Powdery mildew on grapes: how to deal with fungal diseases

Good day. One of my neighbors, living through one house, decided to plant a bush of grapes a couple of years ago.

It quickly grew and began to bring a decent harvest. As a joke, I already offered her to start making homemade wine.

But this year her vineyard was attacked by powdery mildew. It was necessary to save the plant, for which I suggested a neighbor a reliable way. Want to learn how to deal with powdery mildew on grapes? How not to lose the crop? Now I will sign everything in maximum detail.

Protection of grapes from pests and diseases

Grape plants are damaged by numerous pests, viral, bacterial and fungal diseases. They often suffer from adverse soil and weather conditions. The annual loss of grape harvest is about 30%, and in case of untimely or poor-quality protective measures, they reach more than 50%.

Grape diseases are divided into infectious and non-infectious. Of the infectious diseases, the most harmful are: mildew, oidium, anthracnose, gray and white rot.

Anthracnose grape

Anthracnose grape is a fungal disease. It affects leaves, shoots, inflorescences, berries. Widely distributed in Europe, Asia, America and Australia. It mainly develops in areas with a warm and humid climate (Middle Asia and Transcaucasia), in the zone of wet subtropics of the Black Sea coast of the Caucasus, in Moldova, in Ukraine.

Pathogen - Gloeosporium ampelophagum sacc. It hibernates on the affected organs of grapes and persists for a long time (up to 5 years) in the form of mycelium, pycnidia, and sclerotia. It gives up to 30 generations of spores per season. Rainfall in the spring causes early damage to young leaves and grape shoots just beginning to develop.

Signs of the disease. Brown spots appear on the leaves, surrounded by a dark white border, which often merge. In places of spots the fabric dies and falls out. Depressed brownish-brown, and then pinkish-gray oval spots with a dark border are formed on the grape shoots, often capturing entire internodes.

Brownish or gray depressed angular and rounded spots with a dark border are formed on the berries. A strong spread and outbreak of the disease in the vineyards is observed in rainy weather. Anthracnose causes great damage to viticulture.

Methods of struggle: introduction of grape varieties resistant to anthracnose, timely treatment with contact and systemic fungicides. The timing of the treatments is the same as against mildew.

Preparations: Antracol, Acrobat, Bordeaux mixture, Kuprosat, Ridomil, Thanos, Horus.

Mildew

Mildew (downy mildew) is the most common and most harmful disease of grapes. It affects all the green organs of the plant (leaves, berries, shoots). The disease is caused by the fungus Plasmopara viticola Berl. et Toni - an obligate parasite. It was imported in 1878 from North America to the south of France, and then spread to all the vineyards of European countries. In the CIS, it is ubiquitous.

Signs of the disease. The first sign is the appearance in summer on the upper part of young and adult, but still growing leaves of the so-called oily spots of round shape of any size. In wet weather, a white powdery coating forms on the spot on the bottom side.

Gradually, necrosis (cell death) occurs on the spot tissue, covering an increasingly large part; the affected tissue turns yellow at first, then the spot can become reddish-brown, with pronounced processes of dying and drying. Heavily affected leaves fall off; green shoots can be without leaves.

After the initial appearance on the leaves, the disease can also pass to inflorescences (or clusters), which is very dangerous for the crop. The generative organs of grapes are usually more susceptible to mildew than the leaves.

On inflorescences (or clusters), a crest is struck by mildew, on which elongated spots of intensely green color appear, as if saturated with water. The spot tissue later dies, this disrupts the normal sap flow and causes the drying of part of the inflorescence (bunch).

If the mycelium has penetrated into the pedicels (stalks) and flowers (ovaries, young berries), then the inflorescence (a bunch with ovaries of berries) is covered with a white bloom of sporulation of the fungus, and then the buds and flowers dry and crumble. The optimum temperature for the development of the disease is 20-25 ° C and high humidity. Up to 16 generations of the causative agent of the disease can develop per season.

Methods of struggle. Growing complexly resistant varieties, mulching the soil under the bush, timely application of potassium-phosphorus fertilizers, removal of stepchildren and preventive treatment with contact and systemic fungicides.

Estimated processing times: the first is carried out when young shoots have grown to a length of 15-20 cm, the second treatment is carried out before flowering, the third after flowering when the berry reaches the size of a pea.

