Verticillium wilt or wilt is a disease caused by a soil-borne phytopathogenic fungus. It affects various crops, especially nightshades and various greenhouse plants.
It can survive in contaminated soil for several years without showing itself, but under favorable conditions it becomes active again, destroying plantings. Wilt enters the plant through the root system, especially in the presence of a large number of root hairs and microtraumas of the roots. After this, the plant stops receiving the necessary nutrition and moisture from the soil and dies.
How does infection occur?
The pathogen penetrates through the soil into the root system.
- high humidity;
- sudden changes in temperature;
- lack of air ventilation.
Infection occurs through the soil, the source can be plant debris, seeds, seedlings, also spores can be carried by the wind or get into the ground when watered from a poor-quality source.
Why is it dangerous?
Wilt poses a serious threat to garden and vegetable crops. Penetrating through the roots, it begins to actively grow, filling the vessels in the stems and subsequently completely blocking the plant’s access to moisture and nutrients. In addition, it releases toxic substances that have destructive properties.
The disease is dangerous because it is not always possible to recognize it immediately; moreover, it can manifest itself after infection only after a year or two.
What crops does it affect?
The main crops susceptible to this disease:
- ornamental plants: roses, phlox, lilac, chrysanthemums;
- fruit trees and shrubs: raspberries, peach, plums, cherries, currants, as well as strawberries and wild strawberries;
- vegetables: eggplant, tomato, potato, cucumber, onion, zucchini, pepper.
How to detect?
When a plant is damaged at the seedling stage, the sprouts die, and 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.
Externally, the first signs will be drying and wilting of the leaves of the plant, first the lower ones, then throughout the entire shoot. The stems become cottony to the touch, the flowers, like the foliage and fruits, completely die off, darken, dry out and fall off. In order to accurately determine the presence of this disease, it is necessary to make a cut of the affected shoot. Darkening of the tissues – brown dots – will be clearly visible on it.
If signs of the disease are detected, 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 can remain in the soil for a long time and is difficult to fight. However, there are general control and prevention measures:
- constant use of crop rotation;
- timely removal of plant residues and diseased plants;
- if a wilt infestation is suspected, the plant must be carefully dug up and burned;
- Watering should be done 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 and bleach are added to the soil;
- watering plants with solutions of fungicides: foundationazol, previkur, vitaros, etc.;
- treatment of plantings using a solution of charcoal and chamomile.
Features of treatment of different cultures
Pepper
For this crop, three forms of wilt disease are distinguished: dwarf, brown and green. The first sign of infection is wilting of leaves during the daytime. With the dwarf and brown form, they then begin to darken, become covered with uneven spots and subsequently dry out. In the green form, the leaves die off without changing color.
Most often, these signs appear a month after planting, before flowering. Ovaries do not form on the affected bushes. If the disease appears later, the fruits will form, but will be small and wrinkled.
The root system looks healthy, while dark necrotic spots are clearly visible on the stem cut.
Strawberry
The disease caused by fungi quite often affects strawberries and wild strawberries. First, the leaves dry out, from the lower to the upper, despite intensive watering. Afterwards the berries acquire a brown color. Wilt does not affect the amount of harvest, but all berries are affected by rot.
Infection often appears during the formation of mustaches, especially in new seedlings. Subsequently, spots and stripes of brown, sometimes bluish-black, characteristic of wilt, may form on the whiskers, as well as on the petioles.
Also, a sign of this disease in strawberries will be a very small bush size and redness of the plant petioles. The root system is also intensively affected, changes color and structure, turns black at the tips and becomes loose and cottony.
Tomatoes
The very first symptom of tomato damage is the appearance of fan-shaped yellowing on the leaves, later necrotic spots form there. Subsequently, daytime leaf wilting and curling occur. Gradual drying and dying occurs from bottom to top. In some cases, the plant remains green, but the leaves become deformed and fall off. The fruits on diseased stems are small, yellowed on top, and burn in the sun due to the lack of leaves.
The root system appears healthy in appearance at the onset of the disease. After the leaves and stem begin to die, 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 iron sulfate.
Preventive measures
To prevent this disease, it is necessary first of all to observe crop rotation. A plant that grew in a garden bed should be replanted there no sooner than after 3-4 years.
When the soil is contaminated, increased crop rotation is used, crops are alternated as often as possible. At the same time, crops that are easily affected by wilt are excluded from it, and those resistant to it are used: rye, barley and others.
