Tomato seedlings and black leg: what to water and treat against the disease, what to do to save tomatoes that are dying, as it looks in the photo, also the reasons for the appearance

At the beginning of spring, gardeners begin growing tomato seedlings. Often strong plants suddenly begin to break at the base and gradually die, infecting neighboring bushes. The cause of this trouble is the damage to the sprouts by the black leg. The disease can destroy entire seedlings, so it is important to understand how to quickly get rid of it and protect the plantings.

What it is?

Blackleg is a disease that causes stems to rot at the root collar, causing them to darken and soften. It appears after young shoots have formed 2-3 true leaves.

The causative agents of the disease are spores of pathogenic fungi that live in the upper layer of soil. These include:

Olpidium brassicae;
Pythium oxysporum;

Rhizoctonia aderholdii;
Pythium debaryanum.

They feed on dead plant cells, and at high humidity they move onto the tissues of the root system and shoots.

Blackleg is a dangerous fungal disease that can deprive a gardener of all his seedlings.

We invite you to watch a video about what a “black leg” is:

Common mistakes

The infected seedling remains in the common box. This is a serious mistake, which leads to the fact that fungi (bacteria, viruses) continue to multiply in the soil and infect more and more plants.
Lack of treatment after detection of the disease. Some gardeners think that it is enough to pull out diseased seedlings. In fact, this is not true. All seedlings and soil must be treated with a fungicide solution to prevent the disease from spreading in the future.
Pre-sowing treatment of seeds and seedling containers is not carried out. These are simple steps that will help you avoid infecting your seedlings at the very beginning.

Photo

Below you can see a photo of what the disease looks like on tomato seedlings:

Basic treatment methods, what can be treated

If infection occurs and the gardener does not understand why the plants became sick, even when he carefully carried out preventive measures, then the remaining plants should be quickly treated. To do this, you should use the drug Fitosporin. They should water the root system of nearby sprouts.

Important! It is necessary to ensure that the Fitosporin solution does not fall on unformed, weak leaves or stems. This may damage them. If the disease has affected large, well-formed seedlings, then the entire sprout can also be treated with the solution, but do not forget about the soil.

You can also make your own solution from chemicals that protect tomatoes from blackleg. To do this, you should mix: copper sulfate (1%) + chlorine copper oxide (1.5%) + a preparation containing copper (1%). If you want to simplify the process, then you can use a solution of potassium permanganate. Sprinkle the soil around the stem with it.

If diseased plants have been removed, but there is nowhere to replant the remaining tomatoes, then you can scatter 1 teaspoon on the surface of the soil. copper sulfate + 1 tbsp. wood dust, soot. Sprinkle the prepared mixture in a thin layer.

The remaining shoots must be processed.

Even disinfected or calcined soil in the oven must be treated with Baktofit. This can help prevent the appearance of pathogenic bacteria in it, affecting the growth of seedlings and the appearance of a black, thinning stem.

But the most important thing is to prevent the development of the disease. you need to constantly monitor the temperature in the room, the humidity of the soil, and sometimes loosen it so that it is saturated with oxygen.

If you create conditions for good plant growth, but at the same time negative conditions for harmful microorganisms, then you can grow healthy tomatoes, which in turn will bring good results. But if infection has occurred, then quickly taken measures will help save other shoots.

Causes of appearance: why does disease occur on tomatoes?

Compliance with growing conditions will help avoid infection of tomatoes, and deviation from the rules will make the sprouts vulnerable. The main reasons for the appearance of blackleg :

high air and soil humidity;
low temperature;
too dense plantings;
lack of regular ventilation;
bad light.

The combination of two or more negative factors increases the risk of developing a fungal disease several times and the seedlings become infected and disappear.

Blackleg prefers soil with a high level of acidity, so liming is recommended before planting seeds.

