Having found signs of late blight on their site, each gardener begins to sound the alarm. In the article we will tell you about everything related to the disease and how to fight late blight on tomatoes in a greenhouse and in the open field.

What is late blight: causes and symptoms of the disease

If you have not encountered late blight and do not know what it is, then most likely you have not tried growing tomatoes in your garden. Phytophthora is the most dangerous disease of this plant, which is caused by the late blight fungus, which is translated from English as "plant eater". With its rapid development, it can destroy the tomato crop in just a few days.

The causes of late blight

First, this infection affects potatoes and after that it passes on to tomatoes. Therefore, one of the reasons for their infection is their proximity to potatoes. Infection occurs also due to high humidity, low or sudden changes in temperature, lack of sunlight, thickened planting of tomato bushes and due to an excess of nitrogen.

You can notice the appearance of phytophthora on plants in August and July. At this time, the day is still hot, the night is already cold, and in the morning there is a lot of dew, the evaporation of which is slow, especially from densely planted bushes. This moment is the best for the development of late blight.

Signs of late blight on tomatoes

At the first signs of phytophthora on tomatoes, first black specks form on the leaves, then the fruits suffer, and after them the stem is also affected. Black spots on the leaves in the rain are covered with a light oily coating - this is the fungus. Tomato inflorescences turn yellow very quickly, then turn black and fall off. The fruits are covered with black-brown marks, which soften over time. The stem is covered with uneven black spots. The disease quickly depresses the bush, which subsequently leads to the death of the plant.

Phytophthora: how to properly process tomatoes in the open field

Tomatoes that are grown outdoors are most susceptible to this disease. And therefore, in order not to face this problem, it is necessary to carry out mandatory prevention.

Disease prevention

Let's figure out how to protect tomatoes from late blight. In order not to run into her in your garden, you must adhere to the following rules:

1. The infection affects young bushes due to untreated soil, so be sure to remove weeds from the garden and do not plant tomatoes after potatoes and other crops that are also susceptible to late blight.
2. Do not place the bushes very close to each other, as in a wet year this will provoke the development of late blight.
3. Water the tomatoes only at the root, as the water on the leaves can cause disease.
4. A well-lit place for growing tomatoes should be chosen.
5. Do not overdo it with the amount of nitrogen fertilization.

Tomato treatment

If you didn't manage to prevent the disease, you need to know how to deal with late blight on tomatoes. It is completely impossible to get rid of it, since the disease spreads by transmission from bush to bush and appears immediately on several plants.
The first thing to do in this situation is to isolate the affected bushes from the healthy ones. It would be correct to uproot them altogether and burn them immediately to prevent spreading. If late blight has struck a large number of bushes, then chemical active substances will be needed.

With late blight of tomatoes, treatment is carried out with preparations in the form of a powder, which are diluted with water and sprayed on the plants. The most effective of them are boric acid, "Gamair", "Fitosporin".

How to protect tomatoes from late blight in a greenhouse

Stagnant air and moisture evaporation are extreme conditions for growing tomatoes in a greenhouse. In this room, although plants are less likely to be affected by diseases (since there is no direct source of infection), if this happens, then their spread is more intensive. In order to prevent late blight of tomatoes, greenhouses should be regularly ventilated and the bushes should be watered rarely, but a lot.

Did you know? To prevent the tomatoes from getting sick, preventive measures must be taken even before sowing, treating the seeds with a warm solution of potassium permanganate for 20 minutes.

Spraying for prevention

The question of how to spray tomatoes from late blight is very important, since the abundance of chemicals can make the fruits poisonous and unusable. In addition, during the treatments, the bushes themselves can be ruined, causing rot on them. In order not to harm the plant, you need to know how to spray tomatoes from diseases.

As a preventive measure, it is necessary to water the tomatoes with a solution of copper sulfate within a week after planting. Then, after another five days, it is necessary to treat the bushes with a decoction of horsetail, after which the leaves are sprayed with potassium iodide diluted with water. And after another five days, the plants are treated with "Epin".

For preventive treatment, a solution of acid whey of 2 liters, a glass of ash and one spoonful of honey in a bucket of water is also suitable. The bushes are sprayed with this solution every week. The most favorable time for all procedures is the first half of the day.

In order for there to be no reasons for the development of phytophthora in greenhouses, it is necessary to remove dust and cobwebs, to monitor the cleanliness of the interior.

Treatment of late blight on tomatoes

If late blight appeared on tomatoes, then for many gardeners, the question of how to deal with this scourge becomes urgent. There are two ways to treat phytophthora:

• using active chemical substances;
• using folk remedies.

