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Verticillus wilt or wilt is caused by a fungal pathogen from the genus Verticillium. Infection occurs through the soil, and primarily young shoots that are poorly resistant to the disease, as well as plants with damaged roots, suffer.
Diseases of garden and garden plants are caused by various types of infections. Depending on the origin, they are divided into bacterial, fungal and viral.
One of the most common fungal diseases of plants is verticillary wilting.
What it is?
Verticillium wilt or wilt is a disease that is caused by a soil-borne phytopathogenic fungus. It affects various crops, especially nightshade and various greenhouse plants.
It can persist in the contaminated soil for several years, not showing itself in any way, but under favorable conditions it becomes active again, destroying the plantings. Wilt enters the plant through the root system, especially in the presence of a large number of root hairs and root microtrauma. After that, the plant ceases to receive the necessary nutrition and moisture from the soil and dies.
How does the infection take place?
The causative agent of the disease penetrates through the soil into the root system.
Then it spreads into the root collar and stem processes. Plants are especially often infected under unfavorable conditions:
- high humidity;
- sudden changes in temperature;
- lack of air ventilation.
Infection occurs through the soil, the source can be plant debris, seeds, seedlings, as well spores can be carried by the wind or fall into the ground when irrigated from a poor quality source.
Why is it dangerous?
Wilt poses a serious threat to horticultural and horticultural crops. Penetrating through the roots, it begins to actively grow, filling the vessels in the stems and further completely blocking the plant's access to moisture and nutrients. In addition, it emits toxic substances that have a destructive property.
The disease is dangerous because it is not always possible to recognize it immediately, besides, it can manifest itself after infection only after a year or two.
Which culture is striking?
The main crops susceptible to this disease:
- ornamental plants: roses, phloxes, lilacs, chrysanthemums;
- fruit trees and shrubs: raspberries, peaches, plums, cherries, currants, as well as strawberries and strawberries;
- vegetables: eggplant, tomato, potato, cucumber, onion, zucchini, pepper.
How to find?
When a plant is damaged at the germination stage, the shoots die, while they twist into a spiral, which is a characteristic sign of the disease. If the plant is infected later, then as the disease progresses, the roots begin to rot and die off.
Outwardly, the first signs will be the drying and wilting of the leaves of the plant, first the lower ones, then on the entire shoot. The stems become wadded to the touch, flowers, like foliage, fruits, completely die off, darken, dry up and fall off. In order to accurately determine the presence of this disease, it is necessary to cut the affected shoot. It will clearly show darkening of fabrics - brown dots.
If signs of disease are found, the affected plant must be carefully dug up and destroyed, this will prevent contamination of the soil and other crops.
General principles of protection against disease
It is most often not possible to cure a plant affected by wilt, especially in advanced cases. The fungus is able to remain in the soil for a long time, it is difficult to fight it. However, there are general control and prevention measures:
- constant use of crop rotation;
- timely removal of plant residues and diseased plants;
- if a wilt infection is suspected, the plant must be carefully dug up and burned;
- watering with warm water, at least 20 degrees and in sufficient quantity;
- timely apply phosphorus and potassium in the form of fertilizers;
- before plowing the site, fungicides, bleach are introduced into the soil;
- watering plants with solutions of fungicides: foundazol, previkur, vitaros, etc .;
- treatment of plantings with a solution of charcoal, chamomile.
Features of the treatment of different cultures
For this culture, three forms of wilt disease are distinguished: dwarf, brown and green. The first sign of infestation is leaf wilting during daytime. With a dwarf and brown form, they then begin to darken, become covered with uneven spots and subsequently dry out. With the green form, leaf death occurs without color change.
Most often, these signs appear a month after planting, before flowering. Ovaries are not formed on the affected bushes. If the disease appeared later, then the fruits are formed, but they will be small and wrinkled.
The root system looks healthy, while dark necrotic spots are clearly visible on the cut of the stem.
Disease caused by fungi quite often affects strawberries and strawberries. First, the leaves dry out, from the bottom to the top, despite intensive watering. After the berries turn brown. The wilt does not affect the amount of harvest, but all berries are rotten.
Infestation often occurs during the formation of the whiskers, especially in new seedlings. Subsequently, on the whiskers, as well as on the petioles, spots and stripes of brown, sometimes bluish-black, characteristic of the wilt, may form.
Also, a sign of this disease in strawberries will be a very small bush size and reddening of the plant petioles. The root system is also intensely affected, changes color and structure, blackens at the tips and becomes loose, wadded.
The very first symptom of tomato damage is the appearance of fan-shaped yellowing on the leaves, later necrotic spots form there. In the future, there is a daytime wilting of the leaves, twisting. Gradual drying and dying off occurs from the bottom up. In some cases, the plant remains green, while the leaves are deformed and fall off. Fruits on diseased stems form small, yellowed from above, burning in the sun due to the lack of leaves.
The root system looks healthy at the onset of the disease. After the leaves and stem begin to die off, the roots rot. Such a plant must be carefully removed from the ground completely and destroyed. Treat the soil in the hole with a solution of ferrous sulfate.
For the prevention of this disease, it is necessary first of all to observe the crop rotation. The plant that grew in the garden should be re-planted there no earlier than 3-4 years later.
When soil is contaminated, crop rotation is used enhanced, crops are alternated as often as possible. At the same time, cultures easily affected by wilt are excluded from it, and resistant to it are used: rye, barley and others.
Proper care of cultivated plants will also prevent wilt. It is necessary to weed the seedlings in a timely manner and apply fertilizers, as well as destroy weeds, without leaving their remnants on the site. Also, preventive measures will be soil drainage and its timely loosening. Plants that are most susceptible to infection are best suited to fungus-resistant hybrid varieties.
To enrich the soil with organic matter and to improve its microflora, catch crops are sown after harvest. These include alfalfa, rapeseed, mustard, etc.
Verticillium wilting is a serious threat to the future harvest. In addition, it will not be possible to cure an already infected plant; it will have to be destroyed. Therefore, it is important to know about the methods of preventing the disease and have an idea of the first signs of wilt. Then the disease will not be able to spread throughout the site and the soil will not undergo infection, which is subsequently quite difficult to fight.