each other, this leads to poor air circulation between them, and a fungal disease occurs.

The room where tomatoes grow should be as comfortable as possible for the development of sprouts: light, warm, not damp.

— Late blight manifests itself by the appearance of dark spots on the leaves. Soon the affected leaves begin to wither and fall off. Immediately tear out such sprouts and burn them. Treat the remaining sprouts with Zaslon. After two weeks, the seedlings will have to be treated again, but with the Barrier preparation.

To fully ensure that late blight does not occur on the tomatoes again, treat them again with a garlic-manganese solution. Dissolve 1 gram in a bucket of water. manganese and add garlic juice obtained from squeezing a glass of garlic cloves.

Blackleg attacks the stems of tomato seedlings. They become thin, the sprout does not receive life-giving moisture from the soil and soon dies. Remove diseased plants from the cup.

To avoid this disease, some gardeners add a little sifted wood ash and copper sulfate to the soil before planting seeds.

— White spotting is caused by fungal spores. White spotting initially manifests itself by the appearance of black dots on the lower leaves of the sprouts. Without taking immediate action, the disease quickly spreads throughout the plant.

Later the leaves turn black and fall off. If the disease is detected early, the seedlings can be completely saved by treating them with a solution of copper sulfate. Those sprouts that could not be saved should be pulled out and burned.

— Fusarium wilt is caused by a soil fungus. It attacks the roots of plants and causes them to wilt.

If you cut the stem of an affected plant, you will see some brown tufts. This is a manifestation of Fusarium wilt. The disease occurs from insufficient lighting in the room where tomatoes are grown, or from improper care of them.

Signs of late blight on tomatoes

Late blight of tomatoes is a fungal disease caused by lower fungi Phytophthora infestans that live in the soil. Like any disease, late blight leaves traces that are difficult to miss. Brown necrosis with light edges appears on the leaves and stems. If you turn the sheet over, you will notice a whitish coating. This is the mycelium of a fungus that multiplies very quickly. The stems turn brown and soften. The fruits become covered with brown spots on the inside and rot. The whole plant dries out and seems to bend over to the garden bed. See what it looks like in reality.

Late blight on tomato stems

The first signs of late blight can be seen on the stems: they begin to darken and dry out, and later become covered with a white coating. Check your plants regularly to watch for these symptoms. At an early stage of late blight treatment, the prognosis is more favorable.

Late blight on tomato leaves

In twisted, browned leaves, the process of photosynthesis is disrupted, as a result the plant develops worse and fruiting stops. This is the main danger of late blight. The affected parts should be removed immediately, severely damaged plants should be dug up and burned. The clock counts, because... The fungus spreads quickly in greenhouse conditions.

Phytophthora on tomato fruits

Affected fruits lose their taste and are not suitable for food. If the fruits have just begun to turn black, you can still save them: remove the unripe tomatoes and immerse them in hot water (50°C) for a minute. Then dry thoroughly and put in a box for ripening. Slightly damaged tomatoes can be eaten after heat treatment.

Brown color is one of the signs of late blight infection, which is why its second name is “brown rot.” The fungus is also dangerous for potatoes, eggplants, sweet peppers and other nightshades. The disease also occurs on strawberry bushes (garden strawberries).

Phytophthora on tomatoes in a greenhouse is not the only reason for blackening of the fruit. It may also be a manifestation of blossom end rot or lack of fertilizer.

Determinant of tomato diseases: photo, description, control measures and prevention Have the tomato leaves turned black and brown spots are visible on the fruits? Find out what diseases could cause these and other symptoms!

Solving problems with yellowed leaves

Before you start to fight the problem and save the seedlings, you should clearly understand the cause. Each disease has its own individual symptoms, which can be used to clearly understand the problem.

Diseases of tomatoes in a greenhouse and their treatment When planting tomatoes in greenhouses and greenhouses, we, of course, first of all, dream of an early harvest, and also try to protect...

Insufficient nutrition

Very often, changes in leaf color depend on a lack of certain microelements.

With a lack of copper, but an excess of organic substances, the surface of the leaves becomes speckled with a pale light green or yellowish color.
With a lack of manganese, the lower tier turns yellow, and the new one grows speckled.
A lack of iron will cause yellowing and falling leaves.
With a lack of nitrogen, inclusions of light green or yellow color appear.
With a lack of magnesium, pigmentation is not only yellow, but brown or dark red.

It is very easy to correct such a problem of lack of microelements - just start regularly applying fertilizers, which contain a predominance of the missing microelements.

Burn from direct sunlight

The color of the leaves can be affected by improper lighting. Spots of white or light yellow color can appear either from an excess of direct sunlight or from a lack of it.

With a sunburn, the density of the spots can be completely different: from small specks to large spots that cover the entire surface.

