Vertical Wilt - Symptoms, Prevention And Control. Photo

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Vertical Wilt - Symptoms, Prevention And Control. Photo
Vertical Wilt - Symptoms, Prevention And Control. Photo

Video: Vertical Wilt - Symptoms, Prevention And Control. Photo

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Verticillium wilting is a very serious fungal disease. The fungus that causes this dangerous disease is quite insidious, it can stay in the soil for a long period of time and not cause any harm to plants, but at some point it can suddenly start attacking the culture, which often leads to the complete death of the plant organism. In this publication, we will consider the main symptoms of plant damage by this disease and methods of prevention and control of verticillary wilting.

Grapes with signs of verticillary wilt
Grapes with signs of verticillary wilt

Content:

  • How does verticillium wilt infection occur?
  • Symptoms of verticillary wilting
  • Fight verticillary wilt
  • Prevention of wilt

How does verticillium wilt infection occur?

Verticillium wilt, otherwise called "wilt", is caused by a fungus belonging to the genus Verticillium. Usually plants are infected with this most dangerous fungus through the soil. At the initial stage of its development, the disease negatively affects the young shoots of the plant, which are not able to resist the disease, which is why they usually die first.

Plants with various damages on the root system or in the lower part of the stem are most strongly affected by verticillary wilt. This damage can be caused by both pests living in the soil and the person himself. For example, when digging a seedling from a nursery or when transplanting a plant to another place, when planting seedlings, improper (excessively deep) tillage or overly active work with the soil near the trunk.

It is interesting that the fungus that causes verticillary wilting can live in the soil for up to ten, and sometimes even more, years, so if the disease manifests itself, then it is better to keep this area under black steam for at least a couple of years. In addition, the fungus can live for a long period of time in plant debris, including in the remains of plants infected with it, therefore, such plants must be removed from the site and burned outside its territory, preventing the parts of plants affected by the fungus from entering the soil layer.

After the fungus penetrates the root system or the lower part of the stem, it begins to actively spread along numerous xylem bundles along with the upward flow of water and dissolved nutrients through the plant. If the soil is infected with this fungus, then even seedlings that have barely appeared on the surface of the soil can die rather quickly, having previously twisted like a spiral.

The fungus develops most actively on soils that are excessively moistened (subject to excessive watering of the soil or in areas with a close standing groundwater), as well as in years with an excess amount of natural moisture falling in the form of rain or fog.

Also favorable periods for the development of the fungus are seasons with sudden changes in day and night temperatures. In addition, in neglected areas where plants are affected by pests, the fungus also develops very actively.

With regard to temperature, the fungus that causes verticillary wilting is especially active, develops at temperatures from 16 to 21 degrees above zero. If the temperature drops below 16 degrees Celsius, then the fungus may stop developing, during this period you can notice the formation of new shoots in plants, which, when warming, can be infected with the fungus quite quickly.

The fungus that causes verticillary wilting is also dangerous because it can attack a variety of plants, both vegetable and fruit, berry and ornamental. Quite often, you can notice signs of verticillary wilting on apricots, grapes, tomatoes, roses, chrysanthemums, lilacs, phloxes, strawberries and a whole series of very different plants.

Verticillosis on garden strawberries
Verticillosis on garden strawberries

Symptoms of verticillary wilting

The insidiousness of the fungus and the danger of this fungal disease lies not only in the fact that the fungus can be in the soil for a long period of time, both before and after infection of plants, but also in the fact that symptoms of infection, especially on perennial plants, are often observed one or even two seasons after the infection occurred.

Usually, the presence of verticillary wilting on plants can be noticed only after the shoots begin to die off. The death of shoots does not occur at the same time, while the plant may generally look good and even bear fruit, other branches may dry out completely during the same period of time.

The leaf blades on dying shoots first begin to dry out at the edges, marginal necrosis is formed, and then the leaves completely dry up and fall off much earlier than the due date. This leads to a disruption in the work of the photosynthetic apparatus and negatively affects the plant as a whole, including weakening its immunity, reducing winter hardiness (if it is a perennial plant).

Usually, first of all, the leaf blades located in the lower tier begin to turn yellow and die off, gradually the disease kills all leaf blades located on the infected branch. If a plant is severely affected by verticillary wilting, then often only its upper part remains alive.

With a strong infection, drying and falling off of ovaries or fruits is also observed in varying degrees of maturity, which depends on the time of infection and the rate of development of the fungus in the plant.