Preparations: Antracol, Bordeaux mixture, Cuproxate, Ridomil, Strobi, Thanos, Chorus, Copper chlorine.

Oidium

Oidium (powdery mildew) - along with downy mildew, the causative agent of powdery mildew, also called oidium, causes the greatest damage to viticulture. The disease is caused by the fungus Uncinula necator Burril. It was imported from North America.

All inflorescences and clusters of grapes and tops of shoots may look as if sprinkled with ash or flour. Affected inflorescences die off. Infected berries dry out, and pea-sized berries burst and are destroyed by molds or dry out in dry weather.

Oidium causes great damage, primarily as a result of the destruction of grapes. The incubation period, i.e., the time from sedimentation of conidia to the appearance of mushroom plaque, depending on temperature, is 7-14 days.Conidia germinate at temperatures above 5 ° C, but best at 25-35 ° C.

The fungus appears mostly in moderately warm and damp weather, but can also spread rapidly during periods of low humidity. Poorly ventilated locations, as well as clusters inside highly leafy vine bushes, are particularly susceptible to damage.

Gray rot is the only parasite of the vine bush that accompanies it throughout the year where favorable conditions for infection and development arise. All green parts of the bush and annual wood are affected.

The fungus is dangerous when vaccinated, because along with harvested cuttings, it also affects the places of vaccination. It settles on the shoots beginning to grow and can cause a strong loss already during stratification, and later also in the nursery.

Signs of the disease. In the vineyards, gray rot in cold and damp spring weather covers blooming eyes and young shoots. In poorly ventilated plantations, in humid weather, a gray coating forms, covering all parts of the bunch of grapes, which dusts when touched.

Affected inflorescences of grapes or parts thereof die off, turn brown and dry out in dry weather, resembling signs of crest paralysis. In viticulture, gray rot is especially dangerous as the causative agent of rot of berries and ridges. With early infection of bunches, it is important that this fungus primarily affects wound sites or weakened parts of the vine bush.

Methods of struggle. In principle, they do not differ from methods of dealing with mildew and oidium. Timely treatment of plants with fungicides prevents the development of diseases.

Black spotting

Black spotting (phomopsis, escoriosis, dying off shoots). The causative agent of the disease is the highest mushroom in the class of Deuteromycetes. The most harmful disease in viticulture areas with high humidity. It affects all green organs and lignified parts of the bushes.

Signs of the disease. On lignified annual shoots and perennial wood, the disease causes discoloration of the bark, spots appear, as a rule, on the first 6-7 internodes, and when the disease develops strongly, it manifests itself on fruit links, sleeves and boles.

In the faded areas of the bark at temperatures above 10 ° C, fruiting bodies of the fungus — numerous black dots — pycnids are formed. If the mycelium grows deep into the wood, then rotten areas are formed, which first weaken the growth, and later cause the death of whole arms.

The first signs of the disease on the green organs of the grape bush appear in June, primarily on annual shoots in the form of black-brown, round or oval dots. As the shoots grow, most points increase, they often merge into elongated longitudinal spots, the vine tissues crack, become light brown.

Oval and angularly outlined necrosis appear on the affected leaf blades - mostly near a more powerful vein, which is completely painted black. Necrosis of the leaves is surrounded by a light border of compacted tissue.

Due to the tension of the tissue, the leaf blade ruptures. Heavily affected leaves turn yellow prematurely. Sometimes ripe berries are affected, which turn dark purple.

The causative agent affects all green organs of the bush through the wounds and stomata and lives parasitically, mainly in the uppermost layers of cells.

If spores fall on the green parts of the bush, they germinate already at a temperature of 15 to 35 ° C (optim. - 23 ° C) and a relative humidity of at least 85%. Grape plants are often infected with black spotting through wounds inflicted by the debris of shoots, as well as other mechanical damage.

Methods of struggle. It is difficult enough to fight against the mycelium of the fungus, penetrating deep into the tissue of wood and growing rapidly under the protection of the host tissue. The spores of the fungus are protected from fungicides by a thick layer of cells. The chemical struggle with the use of the currently known active substances against the fungal mycelium does not give results.

Therefore, it should be directed against the fruiting bodies of the fungus and, especially, against spreading spores. In case of severe damage, in the fall after falling of leaves or after pruning (winter treatment), the grape bushes should be sprayed with copper contact preparations. Drying sleeves to be cut.