Proper care of cultivated plants will also serve as prevention against wilt. It is necessary to weed seedlings and apply fertilizers in a timely manner, as well as destroy weeds without leaving their remains on the site. Also, preventive measures will include soil drainage and timely loosening. For plants that are most susceptible to infection, it is better to choose hybrid varieties that are resistant to fungi.
To enrich the soil with organic matter and to improve its microflora, catch crops are sown after harvesting. These include alfalfa, rapeseed, mustard, etc.
Verticillium wilt is a serious threat to future harvests. 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 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 area and the soil will not become infected, which is subsequently quite difficult to combat.
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An insidious plant disease is difficult to diagnose at the very beginning of the infection, so often, when it becomes clear what is happening to a favorite flower, which was pleasing to the eye just a few days ago, it is too late to treat, the plant will only have to be destroyed so as not to lose all the flowers.
Symptoms
may proceed slowly; if the cause is detected in time, in this case it gives a chance to cure the plant. An acute defeat almost instantly, in 2-3 days, destroys the flower without options for salvation.
As the disease progresses slowly, a brown tint is observed between the veins of the lower leaves. Gradually all the leaves droop and turn brown from the bottom to the tops of the shoots, the plant stops developing, loses the affected leaves, the stems become limp and bend in an arch. If you cut such a stem, then the brown spots of the vessels are clearly visible on the cut plane - there is no doubt that the plant is infected with wilt.
Pathogens and causes of the disease
Culprits Verticellium wilt- fungi from the genus Verticillium that live in the soil and infect plants through the root system in the presence of tiny damage, which can be mechanical or caused by insect bites or nematodes.
Fungi can survive in the soil for up to several years, remaining in the form of sclerotia. Favorable conditions for germination and development of mycelium are temperatures from 24 to 26 degrees, high humidity of about 60-70%, soil pH can be neutral, in the range of 7-7.5.
Spores, getting inside the root, prefer to settle and germinate in conducting tissues. The developing mycelium fills the vessels of the root system and stem, penetrating from bottom to top of the plant, which is why manifestations of the disease are immediately obvious on the lower branches. By stopping the access of water and nutrients through the vessels, the fungus provokes leaf wilting, browning, curling of leaf plates, drying out and ultimately the death of individual branches and the entire plant.
A different picture is observed in the acute course of the disease. Plants, which just yesterday looked vigorous and retained turgor, suddenly have wilted leaves and stems hanging down; in hot weather they look scalded and literally within a day or two they become yellow and dried out.
Prevention and control measures
Preventive measures Timely prevention of infection by the Verticillium fungus is usually carried out even before planting flower plants:
- seeds intended for planting are disinfected by heating;
- the soil mixture prepared for growing indoor flowers is steamed with boiling water - this way disinfection is carried out in order to get rid of possible pathogenic microorganisms;
- the substrate is treated with Agate or Trichodermin - drugs that destroy microsclerotia of the fungus.
In the process of caring for flowers, to prevent damage to flowers by wilt, you should follow some simple rules:
- do not allow excessive waterlogging of the soil mixture for both indoor and garden flowers;
- when fertilizing with nitrogen-containing fertilizers, try not to exceed the dose when preparing the solution;
- in the process of replanting indoor plants, examine the root system in order to detect damage, treat with charcoal if there are still wounds;
- it is necessary to loosen the soil in flower beds between garden plants carefully and slowly so as not to injure the roots;
- if the flowers are susceptible to attack by pests, it is worth taking preventative measures from the penetration of fungal infection.
In the initial stages of the disease, when the cause is detected in a timely manner, the affected plants are sprayed with fungicidal chemicals - benlate, topsin-M, Vectra or foundationol, observing the doses specified in the instructions for use, usually the concentration suggested by manufacturers is 0.2%.
If it is obvious that the diseased plant can no longer be saved, it is necessary to take action to destroy it. Indoor plants located near such a flower should be isolated and preventive measures should be taken to prevent them from being affected by wilt. In the garden, treating flowers affected by Verticellium wilt is more difficult. The main emphasis will have to be on soil disinfection, and the loss of plants will have to be accepted.
