Fusarium and verticillium wilt of cucumber: treatment and how to deal with it with photo

Sometimes you can notice Fusarium wilt of cucumbers grown in greenhouses and in open beds. Such a problem can be caused by various reasons, but most often it occurs due to fungal infections of the vascular system of plants (verticillium or fusarium).

Causes of occurrence

In some cases, cucumbers begin to wither due to the underdevelopment of the root system. This can happen when planting cucumbers in a greenhouse in too dense soil. At the same time, the root system cannot provide the grown plant with nutrients and moisture.If you examine such a plant, then it will not reveal signs of damage by microorganisms, but only the underdevelopment of their roots.

Pay attention! If cucumber seeds are planted in the affected soil filled with hot water without disinfecting it, then the plants will be affected by thermophilic fungi and pathogens that can cause temporary toxicosis.

Research on withered plants shows that fine roots die off as they grow into the ground. The period from the beginning of germination to the withering of the whole plant is sometimes more than a month. Withering cucumbers lose their ability to resist diseases caused by various bacteria and infections.

If the soil is enriched with a culture of live bacteria and fungi, then the process of its detoxification is accelerated. For this purpose, the following drugs are used: Baktofit, Trichodermin, Fitosporin-M, Integral, Pseudobacterin-2.Compost applied to the soil can have the same effect. It helps restore fungistatic soil.

With insufficient pre-sowing preparatory work of soil with reduced moisture capacity, cucumbers can be affected by a fungal infection of Verticillium albo-atrum. This happens when they enter the vascular system.

Narrow and high beds should not be created. When they are watered, water does not have time to penetrate deep into, and the plants do not receive the right amount of moisture. If the soil temperature is above 28 degrees, then the root system of cucumbers weakens, and the fungus in the ground begins to infect the plant.

If this affects the leaves of the lower tier, marginal spotting may occur. The leaf plate located between such veins begins to die. The foliage of the upper tier loses its turgor and becomes chlorotic. If you make a cut of such a sheet, then under a microscope, you can see the mycelium along with it.

Fusariosis (tracheomycosis and verticillium) cucumber

The danger of this cucumber disease lies in causing great damage to yields. The disease can quickly spread over vast areas. Up to 50% of all grown vegetables can be covered by infection of the above-ground parts of plants.

Characteristic symptoms of the disease

When this type of disease is affected, not only foliage dies, but also the stem and root system. Its occurrence is facilitated by a relatively high air temperature. Fusarium cucumbers are afraid of lower temperatures.

Symptoms of Fusarium begin to appear with damage to the root system (root rot). This problem often occurs in greenhouses and greenhouses. In the soil, the infection accumulates and spreads to new areas.

The first signs after the onset of infection occur after a few weeks. Clogging of vessels with tracheomycosis, shortly before fruit formation, leads to the fact that in the hottest time of the day the foliage wilts, which ultimately leads to the death of the plant.

During the formation of greens, the symptoms of Fusarium on hot days may change. Vessels of plants blocked by tracheomycosis do not affect the development of the root system. The disease proceeds sluggishly, but the plants stop growing ahead of time. Microscopic examination of the stems reveals the mycelium of fungi, as well as neoplasms in the vessels in the form of a granular brown substance.

At the same time, a silver-white mycelium appears at the base of adult plants. The mycelium that appeared on the stems leads to the rapid death of the plant.

Biological feature of Fusarium and Verticillium

For the causative agent of verticillium, the high temperature of the soil (more than +26 degrees), as well as the lack of moisture, is favorable. At the same time, Fusarium is favored by low temperatures and waterlogged soil.

Both of these diseases prefer acidic soil. Plants affected by this disease show the following types of disorders: vascular occlusion, toxicosis, wilting, tissue necrosis.

Fungi can enter plants both immediately after sowing and after the seeds germinate. When the root system is injured, a kind of gate is formed for the infection to penetrate through them.

Mushrooms form colonies in the vascular system, and then gradually reach the parenchyma. If the soil, in which even a small colony of conidia is located, is not disinfected, then it will be practically unsuitable for growing cucumbers.

But the presence of a pathogen does not always lead to drying and death of the plant. With properly organized care, the number of infected bushes is reduced by about 3 times. And vice versa, improperly carried out agrotechnical measures significantly increase this indicator.

Sources of pathogenic infections

The main source of the spread of pathogenic infection are the seeds used for planting. If production technologies are not followed, soil and plant residues can serve as a source of infection.

Measures to protect against fusarium and wilting

Pathogenic microorganisms are very persistent and measures to protect against them are not always successful. The best preventive measures are planting he althy seeds. If, after removing the dead plant, another plant is planted, then disinfection of the soil in the hole should be provided, otherwise the newly planted plant will also die.

How to deal with the Fusarium problem

When growing cucumbers, vegetable growers use special agricultural practices to cope with cucumber Fusarium and prevent the spread of the disease:

1. Using preventive measures to disinfect the soil in the beds using chemicals or heat treatment.
2. Acquisition or preparation of substrates for planting seeds, taking into account their terms of use.
3. To ensure the duration of the growing season of cucumbers, at the time of their active fruiting, additional soil is poured out to ensure the formation of an additional root system. Compost is used for this purpose, and is sometimes rolled for optimal aeration.
4. Drip irrigation requires drainage so that moisture does not form stagnation.

The formation of plants and regular harvesting, reduces the load on plants, as a result of which the aging process of the plant's root system slows down.

Used biological agents

Treatment of Fusarium wilt of cucumbers is carried out using some strains of Trichoderma. Such drugs are created in laboratories. You can treat the finished product by introducing it into moistened soil 2-3 days before planting vegetables. In the future, stems, foliage and soil in the beds are sprayed with such a suspension.

Chemicals

Often, fungicides do not have a significant effect in controlling cucumber wilting. This result is a consequence of increased pathogen resistance.

Conducted studies of means to eliminate seminal infection, it was found that Fundazol is the most effective. Other similar agents had weaker activity.

Good results in the destruction of Fusarium seed infection are obtained by gradual heating of the seeds before planting (the first day - 35 degrees, three days - 55 degrees, the fourth day -72 degrees).

Measures to prevent the fight against the manifestation of fusarium and wilting of cucumbers consist in disinfecting the soil in greenhouses, as well as used composts and other substrates for planting seedlings with steam, with the further introduction of biological preparations.

The prepared fungicide solution is poured under the root of infected plants. If the infection has spread through the beds in the form of a focus, then their treatment should be carried out on the entire affected part. To cope with the spread of the disease, it is necessary to carry out 1-2 treatments.

Benzimidazoles have a positive effect.

In some cases, Fusarium, while in plants, develops slowly, without causing significant harm. This is due to the treatment of seeds with fungicides (as seed companies do).

Also, subject to the rules of agricultural technologies for growing cucumbers, plants develop sufficient immunity to prevent the development of the stem form of the disease throughout the growing season. The Fungicide preparation can protect a plant for only 2-3 weeks, and drafts, changes in the temperature level of soil and air, and insufficient agrotechnological care for plants are considered the main problem for the development of Fusarium.

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