Based on the fact that black spotting is a chronic disease of grapes in a short time, it cannot be completely eradicated even with repeated thorough winter and spring processing.

Preparations: Antracol, Bordeaux mixture, Cuproxate, Ridomil, Strobi, Thanos, Chorus, Copper chlorine.

Other diseases

In addition to the development of diseases, bushes and grape harvest are under constant threat of damage by many pests. These are phylloxera, ticks, leafworms.

Phylloxera - The most dangerous pest of grapes. Lives only on a grape plant. The homeland of phylloxera is North America, from where it was introduced to Europe. Grape phylloxera is a greenish yellow aphid, barely visible to the naked eye. Two main forms of phylloxera are known: root and leaf, or gall.

Individuals of the root form of phylloxera are first lemon yellow and then yellowish-brown in color, with a pair of short three-segmented antennae and a long proboscis. This form of the pest lives on the roots, underground stem of the grape bush and on layering of European, American varieties and hybrids - direct producers.

European varieties are most sensitive to this form phylloxera; root crops and hybrids are less damaged by it - direct producers.

The defeat of the root form of phylloxera occurs as follows. The larva punctures the root or stem tissue with its proboscis. At the injection site with saliva, enzymes are released that contribute to the conversion of the proteins, fats and carbohydrates of the cell into the form most accessible to the phylloxera. Thus, a large number of cells that make up the tissue are destroyed.

Leaf phylloxera does not develop on European varieties. She lives only on stocked vines and on some varieties of hybrids - direct producers. In places where the larvae stick to the leaves, swellings form on the underside called galls, in which the larvae develop.

Phyloxera develops differently on different soils.There are soils favorable for its vital functions. These include fertile light structural chernozem, slate and rocky soils. Less favorable for phylloxera are heavy, structureless, swimming soils - clay, solonetzic, loessial, silty.

But there are soils in which the phylloxera cannot develop - these are sands. They can grow all European varieties on their own roots, despite the fact that the site may be located in the distribution zone of phylloxera.

Methods of struggle. A radical method of controlling phylloxera is that when it is discovered in the vineyard, all bushes in the outbreak and in the quarantine zone surrounding it are completely uprooted.

Against the leaf form, phylloxera are used Actelik, Zolon, Confidor and other insecticides. The most effective and most common way to protect against phylloxera is to grow grapes on phylloxera-resistant rootstocks.

Common spider mite - a polyphagous pest. Lives on more than 200 species of plants, including grapes. It got its name from the fact that its habitat is always surrounded by cobwebs. It settles on the underside of the leaves and feeds on the contents of the cells.

Leaves damaged by a spider mite turn yellow, and in the painted varieties they turn red - first along the main veins, and then over the entire surface. Subsequently, the leaves turn brown, dry and fall.

Grape itch (phytoptus). It is often found in the vineyard, but not all varieties are damaged to the same extent. Lives, as a rule, on leaves, much less often - on inflorescences. In the itch habitats, tubercles form on the upper side of the leaves (in contrast to the leafy form of phylloxera, which forms galls on the lower side of the leaf).

Each tubercle corresponds to a saucer-shaped cavity on the underside of the leaf, densely covered with hairs. First, the hairs are pinkish-white, and then become brownish or reddish. Due to damage, photosynthesis of leaves is impaired.

If the itch affects inflorescences, the petals become dense, redden and crumble. Most often this happens on hybrids - direct producers. On clusters does not cause much change.

Wintering occurs under the scales of the kidneys, at the base of the shoots, in the cracks of the bark. In the spring it goes to the kidneys and sticks to them. After the development of the latter settles on the underside of the leaves. During the year gives several generations.

Methods of struggle. To protect vineyards from ticks, acaricides are used: Neoron, Omayt, Sunmayt, Actelik, Talstar, sulfur preparations. Practice shows that the threshold number of ticks occurs in the second half of May, that is, during the hatching period of the first generation of caterpillars of a bunch of leafworms.

In this regard, it is advisable to carry out treatment against ticks and leafworms at the same time, using insectoacaricides.

Leaflets

There are three types of leaflets - biennial, bunch and grape.

Two-year leaflet. Caterpillars of this pest damage inflorescences, young ovary and grapes. They can also feed on privet, buckthorn, black currant and euonymus. One caterpillar of the first generation destroys about 30-50 buds, and the second - up to 20 berries.

