Whether black spot of grapes can be eaten. Spots appeared on the leaves of the grapes - what to do and how to treat the bushes. The necessary preventive measures are

One of the most dangerous and common fungal diseases in vineyards is black spot. It is also known as phomopsis or escoriasis. This disease causes the greatest damage in areas of viticulture with a humid climate. It is caused by the fungus Phomopsis viticola. The black spot of grapes got its name due to the characteristic signs of damage to stems and leaves.

They arise as a result of the penetration of a pathogenic fungus through the stomata of the leaf plates, which, growing, damages the cells, thereby causing their death. Later, the fungus continues its development on dead tissues, where it enters the sporulation phase. The causative agent of escoriosis is most active in conditions of high humidity combined with moderate temperatures.

The reasons for the appearance and conditions for development

Particularly strong outbreaks of black spot are observed in years with heavy rainfall. Especially if they occur during the budding period and are combined with cool weather. In such conditions, the development of the fungus occurs most intensively, and it causes very large damage to the vineyards.

This disease can also spread by contact.For example, when pruning or when taking planting material from already infected bushes. The development of the fungus in this case occurs during the rooting of seedlings. In the future, plants grown from such stems will serve as a source of infection in the vineyard.

The optimum temperature for the development of Phomopsis is in the range of 20-25 ° C. At lower or higher rates, its development is significantly delayed. At temperatures above 36 °, complete death of the fungus is observed. However, his spores tolerate all these temperature fluctuations without problems, and for a long time retain their viability in anticipation of favorable conditions for development.

Signs and ways to identify black spot

Visual diagnostics play an important role in identifying black spot.

Leaf inspection

Symptoms of damage to leaf plates begin to appear in late May or early June. These terms largely depend on weather conditions. At first, these are small black specks on the surface of the leaves. They are located mainly along the veins. As they grow, they become rounded. A light-colored border is formed along their edge from the affected tissues. Under the influence of this damage, the sheet plate is deformed and takes on a wavy shape.

After a while, the damaged leaves begin to turn yellow and fall off. Black spot can also damage leaf petioles and bunch ridges, which in turn also causes them to fall off. Inexperienced growers, very often the spotted leaf that occurs with phomopsis, is confused with the symptoms of infection with the phyllocoptis tick. The main difference between these lesions is staining. When infected with a tick, they are yellow, and with escoriasis, they are black.

Shoot inspection

Symptoms of black spot on the shoots begin to appear towards the end of the flowering period. First, these are dots of black color on the nodes of the shoots of the current year. As they develop, they grow and merge into single spots. Later, they cause longitudinal cracking of the wood. With severe damage, the tissues below them turn black and become covered with characteristic scabs.

A typical sign of phomopsis in the autumn-winter period is the coloring of the wood of the branches in a specific whitish-gray color. It is observed on the lower internodes of annual shoots. In the absence of appropriate treatment, the fungus penetrates into the deeper layers of the wood, as a result of which the entire shoulder or even the trunk may dry out.

Inspection of berries

Infection of berries with the causative agent of black spot occurs during the flowering period or in the next few weeks of development. Symptoms of the disease do not appear on them until the ripening period comes. At first they turn light brown, later purple. During this period, the maturation of the fungus occurs in their tissues. As a result, the berries rot.

Analyzes

In large vineyards, microscopic tests are performed to prevent the development of the disease. They help to identify the disease at the earliest stages and prevent its further development.

Control measures

To combat phomopsis, both chemical and agrotechnical control measures are used. His treatment will only be effective when combined. In order to significantly reduce the population of the pathogen, the infected bushes are pruned with their subsequent burning. Further growth and progression of the disease significantly reduce the competently conducted agrotechnical measures aimed at improving the conditions for growth and development:

Timely installation of supports and a garter of shoots.
Cutting barren twigs.
Correctly selected balanced feeding with basic nutrients.
The introduction of trace elements, especially boron and zinc.