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Cotton wilt is common in all cotton-growing areas. Most often, the first signs of the disease appear in the budding phase, first on the lower leaves, as yellowing of individual sections of the leaf blade between the veins. Then the diseased leaves droop and fall off. Gradually, wilting covers all leaves. Plants stop growing, their bolls dry out and open prematurely. Sometimes it is possible for plants to wilt quickly when they die without any apparent cause of disease. Both during the chronic course of the disease and during fulminant wilting, darkening of blood vessels is detected in infected plants (Table 59).[...]
The wilt pathogen enters the plant through places of mechanical damage at the root collar and on the roots. Diseased plants do not overwinter well, fall out from year to year, and after three to four years the grass stand becomes very thin.[...]
Verticillium wilt is a very harmful disease. As it develops in the plant, osmotic pressure and cell turgor decrease, transpiration increases, the flow of water and minerals into the roots and above-ground organs of the plant slows down, wood parenchyma cells die and leaves fall prematurely, which leads to a sharp decrease in the yield and quality of cotton. Seeds from diseased plants have low germination and germination energy. Depending on the variety and time of onset of the disease, the shortage of raw cotton with verticillium wilt can be significant - from 22 to 77%.[...]
Bacterial wilt (wilt). Extremely harmful.[...]
The causative agent is the fungus Verlicillium dahliae Kleb, (class DeuteromyceLes, order Hyphomyceiales). The disease causes wilting and death of cotton plants. It appears most often in the budding phase and the beginning of flowering on all above-ground organs of the plant.[...]
On the left, plants (1) infected with wilt were planted in the soil without applying the drug. The middle pair of pots (II) and the far right (III) with healthy plants. Arylate (II) and benomyl (III) were added to the soil at a rate of 200 mg/kg. [...]
When cotton is infected with wilt, browned areas are found on transverse or oblique sections of the stem in the center or on the periphery (color table XXII).[...]
It is possible that cotton will be affected by wilt at an earlier stage - in the phase of three or four true leaves. In this case, the cotyledon leaves turn yellow at the edges, lose turgor, acquire a purple-pink color and dry out. Later, the disease manifests itself as spotting on the first and second true leaves.[...]
The causative agent is the soil fungus Fusarium sporoirichiella Sherb. (sometimes other species) from the class Dcutcromycetes, order Hyphomycctales. The disease is observed throughout the growing season, the degree of its manifestation and symptoms may vary. Plant death occurs approximately 1.5 months after the appearance of signs of the disease. The first symptoms: weak necrosis along the edges of the leaf blade and the attachment of individual leaf lobes. Affected leaf blades and petioles turn brown and die. Sometimes the rosette of a bush falls apart, sick bushes “sit down”, as if pressed to the ground.[...]
The causative agent is a broadly specialized soil fungus Verticillium albo-airum Rein, et Berth, (class Deuieromycetes, order Hyphomycctales). Affects strawberries of any age. The disease appears at the end of May and develops throughout the growing season. Symptoms appear more clearly during the period of butoisation and harvest.[...]
New systemic fungicides are of significant interest for studying against cotton wilt.[...]
Excessive watering contributes to the increased development of wilt disease. Frequent watering in small doses should also be avoided.[...]
However, although PCNB did not reduce cotton wilt infection, it had a positive effect on plant development, increasing the yield of raw cotton. The indirect effect of PCNB in the fight against wilt is achieved by stimulating the development of certain soil microorganisms that are antagonists for the fungus V. dahliae; it has been established that PCNB does not inhibit the development of certain strains of Actinomyces. Moreover, individual representatives of actinomycetes decompose this drug in the soil.[...]
The causative agent of bacterial wilt (wilt) of cloves (Table 55). Bacteria attack cloves.[...]
Biological properties. The drug is proposed to combat wilt (in particular, fusarium of cloves) and peach group X virus. When used on some crops, stimulation of plant development was observed (Davis D. and Dimond A.E., Phytopathology, 1952, 42, 563). The systemic activity of the drug is evidenced by its effect on metabolic processes in plants.[...]
Another important species of the genus is beech ceratocystis, a causative agent of oak wilt, often causing massive death of trees. The disease is common in some states of the United States, especially in the East and Midwest. Its symptoms are similar to Dutch elm disease. The fungus is carried by beetles of the genus Pseudopidyophthorus when they emerge after overwintering on infected trees. In some insects it is found inside the body, in the mycangia. The disease has been observed since the 40s. Until 1952, this species was known only in the conidial stage - oak chalara (Chalara guercina).[...]