The biennial leaflet is a small butterfly (wingspan 14–16 mm) of a grayish-yellow color with a black transverse stripe in the form of a triangle on the front wings. The caterpillar is brownish-red in color, up to 1.5 cm long. The pupa is yellow-brown, 0.5-0.7 cm long, with four pairs of hooks at the rear end.

Bunch of grapes. Caterpillars of this pest cause great harm to inflorescences, ovaries and grapes.

Butterflies are brown in color, with a beautiful pattern of bluish and brownish spots and stripes on the front wings, the wingspan is 12-14 mm. The body length of the caterpillars is 10–13 mm; their color is green or gray-green. Pupa 5-6 mm long, from dirty green to dark brown.

Grape leaflet. Caterpillars gnaw out its swollen buds in spring, twist and eat young leaves. Very often they damage the inflorescences and the ovary of grapes. Butterflies are medium sized.

Methods of struggle. After opening the bushes of grapes, the boles and sleeves must be cleaned of the old bark. The removed bark, and with it wintering pupae of the pest, should be burned. However, the main way to deal with leafworm caterpillars is the chemical method.

Processing is carried out in the following terms: against a biennial leaflet, two sprayings 12-15 days after the start of flight of the butterflies of the first and second generation, the third - 10-12 days after the second treatment; against a bunch of leaves for the first time 12-15 days after the start of flight of butterflies of the first generation, the second - ten days after the first (usually on the eve of flowering grapes), the third - 12-15 days after the start of flight of butterflies of the second generation; against the grape leafwort for the first time during swelling of the kidneys, the second after blooming.

Be sure to use personal protective equipment and follow the deadlines for reaching the site after pesticide treatments.

Powdery mildew (oidium) on grapes: how to fight

One of the most pressing problems for winegrowers at the present stage is powdery mildew. The scientific name for this disease is oidium. Powdery mildew pathogens live on green tissues and make berries unsuitable for both their consumption in food and for the production of wine.

Therefore, the fight against dew is of paramount importance to gardeners. Most often, phytosporin is used to get rid of the disease.

How is this disease manifested?

External signs of powdery mildew manifest themselves in different ways at different times of the year. So in the spring, the presence of the disease can be judged by the following symptoms:

If the disease manifested itself in the summer, then such signs indicate it:

• excessive fragility of the leaves;
• death of young clusters and flowers due to drying;
• the appearance on the peel of young berries of dark spots with a mesh pattern and cracks.

Ways to fight

Powdery mildew should be fought at the first detection of signs of damage to the grapes by the disease. There are several tried-and-true ways to help deal with this problem. The most popular solution is grape processing with sulfur. But it should be remembered that the effectiveness of this method depends on air temperature.

For sulfur treatment to be effective, the air must warm up by at least twenty degrees. In this case, the fungus freely absorbs a chemical element, which is subsequently transformed into hydrogen sulfide and destroys it.

If the air temperature is below twenty degrees, then ordinary sulfur loses its effect. In such a situation, treatment should be carried out with a sulfur-containing drug or colloidal sulfur.

It is recommended to treat clusters affected by sulfur in the morning or in the evening. If this procedure is carried out during the day, then too high a temperature leads to burns on the leaves and berries.

To get rid of powdery mildew, you need to dissolve one hundred grams of sulfur in ten liters of water and carefully spray the affected plants with the resulting solution. For prevention, the concentration of the solution should be reduced by dissolving in water no more than 40 grams of a chemical. The processing procedure is repeated every ten or twenty days. The intensity depends on the degree of damage to the grapes.

Biological Remedies

Grape treatment is also carried out by biological methods. It is easiest to prepare humus from saprophytic microflora in spring. It is prepared as follows:

1. humus is placed in a stolitrovy barrel. Moreover, it should occupy at least a third of its volume;
2. the container is carefully covered with a dense burlap;
3. the mass must be thoroughly mixed every day.

After six days, the substance will reach the desired condition. But immediately before use, it should be filtered through gauze. The resulting liquid is poured into atomizers and sprayed in order to prevent fungal diseases on young leaves and shoots of grapes. The procedure is recommended to be carried out on cloudy days or in the evening after sunset.