Varieties less prone to disease

There are no tomato varieties that can withstand blackleg with a 100% guarantee. Breeders have bred hybrids with excellent immunity that are not susceptible to most diseases: Lena, Vologda F1, Boheme, Charisma F1, Blitz, Virtuoso F1.

On packages of tomato seeds, manufacturers write about the resistance of varieties and hybrids to fungal, viral, and bacterial infections. But this assurance is rather conditional, since the protective forces of the plant reach their peak in the adult state of the bush, and the black leg mainly affects young, underdeveloped shoots, regardless of the variety.

Black leg in tomato seedlings is dangerous because one seedling, having become infected, quickly transmits it to everyone else. Small plantings can go down literally overnight. Large plantations die within a week. Only proper preparation of seeds and soil, proper planting and care help prevent the development of fungal infections and mass death of seedlings.

Signs of the disease

In order to notice the onset of the development of the disease in time and have time to provide first aid to the seedlings, it is necessary to inspect it daily for the appearance of the main signs of infection. These include:

darkening of the root collar;
rotting of the lower part of the stem;
withering of sprouts on sunny days.

If you touch the shoots of infected plants, you will feel that they are very soft.

Signs of seedlings being affected by disease

There are several signs by which you can quickly identify an affected plant:

Poor seedling growth.
The stem turns black or darkens in some places (most often this appears at the root).
The sprout bends towards the ground and begins to dry.
The leaves develop poorly due to blockage of the stem by bacteria.
Another symptom is a weak root system.

The disease can be recognized by certain signs.

The plant is especially weakened after a dive. It is at this time that one needs to observe its growth and development. The fungus can become more active during this period and harm the development of the stem and root. It penetrates the tomato through mechanical damage.

Fusarium is a particularly active bacterium that harms seedlings by penetrating the stem through the subcotyledon. At the same time, it immediately begins its activity, spreading toxins throughout living tissue. The stem weakens, bends or twists.

Features of bacterial damage

High humidity encourages fungal spores to travel to tomato stems and feed on living plant tissue. It takes 7 days for the blackleg to infect all the seedlings and destroy them.

Stages of disease development:

Fungi attack the root collar of tomatoes.
Dark spots appear at the base of the stems, which actively increase within 4 days.
On seedlings growing in the same container with infected specimens, signs of black neck appear.
After another 3-5 days, the tomatoes begin to break and die.

It is impossible to delay treatment, as the affected area will quickly expand and the gardener may be left without seedlings.

Soil preparation

First of all , the soil needs to be heated to no more than 120 degrees for 45 minutes. Then mix the soil with vermicompost to saturate it with useful substances. Moisten it with Fitosporin solution. Rinse the cups for seedlings thoroughly with detergents or , if the material allows, pour boiling water over them and immerse them in a 2% solution of potassium permanganate for several minutes. Spill the soil with Formaldehyde (take 10 ml of product per 1 liter of water). Loosen the soil and weed out the weeds more often.

The soil in garden plots is treated with bleach for leaching (at the rate of 200 g per 1) and leveled using a rake. 4 weeks before planting, the soil is dug up and spilled with formaldehyde solution.

What to do and how to fight?

The following describes how to treat tomatoes in order to save them. If the disease does affect the plantings, it is important to remove the diseased shoots as quickly as possible.

If the black leg has destroyed most of the seedlings, then healthy plants will have to be planted in separate containers filled with disinfected soil . In addition, tomatoes need to be treated with special means. They can be purchased at the store or made yourself.

Folk remedies: what to pour or sprinkle with?