In these places, the tissue dies off completely, which is quite dangerous and can lead to death if the plant is not saved. For faster recovery, you can use the Epin solution, which is sprayed on plants after removing the affected areas. The tomatoes will develop more slowly, but you will still get the desired harvest. The only consequence is that it may ripen a little later than expected.

On a note!

Most often, spots form in those places where water gets during irrigation. Its drops become a kind of lenses. Therefore, when watering seedlings, make sure that water does not fall on the vegetative part of the plant, but is only absorbed into the soil.

To avoid sunburn, you should follow simple care rules.

It is necessary to grow tomato seedlings in the brightest place in the house, and after transferring them to the greenhouse, young bushes are protected from direct sunlight.
Tomatoes should be watered in the evening or in the morning, when there is no scorching sun.
Watering is carried out strictly at the root.

Such simple measures will help to avoid the death of plants from direct sunlight.

High humidity

If the room has high humidity, is not regularly ventilated, or is watered too often, then yellow spots will begin to appear on the leaves. In such conditions, fungal diseases begin to develop.

To correct the situation, it is enough to normalize the watering schedule. Tomatoes need regular, abundant but infrequent watering. It is enough to water the crop 2 times a week.

Brown spot

This is a fungal disease that first affects the lower tier of leaves and then moves up the bush. First, small yellow spots appear, which gradually grow and merge. The fruits of adult plants are not affected. If you do not take action, then gradually all the leaves will turn brown, dry out and fall off.

Action should be taken when spots appear on the lower leaves. They are removed, and the plant should be treated with a biological fungicide. The rules and number of procedures are always indicated in the instructions for the drug.

You can reduce the rate of fungal development by adjusting humidity. When humidity is less than 70%, the development of fungal pores stops. Similar actions are carried out to treat any fungal diseases.

Viral mosaic

The first sign of the disease is uneven coloring of the leaves, yellowish spots and inclusions appear on them. The leaves also curl downward. The affected plant can no longer be saved; it is destroyed so that the virus does not switch to other plants.

As an effective preventive measure, seeds should be disinfected by soaking them in a solution of potassium permanganate. The most common cause of this disease is initially infected seeds.

The main thing for a gardener, if yellow spots or spots appear on the leaves of tomatoes, is to correctly identify the cause and take the necessary measures. The sooner treatment is started, the higher the likelihood that the future harvest will be virtually unaffected.

Powdery mildew as a pathogen

One of the possible reasons why the seedlings are covered with white spots is the fungus “powdery mildew”. It settles both on the upper surface of the plate and on the bottom. He often chooses this crop and has a bad effect on the harvest.

Many effective drugs have been developed to combat fungi, viruses, and parasites on tomatoes. Much is known about their existence, habits, structure, and life cycle. People are well aware of the harm they can cause. It does not boil down to the fact that the leaves will lighten, and that’s all. If white spots appear on the leaves, the plant needs help - this is the beginning of wilting.

Each leaf is important for the plant. It accumulates useful substances and important processes take place. When faced with such a scourge as whitefly, mosaic, powdery mildew or lack of chlorophyll, the main thing is to act without hesitation or hesitation.

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Problem two: tomato seedlings turn pale, yellow, leaves dry out and fall off

Is it possible to save already affected plants? It is possible if you transplant them into fresh soil. The roots of each seedling must be freed from the previous soil, make sure that they are white and healthy (if the roots are yellow, black or rotten, the seedlings cannot be saved) and transplanted into light, slightly moist soil. Pour 20 ml under each plant. pink solution of potassium permanganate and place the cups in a sunny window. It may happen that during the transplantation process the roots are damaged and the seedlings wither in the light. Then you should shade them for the first time. But after rooting, good lighting and infrequent watering are mandatory and necessary conditions for the further development of seedlings.

If you follow the rules of watering and your seedlings have enough light, but they still turn yellow or pale, you should pay attention to the nature of the change in leaf color. Perhaps the plant is lacking one or another nutritional element that needs to be replenished

Brown round spots with dark edging

If the tomato leaves are covered with small dirty white spots with dark rims, then the plant has become infected with septoria or white spot. Fungal spores persist in the upper layers of soil and in fallen leaves.

The disease can appear at any time of the summer season, but it is especially dangerous in the early stages of the growing season: the leaves dry out and fall off, and this prevents further growth of the bush and the formation of ovaries.

To prevent the disease, you need to regularly inspect the tomatoes, tie them up, preventing the lower leaves from coming into contact with the soil, reduce the volume and frequency of watering in rainy weather, dig up the area and disinfect it before planting garden crops, remove affected leaves and shoots.