PCNB introduced during the sowing period did not reduce the overall infestation of plants by wilt. Mixtures of PCNB with TMTD or kaitam or other known fungicides were more promising, but in this case, complete freedom from cotton wilt was not observed. [...]
The taste is good, the yield is 0.8-1.5 kg per 1 m2. Severely affected by wilt. Ripens between 18 and 27 June.[...]
Over the past 10 years, a large number of drugs have been tested in the Soviet Union and abroad as soil fungicides against verticillium wilt of cotton, caused by the fungus Verticil-Hum dahliae. All these drugs are well known in our country and abroad.[...]
Tests were carried out by introducing them into the soil in the fall in a continuous way, in the spring using a line-precise method immediately after sowing the seeds, as well as by adding them to the soil and then spraying the plants twice during the growing season. Drugs were applied to the soil at the rate of 50 and 100 kg/ha, and spraying was carried out at a 0.1% concentration. The BMK turned out to be the most effective in all respects.[...]
In 1970, with the continuous application of benomyl to the soil in an area with a strong infestation of wilt, we again did not achieve complete recovery; the infestation of cotton decreased only by about half compared to the control. In this experiment, an increase in the yield of raw cotton was obtained at the first and second harvest (Table 5). Thus, it has been convincingly proven that when using relatively small rates of benomyl consumption, a protective effect was obtained, an increase in raw cotton and a decrease in plant infection with wilt.[...]
Nikolyuk V.F., Tapilskaya N.V. The importance of soil amoebas A. albida in protecting cotton from wilt damage.[...]
The disease manifests itself from the beginning of budding to the end of the growing season of plants. In appearance it resembles wilt, but it occurs very quickly: the plant withers within 2-3 days due to rotting and softening of the bark of the main root and lateral roots. The surface tissues of the root become cracked and are easily separated from the wood. On the root bark of the affected plant, dirty-ocher mycelium strands, clearly visible to the naked eye, are found, and in moist soil there are white or yellowish pads. [...]
Illnesses. 1[ ...]
BMK, tested in the Namangan region, when spraying plants at a concentration of 0.1% d.i. reduced cotton wilt disease by 2.5 times compared to control.[...]
Large doses of nitrogen fertilizers and increased irrigation rates for cotton, as studies have shown, enhance the development of verticillium wilt and lead to a delay in the ripening of bolls. From such crops, a lot of unripe raw cotton is collected in the form of kurak. In this regard, the combination of optimal rates of nitrogen fertilizers and irrigation rates is important in curbing the development of verticillium wilt and increasing the yield of raw cotton.[...]
According to DuPont (USA), only 2.5 kg per hectare (125-500 g of active substance per 1 km of row) is enough to completely prevent the development of wilt, even in field conditions.[...]
Trichodermin is obtained from the mushroom Trichoderma lignorum Harz. The drug is intended to combat root rot of wheat, cucumbers in greenhouses, cotton wilt, potato rhizoctonia and other wilting diseases. The industrial production of the drug has not yet been mastered, so it is prepared on the basis of surface cultivation of the fungus on solid nutrient media using a method available to every farm.[...]
The least development of the disease was observed when BMK was added to the soil (24% of plants were infected with wilt, while 63% were affected in the control). The highest yield of raw cotton was obtained when BMK was added to the soil (yield increase compared to the control of 4.4 c/ha). When semikar, ochlosome and trilan were added to the soil, the increase in raw cotton yield was 1.8-2.3 c/ha compared to the control.[...]
As a result of quarantine measures, dangerous bacteria such as the causative agent of fruit blight, bacterial wilt of corn, and citrus canker did not penetrate into our country. International organizations have been created that deal with the issues of protecting plants from bacterioses.[...]
Externally, the disease manifests itself in plant growth retardation, chloroticity, and then in wilting and drying of leaves. Often the entire plant withers and dries out, which is why the disease is often called wilt, or wilt.[...]
For this purpose, intermediate crops are sown, for which it is advisable to use rye, winter rapeseed, winter peas, etc. They are sown after machine harvesting of raw cotton or into growing cotton in fields heavily infected with verticillium wilt. [...]
The physiological role of chlorides in the body is associated with participation in a variety of metabolic reactions. Hydrophilic chlorine ions, unlike sulfate ions, stimulate the absorption capacity of colloidal protoplasm; this explains the increase in wilt resistance caused by chlorides (see Fig. 13). An increase in the yield of chlorophyll-bearing plants can occur due to the replacement of nitrate ions with chloride ions in chemical reactions occurring in a colloidal medium (Schmalfufi, 1950).[...]