Traditional methods of combating fungal disease do not have harmful side effects, so summer residents prefer to use them. The most effective include:

Covering the soil with wood soot or ash, a layer 2-3 ml thick is enough.
Dilute one teaspoon of soda in a glass of water and water the seedlings once a week. This volume of product is enough for 1 sq. m of soil.
Pour half a glass of onion peel into a liter of water, bring to a boil and cook for 20-30 minutes. The product is cooled and used to water the plants once every 6 days.
The soil in which infected tomatoes grow can be treated with a solution of potassium permanganate. To do this, 0.1 g of antiseptic is dissolved in 1.5 liters of water.
A special mixture of river sand, wood ash and dolomite flour can stop the development of the disease. The components are mixed in equal proportions and used to sprinkle the soil. Sand will eliminate moisture, flour will increase the immunity of the plantings, and ash will bring the acidity of the substrate back to normal.
Egg shells are crushed into powder and covered with it on the soil.
Copper sulfate (4 g) is dissolved in 1 liter of water and sprayed onto the soil.

For the decoction, it is better to use red onion peelings. They contain a high concentration of quercetin, and this substance can accelerate the growth of plantings, strengthen their immune system and improve the health of weak bushes.

What to treat: specialized preparations

Chemical and biological remedies are the most effective and quickly suppress the development of pathogens. The best drugs are those from the following table.

Name	Price	Usage
Maksim	2 ml – 25 rub.	Fungicide (2 ml) is diluted in 1 liter of water and watered at the roots of the plants.
Fitosporin M	100 g – 30 rub.	The biological product has an inhibitory effect on fungi and is used for watering seedlings and spraying the soil. To do this, mix 2 g of the product with 1 liter of water and let it brew for 2 hours.
Baktofit	10 g – 28 rub.	Biofungicide for watering seedlings, 3 g of the drug is diluted in 1 liter of water.
Previkur	20 ml – 259 RUR	Restrains excessive growth of plantings and suppresses pathogens. They spray the soil and water the plants. The solution is prepared from 5 ml of product and 3 liters of water.
Planriz	100 ml – 400 RUR	Biological product to combat fungal diseases, used for spraying and watering. 5 ml of the drug is diluted in 1 liter of water. It is worth considering that after treatment the plants must be protected from direct sunlight for about a week.

Other control methods

After processing the crop, it is necessary to adjust the conditions of detention. For this:

Diseased sprouts are transplanted into fresh and disinfected soil.
Stop watering and begin to regularly ventilate the plantings, protecting them from drafts.
If the bushes cannot be planted, then they are thinned out and hilled at the base.
The soil is carefully loosened to improve the evaporation of excess moisture and ensure air flow to the root system.

Answers to frequently asked questions

How to recognize a black leg?

Main signs: lodging of seedlings, black or brown zone at the base of the stem, wilting of foliage (in potatoes).

What to do if the seedlings become infected?

Burn the diseased plants and treat the remaining ones with Fitosporin solution.

Is it necessary to replant seedlings if several seedlings in a common box are infected?

Ideally, of course, it is necessary. But in practice this is difficult to achieve. Therefore, use methods to combat blackleg.

Which drug is the most effective?

Start with Fitosporin. If it doesn't help, then use stronger remedies. Including copper sulfate and Bordeaux mixture.

Prevention measures

Blackleg is a dangerous disease that is easier to prevent than to cure . Bushes that have been ill will weaken, which will affect their yield. Before starting sowing, it is recommended to treat the soil as follows :

The earth is frozen by leaving it on the balcony or in a cold garage until spring.
A week before use, the substrate is poured with a small amount of boiling water and placed in an oven heated to 180 °C for 30 minutes.

This procedure will destroy fungal spores, but beneficial microorganisms will also die.

It is also important to follow the rules of care and maintenance of tomatoes.:

Seedlings are watered rarely, but abundantly.
Provide the sprouts with 10 hours of daylight. If necessary, in the evening they resort to the help of phytolamps.
The room in which the culture is kept is regularly ventilated.
Before planting, the seeds are soaked in a special preparation that increases immunity and resistance to various diseases. For these purposes, you can use Irtan-Micro, Epin, Immunocytophyte.
When sowing, keep a distance to prevent crowding of seedlings.