Author: Zimina Tatyana
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Causes of spots

Spots should not form on healthy tomato seedlings. Whatever their nature, this is a signal of trouble. Before deciding what to do and stuffing tender seedlings with chemicals or treating them with folk remedies, you should understand the reasons.

Some gardeners do not consider these causes to be a disease. It is not right. Disease is a condition of the body, including plants, manifested in disruption of vital functions. And entailing negative consequences.

The second most common source of spots is infection. Even if tomato seedlings are infected, most diseases will appear only after moving them into the ground or greenhouse. But for some, the first signs can be seen on seedlings.

Sometimes spots on seedlings appear due to pests. This usually happens in untreated areas or in close proximity to indoor flowers.

A completely advanced case is when pests emerge from a heated substrate, if one of its components is not disinfected greenhouse or garden soil. Pest larvae and sexually mature fertilized individuals overwinter there. As the temperature rises, they emerge from hibernation earlier and begin to feed. Some leave spots on the seedlings.

Infectious diseases

The appearance of spots on tomatoes caused by microorganisms is common. In seedlings, they usually appear overgrown, ready for planting in the ground or greenhouse.

There is no cure for viral diseases. Bacterial and fungal infections are controlled with appropriate fungicides. It is imperative to regulate care, since the spread of infection is usually accompanied by high temperature and humidity, and lack of ventilation.

White spots

White spots on tomato seedlings can be caused by infectious diseases:

Powdery mildew. Fungal disease. Spots appear, eventually covering the entire leaf. It is a coating that really looks like flour, as can be seen in the photo. Usually, already picked seedlings suffer. The spread of the disease is facilitated by high temperature, humidity and excess nitrogen.
Septoria. This fungus is called white spot. Starting from the lower leaves, frequent dots of the corresponding color appear. Then they merge, turn brown, and the plate dies.

Yellow spots

Diseases of seedlings, the external manifestation of which is yellow spots on tomato leaves:

Root rot. A fungal disease, one of the signs of which is yellow spots on the leaves. At the base of the stem, a brown coating and constriction are clearly visible.
Fusarium wilt. Fungal disease. It begins with wilting of the top and yellowing of the lower leaves of tomatoes.
Mosaic. Virus. Yellow dots appear only on young leaves. Gradually they grow and form a bizarre pattern. There is no cure.
Bacterial wilt. Tomato leaves turn yellow. If the tomato seedlings are large enough, aerial roots form on the target.

Black and brown spots

Dark spots may appear on seedlings due to disease damage:

Cladosporiosis or brown spot. The fungus is very similar to septoria, only the spots literally immediately become dark. It rarely affects seedlings.
Sooty mushroom. Appears only in close proximity to infected indoor flowers. Looks like a black coating.

Dark sunken spots on tomato fruits

The fruits are covered with softened spots up to 1 cm in diameter. At first they are hardly noticeable and do not differ from the color of the skin. Then they darken and turn black. The fruits are completely mummified. Brown flaky spots are visible on the roots.

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Diagnosis: tomato anthracnose is a fungal disease.

Anthracnose is widely found both in open ground and in greenhouses. More often, mature bushes suffer from it. The peak of the disease occurs in late summer and early autumn. Mainly fruits, roots and root collars are affected. Ripe tomatoes cannot be eaten; they are watery and tasteless. The spots darken over time, and fungal spores become visible on them. Anthracnose often appears on bushes together with Alternaria, causing a mixed infection.

Control measures. Remove the affected fruits and spray the bushes with copper oxychloride (40 g per bucket of water) or 1% Bordeaux mixture. The latter can also be used to prevent disease. To do this, spray the plantings 3-4 times every 10-12 days. When the greenhouse is empty, completely disinfect it with bleach (200 g per 10 liters of water).

Septoria

This disease is also called white spotting. It often appears in plants grown in greenhouses. Most often, septoria develops due to waterlogging of the air or soil.

Treatment should begin immediately after the first signs appear. It’s even better to take preventive measures in advance.

Causes

White spotting develops most often for the following reasons:

poor harvesting of plant residues - the septoria fungus settles on the remains of nightshades and spreads over time to other young crops;
high air humidity (above 80%) and high temperatures (more than 20 degrees);
infection through garden tools used to process infected crops;
transmission of the fungus by humans;
watering seedlings with contaminated water;
spread of spores by insects and wind.

Signs

The main symptom of the disease is small light pigmentation, which grows over time. Also, then a brown border forms around the spots, the middle of the spot becomes dark. It is these signs that distinguish this disease from powdery mildew.

If left untreated, the spots enlarge, the leaves dry out and fall off.

How does it develop and why is it dangerous?

The disease develops rapidly. Also, fungi are easily transmitted, so other plants quickly become infected.

Crops die quickly - 2-3 weeks of disease spread are enough, and the leaf blades will disappear. Because of this, photosynthesis will not occur, which will lead to the death of the seedlings.