It will not be possible to cure black spot on grapes with agrotechnical measures alone, therefore, chemical preparations are used to combat it. So, how to treat phomopsis?

Chemical protection

The chemical protection scheme is selected depending on the degree of contamination. If a severe damage was observed in the previous growing season, then the following scheme is used:

Treatment with copper-containing fungicidal preparations until the leaves bloom, you can also use a 1% solution of Bordeaux liquid.
Attention! Early spring treatment destroys spores only beginning to germinate; it is ineffective against the mycelium found in wood.
Spraying in the phase of swelling buds or opening leaves.
Processing during the growth of shoots to a length of 5-7 cm.

The first two treatments are carried out using contact fungicides. For example, you can use the following drugs:

Tiovit Jet;
Bordeaux mixture;
Ridomil Gold.

It is recommended to use systemic fungicides for the treatment of affected shoots during the last spraying. They have the ability to accumulate in tissues, due to which their protective effect lasts for a longer period of time. For these purposes, for example, you can use Quadris or Speed.

In order for spraying to be as effective as possible during their implementation, the following rules must be observed:

Processing should be carried out in dry, calm weather.
The solution of the drug should evenly wet the entire surface of the shoots, buds and leaves.
Spraying should be carried out strictly in the morning or evening hours.

Winegrowers treating Phomopsis in their vineyard must necessarily carry out preventive treatments for still healthy bushes. Their main goal is to reduce the risk of primary infection, therefore, drugs with a milder sparing effect are selected for this:

Folpet;
Mancozeb;
Propineb;
Dithianon.

Preventive treatments to reduce labor costs are usually combined with powdery mildew treatments. In order not to constantly fight against Phomopsis, or at least to reduce the number of treatments, varieties resistant to this disease can be grown. Black spot is a very resistant disease, therefore, treatment should be systemic and consist of a whole range of agrotechnical measures and chemical treatments.

A grape disease that affects all organs of the grape plant, which got its name from the characteristic sign of damage to shoots and leaves.

Causative agent Phomopsis viticola according to the way of feeding, it belongs to the group of facultative saprophytes, that is, it is able to penetrate through stomata or wounds into the tissue of the host plant and spread in its uppermost layers under the epidermis, causing necrotization of parenchyma cells. After the areas of the affected tissue die off, the fungus continues to grow and develop on them as a saprotroph. 2 weeks after infection, pycnidia begin to form on these dead and blackened areas - the sporulation organs in which the spores of the fungus mature. The causative agent of black spot is most active in cool and humid conditions.

VISUAL DIAGNOSTICS, PHOTOS

Visual diagnostics the affected material is carried out taking into account the biological characteristics of the pathogen and the symptoms of the manifestation of the disease.

Leaves (fig. 1). Symptoms appear in May – June as several small black spots or chlorotic spots with a black center. They form along the veins, then grow, acquiring rounded or angular outlines. Necrotic spots are surrounded by a light border of compacted leaf tissue. Due to the uneven tension of the tissue, the leaf blade acquires a wavy shape (curl), after a while holes and tears form on it. Severely affected leaves turn yellow and fall off prematurely. Leaf petioles and bunch ridges are also affected, which can cause them to fall off. Symptoms of the manifestation of black spot on the leaves can be confused with the defeat of the leaves by the phyllocoptis mite.

If you look at the leaves inhabited by grape leaf mites, against the light, then small yellowish spots are clearly visible, while with a lesion with black spot, the center of the spot is painted black. Through a magnifying glass, you can see how the veins of the leaf converge to one point - the place where the tick sucks.

Shoots. Symptoms most often appear towards the end of flowering in May – June on the nodes of annual shoots in the form of silver oval dots or streaks. The first 6-7 internodes are usually affected. As they grow, they increase in size and merge, forming elongated spots that crack in the middle along the shoot (longitudinal necrosis) (Fig. 2). With a strong defeat, the internodes located below the shoots completely turn black and look covered with scabs. A typical sign of damage is whitish-gray staining of the wood of the lower internodes of annual shoots.