Verticilliums are a large group of whorled fungi that can be found when examining air, water and soil. The greatest number of verticilliums is found in acidic soils. Among soil verticillium there are several species that are pathogenic to plants (p. 395). They cause plants to wilt (wilt). When infecting a plant, a pathogenic fungus penetrates the vascular system, developing mycelium in vessels that conduct water, causing tracheomycosis, which manifests itself in plant wilting. As a result of this disease, the plant may lose all its foliage, dry out and die.[...]
Even in monoculture, fertilizers significantly increase cotton yields. In cotton-alfalfa crop rotations on gray soils, their efficiency increases greatly. After alfalfa, raw fiber is collected 5-7 quintals per 1 ha more than in old arable land. In addition, cotton wilt disease is reduced in crop rotation. Mixtures with a predominance of phosphorus over nitrogen work better in the layer; on meadow soils - only phosphorus. With increasing distance from the time of formation plowing, the efficiency of nitrogen increases and the role of phosphorus decreases.[...]
According to our observations, at this moment the formation of low-molecular membrane-tropic antioxidants is induced in the assimilation tissue and roots. UV irradiation activates the biosynthesis of α-tocopherol and bioflavones in leaves. In pea roots, under the influence of 7 and neutron irradiation, as well as environmental salinity, the antioxidant activity of the sum of endogenous phenols increases.[...]
In the Yangiyul laboratory of the All-Russian Research Institute of Chemical Plant Protection (Tashkent region), a number of contact-action preparations were tested by adding them to the soil. Various application rates, timing, and application methods were studied. It was found that carbation, introduced into the soil 15-20 days before sowing at a rate of 500-1000 kg/ha, significantly reduced the infestation of cotton with wilt. Tiazone (mlon) at a rate of application of 200 kg/ha had a weaker effect; attempts to enhance the activity of Tiazone by increasing the rate of application did not produce positive results, since in many cases a phytocidal effect of this drug on cotton seedlings was observed. The preparations carbathion, PCNB and its mixtures reduced the infection of seedlings with root rot and increased the yield (Fig. 1 and Fig. 2).[...]
It has been established that, with appropriate changes in survey technology, aerovisual methods can be used to identify the spread of pests in rice crops, weeds in fields, ground squirrels, grass locusts, meadow moths, fall armyworms, fall armyworms, wireworms, honey beetles, rapeseed leaf beetles, root rots of wheat, sclerotinia and downy mildew of sunflower, cotton wilt, powdery mildew of cereals, some cyst nematodes, rose sow thistle, field mustard, Lezel's grass, tenacious bedstraw, millet, reed, etc.[...]
The disease range covers the area between 30 and 35° northern and southern latitudes. It can be found in temperate (USA, southern Canada, France, Moldavian SSR), subtropical (California, Yugoslavia, Georgian SSR) and tropical zones (some areas of Australia). Most often, the disease affects plantings of stone fruit trees (peach, apricot, almond, plum, Table 63) and is much less common on pome-bearing trees (apple, pear). Wilt usually appears in mid-summer, when affected trees begin to turn yellow and drop leaves from the fruiting branches at the base of the skeletal branches. Subsequently, chlorosis spreads to young growth and the entire crown. External signs of verticillium dieback are accompanied by wood necrosis. It is noticeable not only on transverse, but also on longitudinal sections, in the form of intermittent or continuous dark wide stripes.[...]
Phytoalexins from plants belonging to different families are quite dissimilar to each other, but within the family they usually belong to similar structural types, as well as, possibly, a number of glycosides with the structure of solavetivan.
Clematis wilt, treatment and prevention is the main message of this article. Let's try to give a clear description of the disease and methods of combating it.
Clematis are beautiful ornamental plants that are widely popular among gardeners. They are unpretentious and resistant to low temperatures. This plant is used for landscaping arbors, hedges, and vertical planes. Clematis attracts with its long and abundant flowering. But a disease such as wilt or wilt not only spoils the appearance, but can also lead to the death of the plant. If you don't take any measures.
Wilt is a disease, the first signs of which are wilting of the tops of shoots, especially young ones. It appears as a result of the active activity of fungi that live in the soil and, when favorable for them, begin to penetrate the stems of the plant. Fungal spores, developing in the middle of the stems, disrupt the patency of their internal vessels, which entails a lack of nutrients and moisture.