The effect of this method is based on the penetration of beneficial microflora into the kidneys and the use of fungal spores as a nutrient. Thus, in the process of applying the biological method, a double effect is achieved: grapes receive the nutrients necessary for it and harmful spores are destroyed.

Use of contact preparations

Experienced gardeners do not recommend the use of chemicals. After all, they remain on the surface of the berries and then enter the human body. They are addictive, as a result of which the effect weakens over time. It is best to use complex agents such as phytosporin.

It is based on living bacteria - hay bacillus, which is obtained from hay extract. Previously, they were considered harmful, but American scientists proved the fallacy of this theory and now bacteria are actively used to prepare the drug phytosporin.

The drug has a fairly wide spectrum of action:

Phytosporin is produced in the form of a paste and powder. Moreover, the latter has a white color, and the paste is a thick dark shade. Treatment with these forms has an equivalent effect. However, these two options have a small dosage.

To start using it, it is enough to dissolve a certain amount of the product in water. Another advantage of the drug is its long shelf life.

Folk remedies

Treatment with folk remedies is becoming increasingly popular. They allow you to get rid of the disease without harming the plant itself and the environment. You can prepare effective products from the following ingredients:

• dissolve four grams of soda ash in a liter of infused water;
• add four grams of laundry soap.

The resulting solution must be sprayed onto the affected plants. The procedure is repeated again, after seven days.

Another effective remedy is fermented water, for the preparation of which ordinary weeds are used. Weed plants need to be finely chopped and placed in a bucket, and they should occupy at least half the volume of the container.

The bucket is filled with hot water, and the liquid is infused for several days. After this time, the liquid must be filtered and used to spray the grapes.

The fight against fungal disease should be carried out comprehensively. This approach will make it possible to protect grapes from powdery mildew and other diseases that destroy the crop.

How to deal with powdery mildew on grapes

If earlier fungal diseases of grapes were not too often reminded of themselves, now this problem is becoming increasingly important. One of the most common was the oidium grape disease, which affects an increasing number of plants in all regions of the country, causing a lot of trouble to winegrowers.

What is an oidium?

Oidium is the most common fungal disease, which has other names - an ashtray or powdery mildew. Its pathogen lives exclusively on living and green tissues. Powdery mildew makes grape berries unsuitable for consumption and for the production of wine from them.

Promotes the development of fungus and high humidity. But rains can significantly slow down, and in some cases, stop its spread.

To reduce the chances of infection in grapes, it is necessary to select varieties that are highly resistant to the disease, remove excess shoots, cut off diseased parts of plants and burn them. Do not use fertilizers with an excess of nitrogen.

Signs of the disease

Symptoms of oidium, manifested at different times of the year, are different. In spring, the following symptoms appear:

In summer, these symptoms are slightly different:

1. Flowers and young clusters dry out, and leaf crests become fragile.
2. As they grow, young berries become covered with dark spots, and later a net pattern appears on them and it is tested.
3. The berries begin to crack and rot. The development of the disease on them can continue until harvest.

Disease Prevention and Control

If powdery mildew was discovered on grapes - how to deal with it becomes a very urgent issue. There are several ways to get rid of this fungal disease.

The use of sulfur and sulfur preparations. Being in dispersed form, sulfur is very effectively absorbed by the fungus, where it turns into hydrogen sulfide, which kills it. Sulfur is best treated in the morning or evening, because with extreme heat, burns can occur on leaves and fruits.

Before spraying grapes, it should be noted that sulfur treatment is effective only at an air temperature of more than + 20 ° C, at lower temperatures it is ineffective. If the temperature drops below, then it should be treated with colloidal sulfur or one of the sulfur preparations.

Contact and systemic drugs. Do not use chemicals during ripening. Therefore, a solution of potassium permanganate is used to delay the development of the disease. For treatment, complex preparations that are allowed for use during ripening are best suited.

Biological methods against oidium

The most accessible of all methods is to prepare concentrated saprophytic microflora from humus in spring. It is done in the following way: a third of a hundred-liter barrel is covered with humus and poured with water heated to 25 ° C, then covered with burlap and waiting for 6 days in the heat, stirring regularly.

Re-processing should be done after seven days, and one more - before flowering. With a strong development of infection, at the end of flowering, it is necessary to process the plant several more times with an interval of a week.