Important! In the treatment of phytophthora remedies on tomatoes, they are used together with plant nutrition that strengthens their immune system. With late blight on tomatoes, treatment is carried out with such chemicals as "Alirin-B", "Gamair", "Baikal EM-1". Another effective remedy is Bordeaux liquid.

How to deal with late blight with folk methods

We list the most common folk remedies for phytophthora on tomatoes:

1. Garlic tincture with potassium permanganate. You will need 100 g of minced garlic, which is poured into a glass of water and left for 24 hours. A day later, filter and dilute with 10 liters of water and 1 g of potassium permanganate. You need to spray the bushes every two weeks.
2. Milk serum. In a 1: 1 ratio, the whey is diluted with water and tomatoes are processed daily since July.
3. Ash. Seven days after planting and when setting the fruits, the ash is sprayed between the rows before watering.
4. Tincture of rotten straw or hay. It is necessary to pour 1 kg of hay with 10 liters of water, add a handful of urea there and leave for 3-4 days. After a while, strain and process the bushes after 1.5-2 weeks.
5. Iodine with milk. Take 10 liters of water, 1 liter of low-fat milk, 15 drops of iodine, mix everything and treat the bushes with the resulting solution every two weeks.
6. Salt. For one glass of salt, take a bucket of water and process large green fruits once a month.
7. Copper sulfate solution. Add 2 tablespoons to a ten-liter bucket of water. l. copper sulfate and water the plant with the resulting solution.
8. Yeast. For 10 liters of water, you will need 100 g of yeast. The plant is treated when phytophthora appears.
9. Wrapping the roots of seedlings with copper wire before planting or piercing the stems of tomatoes. It is necessary to anneal the copper wire and cut into pieces of 4 cm, and then, at a distance of 10 cm from the surface of the ground, pierce the stem, insert the wire and bend its ends down.

The fight against late blight on tomatoes with folk remedies is as effective as the fight with chemical agents.

Did you know? Copper sulfate can help get rid of late blight, but it is very dangerous for the leaves. Falling drops of solution can burn the plant, after which it may die.

Late blight-resistant tomato varieties

Unfortunately, there are no tomato varieties that will be completely resistant to late blight. Despite their great variety, there are tomatoes that are less and more resistant to this disease.

For cultivation in greenhouse conditions, varieties of a determinant type are more suitable. They are short, early ripening and yield a good harvest.

Determinant tomato varieties:

Indeterminate varieties are characterized by tall stature and large fruits. They can be grown both in greenhouses and outdoors. A prerequisite for their normal development is pinching.

Important! When growing indeterminate varieties in your garden, you should tie them to high racks, since the main stem may break due to the large weight of the tomatoes. More resistant varieties of the indeterminate species are:

Prevention of phytophthora

Proper care of tomatoes will help protect tomatoes from late blight. Care is carried out depending on the type of development, which, in turn, is divided into generative and vegetative.

When grown vegetatively, plants develop quickly, but fruits are formed slowly. And because of the late fruiting, especially in a rainy summer, late blight will not keep you waiting. And in order to prevent this, you need to carry out pinching. This will provide improved air circulation and accelerate fruit growth.

With the generative method, active fruiting occurs. A large number of tomatoes on the bush leads to a stressful state of the plant, which reduces its resistance.
In order to prevent the appearance of late blight, it is necessary to regulate the number of tomatoes on the bush. At unfavorable times, it is better to reduce the number of fruits and remove peripheral buds. This will ensure quick ripening and increase the plant's resistance to diseases. In order to prevent phytophthora from appearing in rainy weather, even an unripe crop can be harvested, this will help the plant fight the disease.

How to save and consume affected tomatoes

Tomatoes that have already overtaken late blight can be preserved by heat treatment. To do this, you need to pour 60 ° C water into a basin and lower the affected fruits into it. Be careful: the tomatoes should be warming up, not boiling. When the water cools down, add a new one until the tomatoes are completely warmed up. After the water procedure, the tomatoes are dried and placed in a dark place or on a windowsill for ripening. During warming up, phytophthora spores die, and then tomatoes can be eaten. They can also be canned. If the fruit is damaged until it is completely blackened, the thermal effect will not help, and they will have to be disposed of.

One hundred percent getting rid of late blight cannot be guaranteed in any of the ways. However, it is in your power to prevent the onset of the disease and fight late blight of tomatoes. To do this, you need to follow all of the above recommendations, carry out preventive measures, and then you will get a large harvest of healthy tomatoes.

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