Black leg of cabbage: how it manifests itself, how to fight, pathogen

The black leg of cabbage seedlings appears due to high humidity, spreads through infected seeds or soil. To combat it, fungicides, biological preparations are used, and less often – folk remedies. The main methods of treatment and prevention are described in the article.

Damage symptoms

Blackleg of cabbage is an infectious disease caused by bacteria (in Latin they are called Pectobacterium), as well as fungi (for example, Olpidium brassicae). Sometimes it is also called black rot, because due to the infection, the stems of plants rot and soften, and then die.

The main signs of the disease are:

• the root neck becomes black;
• she rots;
• becomes thinner;
• plants lag behind in development;
• with a mass defeat, seedlings of seedlings die rather quickly.

Causes of appearance

You can determine the black leg of cabbage seedlings by the characteristic symptoms (pictured). It is also important to understand the causes of this pathology. The most common factors include:

1. High humidity level. Most often, it is associated with a violation of the norm of irrigation, so you need to monitor this especially carefully.
2. The weather conditions are warm combined with frequent rains.
3. The black leg affects cabbage even if it is planted too tightly.
4. Excessive fertilization with nitrogen.
5. Too sharp and frequent temperature changes, drafts (when growing at home).
6. Infected seeds or soil from the previous season.
7. Lack of ventilation and loosening.
8. Too acidic soil. If the pH is less than 5,5, it is necessary to feed with dolomite flour or wood ash.

Thus, there are a lot of reasons for the appearance of a black leg on cabbage seedlings. Most often they are associated with improper care, for example, excessive watering, lack of preplant seed and soil treatment. On the other hand, the disease can affect seedlings and adult plants with good care. If the climate is too humid, temperature changes are often observed, it is better to grow a crop in a greenhouse or greenhouse.

Signs of the disease

The black leg appears both in cabbage seedlings and in relatively adult seedlings.

The disease affects plants in two stages:

1. At the time of the appearance of cotyledons or the first 2-3 true leaves.
2. After transplanting seedlings into a greenhouse or open beds.

In both cases, the signs of damage to cabbage seedlings by the black leg are approximately the same. But there are certain differences, which are detailed in the following sections.

seedling

If a black leg has struck cabbage seedlings, identifying the signs is quite simple. Young seedlings noticeably lag behind in development, the stems soften and become, as it were, watery. And not along the entire length, namely in the root zone, i.e. in the neck area.

They quickly rot, then thin out. Therefore, the sprouts bend to the ground and begin to die en masse even with good care. The black leg of the seedling extends to neighboring cabbage plantings. Because of this, almost all plants stop developing.

On mature bushes

If the black leg struck not seedlings, but adult cabbage, the main signs are as follows:

• thinning of the root region of the neck;
• blackening;
• the stems begin to dry out;
• plants lag behind in development, but do not die;
• cabbage heads are often formed;
• however, on the side of the fork, like the leaves, they begin to rot;
• they wither and die;
• swellings are formed on the surface of the leaf plates – the fruiting bodies of fungi.

What is the danger of the black leg

The causative agent of the black leg of cabbage seedlings is dangerous because it is very active. At the seedling stage, mass infection is often observed, due to which almost all seedlings die.

Another risk is that the disease is difficult to treat. And if it has passed into a neglected form, it will not be possible to cope with it. Therefore, it is easier to prevent the development of the disease than to deal with the consequences.

It is important to understand that the pest infects seedlings not only of cabbage, but also of other plants. In addition, it will certainly remain in the soil. Therefore, such soil should be disinfected or frozen. Otherwise, from year to year there will be large crop losses.

Fighting black leg on cabbage seedlings

There are many ways to deal with a black leg on cabbage seedlings. First of all, it is recommended to remove all affected plantings, since they will certainly infect healthy plants. Next, it is necessary to carry out treatment with special preparations. How to proceed in different cases is described in detail in the following sections.

Agrotechnical methods

First of all, for the prevention and control of the black leg on cabbage seedlings, it is necessary to observe the agricultural practices of cultivation. Seedling crops should be at least 3 cm apart. After the appearance of 2-3 true leaves, they must be swooped down or thinned out.

Cabbage should not be grown in the same place for more than three years in a row

When planting in open ground, a scheme of at least 40 * 40 cm is observed. Another common option is 40 cm between seedlings and 50 cm between rows. It is better to plant in a checkerboard pattern, then all plants will be evenly lit.

It is also important to understand that cabbage should not be planted in a field where any cruciferous representatives have grown for several years in a row. This is cabbage itself of any variety, as well as radish, radish and other crops.