How to treat?

Traditional methods

Tomatoes can be cured using folk remedies. However, this is only possible if the fungus is noticed immediately.

The following remedies work best against white spotting:

Salt solution. Dissolve a glass of salt in 10 liters of water. The culture is treated with the prepared mixture. Frequency of treatment – 2-3 times a week.
Garlic tincture. Pass ten heads of garlic through a press and add a liter of water. Dilute the resulting solution with a bucket of water and leave for 2-3 hours. Before use, strain the solution so that no garlic residue remains in it. Treatment is carried out every other day.
Iodine solution. Take a liter of milk and 20 drops of iodine per bucket of water. Mix all components thoroughly. Process tomatoes in the evening for a month once a week.

Chemicals

The following drugs will help cope with spotting:

"Thanos." Dissolve 6 mg of the product in 10 liters of water and treat the tomatoes. Pay special attention to the lower leaves. Spray tomatoes twice with a break of two weeks. Cost 400 g 1200-1400 rub.
"Revus top." In the first stages of damage, 6 mg of the drug per 10 liters of water is sufficient. At an advanced stage of the disease, you will need twice as much product. Spray the crop no more than 3 times, maintaining an interval of at least two weeks. Packaging price – 60-70 rubles.

When processing tomatoes, wear protective clothing and ventilate the room.

Biological drugs

The following remedies also kill septaria, but they are absolutely harmless to humans:

Planriz. The solution is prepared according to the instructions. Treatment is carried out every 2 weeks. The drug is also suitable for preventive treatment of seeds.
Fitosporin M. The drug helps not only to destroy pathogenic microorganisms, but also to increase immunity. The prepared solution can be used to treat soil, seeds and seedlings.

other methods

The following methods of combating white spotting cannot be independent; they must be combined with treatment with chemical or biological agents.

Such control methods include removing affected leaf blades from the bush, as well as normalizing soil and air humidity.

Prevention

Preventive measures will help prevent white spot infestation.

Such events include:

Soil cultivation. Before sowing seeds for seedlings, the soil must be calcined in a microwave or oven. In the first case, process for 2-3 minutes, and in the oven for 15-20 minutes at a temperature of 180-200 degrees.
Seed treatment. They need to be soaked in a weak solution of potassium permanganate for a day. After that, let them dry.

Causes

White spots on seedlings can appear for three reasons:

sunburn;
fungal disease;
iron or manganese imbalance.

It is quite easy to determine the origin of spotting - all three types of spots differ in appearance. Thus, burn marks usually appear in the upper part of the bush; the tissue in the damaged area looks dried out. Fungus spots primarily affect the lower leaves and are often covered with a velvety coating. When the balance of nutrients is disturbed, only the leaf blade between the veins changes color.

Sunburn

If seedlings are exposed to direct sunlight for several hours without prior hardening, the plant may suffer serious damage. You can avoid unpleasant consequences if you gradually accustom the seedlings to the sun. The first time the tomatoes need to be taken out into the fresh air for 10 minutes, with each subsequent day the procedure time needs to be extended by several minutes.

Attention!

Even a hardened adult plant, if exposed to the sun after watering or spraying, will get burned. Drops of water on leaves and stems act like lenses - focusing the rays and increasing the strength of their impact.

Burn spots appear almost transparent and can vary in size, depending on the degree of damage. Sometimes the entire leaf may turn white.

Lack of microelements

Pale spots may be a symptom of iron deficiency or excess manganese in tomato seedlings.
In both cases, white spots appear on the lower leaves. If there is a lack of iron, some leaves on the bush will turn yellow between the veins. Manganese poisoning is manifested by brown specks at all levels of the bush and deformation of the leaves of the upper tier. The cause of iron deficiency in seedlings may be excessive calcium content in the substrate. In addition, iron is not absorbed if the seedlings do not turn off the lighting even at night. For normal development, tomato seedlings require 10-12 hours of daylight, but no more.

Fungal diseases

There are several diseases that can cause seedling leaves to turn white.
Some diseases can also affect adult bushes, especially those growing in a greenhouse. They are caused by fungi. Diseases that cause leaves to turn white:

Powdery mildew. White spots covered with fluffy “moss” appear on the back side of the leaf, and on the outside there are areas of gray plaque in the corresponding places. Spreading up the bush, the colony of the fungus takes over the entire plant, causing it to dry out. The appearance of fungus is favored by too high air humidity and temperature in the room with seedlings, as well as excessive watering.
Cladosporiosis. Upon closer examination, the whitish coating has a light yellow tint; over time, it changes color to brown. Velvety brown spots appear on the reverse side of the leaf. In the advanced stage, the leaves curl, dry out and fall off. The occurrence of the disease is facilitated by a lack of light and high air humidity. Hybrid tomato varieties are more susceptible to the fungus.
Septoria. White spots appear on the leaves, growing up to half a centimeter in diameter. The edge of the spot is bordered by a gray ring, and a dot of the same shade is formed in the center. As the disease progresses, spots appear on the stem. More often, septoria occurs on plants suffering from excess watering and heat.
Mosaic rot. With this disease, white areas appear on the back of the leaves, their upper part is covered with yellow spots. Activation of the fungus is facilitated by temperature disturbances.
White rot. A velvety, whitish coating first appears on the stem. The affected areas begin to rot, secreting mucus, as a result of which the plant dies. Occurs at high humidity and cool temperatures.

