Black leg in cucumbers: causes and prevention measures

The appearance of a disease such as blackleg on cucumbers is a problem that almost every garden owner faces. This disease quickly spreads throughout the entire planting and destroys the plants. Therefore, it is very important to react quickly and take measures to get rid of the dangerous fungus, and in the future carry out competent prevention of its reappearance.

What is the disease

Blackleg is an infectious disease that can appear both on the roots of plants already planted in the ground and on seedlings. As a rule, the disease affects the weakest and youngest shoots.

Symptoms of the disease appear at the moment of rapid development of cotyledon leaves: the brown color of the roots and stem is a signal that urgent measures need to be taken.

The main causative agent of the disease is a parasitic fungus that can spread through organic fertilizers, such as manure, or through soil. For some time it remains in the soil or on the remains of vegetation and, if favorable conditions arise, it begins to quickly spread and infect one plant after another. If you don’t react quickly, then in just a couple of days the entire cucumber plantation can get sick, or, in the worst case, die.

From cucumbers, the disease can easily spread to other plants - tomatoes, potatoes, eggplants, which will lead to complete loss of the crop.

Useful tips

To save cucumber seedlings from blackleg, do not forget about simple nuances:

Sow seeds in slightly moistened soil.
Disinfect the soil before planting.
Maintain moderate watering.
Maintain sowing density.

At the initial signs of blackleg infection, action must be taken. First of all, remove diseased plants, stop watering, and cover the soil itself with ash.

How to identify the disease at an early stage

When a plant is affected by a disease, the root collar of the seedling becomes brown and changes shape, forming a constriction. The lower part of the stem darkens and becomes wet. Destructive processes begin in the root system: the root turns yellow and becomes rotten. The lower leaves gradually turn yellow and fade.

Before planting seedlings, you must first inspect the condition of the soil and neighboring plants. You can tell that the soil in this place is infected with a fungus by the flowering perennial plants. Most often, the victims of the fungus are the lion grass and snapdragons.

How to deal with black leg in cucumbers

The best method of control is prevention, but if the plant has already suffered from the fungus, then the weakest seedlings should be removed along with a clod of earth and destroyed. This should be done if the infection has not yet spread widely. In the event that a whole epidemic is raging in the area, then other measures will be required.

How to water black leg cucumbers

Some gardeners do not recommend using chemicals - they can damage young plants and deprive them of their harvest. In any case, you definitely shouldn’t abuse them.

Drugs against blackleg

Among the industrial products you can use:

Planriz is a drug against a complex of vegetable diseases. Special bacteria enter the cucumber roots and fight root rot with the help of antibiotics and enzymes.
TMTD is a yellowish-gray powder used for dry seed dressing.
Baktofit - helps if the disease has spread to vegetable, fruit, or grain plants. It acts against many fungal diseases and has a positive effect on productivity.
Phytoflavin 300 is an antibiotic that actively fights bacteria and fungi, and also stimulates the growth of vegetables.

Folk remedies

To combat blackleg using folk remedies:

A solution of vodka and water in a ratio of 1:10, which is used to spray cucumbers and soil.
Infusion of onion peels - seedlings and soil are treated once a week.
Sprinkle the surface of the earth with ash or charcoal. When carrying out the procedure, it is necessary to reduce the number of waterings.
The ash is mixed with copper sulfate (1 tsp of sulfate per 1 cup of ash) and scattered under the roots of the seedlings.
Young seedlings are sprayed with a soda solution (1 tsp per 250 ml of water).
Diseased seedlings can be watered with an infusion of onion and marigold peels.

Soil and seed requirements

It is not recommended to plant seeds in poorly prepared soil. Before planting, it would be a good idea to pour boiling water with the addition of potassium permanganate on it - this will help destroy pathogenic bacteria and fungal spores. After treatment, you need to wait a couple of days for the soil to rest, then you can start planting the seeds.

Do not plant seeds in freshly treated soil. They can “burn out”, then it will definitely not be possible to grow a crop.

The choice of place to purchase seeds should also be approached responsibly. If there is a suspicion that diseased seeds were purchased (this happens especially often if taken from hand at the market), you should keep them for half an hour in a solution of potassium permanganate.

To prepare the soil for planting seeds and not be afraid of diseases, you must follow several rules of agricultural technology:

Disinfect the soil for seedlings. In winter, it can be taken out into the cold to kill the microorganisms living in it. In spring, water with weak concentrated potassium permanganate.
Sometimes the cause of the disease can be increased acidity of the soil. Its level can be reduced by spraying with dolomite flour or wood ash. Among industrial products, Trichodermin is suitable - it contains fungal spores, with the help of which it suppresses bacteria.
Before planting, treat the seeds with Planriz, Bactofit or Fitosporin. They will help prevent the disease and eliminate existing symptoms.
If mold appears on the surface of the soil after watering, the top layer of soil can be sprinkled with river sand or ash.