In addition, the stems of clematis begin to be damaged at the base.
Wilting of shoots is most often caused by the action of a fungus from the genus Phomopsis. It can remain dormant in the soil for a long time, and when it begins to develop, it first attacks the roots, then the shoots. If you carefully examine, you will notice a large number of black spots on the clematis - these are the fruiting bodies of the fungus or pycnidia. It is in them that the spores mature.
Wilt is the most dangerous fungal disease that can affect clematis. It appears precisely during the flowering period of the vines. When young shoots, leaves and flowers suddenly begin to fade. The affected plant is almost impossible to save and this is due to the fact that the focal lesion is concentrated precisely in the lower internode above the very surface of the earth, and sometimes in the part that is located in the ground.
What to do when a fungal disease is detected: Wilt
If wilting of shoots, which is one of the most dangerous, was discovered in the garden on ornamental clematis vines, it is necessary to take immediate action. And so withering or Wilt, clematis, what to do to prevent the further development of the fungal disease.
First of all you need:
- immediately remove all damaged shoots to the very base;
- Burn the cut branches.
Then you need to treat the soil and the remaining stems (if they are not affected, although this happens extremely rarely) with special preparations:
- foundationazole;
- potassium permanganate;
- copper sulfate in combination with soap solution;
- or other targeted chemicals.
You should also take preventive measures to reduce the likelihood of fungal disease. It is recommended that the soil be treated with the biological preparation “Trichodermin” before planting young clematis seedlings, especially if there have previously been cases of fungal infection of plants in the garden.
In addition, preventive treatment of clematis with a foundation solution should be carried out in early spring, before the buds begin to bloom and after the leaves fall in the fall. As a preventative measure, it is necessary to water the soil in which the vine grows twice a year with this solution.
Preventive measures also include timely removal of weeds and fallen leaves, which can become a source of disease development.
You should also regularly loosen the soil and periodically disinfect it with an aqueous solution of lime.
Compliance with the rules of cultivation and implementation of preventive measures will avoid the death of clematis from Wilt.
Verticillium is a fungal disease that affects a huge number of plants. The disease occurs in all regions of Russia, but vineyards and gardens in the southern regions suffer the most.
Depending on the type of plant and its age, the disease can manifest itself in different ways. In general, the first noticeable signs are wilting or curling leaves on the lower part of the stem. At the same time, brown or yellow spots appear on them. Subsequently, the leaves dry out and fall off.
A distinctive feature of verticillium is that on the affected plant, signs of the disease may appear on only one branch or shoot. If you cut it off, you can find brown spots inside that appear due to blockage of the capillaries. Fruits on infected bushes and trees may lag in development, growth, or even become mummified. Often, instead of damaged and dying shoots, new ones actively begin to grow, but they are sterile.
Verticillium can be in a sluggish or active form. The first option leads to the fact that the tree is sick for many years, partially dries out, does not bear fruit, and eventually recovers or dies. In the second case, it may happen that within 10 days, a seemingly healthy tree or shrub completely sheds its leaves and dries out.
Diseased plants
Verticillium causes great harm to tomatoes, potatoes, peppers, cucumbers, sunflowers, and strawberries. Trees and grapes suffer from it. Among fruit trees, stone fruits are more susceptible to this disease: peach, plum, cherry, sweet cherry.
Ornamental tree crops that suffer from verticillium include: forsythia, ash, almond, rhododendron, rowan, rose, lilac, chestnut, maple.
Pathogens and routes of spread
The carrier of the disease is the fungus Verticillium dahliae. It lives in the soil and feeds on plant debris. But once it gets into the root system, it spreads throughout the above-ground part, grows throughout the vascular system, clogs it and poisons it with toxins (waste products).
A colorless fungus that lives in the soil, forms microsclerotia and conidial sporulation. Moreover, it produces both of them only on dead parts of plants. Conidial sporulation does not develop on living animals, even if they are infected.
Microsclerotia can remain dormant in the soil for 8-10 years. Frost is not scary for them. They die only at temperatures above 60 °C. They germinate at a temperature of 20-23°C and a humidity of 70-80%. They prefer soils with a pH of 6-7.