Folk ways of protection

During the day, insist half a bucket of ash in seven liters of water. Before processing, it should be diluted with water in a ratio of 1: 1 and add 10 grams of green soap. With a lack of time, ash can be boiled for 20 minutes.

Pour straw in a 1: 3 ratio with straw or fresh manure. Insist for three days. Dilute with three more parts of water and treat in the evenings for any time.

How to deal with grape mildew (downy mildew)

Grape mildew is also called false powdery mildew. This is the most common fungal disease of crops grown in the open field. It manifests itself by the appearance of a white fluffy coating on the inside of the sheet.

On the outside of the leaf plate, over the white plaque area, its tissues acquire a distinct yellow or brownish stain. At this point, living tissue dies. Gradually, the disease spreads to the grapes, where the berries are affected. They are covered with a gray coating, turn brown and eventually begin to rot.

Powdery mildew (mildew) that appears on grapes adversely affects the growth of the whole plant. Young shoots are usually stunted. Spreading on inflorescences and fruits of the grape, the fungus can cause not only decay of the fruit, but wrinkling of the fruit.

Such fruits affected by the fungus acquire a peculiar appearance of senile skin. It is possible that those who have never faced such an affliction one on one, still saw the grapes with such shriveled fruits, buying grapes in the market.

The causative agent of the disease and its development

As mentioned above, the cause of mildew is a microscopic mushroom that settles on the vine.Its feature is that it easily tolerates severe frosts on fallen leaves and other plant remains of grapes.

At the same time, the ambient temperature should not fall below + 13 ° C. As soon as the conditions become favorable in one-, two- weeks on the surface of the foliage, the manifestation of the first signs of the disease can be detected.

Preventive measures

The very first measure to start with is pruning and burning the remains of the vine. This preventive measure will prevent the occurrence of diseases of the grapes with powdery mildew, if carried out on time.

What is needed for this. First of all, proper grape care. Every time after the autumn pruning, wherever it may be, the whole vine and fallen leaves gather at the edge of the plot. The dead bark is removed there after the sanitary cleaning of the vine.

The next preventive measure against grape mildew is the use of contact preparations in a period of drought. All processing is necessary in four stages during the growing season:

• Stage 1. It is produced at a time when the inflorescences become loose. For this, Bordeaux liquid is taken 1.5% or 2%.
• 2 stage. A 1% solution of the same Bordeaux liquid is used, but already after the flowering of grapes.
• 3 stage. It is produced immediately after the berries have reached the size of a pea. A 1% solution is also used.
• 4th stage. Using a 0.4% solution of copper chloroxide. Processing is carried out on 10 - 12 days after the third treatment.

Another preventive measure, but already in a period of high humidity, may be the treatment of the vine with a systemic fungicide Ridomil Gold or simply Ridomil. This product is used against powdery mildew according to the attached instructions.

And remember, these remedies are most effective in controlling grape mildew only when pruned. So the drugs will fall on each leaf and on each branch.

Oidium (powdery mildew)

Symptoms of powdery mildew of grapes: on the leaves, a white powdery coating appears. With the development of the disease, the leaves curl and dry. The first symptoms of powdery mildew are observed in May, when the air temperature reaches + 25 ° C (with an air humidity of 70%), the disease spreads throughout the vineyard.

Ill berries do not grow, dry and fall off. Young shoots lag behind in growth, do not ripen by winter, turn brown and die. Infected flowers covered with powdery mildew turn brown and crumble. Berries stop growing, often crack, turn brown. Powdery mildew (oidium) is one of the most common and dangerous diseases of grapes.

Measures to control powdery mildew of grapes: apply spraying with fungicides. Before budding, the grapes and soil underneath are sprayed when the air temperature is already above + 4 ° C, but does not exceed + 20 ° C.

If necessary, to combat the oidium and mildew of the vine, Bordeaux can be used, and in heavily infected vineyards it is recommended to use potassium permanganate (10-30 g per 10 liters of water) followed by dusting of colloidal sulfur (1%).

Bacterial methods of controlling powdery mildew of grapes can be used. To do this, well-rotted manure is poured with three parts of water and insisted for three days.The finished infusion is diluted 1: 2 with water, filtered and sprayed on the affected bushes. The method is based on the ability of bacteria contained in manure to destroy powdery mildew.

If necessary, such spraying is repeated after harvesting the berries. Spraying is carried out in compliance with all the rules. It is necessary to cut and destroy the affected shoots, berries. In the spring and autumn, the soil under the bushes is dug up, in the spring - mulched.