On a note!

At the onset of the disease, late blight and brown spot also appear as a white coating on the leaves. With late blight, the white spots dry out, and with brown spot, their color quickly changes to brown.

What types of spotting are there?

Agronomists distinguish 4 types of spots, photos of which can be found on specialized websites. Depending on the type of spots, treatment for the plant is selected, as well as preventive measures.

What types of spots are there?

Dry. They arise as a result of damage to the crop by a disease such as Alternaria. This pathology is quite common and is most often observed in plants growing in greenhouses. Poor quality planting material can provoke damage. A fungal infection affects the lower foliage of the tomato, then begins to spread throughout the plant. As a result, on the future harvest you can notice brown depressed spots that are located around the stalk. The diameter of the affected area reaches up to 0.8 cm, which also occurs on the petiole with a stalk. If measures are not taken to combat the disease, this will lead to complete loss of the crop.
White. This type of spotting occurs as a result of damage to tomato seedlings by septoria. Most often observed in crops growing in open ground. A sign of damage is small light spots with dark gray edges. If you do not provide timely assistance to the plant, it begins to lose foliage and stops growing and developing. As a result, there is a complete loss of yield.
Brown. This spotting occurs as a result of the development of cladosporiosis, which is characterized by the appearance of rusty spots on tomatoes on the back of the leaf. Most often observed on crops grown indoors. Upon careful examination, you will notice that the foliage is white on top. If treatment for this disease is not started, it will cause the death of the seedlings.
Black. It is observed in plants that are affected by black bacterial spot. The disease begins to develop with the appearance of small light spots on the foliage, the diameter of which is no more than 0.2 cm. The cotyledon leaves begin to twist, turn yellow and fall off. As the disease progresses, the spots increase and black dots appear that completely cover the crop. A crust appears on the bushes, which prevents the penetration of nutrients, causing the death of the bush and fruits.

How to prevent stains and improve seedling health

Therapeutic treatments on tomato bushes after white spots grow on them rarely give a positive effect. Based on this, preventive actions should be promptly taken to forestall the onset of the disease. To avoid encountering similar difficulties, follow a number of recommendations from experienced summer residents:

The row spacing of the bushes should be well ventilated, so do not place the seedlings close to each other. This will help avoid a number of fungal formations.
Provide adequate watering, avoiding excess moisture. For watering, use warm water.
During hot weather, water in the evening. When the air temperature is normal, water your vegetables in the morning so that the moisture evaporates evenly throughout the day.
Place the beds in a well-lit area, this will allow the fruits to reach larger sizes.
Observe the conditions and procedure for growing seedlings and planting them in the ground. Hasty actions can lead to the death of tender young seedlings from sunlight.
Carry out timely treatments of plants and soil with fertilizers that protect against damage and promote strengthening.
Burn tomatoes affected by a viral or fungal infection and disinfect the greenhouse, soil, tools and clothing.

The main thing is to correctly determine the cause of the appearance of white spots and take timely measures to eliminate them. By following professional advice on growing healthy seedlings, you can protect tomatoes from disease and achieve high-quality yields.

Necrotic spots

In conditions of high humidity and stable temperatures (approximately 25 ° C), tomatoes have a high risk of developing bacterial cancer. The pathogen can also penetrate into mature fruits if they are cracked due to too much watering.

But the first signs of the disease appear on the leaves. Spots resembling ulcers form on them, the leaves become lethargic, despite regular irrigation, dry out on one side, curl and fall off.

Bacteria infect the entire bush and, multiplying, clog the stems and prevent the plant sap from moving through the vessels.

The main cause of the disease is the use of undisinfected seeds for planting. But a sharp decrease or significant increase in ambient temperature can reduce the spread of the disease and even lead to complete healing of the plants.

Control measures

As soon as the cause of the disease is established, we must immediately begin to save the culture. If the sun burns the leaves too much, then the tomato bushes need to be shaded a little.

If the leaves of transplanted tomato seedlings begin to turn white, you need to change the hardening time. Take it out a little earlier in the morning or a little later in the evening. During the day, place the seedlings in the shade for a few minutes, then gradually increase the walking time. Agronomists recommend using the drug “Epin”, this will help the seedlings better survive stress and bring them back to normal faster.