Most often, infection occurs through damage to roots or shoots. The fungus primarily affects young or weakened plants. Infection occurs especially often at the beginning of the growing season, when trees and shrubs are blooming and actively developing. At the same time, there is another negative factor that contributes to the spread of the disease - pruning of trees, as a result of which there are open wounds on the branches and shoots actively begin to grow.
Preparations against verticillium wilt
If the plant is severely infected, no means will help. If the first signs appear, you need to spray with fungicides:
- Vitaros;
- Previkur;
- Fundazol;
- Topsin - M;
- Maksim.
The same means are used to cultivate the soil in the beds and in tree trunk circles.
When planting vegetables and strawberries, the holes are additionally disinfected.
To protect seedlings from the penetration of fungus through damage to the roots, prepare a “matter” of soil and a fungicide solution. The seedlings are dipped in this mixture and planted in the holes.
If you do not want to use chemicals, you can use Trichodermin, which is capable of suppressing a large number of known pathogenic microorganisms.
Verticillium wilt of pepper
All of the above preparations are suitable for preventive spraying of grapes and fruit trees. It is carried out once a month. Before harvesting, maintain the interval recommended by the manufacturer in the instructions.
In general, in the fight against verticillium, the main thing is to observe agrotechnical and organizational measures. In this case, the likelihood of infection will be minimized, and diseased crops will have enough strength to recover within 5-7 years.
Preventative measures for the garden
Fruit crops can be planted only in areas where plants susceptible to verticillium have not been grown over the past 5 years. Strawberries, tomatoes, peppers, and potatoes cannot be planted between rows in the garden.
It is better to mulch the soil in the tree trunks or sow with green manure. As an option, keep the soil under black fallow (in a loose, dug up state).
When choosing the latter option, you need to remember that when cultivating the land, mechanical damage to the root system of plants is unacceptable.
When watering, do not over-moisten the soil. Do not use a furrow irrigation system, as the infection quickly spreads from the source throughout the drain.
For irrigation, you need to use only warm, settled water. In rainy weather, you should avoid watering altogether. For mature trees and grape bushes, 1-2 treatments per month are enough.
You need to be careful when applying fertilizers. The fungus actively develops in soils with a large amount of organic matter and nitrogen. Therefore, fresh, unrotted manure cannot be used as fertilizer. Nitrogen fertilizers can be applied only in early spring in small doses. Under grape bushes and large trees, apply 50-60 g of granular nitrogen fertilizer. During the season, plants need to be fertilized with phosphorus and potassium, which increase resistance to various diseases.
When pruning, you should not shorten the shoots too much, as this stimulates their new growth, which reduces the plant’s resistance to verticillium.
If diseased trees are found in the garden, you need to remove the affected branches and cover the cuts with garden varnish. There is no need to rush to remove them completely. With proper care, there is a high probability of self-healing.
A completely dead bush or tree must be uprooted and the hole disinfected. To do this, use the soil sterilizer Carbation at a concentration of 0.2 l per 1 sq.m.
Prevention for vegetable crops
With annual vegetable crops, of course, everything is much simpler. He grew them, harvested them, mercilessly uprooted and destroyed diseased bushes. The next year, in order not to step on the same rake, I planted crops resistant to the disease.
Verticillium does not affect onions, garlic, legumes, cabbage, carrots, beets, celery, and lettuce.
If infection occurs in a greenhouse, it is necessary to remove diseased plants, replace the soil, carry out disinfection and preventive spraying.
Well, in order to prevent the spread of verticillium, before planting seedlings in a greenhouse, the soil is disinfected and steamed to the depth of the roots.
The soil in the beds is dug up and treated with fungicides. In the fall, after harvesting, the beds are sown with green manure and then plowed under. During the rotting process of peas, rye, vetch, and mustard, saprotrophic organisms accumulate, which inhibit pathogenic microflora.
After the seedlings are established, they need to be regularly fertilized with a complex mineral fertilizer with a high potassium content and a minimal amount of nitrogen.
To reduce the number of waterings and thereby reduce the likelihood of the disease spreading, it is advisable to mulch the beds.
Verticillosis - a sentence or a nuisance
There was a time when farmers lost up to 50% of their grape and sunflower harvests due to this insidious disease. Today, in regions where verticillium infection most often occurs, they are trying to plant fungus-resistant hybrids.
In all other areas, when carrying out agrotechnical measures aimed at improving and healing the soil, verticillium does not cause much harm.