Biological agents

If any preparations can be used against the black leg of cabbage at the seedling stage, then only biological preparations should be used during the tying of heads of cabbage. The most effective include:

• “Fitosporin”;
• “Trichodermin”;
• “Baktofit”;
• “Gaupsin”;
• “Effect”;
• “Gamair” and others.

Chemicals

Measures to combat the black leg of cabbage seedlings include chemical treatment, for example:

• Fundazol;
• “Energodar”;
• “Polycarbazine”;
• “Previkur Energy”;
• “Zineb”;
• “Daconil”.

Folk remedies

You can also fight with the black leg of cabbage seedlings with folk remedies. They are used at an early stage in the development of diseases, as well as in cases where plants have already begun to tie heads. The main methods are:

1. Treat the soil surface and seedlings with vodka diluted 10 times with water.
2. Spray plants and soil with infusion of onion peel (2-3 times with an interval of 5 days). For cooking, take 100 g of husk, pour a liter of boiling water and insist for a day. Then filter and start processing.
3. Spray with infusion of wood ash. It will take 20 g of powder per 1 liter of water.
4. Prepare an infusion of marigold flowers – 500 g per 10 liters of boiling water. Infuse for two days, strain and process the cabbage.

preventive measures

Since it is difficult to treat the black leg of cabbage, and in the case of seedlings it is almost impossible, it is recommended to follow preventive measures. They are simple, but significantly increase the effectiveness in the fight against the disease.

For prevention, it is necessary to disinfect the soil and seeds

Soil disinfection

To disinfect the soil before planting seedlings, there are several ways:

1. Spill with a solution of potassium permanganate concentration of 2-3 g per 1 liter. It is a powerful antiseptic that destroys both fungi and bacteria.
2. Keep a few days in the freezer.
3. Pour over a solution of “Fundazol” or another fungicide (prepare according to the instructions).
4. If there is no time, hold for 15-20 minutes in the oven at a temperature of 120 degrees.

Regardless of the chosen method of disinfection, not only harmful, but also beneficial soil bacteria are destroyed. Therefore, after processing, it is recommended to apply bacterial fertilizer. It can be Rizotorfin, Azobacterin, Phosphorobacterin and others.

Seed disinfection

Along with soil disinfection, it is recommended to pickle the seeds to prevent the black leg of cabbage seedlings. To do this, use, for example, the drug “Planriz”. It is bred according to the instructions (concentration 1%) and the seeds are treated the day before sowing.

The Fitosporin remedy is also used – only four drops are added to a 200 ml glass of water and the seeds are pickled for two hours immediately before planting. Another way is to use potassium permanganate (1 g per 1 liter). The tool is quite powerful, so you can keep the seeds in the solution for no more than 25-30 minutes.

Treatment of seedlings

One of the effective ways to prevent the black leg is to treat cabbage seedlings with special means:

1. “Fitosporin” (bred according to the instructions). It should be sprayed after germination, as well as immediately after transplanting into open ground or into a greenhouse.
2. A mixture of mullein 5 kg with clay 1 kg per 10 liters of water. The roots of seedlings are treated with this solution during transplantation to open beds.
3. Also, cabbage roots can be sprinkled with wood ash powder by mixing it with sand. This is especially effective in acidic soils as it helps bring the pH down to 6-7 (acceptable values ​​for most plants).

“Fitosporin” – one of the fungicides for the prevention and treatment of black leg

Other measures

Also, for the prevention of the black leg of cabbage, other rules for caring for seedlings should be observed:

1. Be sure to observe the rate of watering at the stage of growing seedlings. The soil should not be excessively moistened – it is enough to give water three times a week, i.e. in the “every other day” mode.
2. After transplanting cabbage seedlings into open ground, for prevention, it is also not watered too often – about twice a week, and in the presence of rain they do not give water.
3. If the climate is unfavorable, there are often temperature drops, rains, it is recommended to plant seedlings not in open ground, but in a greenhouse.
4. To prevent the black leg, seedlings must be ventilated. The film is periodically opened, and after the emergence of shoots, it is finally removed.
5. The soil is periodically loosened, if necessary, weeding is done. This is especially important after watering, applying liquid fertilizers.
6. If there is a suspicion that the soil is too acidic, it is recommended to measure the pH beforehand. This can be done using indicator paper or a pH meter. If the indicator is less than 5,5, wood ash or dolomite flour (150-200 g per 1 square meter) must be added to the soil.
7. When growing in a greenhouse, the room also needs to be periodically ventilated, especially after watering. If at night the temperature does not drop below +14, it is left open around the clock.

Conclusion

The black leg of cabbage seedlings is a rather dangerous disease that can lead to the death of all seedlings. To prevent this from happening, it is recommended to disinfect the soil in advance and pickle the seeds. It is also important not to violate the norm of watering, regularly ventilate the greenhouse and greenhouse for seedlings.