Fungal diseases will have to be fought. First, remove the infected foliage. Since a fungal spore may be in the soil or seed material, the seeds must be treated before planting. To do this, they are soaked for several hours in a pink solution of manganese.

Small spots with a black coating

The fungus that causes Alternaria or dry spotting becomes active in the early stages of the plant's growing season. The spores of the pathogen overwinter in the soil and are quickly transported across the site by the wind, the soles of summer residents and insects.

Round dry spots several millimeters in size appear on the yellowed tips of the leaves. Then they enlarge and merge.

These stains do not get wet even in rainy weather.

The main methods for preventing this disease are: proper care of the site (digging the soil, killing weeds, timely removal of the remains of last year's plants), abundant but rare watering of the bushes, tearing off the lower leaves of the plant, which are especially susceptible to infection.

Preventive measures against tomato diseases

Any disease, including for tomatoes, is better to prevent than to treat. After all, many diseases of plant crops significantly reduce the yield and quality of the resulting fruits, and some are difficult to treat.

Gardening specialists recommend the following preventive measures against a number of tomato diseases:

Adhere to all rules for crop rotation. Do not plant tomatoes in an area where tomatoes and other representatives of the nightshade family, suffering from the same ailments, grew last season. They dig up the ground in the autumn before frosts so that the larvae of insect pests and pathogens freeze out. Remove all remnants of vegetation in the fall so as not to create comfortable conditions for harmful microorganisms to overwinter. In the autumn and spring, carry out complete disinfection of the greenhouse, as well as the soil. If diseases are detected in large quantities, replace the soil in the greenhouse.

Find out in more detail what pests and diseases affect tomatoes in a greenhouse.

Carry out preventive treatment with biological products such as Bayleton and Actellik. Disinfect seeds before planting in the soil using appropriate chemicals (Epin, Humate or Zircon solution). Use “Gumat” for watering, and also spray seedlings with it in the morning at a concentration of 0.002%.

Carry out proper watering with warm, settled water. Water at the root and avoid oversaturation with moisture, as well as drying out of the soil. Water the seedlings during the day rather than at night when the temperature drops. But plants planted in the ground in warm weather are watered when there is no heat (morning and evening). Disinfect containers for planting if they have already been used. Disinfect the soil (in the oven, with manganese, boiling water). Be sure to add fertilizing to enrich the soil with beneficial microorganisms. For this purpose, drugs are used that include fungicidal, phosphomobilizing and nitrogen-fixing bacteria and potassium. After applying such preparations and planting the seed, 2–3 days should pass.

Carry out seed treatment - calibrate, soak, harden, warm up, treat with fertilizers and growth stimulants, disinfect, bubble. There is no need to do all the procedures at once. It is enough to select 2-3 treatments. For example, harden and disinfect. Disinfection must be carried out without fail, for example, soak in potassium permanganate for 20 minutes. and rinse. Observe the timing and depth of sowing. Do not use fresh manure for the soil mixture, as the salt it contains interferes with the absorption of nutrients. Maintain the temperature within +22…+25 °C and optimal humidity. Heat greenhouses and do not plant seedlings until the ground has warmed up and the threat of frost has passed. When growing seedlings, avoid drafts and ensure good lighting. If there is a lack of light, you can use lamps (fluorescent or phyto). Apply fertilizers in a timely manner to strengthen and develop the plant.

We advise you to read about how to spray tomatoes for ovary.

Avoid very dense plantings. In cramped conditions, seedlings develop poorly, but good conditions are created for fungi and bacteria. Use chemicals to strengthen the plant, treating the roots when diving. Conduct preventive spraying (boron, iodine, yeast, copper sulfate, garlic infusion)

Buy seeds of varieties resistant to various diseases from reliable suppliers and pay attention to the expiration date.

Features of growing tomatoes in a greenhouse

The process of growing tomatoes in greenhouse conditions is long and labor-intensive. But if everything is done correctly, the result will not disappoint, and all efforts will be rewarded with a good harvest.

Important! To harvest a good harvest of tomatoes, you need to consistently and clearly follow all the steps described.

The sequence of growing tomatoes in a greenhouse is conventionally divided into several stages:

Preparation of seeds, soil and containers for seedlings.
Sowing seeds and germinating them in a prepared container.
Pick tomato sprouts after 2–3 leaves appear on them.
Planting tomato seedlings in a greenhouse.
Caring for tomato sprouts in greenhouse conditions: watering, fertilizing, pinching, staking.
Harvesting.