This process takes place during the autumn-winter period. On discolored areas of the bark, pycnidia of the fungus ripen in spring. With deep penetration into the wood, the pathogen can cause shrinkage of the shoulders or the entire trunk. Affected shoots quickly freeze. Young shoots are most susceptible to infection in early spring in rainy cold weather (air temperature +5 - + 7 ° С).

Berries. The pathogen causes berry rot. Infection can occur during the entire growing season, but in most cases, infection occurs during flowering or within 2-4 weeks after flowering. However, the symptoms of the disease do not appear until the berries are ripe. At first they become light brown in color, then they turn dark purple. Pycnidia ripen under the epidermis (Fig. 3).

MICROSCOPIC ANALYSIS

For the analysis, material with mature Phomopsis pycnidia is used (affected areas of shoots, leaves, berries), given that pycnidia ripen on wood and fallen leaves in spring. The samples are placed in a humid chamber at a temperature of +5 - + 7 ° C. After 24–48 hours, a mass of pycnospores of the pathogen emerging from the mouth of the pycnidia in the form of adhesive tape can be observed in the field of view of the microscope. Pycnospores are of two types: alpha - oval, 2–4 µm and beta - filamentous, curved 0.5–1 µm. The role of beta-pycnospores has not been identified. In pure culture, the mycelium of Phomopsis forms a dense colony with concentric circles and sectors that differ in color (white and black). Pycnids form in the black areas of the colony singly or in groups.

DEVELOPMENT CYCLE AND METHODS OF ITS CONTROL

The pathogen overwinters in infected buds or last year's ridges as mycelium or pycnidia on the shoots. In spring, at temperatures above + 8 ° C and in the presence of a water film, pycnospores (conidia) emerge from the pycnidia and spread with the help of rain drops to shoots, leaves and inflorescences. The spread of the fungus inside the grape bush can also occur due to the growing mycelium, which can start growing at temperatures slightly above freezing. Infection of ovary, ridges and shoots occurs in early spring and during flowering. The symptoms of the disease on the leaves and shoots appear 3-4 weeks after infection. Signs of infestation of berries and scallops remain latent (unnoticeable) throughout the growing season, almost until harvest.

BLACK SPOT OF GRAPES. TREATMENT, CONTROL MEASURES, DRUGS

Chemical protection by fungicides is based on lesions observed in the previous year or during winter pruning. The first two treatments are recommended to be carried out during the blooming period of 40% of the buds and the appearance of three fully blooming leaves with the contact fungicide TIOVIT JET or fungicides containing mancozeb RIDOMIL GOLD. During the period of flowering and ovary formation, treatment with a systemic fungicide - SKOR or KVADRIS - should be carried out.

Systemic drug for fungal diseases "Ridomil Gold"

You can read more about the timing and preparations for treating grapes from diseases and pests in the article .

Everyone who grows grapes on their site knows how much work goes into caring for this plant, and therefore must be able to cope with various diseases and pests. For the fight against diseases and pests of grapes to be most effective, you need to be able to recognize the symptoms and correctly select the necessary means of treatment.

Types of diseases that grapes are susceptible to

There are many diseases that grapes can suffer from. It is necessary to study their symptoms in order to be able to find the right treatment.

Non-infectious chlorosis

In the case of non-infectious chlorosis, the leaf blade of grapes first changes from dark green to light green. Then the leaves turn yellow and only the veins of the leaf and a small amount of tissue next to them remain green. Subsequently, the affected leaf dies off.

Non-infectious chlorosis affects not only the leaves, but the entire plant as a whole. The vine slows down its development, the growth point of the entire shrub dies off, the ovaries crumble. In addition, there is a great risk that diseased shrubs may not survive the winter.

