What to do if white spots appear on the leaves of tomatoes in the greenhouse

Have you noticed spots on the leaves of tomatoes and do not know what to do? There can be many reasons for their occurrence. Tomatoes are a rather demanding garden crop to grow. When the slightest deviation in the development of the plant appears, it is necessary to immediately respond to this "call for help".

The sooner you know what is going on, the more crops you can save. Next, we will figure out why white spots appeared on the leaves of tomatoes in the greenhouse and how you can solve this problem.

Possible causes of occurrence

White spots on tomato leaves can occur due to completely different factors: it can be exposure to the sun, and a lack of useful elements, and even a serious illness that has begun. Let's consider all the possible reasons in more detail.

Sunburn

Quite a common reason, especially among inexperienced gardeners. Most often, burns appear on the leaves of seedlings, which are specially exposed to the sun for hardening.

Not only dried and yellowed leaves indicate the negative effects of ultraviolet radiation, but also small white spots. Over time, they can grow and cover the entire leaf plate. The leaf will not be able to fully function and the plant will most likely die. Therefore, it is very important to notice the problem at the initial stage.

If small white spots only appear on the leaves from exposure to sunlight, the plant should be shaded immediately. It is also imperative to use growth stimulants and mineral fertilizers. However, be prepared that the harvest will still be less.

To prevent sunburn, the seedlings should be hardened gradually. It is better to transplant the plant into the ground in the evening or on a cloudy day. Plants should be watered carefully so as not to splatter the leaves: water perfectly absorbs light and acts as a magnifying glass.

Bacterial or viral infection

Very often bacteria are the cause of white spots. Diseases that can begin to manifest themselves just like this:

1. Septoria (white spot).
2. Powdery mildew.
3. White rot.
4. Mosaic.

Septoriasis

The causative agent of the disease is a fungus. Additional symptoms: The leaves dry out and curl, like the stem itself. Light spots gradually darken and cover all leaves. The disease spreads quickly and can infect not only tomatoes, but also other crops: gooseberries, currants, grapes and some cereals.

Hot weather and high humidity contribute to the growth of the fungus. Animals, insects and garden tools can be carriers of adversity.

reference... The incubation period for septoria is 1-2 weeks.

Powdery mildew

A very dangerous fungal disease that can destroy all plantings in a greenhouse in one day. It all starts with small white dots, which gradually grow into large spots. The main cause of the disease is high humidity. Air temperature in this case does not play a key role. All parts of the plant are affected.

White rot

Caused by fungal spores. Unlike septoria, low temperatures with high humidity are considered favorable. The fungus is often activated during spring frosts.

White bloom covers leaf plates, stem and fruit. The plant rots completely very quickly. In this case, usually the leaves are covered with bloom from the back.

reference... In small greenhouses, tomatoes are most susceptible to rot.

Mosaic

Viral disease. It is accompanied by not only white, but also colored spots. Tomatoes grown from seedlings are more likely to suffer from this disease. In the process, plants are constantly experiencing various mechanical influences and can become infected by contact with garden tools.

The initial stage of late blight

At the very beginning of its development late blight can manifest itself in the form of small specks of white. Then they darken, grow, the fruits become soft, and the leaves curl and fall off.

Late blight can be determined by the less pronounced color of the spots, which begin to change color very quickly.

Oedema (leaf edema)

This is not a disease, but a physiological problem. Swelling of the leaves occurs due to excessive watering at low temperatures.

Water droplets remain on the surface of the leaves, under which blisters form. At first they are transparent, then they turn white. If severely damaged, the entire sheet may swell completely.

Lack or excess of micronutrients

Such external signs can be provoked by a lack of important elements, in particular boron, which strengthens the plant's immunity to diseases. In this case, spots appear first at the base of the leaf plate, gradually moving towards the tip. They have a light greenish color, which helps to recognize the problem in time and start applying fertilizers.

An excess of certain substances can provoke the same symptoms. For example, an excess amount of manure in the soil, excess fertilizers with potassium and sodium will show such a picture.

Mistakes in using pest chemicals

If the chemical solution is improperly prepared or if it is oversprayed with a ready-made commercial mixture, it can seriously harm the plantings. Due to the high concentration of the active substance in the solution, chemical burns appear on all parts of the plant.

The danger is that this process is irreversible.... Therefore, it is very important to strictly follow the directions on insect or disease repellent.

How to save the harvest

The first and most important thing to do when detecting white spots is to determine the cause of their occurrence and assess the extent of the lesion. Treatment methods will vary depending on this.

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

With a fungal disease, you should use copper-containing preparations. They will stop the process of reproduction and the development of infection. These drugs include fungicides "Cineb" and "Hom", Bordeaux liquid, copper sulfate and 3% copper oxychloride. In this case, the infected plates must be removed with a previously disinfected instrument. Sprinkle fresh cuts with ash or treat with a solution of potassium permanganate.

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

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Preventive measures

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

1. Disinfection of seeds and soil before planting.
2. Regular disinfection of garden tools.
3. Correct crop rotation (change the location of the beds every three years or more).
4. Timely weeding.
5. Compliance with the watering regime.
6. Maintaining a constant climate in the greenhouse (temperature from +20 to 28 degrees, humidity not more than 75%).
7. Airing.
8. The introduction of the necessary fertilizers into the soil.
9. No mechanical damage to landings.

Tips and tricks from experienced summer residents

Use the advice of experienced gardeners on how to prevent crop loss:

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

Conclusion

With careful observation of the plantings and a responsible approach to growing tomatoes, there is a high probability that no negative moments will arise in the process. The best treatment for bacterial and fungal diseases, burns, etc. Is prevention.

By following the advice of experienced gardeners, you can minimize the chance of chemical, mechanical or painful spots on tomatoes, with all the ensuing consequences.