To avoid most preparatory measures, it is better to buy seedling soil and seeds in specialized stores.

Unsuitable conditions

One of the reasons for the development of the disease may be unsuitable conditions for planting seedlings. Several rules must be followed to create favorable conditions for growing plants:

Water the seedlings abundantly, but not too often - the soil should be moist, but its surface should be dried in the sun.
There may be excess humidity in the greenhouse or the temperature may be too high. You should regularly ventilate the room, but avoid strong drafts, which can also damage the plants.
Monitor the lighting and protect the seedlings from the cold using film.
Don't plant the seeds too thickly. This is necessary so that the disease does not quickly spread to the entire garden bed.
To prevent the soil from drying out, systematically loosen the plants at the stems.
To prevent rotting of the sprout, and to prevent water from stagnating at the neck of the root, its base can be sprinkled with sand in a layer of no more than 2 mm.

Do you always disinfect the soil before planting seeds?

Yes

What to do if a black leg appears on cucumber seedlings

A common cause of the disease is planting seeds ahead of time indicated on the package - seedlings have reduced immunity from being on a cold windowsill and lack of lighting.

To prevent the disease from spreading further, all affected seedlings must be removed as quickly as possible and destroyed along with the soil. Treat the remaining plants with a solution of Fitosporin (100 ml per 10 liters of water) from the place where two true leaves form to the root. Seedlings can be watered with 1% Bordeaux mixture or a raspberry solution of potassium permanganate. It would not be superfluous to sprinkle the soil with a mixture of copper sulfate and wood ash (1 tsp of vitriol to 1 cup of ash).

If, nevertheless, the fungus has spread to most of the seedlings, then healthy plants should be isolated in good soil and placed in a warm place (affected cucumbers will need to be destroyed along with the soil). As soon as the soil dries out a little, it should be watered with a solution of Fitosporin or Baktofit. Within a week after treatment, the plants should take root. Then you can put them in a cooler place.

Blackleg-resistant cucumber varieties

It is prudent to immediately purchase seeds that are resistant to the appearance of blackleg. These include:

“Nezhinsky” marked F, which means a hybrid bred specifically for growing in cold weather and low light conditions. It is resistant to blackleg and other putrefactive diseases. Cucumber fruits are small in size and are best suited for canning.
“Murashka” - cucumbers are unpretentious for open ground and can withstand even swampy soil. The fruits are medium-sized with large pimples.
“April” - suitable for regions of central Russia and southern climates, where the first cucumbers can be obtained already in April. Gives large fruits.
“Delicacy” - perfectly resists cold, high humidity and most fungal diseases. The fruits are born with a high sugar content, which gives them a special taste.
“Rodnichok” tolerates heavy soils well and is immune to most fungal diseases even in open ground. Medium sized fruits.

All of the listed varieties have a weak point - they do not produce seeds and their price is much higher. So the gardener will have to choose: either spend more money or take risks.

What is the reason

The cause of plant damage is the proliferation of fungus not only on the roots, but also in the soil itself. This form is resistant to negative external influences and easily takes root even in conditions of nutrient deficiency.

Important!

The fungus can exist for a long time not only in open ground, but also in greenhouse conditions, on organic debris and even on the walls of seedling containers.

The accumulated critical mass of the parasitic fungus leads to damage and the appearance of the first visible signs. This happens due to insufficient care of the soil itself or due to the introduction of contaminated fertilizer. One of the obvious reasons for the appearance of black leg on cucumbers is insufficiently thorough cleaning of containers, lack of healthy crop rotation and lack of movement of crops on the site for several years.

The rapid development of a fungal disease is always facilitated by factors such as:

excessive watering;
sudden changes in temperature;
lower temperatures at night;
insufficiently loose and fertilized soil;
low illumination.

Effective prevention

To avoid the appearance of pathogenic bacteria on cucumbers, you should carefully select seedlings in stores and avoid buying seedlings by hand. If there is no other way out, you need to carefully examine the seedlings, and at the slightest sign of illness, it is better to refuse the purchase altogether.

Before planting, the soil must be carefully prepared by pouring boiling water with potassium permanganate on it. It is better to carry out the procedure several times if there have already been cases of infection on the site. The walls of the containers for carrying seedlings can also be wiped with the solution, since harmful bacteria may remain from the last time.

It is easier to prevent any disease than to spend energy on treatment later. You must carefully follow the advice on growing, do not be lazy in preparing the soil and carefully inspect each sprout so that one does not cause the death of all. These simple rules guarantee a healthy and abundant harvest.

Important

Blackleg is a fungus that lives in any soil. Development begins only after the onset of favorable conditions.

To get rid of fungus, it is first recommended to pay attention to the ambient humidity and temperature. These indicators should not be high.

The disease is quickly transmitted from one plant to another with insufficient air ventilation. Usually the sprouts are planted very densely together. It is better to take pots with soil outside for the winter. The soil will freeze, and at the same time it will be disinfected.