The most effective way to prevent blackleg is to grow tomatoes without using soil. To do this, you can purchase peat tablets or coconut substrate.

Prevention of black leg on tomato seedlings

Blackleg is a seedling disease that cannot be cured. Therefore, it is very important to immediately pay attention to prevention. After all, it is easier to prevent a disease than to deal with the consequences and try to save the remaining healthy seedlings.

Note! Ideally, comprehensive implementation of all the methods described below will help reduce the risk of developing the disease as much as possible.
If you do not have the desire or ability to perform all the manipulations, then at a minimum you need to provide the tomato seedlings with normal conditions and care.

Selection of quality seeds, pre-sowing treatment

Initially, it is recommended to choose high-quality tomato seeds . It is advisable to choose products from a reliable, trusted manufacturer. The package with seeds must contain all information about the product: variety, its description, brief information about agricultural cultivation techniques, date of production, packaging, expiration date, contact information and address of the manufacturer. You should not buy seeds that have expired or are about to expire, or in damaged or dirty packaging.

Very often, tomato seeds are treated before sowing to improve germination. However, pre-sowing treatment is also important for disinfection, that is, to eliminate possible pathogens from the surface of the seeds. The most effective ways to disinfect seeds by soaking:

in Fitosporin-M . The solution should be prepared and soaked according to the instructions for the product.
in Chlorhexidine 0.05% . The seeds are immersed in a pharmaceutical product without dilution with water for 30 minutes.
in Zelenka (Diamond Green). 1 milliliter of product is diluted in 100 ml of clean water, soak for 30 minutes.

After any manipulations, you need to rinse the seeds with clean water and immediately sow them for seedlings!

But other manipulations, for example, soaking in a growth stimulant (Epin, Zircon) increases the immunity of future seedlings, which makes the plants more resistant to disease pathogens.

By the way! This article describes in detail the pre-sowing treatment of tomato seeds.

Soil disinfection

Soil disinfection is one of the most effective ways to prevent the disease, because with the help of such manipulation you can get rid of pathogenic microorganisms that cause blackleg in the soil. It is recommended to disinfect both the soil purchased in the store and the soil mixture that you made with your own hands at home.

Advice! It is advisable to disinfect the soil 1-2 months before sowing seeds, or at least several weeks.

The most effective ways to disinfect soil:

Steaming . The meaning of the method is to literally treat the soil with steam: you need to lay a cloth on a colander, pour earth into it and place it over the steam. It takes 1.5 hours to steam the soil; it is important to stir the soil regularly so that it is evenly disinfected.

Calcination in the oven . A more risky method; if done incorrectly, it can make the soil unsuitable. It is necessary to spread the slightly damp soil in a thin layer on a baking sheet (a layer of about 1.5 cm), and then place it in a preheated oven at 90 degrees and keep it at the same temperature for exactly 30 minutes.

By the way! Here we talk in detail about methods of soil disinfection, the pros and cons.

Unfortunately, disinfection can destroy both pathogenic and beneficial microflora in the soil. Therefore, a mandatory point of disinfection is the restoration of beneficial microflora to the soil . This can be done in a simple way: spill the soil with a solution of a biological fungicide, for example, Fitosporin, Alirin. It is important to do this in advance, several weeks before use!

Choosing the right soil

It is very important to sow tomatoes for seedlings in suitable soil.

Firstly, it must be neutral in acidity (acidic soil is the most comfortable for the proliferation of pathogenic fungi). By the way, to reduce the acidity of the soil, you can add wood ash or dolomite flour to it.

Secondly, it must be loose, light, air and moisture permeable . If the earth does not have such qualities, then the water will stagnate and the earth will sour.

High-quality drainage system

To avoid waterlogging of the soil and stagnation of moisture in it after watering, it is important to take care of the drainage system in advance. Such a system will remove all excess moisture.

By the way! It is important not only to make holes, but also to disinfect the container . However, you only need to disinfect it if you have already used this container before! For example, you can spill the container with a dark solution of potassium permanganate and wipe it with chlorhexidine.