The following varieties are most susceptible to non-infectious chlorosis: Don Agate, Italy, Magarach, Isabella, Pino (black and blanc), Aligote. The least affected are Chasselas (white and pink), Saint Laurent, Muscatel, Pinot Meunier.

With non-infectious chlorosis, the leaf turns yellow, but its veins remain green

There can be several reasons for the occurrence of non-infectious chlorosis.

unfavorable climatic conditions. Non-infectious chlorosis often results from cold, rainy weather;
unsuitable soil. Grapes can get sick if they grow in airtight clay soil. The level of alkalinity of the soil also plays an important role. If the level is high enough (pH8 and above), then it will be difficult for your grapes to extract iron from the soil, which is necessary for the synthesis of the green pigment - chlorophyll, and to assimilate it, so the leaves will begin to change color and turn yellow.

Treatment of non-infectious chlorosis

If you notice signs of non-infectious chlorosis on grapes, then take the following actions:

Check the alkalinity of the soil. If the indicators are high, then adding ammonium sulfate salt to the soil at the rate of 100-150 g per bush, as well as using a solution of ferrous sulfate, will help you. To make it, dissolve 50 g of powder in 10 liters of water. Spray the bush for 5 days. Remember to do this in the spring before bud break or in the fall after the foliage has fallen. If you need urgent treatment of the plant, then the concentration of the solution should be weaker, otherwise you risk burning the leaves. In this case, dilute 2–5 g of powder in 10 liters of water. Spray the plant for 5 days until the leaves regain their original color. It is advisable to do this procedure in the evening.
In the spring, it is useful to spray with preparations containing iron in a chelated (transformable) form, for example, Fe Brexil, Iron Chelate, etc.
Also, as a foliar feeding, preparations enriched with such macroelements as phosphorus and potassium are suitable (for a superphosphate solution, dilute 20 g of a pot in 10 l of water, for a solution of potassium sulfate - 5 g of powder per 10 l of water), as well as containing trace elements zinc, boron , manganese and magnesium (for example, a solution of marrgan sulfate - 4 g per 10 liters). They must be used simultaneously with chelating drugs.
Improve soil quality. For this, an effective measure is a deep digging of the site. In this case, you remove excess moisture from the soil due to its evaporation. And if your site has heavy soil, then regularly loosen it and do not forget to make compost.

With infectious chlorosis (otherwise this disease is called yellow mosaic), grape leaves are covered with yellow spots, including veins. Infection of grapes with this ailment entails such consequences as peas (crushing) of berries, leaf death, and decreased frost resistance. In Russia, infectious chlorosis is more common in regions with a warm climate and mild winters.

With infectious chlorosis, grape leaves also turn yellow veins

The causes of this disease can be as follows:

The presence of nematodes. Worms and their larvae are carriers of this disease. Nematodes settle on the stems, leaves and roots of the plant, causing the plant to become sick. Note that humid environments are most favorable for nematodes.
Using an infected scion.

Unfortunately, grapes affected by the yellow mosaic cannot be treated. If you notice the symptoms of this disease on your grapes, then it is best for you to uproot and burn the bush, and treat the ground with a solution of ferrous sulfate (50 g per 10 liters of water).

Rolling the leaves

Curling vine leaves can be caused by both infection and unfavorable conditions.

Infection. When infected, the grape leaves curl and dry out. The fruits become less sweet, decrease in size, and also change their color. All this inevitably leads to a decrease in the quality and quantity of the crop. Symptoms usually appear at the end of August, and if the bush is irrigated, then at the beginning of June. The leaves begin to curl inward. This primarily occurs with the leaves located at the base of the bush. Closer to the top, the leaves curl outward. Their color also changes: in white grape varieties, the leaves turn yellow, in colored varieties - red, while the veins remain green. Infection usually occurs through the graft, so try to use healthy graft material.Unfortunately, such a shrub is not amenable to treatment. You will need to destroy it immediately to avoid infecting other plants.
Unfavourable conditions. These include insufficient humidity, hot, dry weather and lack of nutrients (potassium, nitrogen, sulfur, manganese). Control measures. This problem can be solved by providing the grapes with regular watering, as well as by introducing potassium sulfate (about 50 g per bush), ammonium nitrate (30 g per 10 L of water) or ammonium sulfate (40 g per 1 m 2) into the soil.