There are grape varieties (mainly American breeding) that are resistant to powdery mildew. Cause of the disease: fungal disease. An excess of nitrogen fertilizers reduces the resistance of plants to powdery mildew. Powdery mildew spreads during the summer by conidia carried by the wind.

Treatment and prevention of powdery mildew on grapes

Oidium is a fungal disease, respectively, the cause of its occurrence is a fungus that lives on the leaves, vine and other green tissues of the vineyard. A diseased plant cannot produce berries suitable for food or juice production.

Powdery mildew is dangerous in that it affects all shrubs, so it is so important to start treatment of plants in a timely manner. Most often, vineyards are affected in early spring. In the winter, spores of the fungus are located on the eyes, or rather, under their scales. As soon as the air temperature rises to 18 ° C, the disease begins to actively progress.

Breeders bred varieties that are resistant to fungal diseases. It is them that should be cultivated in suburban areas. If the plant is infected, all diseased leaves and vines need to be cut and removed from the cottage. Better yet, burn the affected parts of the plant.

How to recognize an oidium

Recognizing powdery mildew on grapes is not difficult. But it is worth noting that at different times of the year, the disease manifests itself in different ways.

If we talk about spring, then:

The last symptom indicates that the degree of damage to the vineyard is high. In this case, any treatment may not give the desired result, so it makes sense to grow new bushes, after removing the infected grapes from the site.

As for the summer symptoms of oidium, then they include:

• drying and falling of flowers in the vineyard;
• the appearance of brown spots of unknown origin on the berries;
• rotting bunches of grapes.

There is also downy mildew, which in symptoms is very similar to oidium. But when the plant is affected by downy mildew, the leaf begins to turn yellow from the veins. As for powdery mildew, the leaves turn yellow from the edges.

They are quite effective, but their disadvantage is toxicity, so they can be used only until the berries appear in the vineyard.

Sulfur

More often, summer residents use sulfur and drugs that contain it. It is possible to process the vineyard with such means both during the flowering period and during the ripening of the berries. Such plant treatment takes a long time. For one treatment of shrubs, getting rid of powdery mildew will not work.

The affected plants should be treated once every 7-10 days in the morning, before sunrise, and in the evening, after sunset. This is because sulfur preparations can cause burns on the green parts of the plant. To cure the bush, you need to breed about 90 g of sulfur in 10 liters of water.

Sulfur preparations are used not only for the treatment of oidium, but also for the prevention (30 g per 10 l of water) of this disease. Sulfur can also be used to treat downy mildew on grapes.

Sulfur and sulfuric preparations help only if at the time of processing the air temperature exceeds 20 ° C.

Potassium permanganate

The treatment of grapes for powdery mildew with potassium permanganate is justified during the fruiting period. This folk remedy helps against many diseases, but treating them with oidium is quite difficult. Potassium permanganate is good only because it does not allow the development of powdery mildew. Completely destroy the spores of the fungus with its help will not work.

This tool is more suitable as a prophylaxis than a treatment.

Humus

You can process grape bushes from powdery mildew with humus with sapophytic microflora. This is perhaps the most effective remedy after insecticides. But you need to cook such humus in early spring.

The container is filled completely, covered with a dense cloth and placed in a warm place. Over the next week, the contents of the container interfere. As a rule, humus is prepared in barrels, the capacity of which is 100 liters.

Before using such humus, it must be filtered. Spray the plant throughout the summer to prevent disease. It is best to carry out processing in cloudy weather. The first time it is carried out on the blossoming leaves.

If there are no signs of the disease in the vineyard, then you need to re-spray the plant after a week. The third processing is carried out immediately before the flowering of the vineyard.

Ash and trash

From a grape disease such as powdery mildew, ash will also help get rid of it. This is a folk remedy that not only destroys the spores of the fungus, but also acts as a fertilizer. Before use, the ash is diluted with water at the rate of 7 liters of ash per ½ bucket of water. Such a solution is infused for 24 hours, then diluted with water (7 liters of solution 7 liters of water) and add about 10 g of crushed green soap.

Such a remedy against oidium can be used at any time of the day. As for the frequency and duration of processing the vineyard with straw dust, there are also no restrictions. The tool can be used for any time.