In order for plants to grow well and produce a lot of ripe fruits, you need to create a microclimate suitable for the plants in the greenhouse and provide them with the necessary care:

Optimal air temperature. To prevent the sprouts from freezing when the seedlings are planted, the greenhouse is covered with a double layer of film. For better thermal insulation, it is useful to leave a small layer of air between the layers of film. Even in cloudy weather, the temperature inside the greenhouse should remain at least +18 °C, and on a clear and sunny day - +24–26 °C. At night, the air temperature in the building should not fall below +15 °C.
Good ventilation is needed to eliminate dampness and is carried out 2 hours after each watering of tomato bushes. For good ventilation, open all existing doors and windows of the structure, lift the film to open the lower part and ends of the greenhouse.
Disinfection and fertilization of the soil are necessary for the normal growth of tomatoes and the prevention of plant diseases. To get rid of last year's layer of soil, you need to remove the top 12 cm of soil. Then the soil is watered with a solution of copper sulfate to eliminate possible infection and humus is added as fertilizer. 2 weeks after planting the seedlings in the greenhouse, the soil is treated with phosphorus-potassium preparations. Fertilizing needs to be done 3-4 times per season.
A suitable planting scheme is selected depending on the variety of tomatoes that will be grown in the greenhouse. Low-growing varieties of tomatoes are planted in 2 rows, the distance between which is 55–60 cm. 35–40 cm are left between plant bushes. If a tall variety of tomatoes is grown in a greenhouse, then they are planted in a checkerboard pattern. A distance of 75–80 cm is left between the rows, and 60–70 cm between the tomato bushes.
Timely watering is carried out for the first time only 1.5 weeks after transplanting the tomato bushes into the greenhouse. Tomatoes are watered with warm water every 4 days. During the flowering period of plants per 1 sq. m of soil you need to consume about 13 liters of water.

Did you know? The world's largest greenhouse was created in the UK. It consists of two interconnected dome-shaped structures in which more than 1000 species of plants grow.

Pinching and staking tomato bushes help the plants to withstand the weight of the tomatoes and are a preventive measure for certain diseases. Pruning of side shoots is carried out in the morning so that the cut area dries in the sun. Tomato gartering is done 3-4 days after planting. In greenhouses, linear and frame trellises are usually used for tying up tomato bushes.

Problems when growing tomato seedlings

Main problems:

seedlings stretch;
plants dry out;
weak tomatoes with small leaves;
yellow leaves with green veins.

With proper care, there are no problems with tomatoes.

Difficulties in growing tomato seedlings are much more common than diseases.

The seedlings are stretched

In indoor conditions, tomatoes always stretch out due to lack of light. Even with backlighting, but cloudy weather, the plants still stretch, although not as much. For normal development of seedlings, they need the sun, which nothing can replace. To enhance the illumination of the tomatoes, place foil, reflective film or a mirror behind them.

On the windowsill, seedlings almost always stretch out.

Simultaneously with the increase in illumination, very moderate and infrequent watering is carried out. Plants on the windowsill are placed freely, since in cramped conditions tomatoes stretch upward and, at the same time, release substances that inhibit the growth of competitors. In such conditions, seedlings grow frail and elongated.

Plants wither

If the tomatoes begin to dry out, but look healthy, then the reason is a lack of moisture. They haven't been watered for a very long time. It is usually recommended to water the seedlings once a week, but it must be based on the growing conditions. If plants are kept in a sunny window at high temperatures, water more often. In cloudy weather and cool air, watering is reduced to a minimum.

The plants just haven't been watered for a long time.

The lower leaves of tomatoes always dry out as they grow. If only the lower leaves of plants dry out, but otherwise they look healthy and of normal color, then there is no need to worry - this is a natural process.

Seedlings are weak with small leaves

If tomatoes are healthy and grow in good conditions, then weak plants always indicate a lack of nitrogen in the soil. The plants are frail, light green in color with a yellowish tint.

If tomatoes grow weak and frail, then they should be fed with potassium humate or universal fertilizer for seedlings

You can use fertilizers for indoor plants, but you should never feed tomatoes with nitrogen alone. Firstly, it accumulates in the limited space of the container, and the plants begin to grow very actively, stretch out and weaken. Secondly, for such a small volume of soil it is difficult to choose the optimal dose.

Tomatoes can also be weak if they are placed too close to the window. They should be spaced more freely so that they do not oppress each other.

Yellowing of leaves

Leaves can turn yellow for several reasons.

Sunburn. The plant itself takes on a light green tint. White spots appear on the leaves, the tissue in the burned area dries out and begins to crumble. If the burn is small, the fabric dries out and the sheet becomes deformed.

If the burn area is large, the leaf curls and falls off. With severe burns, tomatoes can die completely.

To prevent tomatoes from burning, shade them from the bright spring sun.