If the curling of the leaves started from the top of the bush, then this is a sign of a lack of nutrients, curling at the base indicates the presence of infection.

Curling of vine leaves can be caused by both diseases and adverse conditions.

Anthracnose appears in the form of small brown rashes on leaves and shoots, which then merge into a large spot. The stain dries up and tears, so the leaves of the grapes appear perforated. This disease undermines the vital activity of the entire shrub, since it loses foliage and cannot produce the necessary substances with it.

If you are treating in the spring, then keep in mind that you can do this until the shoots reach a length of 10 cm.

How to treat anthracnose:

Bordeaux liquid 3 is suitable for processing, after a week 1. You can spray the bushes only in the morning or in the evening.
After twice applying Bordeaux liquid, use Previkur, Ordan or Fundazol for spraying every 10 days.
In autumn after pruning or in spring before bud break, you can treat the shrub with a solution of DNOC (2.2%).

With anthracnose, the leaf is covered with flat brown spots.

Symptoms of black spot appear on different parts of the plant in May-June, towards the end of flowering, in the form of small black spots or chlorotic (gray-yellow) spots with a black center. The spots are formed along the veins of the leaf, gradually increasing in size. The spots have a light border of a light shade. The affected leaf becomes wavy to the touch, and then holes appear on it. Subsequently, the leaves fall off.

On shoots, especially annuals, the disease manifests itself as follows. First, dark dots or streaks appear on the nodes within the first 6–7 internodes. Then the dots grow and merge into large spots, which, in turn, spread and crack along the middle. The wood of the lower internodes becomes grayish white. If the disease has struck the trunk deep enough, then it can dry out. Also, with black spot, frost resistance decreases, and in winter the shrub can freeze.

Black spot is one of the most dangerous diseases of grapes, leading to its death.

As for the berries, the symptoms appear after ripening. The berries turn first brown, then purple, and then fall off. If you do not start treatment in a timely manner, then in 5-6 years the bush will die.

At the beginning of the disease, the symptoms of black spot can be confused with the lesion of the phyllocoptis tick. To distinguish them, examine the leaf against the light and through a magnifying glass: if the veins of the leaf converge in one place, and this spot has a yellow center, then the grapes are affected by a tick.

The disease is caused by a fungus that invades and spreads in plant tissue, causing cell death. Spores of the fungus are transferred by drops of water.

The most resistant to black spot are Cabirnet-Sauvignon, Riesling, Relay, Tavrida. The least resistant are Italy, Aligote, White Muscat, Cardinal, Chardonnay.

The treatment of grapes for this disease is long-term:

When the first signs appear, remove the affected parts of the shrub and burn.
Treat the shrub with a solution of sulfur or sulfur-containing preparations (Ditan, Poliram). This must be done between the swelling of the buds and the growth of shoots up to 10 cm.
You can also treat the shrub with 1% Bordeaux liquid.
In the autumn, after the foliage has fallen, treat the grapes with DNOC.

It manifests itself in the form of olive-colored rashes on the leaves, subsequently the rashes are covered with a velvety bloom. The leaves shrink and die off, the ovary crumbles, and the fruits, if they ripen, become of different sizes, crack and become covered with the same spots. The following remedies can be used as treatment:

Colloidal sulfur solution (100 g of powder per 10 l of water). Spray the shrub in the morning or evening when the sun is at its least active, otherwise the leaves can burn.
Fundazol (10 g per 10 L of water) or Cuproscat in the same dosage.

