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There is hardly a gardener who is not at all familiar with late blight. Unfortunately, anyone who has ever grown tomatoes knows firsthand about this disease. Late blight is very dangerous, because it appears suddenly, and spreads very quickly - in a couple of days, the farmer can lose all the plants if he does not take any measures.
How to protect tomatoes from late blight, what preventive measures to take, and what to do if tomatoes are already infected with a fungus - all this is in this article.
What is late blight and how is it dangerous
Late blight is a fungal disease that affects mainly plants from the Solanaceae group. Most often, potatoes are infected with this disease, and after it tomatoes suffer.
Late blight is translated from Latin as "devouring the harvest." And this is really so: first, the fungus appears on the seamy side of tomato leaves and looks like small brown spots, then the foliage turns black, dries up and falls off, then the phytophthora passes to the inflorescences and fruits, and lastly affects the stems of the bushes. As a result, tomatoes simply die, and almost ripe fruits become unsuitable for human consumption.
Today, more than a hundred species of late blight are known, any of them is very dangerous. The spores of the fungus that causes late blight are so tenacious that they can remain in any environment for up to three years:
- on the seeds of a tomato;
- in the ground;
- in the remains of plants;
- on garden equipment;
- on the walls of the greenhouse.
Phytophtora loves cool weather, lack of direct sunlight, poor access to fresh air, sudden temperature changes and high humidity. To protect tomatoes from a dangerous disease, you need to exclude all factors favorable for the development of phytophthora.
What causes late blight on tomatoes
There are many reasons for the infection of tomatoes with late blight. But, strong and healthy plants, for which proper care is carried out, which are timely fed and watered competently, almost never get sick, including late blight they are not dangerous.
And the peak of phytophthora occurs in August, when it is still very hot during the day and already cool at night - as a result of which dew falls on the tomatoes.
The main task of the gardener is to prevent a combination of such factors. It is important to remember that the phytophthora fungus will definitely appear when:
- Tomatoes are planted too close to potatoes or other plants of the nightshade family;
- last year, solanaceous crops grew on the plot with tomatoes, and spores of the phytophthora fungus remained in the ground;
- constant high humidity remains on the site or in the greenhouse;
- the air temperature is too low;
- temperature jumps occur, which leads to dew falling on tomatoes, the appearance of fogs - all this contributes to an increase in humidity;
- tomatoes do not have enough sunlight because the tomatoes are planted in the shade or are too thickened;
- normal air circulation between tomato bushes is disrupted;
- tomatoes were fertilized too abundantly with nitrogen fertilizers;
- the soil in the area with tomatoes contains too much lime (acidic soils);
- planted with knowingly infected seeds or tomato seedlings.
In order not to have to use "heavy artillery" and use chemical agents against phytophthora, it is necessary to provide tomatoes with competent prophylaxis.
Prevention of late blight on tomatoes
Protect tomatoes primarily with proper agricultural technology: adherence to planting schemes, fertilization, watering. Agrotechnical measures directly depend on the method of growing tomatoes: in the open field or in a greenhouse, as well as on the variety and type of tomatoes: tall or determinant, early or late, resistant to fungal infections or not having immunity.
So far, there are no tomatoes that absolutely do not get sick with this infection; many varieties of tomatoes with increased resistance to phytophthora have been developed.
The next stage in the prevention of tomatoes from late blight is the proper processing of tomato seeds before planting on seedlings. To increase the immunity of a tomato and kill the spores of fungi that may be present on the seeds, the planting material is placed in a warm solution of potassium permanganate (pale pink) for 20-30 minutes. After treatment, tomato seeds are washed with running water and planted as usual.
Experienced gardeners also strongly recommend disinfecting the seedling soil and the containers themselves. Potassium permarganate is also used for this purpose.
How to protect tomatoes from late blight in the open field
The fight against late blight in garden beds consists in agrotechnical measures. So that the fungus has no chance, farmers do the following:
- Deacidify soils with a high lime content. Peat is used as a neutralizer, which is scattered over the site and dug up the ground. This will help restore neutral acidity, late blight does not like such an environment.
- During the transplantation of tomato seedlings, a handful of dry sand is poured into the holes, and tomatoes are planted in it.
- For three years, tomatoes are not planted in the place where onions, turnips, carrots, potatoes, cauliflower, cucumbers or beets used to grow - they observe the crop rotation.
- For tomatoes, choose the highest place on the site, it should be well lit by the sun throughout the day and ventilated normally. If the plot is low, it is recommended to do it for tomatoes high beds.
- Tomato seedlings are planted strictly according to the scheme developed by agronomists and indicated on the seed bag. In no case should tomato plantings be made too thick, this interferes with normal air circulation and shades the plants.
- Tomatoes are watered in the morning or late in the evening, when the sun's rays no longer bake and cannot burn the leaves. Watering must be carried out strictly under the root of the tomato, making sure that the stems and leaves remain dry.
- If there is enough rain in the region, tomatoes are not watered at all, so as not to increase the already high humidity.
- The soil between the tomato bushes must be loosened regularly so that the roots of the plants can also be ventilated.
- Fertilizers such as potassium and phosphorus are applied under the tomatoes, which help to strengthen the immunity of plants.
- Control the amount of nitrogenous fertilizers in tomatoes, there should not be too much of them.
In addition to all the above safety measures, gardeners regularly inspect tomatoes in the beds, turn over the leaves, and monitor the condition of the tomato stems. If phytophthora is detected at an early stage, there is a chance to save the crop.