Sometimes it is possible to determine whether a plant is infected with verticillium wilt by cutting off the shoot. On a cut, a strong darkening of tissues is sometimes noticeable, but, unfortunately, such obvious signs do not always appear.

On the cut of shoots infected with wilt, a strong darkening of tissues is noticeable
On the cut of shoots infected with wilt, a strong darkening of tissues is noticeable

Fight verticillary wilt

It can be extremely difficult to cure plants infected with verticillium wilt and exterminate the fungus in the soil. In the event of the onset of very unfavorable conditions for the life of the fungus, it can form sclerotia, form mycelium, even being at rest. With the formation of sclerotia, the fungus can live in the soil for several seasons, even if extremely unfavorable conditions for its existence are created.

Of course, the earlier you identify the disease and the faster you start to fight it, the higher the chances of getting rid of the plant organism from this disease. Otherwise, the fungus can develop in the soil and actively spread, infecting an increasing number of various plants grown on the site.

The first stage in the fight against verticillium wilt can be multiple (4-5 times) treatment with copper-containing preparations or approved fungicides. In the case of fungicides, it is better to start with biological drugs, such as, for example, "Glyocladin", which is an analogue of "Trichodermin". It is good because it has a contact and systemic effect, does not cause addiction to the fungus, restores the soil microflora and even removes the toxicity of the soil after using other chemicals.

Biological fungicides include "Fitosporin-M, P", this drug can also be used to disinfect seed material, because often the fungus that causes verticillary wilt enters the soil, and then into plants with seeds infected with it.

Of the chemical fungicides, the drug "Maxim, KS" fights well against verticillary wilting, this drug is used to combat fungus in the soil, to disinfect seed material and bulbs of flower plants.

Unfortunately, these drugs and many others do not always cope with verticillary withering. If no effect is observed, then it is necessary to remove the plant from the site, treat the place where it grew with copper-containing preparations and not plant this type of plant on this site for at least five years.

The death of the shoots of a plant infected with wilt does not occur simultaneously
The death of the shoots of a plant infected with wilt does not occur simultaneously

Prevention of wilt

Of course, it is much easier than fighting to prevent the appearance of a fungus that causes verticillary wilting in your area. To do this, you must follow a number of important, but simple rules for growing plants.

The first rule is observance of crop rotation and crop rotation. So, if we are talking about perennial crops (for example, apricot), then they should be planted in the same place after the uprooting of the site no earlier than five years later. If we are talking about annual vegetable or flower crops, then they should be planted on the site after three or four years.

After harvest or at the end of flowering in the case of annual plants, remove all residues from the plot. On perennial tree crops or berry bushes, the entire crop must be harvested completely, diseased and rotten fruits should also be removed from the branches and burned outside the site. In years with high soil and air humidity, characterized by sharp temperature changes, it is also necessary to remove all leaf litter and burn it outside the territory of the site.

Another important, but rather simple, precautionary measure is to try to prevent the soil from drying out too much on the site. The moisture content of the soil must be constantly maintained at a normal level, that is, to prevent it from drying out or waterlogging, and if excessive waterlogging is observed due to heavy precipitation, then it is necessary to loosen the soil more often (once every 2-3 days) in order to allow moisture to evaporate better.

When watering, it is important to use water at room temperature, but it is impossible to water plants with cold and ice water from a hose, contrary to the common misconception, this will not lead to hardening of the plants, but can cause stress and a decrease in their immunity.

Apply enough fertilizer to the soil, do not overuse nitrogen, and do not allow plants to become deficient in phosphorus and potassium fertilizers. In order for fertilizers to be absorbed by plants as fully as possible, the soil must be neutral in acidity, but if it is acidic, then dolomite flour or lime must be added to it.

As a preventive measure against verticillary wilting, it is advisable to treat the soil and seeds with natural fungicides, as well as the root system of the seedlings when planting. Thus, infusions and decoctions of tobacco leaves, chamomile plants, as well as infusions of wood ash, soot and charcoal have a fungicidal effect.

In conclusion, about some of the secrets of experienced gardeners and gardeners. It is noticed that the fungus does not develop or does not appear at all, on sandy, well-drained soils, with a neutral reaction of the environment. It is also recorded that many weeds also suffer from verticillary wilting, therefore, weeds must be fought and tried not to embed their vegetative mass in the soil, especially in areas and in those years when the risk of disease is high.

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