Usually three treatments are enough, but if the disease is neglected, then their number can increase to five. It is also useful to feed grapes with ammonium nitrate (10 g of powder per 10 L of water) or ammonium sulfate (10 g per 10 L of water).

With scab, the leaves are covered with a bloom, which then darkens

Oidium, or powdery mildew, appears in the form of a gray-white bloom that covers the leaves on both sides, and also affects the inflorescences and berry clusters. The inflorescences fall off, and the berries become smaller and burst so that the bones become visible. The plant's frost resistance decreases and in winter it can die.

It is noted that a strong smell of rotten fish emanates from diseased plants.

Reason for appearance: powdery mildew is a fungal disease, the fungus lives on the surface of the shrub and its spores are easily carried by the wind, infecting plants. The incubation period of the disease takes no more than two weeks.

The defeat of grapes by powdery mildew significantly reduces the quality of the fruit and can lead to the death of the shrub

The most susceptible to powdery mildew are Chardonnay, Cabernet Sauvignon, Rkatsiteli. The varieties Aligote, Merlot, Semillon are relatively resistant.

Powdery mildew is successfully treated with sulfur (colloidal can be used). To prepare the solution, dilute 100 g of powder in 10 liters of water. Remember that spraying is necessary in the morning or evening, when the sun is least active, otherwise you risk burning the leaves. The temperature at the time of the procedure should be at least +20 o C. Repeat the treatment of the bush every 10–20 days until recovery.
Also, gardeners often use humus infusion to combat this disease. It is done like this: one-third of a one-liter barrel is filled with humus, filled with water at temperatures of + 25 ° C, covered with burlap and infused for 6 days, stirring regularly. The resulting solution must be filtered, and then sprayed with shrubs with it in cloudy weather or in the evening. Re-processing is carried out in a week.
If you want to use a special preparation, then treat your affected shrub with Fundazol, Topaz, Tiovit, preparing it according to the instructions. As a rule, two treatments at intervals of a week are sufficient. But remember that chemicals cannot be used during the ripening period of the berries, so at this time spray the bushes with a solution of potassium permanganate to contain the disease.

Video: oidium in the vineyard

Mildew, or downy mildew, is one of the most common and dangerous fungal diseases of grapes. The main symptom is the formation of oily yellow spots, which then turn brown on the outside of the leaf and white bloom on the inside, but this may not appear in dry weather. Infected inflorescences turn yellow and curl, and then dry up. The berries are much smaller.

When infected with mildew, the leaves of the grapes are covered with a white coating on the inside.

Treatment

One of the most effective mildew treatments is a mixture of Bordeaux liquid and lime mortar. The concentration of copper sulfate depends on the spraying time: before the buds open, a 3 percent composition is used, in a later period - 1 percent. The solution is prepared as follows: dilute 100 (300) g of copper sulphate in 5 liters of hot water, dilute 75 g of quicklime and 10 liters of water in a separate bowl, and then mix both compositions, strain and process the shrub, paying particular attention to the back of the leaves. If it rains shortly after the procedure, repeat the treatment.

Of the drugs for fighting mildew, Kuprozan, Antrakol, Kuproksat are suitable. Keep in mind that, if effective enough, they can also slow down shrub development.

Blackleg

Blackleg is a fungal disease. Grapes can be damaged if you plant them in contaminated soil. It is manifested by the fact that the shoot turns black from below and looks stained, it can soften. Young plantings suffer the most. From the stem, the disease spreads to other parts of the plant, and in grapes the leaves may begin to turn yellow and the stalks rot.

When a black leg appears on the stem, the stem looks stained with earth.

Treatment: the fungus multiplies well in a humid environment, so adjust the amount of watering, and also dry the soil (dig up, loosen and sprinkle with ash), water the plants with a solution with the addition of Energen 10 g per 10 l of water or Hom 4 g per 10 l of water.