Tomato bushes with signs of infection are recommended to be removed along with the root and burned. But, when most of the plants are already affected, you can try to treat them with chemicals.
The gardener must remember that late blight initially affects potatoes, and after that it is taken for tomatoes. That is why it is forbidden to plant these two crops side by side.
What to do to protect tomatoes in a greenhouse
A greenhouse is an excellent habitat for any infections; late blight fungi are no exception. Mushroom spores love moisture and stagnant air, and in greenhouses, this is more than enough.
If the greenhouse is new, the gardener has nothing to fear - the likelihood of phytophthora appearing in a closed, uninfected room is extremely small. But, when the greenhouse is reused, it first needs to be thoroughly disinfected.
Greenhouse cleaning is as follows:
- remove the cobweb;
- wash the film or glass with a disinfectant;
- remove the remnants of last year's plants;
- change the soil.
The agrotechnology of greenhouse tomatoes is as follows:
- Before planting, tomato seedlings are powdered with a mixture of tobacco dust and wood ash. This composition is prepared from two glasses of dust and a bucket of wood ash. Tomatoes should be processed with goggles and a mask.
- The walls of the greenhouse are treated with one of the disinfectants: Baikal, Fitosporin, Radiance or another.
- It is better to water greenhouse tomatoes with a drip method, using only warm water. So, moisture will flow in small doses directly under the root of the plants.
- A greenhouse with tomatoes needs to be often ventilated by opening the vents and doors.
- There should be no condensation on the walls of the greenhouse, if moisture accumulates, it is wiped with a dry cloth.
- Carry out preventive treatment of tomatoes at least three times per season.
Means of fighting late blight
It is necessary to process tomatoes for the prevention of late blight at least three times per season. They do it according to the following schedule:
- 7-10 days after the tomato seedlings were planted in a permanent place, and the tomatoes began to grow, that is, they took root in a new place.
- Just before the first flowers appear.
- Before the formation of tomato ovaries.
This schedule is only suitable for preventive treatments, if the tomatoes are nevertheless infected with late blight, the treatment must be carried out in accordance with the instructions for the selected drug.
Phytophthora can be fought against both with purchased chemicals and folk remedies. Moreover, the former are more effective, but the latter will not harm either the plant itself or the person, since they are non-toxic and do not accumulate in the fruits of tomatoes.
It is necessary to treat tomato phytophthora with fungicides - drugs that fight fungi. Gardeners most often use the following tools:
- Fundazol;
- Quadris;
- Trichopolus;
- Fitosporin;
- Previkur;
- Horus;
- Tiovit.
In addition to special narrowly targeted agents, they fight with late blight with a Bordeaux mixture, copper oxychloride, and copper sulfate. All substances are diluted with water in accordance with the manufacturer's instructions. Usually, apply fungicidal preparations to tomatoes by spraying, sprinkling tomato bushes with a mixture.
Today there are a lot of antifungal medicines for tomatoes, but the active ingredient in them is usually the same. Because of this there is a rapid addiction of the tomato to the drug, if it did not work out to overcome the phytophthora of tomatoes in one or two times, you will have to resort to folk remedies - chemistry is already powerless.
Traditional methods
Folk remedies are used more often, as they are harmless, cheap and give good results.
There are many folk ways to combat late blight of tomatoes, the most popular among the population are:
- Fermented milk whey... Whey is bought in a store or prepared on its own based on kefir. To prepare a medicine for a tomato, the whey must be diluted with water in a 1: 1 ratio. Starting from the first days of July, you can spray tomato bushes at least daily (depending on the state of the plants).
- Garlic tincture is also a strong remedy against tomato phytophthora. To prepare the composition, take not only chives, but also greens, arrows, any part of the plant. All this is thoroughly crushed (can be twisted in a meat grinder), filled with water and left for a day. After 24 hours, the liquid is drained, filtered and diluted with clean water. For a greater effect, you can add potassium permanganate to the same composition (about 1 gram). The solution is irrigated with tomato bushes.
- Wood ash it is good to use as a primary processing of tomatoes - 10 days after planting seedlings in the ground. The ground between the tomatoes is sprinkled with a thin layer of ash and watered with warm water. The processing can be repeated during the flowering period of the tomato.
- Rotten hay or straw are also a good remedy for late blight of tomatoes. The tincture is prepared as follows: a kilogram of hay is poured with a bucket of water (10 liters), a little urea is added there, and the liquid is left to infuse for 3-4 days. Then the solution is filtered and tomato bushes are treated with it at intervals of two weeks.
- Iodine you can also process tomatoes, because it is known as a strong antiseptic. To prepare the solution, take a bucket of water, a liter of fresh, but low-fat cow's milk and 15-20 drops of iodine. The fresh composition should be sprayed onto the tomato bushes, repeat the treatment every two weeks.
The salt film on the tomatoes will prevent the development of the fungus and the tomatoes will be able to ripen normally.
Outcomes
Fighting late blight in tomatoes is much more difficult than preventing this disease. Therefore, all the forces of the agrarian should be directed to preventive measures - prevention of tomato infection. In order to save tomatoes, it is necessary to observe agricultural practices, try to identify bushes infected with late blight at the earliest stage.
For an effective fight, the gardener must use combined means: alternate chemical preparations with folk antifungal compositions. Too often it is not recommended to irrigate tomato bushes, as this can increase the humidity and further exacerbate the disease. The ideal interval for processing tomatoes from late blight is 10-14 days.