First, there should be drainage holes . If they are not in the container, then you should make them yourself (with an awl, scissors, a nail).

Secondly, you need to put a drainage layer , for example, perlite, fine expanded clay, broken brick. The layer thickness is acceptable about 1.5-2 cm.

By the way! Here we talk about how to make the right drainage layer.

Sowing according to the correct pattern

Thickened crops of tomato seedlings are more likely to be susceptible to disease. Therefore, you need to sow the seeds according to the correct pattern: the distance between the seeds in the row is 2 centimeters, the gap between the rows is 3 cm.

If you have already sowed the crop densely, then you need to thin out the seedlings, leaving the strongest and strongest seedlings at the optimal distance (or dive into separate containers if it is a pity to remove some plants).

This material provides information on planting tomatoes at home.

Proper care and conditions for growing seedlings

As previously noted, blackleg pathogens can be present in the soil, however, if you follow agricultural cultivation techniques and with proper care, you will certainly be able to protect your tomato seedlings from the disease!

So what should you do?

At the stage after sowing and before germination, the seeds are kept in a mini-greenhouse (covered with film or a lid). The greenhouse creates increased humidity for seed germination. However, such conditions are also optimal for the development of fungi. Therefore, it is important to ventilate the containers daily by removing the lid for 30 minutes; Be sure to wipe away any condensation.
It is very important tomato seedlings correctly Excess moisture is very dangerous for the occurrence of blackleg, so it is important to water moderately and not too often. Watering is carried out only after the top layer of soil has dried. The water should be at room temperature; cold water should not be used. It is very important to have a good drainage system!

If you find that you have overwatered the soil, it is advisable to sprinkle the surface of the earth with dry river sand.

After watering, an earthen crust may form on the surface, preventing the penetration of oxygen, promoting stagnation of water and the activation of fungi and bacteria. Therefore, it is recommended to periodically loosen the soil surface a few hours after watering (to a depth of no more than 1.5 cm!).
It is important to ensure the correct temperature conditions: Before emergence: around 25 degrees.
After germination of the seedlings, you need to lower the temperature to 15 degrees Celsius and maintain the temperature for 7 days.
After 7 days, increase to 20-22 during the day and 16-18 at night.
It is important to avoid temperature changes and strong drops.

It is necessary to provide plants with normal air circulation , it is important to avoid stagnation. However, when ventilating, it is also important to protect your plantings from cold drafts!

Tomato seedlings should receive full lighting (12-14 hours a day). When there is a lack of natural light, it is advisable to use phytolamps. A lack of light will cause the seedlings to stretch out and weaken, which means they will be more susceptible to blackleg.

During the period of growing seedlings, you can sprinkle the surface of the earth with a thin layer of river sand (2 millimeters). Thanks to the layer of sand, the root zone will be dry, without waterlogging, because sand dries out much faster than ordinary soil.
If the window sill on which you grow seedlings is too cold, then you can place insulating material under the container, for example, polystyrene foam, foil polystyrene foam.

By the way! It was already said earlier that proper care of tomato seedlings is of utmost importance in the prevention of blackleg; this material describes in detail all the nuances!

Preventive use of fungicides

The use of fungicides can be called one of the most effective ways to prevent blackleg. The method is especially relevant if you have not disinfected the soil for seedlings in advance.

For example, after sowing tomatoes, you can water the soil with the following fungicidal preparations: Fitosporin, Alirin, Gamair, Zdorovaya Soil, Previkur. You can also bury a Glyocladin tablet into the soil.

Thus, fungicides will provide more reliable protection against dangerous fungal diseases. However, you need to use the drugs very carefully, strictly according to the instructions!

By the way! In addition to purchased drugs, you can use folk remedies. For example, to prevent blackleg, dusting the surface of the ground with wood ash is effective.