Video: mildew in the vineyard

Damage to grapes by pests

Wasps

Wasps are a common grape pest, and it is possible that you will find berries bitten by them on your bush. Usually, these insects do not finish the berry, and, having spoiled one, move on to the next, so even a small number of pests can spoil a significant part of the crop.

Wasps are attracted by the sweet smell emanating from ripening grapes

Wasp control measures are as follows:

Destruction of the wasp nest. This activity is best done in low light conditions (late evening, night or early morning) when insects are least active. Spray the nest with a poisonous substance (Dichlorvos, Raptor, Reid), after 20-30 minutes, carefully put it into a sealed container and burn it. Please note that for this event you need to wear tight clothing that completely covers your body and protect your face, for example, with a net.
Use of protective bags. If there is no nest nearby, then you can protect the grape clusters by putting on special fabric bags in a small cell. The advantage of this method is that in this way you will also save the grapes from birds. The downside is the high labor intensity of the event, so this method is best used in small areas with a small number of grape bushes.
Manufacturing poison. You can place flat dishes with diluted honey or jam mixed with Regent or Aktara (per 100 g of product, 1 g of pearate) next to the bushes.

Mites

There are several types of mites that can damage your grapes. Infection with ticks causes slow growth and development of shrubs, destruction of young shoots, and a decrease in the quality and quantity (by 20–50%) of the crop.

The main signs of this pest include the presence of red, silvery and pale yellow spots on the outside of the leaves, as well as the appearance of membranes between the leaf and the stem.

The presence of small yellow peas on the leaves of plants indicates the appearance of a spider mite

If you notice red swells and bumps on the outside of the grape leaves, and brown spots on the inside, then this indicates that a felt mite has wound up on your bush.

The main symptom of a grape mite infection is the presence of red raised rashes

Remove affected leaves and shoots from the bush
Treat the grapes with the following preparations, paying special attention to the inside of the leaf if you use them in the summer:
Colloidal sulfur solution. It is used for the growth of shoots by 5 cm and at a temperature not lower than 20s. To prepare the solution, dilute 100 g of powder in 10 liters of water. Please note that this solution affects only adult insects, so carry out one more treatment with a special preparation (Apollo, Neoron, Fitover) in the fall after leaf fall.
Special preparations (Apollo, Neoron, Fitover) prepared according to the instructions. But keep in mind that it is undesirable to use them during the ripening period.
DNOC. Used in spring (before bud break) or autumn (after leaf fall). Prepare in the usual way.

Red tick

If this pest has wound up on your grapes, the leaves will acquire a bronze tint. Treatment is reduced to removing all affected leaves and treating the shrub with a sulfur solution or a special device, as in the fight against other mites.

Phylloxera

Phyloxera, or grape aphid, is one of the most dangerous pests of grapes. An unpleasant feature of this pest is its rapid spread throughout the vineyard.

You can also fight phylloxera with the help of Fozalon, Kimnix (suitable for both types of phylloxera), Actellik. They are especially suitable for small vineyards.

Calendar of protection of grapes from lesions

You can protect grapes from damage according to the following calendar:

First treatment: carried out in the spring, until the shoots have reached 10 cm in length. Preparations: Tiovit Jet (100 g) + Abiga Peak (40 ml) + 10 liters of water. This mixture will enrich the grapes with sulfur and copper, which are the least effective pest control agents.
Second treatment: carried out 3 weeks after the first. Thanks to them, you will completely protect the grapes from anthracnose.
Third treatment: carried out just before flowering. Mix Cabrio Top (30 g) and Actar (4 g) in 10 liters of water. The validity period is about two weeks.
Fourth treatment: try not to tighten, as the ovary is not protected and is an easy prey for pests and infections. It is necessary to treat the grapes with Cabrio Top solution with the same dosage.
The fifth treatment: carried out after 10-12 days, the berries are already pea-sized. Make this mixture: Ridomil Gold (30 g) + Topsin M (20 g) + Aktara (4 g) + 10 liters of water.
Sixth treatment: carried out after 14 days. Required solution: Thanos (4 g) + Topaz (4 ml) + 10 liters of water. These preparations do not leave marks on the berries.