Lack of microelements. It is more common in seedlings grown on purchased soils that have a neutral or slightly alkaline reaction. Tomatoes need a slightly acidic soil reaction (pH 5-6); if it is higher, then the plants do not absorb microelements. Iron deficiency often occurs at home. The leaves become light green in color, but the veins remain dark green. With a pronounced iron deficiency, the leaf becomes yellow with green veins, but looks healthy, elastic, and does not deform.

To eliminate the causes of yellowing, water the soil with a slightly pink solution of potassium permanganate. It simultaneously deoxidizes the soil and disinfects it. If this was not enough, then fertilize with microfertilizer.

With proper care of tomato seedlings, usually no problems or diseases arise.

Causes of yellowing leaves in tomato seedlings
How to feed tomato seedlings
Rules for planting tomato seedlings in a greenhouse and open ground

Pests of seedlings

Insects for tomato seedlings are no less dangerous than diseases

It is very important to identify the pest in time and destroy it. It is worth saying that insects, of course, more often infect seedlings in a greenhouse than on the window sills of city apartments

Nevertheless, it is better to know the manifestations of these pests and be prepared for protective actions.

Thrips

These small insects are extremely difficult to distinguish on the surface of the leaf. Thrips begin to destroy tomatoes from the tops. After a few days, the foliage loses its aesthetic appearance and changes color to an extremely light shade. This pest is capable of multiplying quickly, doubling the number of individuals in less than a week. As a preventative measure, seedlings are sprayed with an aqueous infusion of garlic.

Preparation of garlic infusion:

Chop the garlic.
Dilute it with water at the rate of 1 tablespoon of mixture per 200–250 ml of water.
Let the solution sit for 2–3 hours,
Strain through cheesecloth or strainer.

You can spray the seedlings with garlic infusion using a spray bottle. If thrips have already appeared on the seedlings, they need to be treated with Karate, Actellik or Fitoverm.

Thrips are only 2 mm long

Whitefly

The whitefly is a small butterfly up to 3 mm long. It feeds on the sap of the plant and also lays a large number of larvae, which are visible as a characteristic white coating on the leaves of the seedlings. Sometimes this coating contains black specks, as this insect carries sooty fungus spores. Whiteflies reproduce quickly and can destroy an entire plant in two days. As such, there are no preventive measures against whiteflies, but butterflies and larvae are well destroyed by the drug Fosbecid.

Whitefly is the most dangerous insect for tomato seedlings

melon aphid

The larvae of this pest usually overwinter in the ground. So the first preventative measure is to thoroughly prepare the soil for seedlings. Since aphids usually live in large colonies. Typically, aphids settle on the back of the leaf and then spread to the stems of the plant. The leaves turn yellow and curl, and then die. The drugs Actellik and Fitoverm will help you get rid of aphids.

It is not difficult to notice melon aphids on a tomato, since the insects are approximately 4 mm in length

Methods for preventing the development of diseases

As such, there is practically no treatment for white spotting; these are mainly preventive measures. To be able to prevent infection by fungi, the seed material is soaked in a solution of potassium permanganate before planting or treated with fungicides. This is the first step to getting a good harvest. You also need to take care of the quality of the soil mixture in which the seeds will be sown. It is better to purchase universal soil in the store; if the soil is taken from the street, then it is better to fry it in the oven.

Tips and recommendations from experienced summer residents

Take advice from experienced gardeners on how to prevent crop loss:

Do not plant seedlings on a hot day. If weather forecasters predict hot weather, it is better to postpone planting for a couple of days.
Hopelessly diseased plants should be uprooted and burned. After the procedure, thoroughly wash your hands and wash your clothes to prevent re-infection.
Before planting, it is better to prepare the seedlings for sunlight. To do this, place containers with seedlings in the sun every day for 1.5-2 hours for a week.
When watering, the water should be warm or slightly cool.
Everything should be in moderation: sun, water, and fertilizers.

How to save the harvest

The first and most important thing to do when white spots are detected is to determine the cause of their occurrence and assess the extent of the damage. Depending on this, treatment methods will vary.

If it is sunburn, then the plants must be protected from the sun. There are also special “first aid” products: succinic acid, “Epin” and “Zircon”. These substances will help cope with stress, but it will not be possible to return burnt tissue.

In case of a fungal disease, you should use copper-containing preparations. They will stop the process of reproduction and development of infection. Such preparations include the fungicides “Zineb” and “Hom”, Bordeaux mixture, copper sulfate and 3% copper oxychloride. In this case, contaminated plates must be removed with a previously disinfected instrument. Sprinkle fresh sections with ash or treat with a solution of potassium permanganate.

There are no effective drugs to combat mosaic, so it is very important to choose only healthy seeds for planting and carry out annual soil replacement in the greenhouse and thermal disinfection.