Summing up, we can say that although the treatment of grapes will require a lot of effort from you, with the correct implementation of all medical measures and timely preventive treatment, you have every chance to preserve your shrub and ensure its healthy development.

Grape leaves are a catalyst for the state of a plant, the slightest developmental problems, diseases or pests are immediately reflected in their appearance. An attentive owner will immediately decipher the signals and understand that the vine needs immediate help. Why do the leaves sometimes turn black on grapes?

Blackened leaves indicate grape disease

Possible reasons

There can be several reasons for blackening:

This happens when the mildew has already severely damaged the grapes and, dying off, the leaf affected by the disease turns black, but the signs of infection are completely different.
With anthracnose, brown, angular lesions on the foliage are bordered by a black stripe, and mold develops.
A grape leaf on cuttings often begins to turn black at the edges from excess moisture or from the drying out of an earthen coma.
Sometimes on young plants the leaves react negatively to the type of soil, dense clay areas do not allow the roots to breathe, and the plant “suffocates”. Here the situation will be saved by the organization of high-quality drainage, the introduction of sand and humus.
When there is not enough potassium in the soil, the leaves become covered with yellowish spots, with a catastrophic lack of substance, light flaws turn black.

It is not difficult to eliminate the deficiency in the latter case, it is enough to apply fertilizer to the soil, and the green parts will restore their original healthy color, the leaf will again return a bright color.

Why does a leaf on a grape bush turn black, what other reasons cause this phenomenon? If black spots cover leaves and branches, then black spot develops. The disease is dangerous, it is capable of destroying half of the crop in the season, it significantly weakens the plant, it is difficult for it to endure the winter, and after a few years, if untreated, it dies.

Black spots on the vine can be a symptom of black spot

The causative agent and methods of spread

Black spot is an infection caused by a fungus, its other name is phomopsis or escoriasis. Microorganisms can be introduced during pruning or when infected seedlings enter the area:

The fungus infects the green parts of the grapes, penetrating them through lesions or stomata, and is located in the upper part of the epidermis.
Spores begin to germinate and destroy plant tissue.
Later, the infection spreads to the wood and parenchyma.

The fungus hibernates in infected buds, as soon as the temperature rises above 8 degrees, with the help of raindrops or insects, it is transferred to branches, flowers and leaves. A month passes from the moment of infection and visual evidence of the development of infection. And after half a month, sporulation organs - pycnidia - are formed on the black necrotic areas, which continue to spread the fungus.

Spores develop constantly, so the plant can become infected at any growing season. But more often the infection penetrates the bush in early spring or during the blooming period. On the bush, spreading occurs also by the growth of the mycelium of the fungus. In a rainy, cool spring, the development of black spot is most active.

The favorable temperature for the development of the causative agent of black spot is from 5 to 35 ° C, but its spores germinate when the temperature rises 1 degree above 0 ° C.

Escoriosis of grapes begins with small spots on the leaves

Signs of infection

The symptoms of the disease are fully consistent with their name. A typical symptom of the disease is the death of cortical cells and tissues. First of all, the green parts of the plant, branches and leaves are affected:

Initially, black spot appears as small black or dark brown dots on the nodules of young green branches. If the damaged areas are enlarged many times, the swelling of the tissues of the cortex will become noticeable, at the top of which there is a dead mouth, in this place there are necrotic foci.
After a while, the points grow and join together, become oblong, sometimes they completely ring the shoots.
Subsequently, as the branches grow, they open up in the center, change color, and become light brown.
Usually, on the shoots of the first year, lesions spread to 7 internodes. But when development occurs intensively, the entire branch becomes covered with ulcers and necrosis, cracks, over time they dry out completely.
On wood, a sign of fungus is the appearance of gray-white spots in the area of \u200b\u200bthe lower internodes.

On the leaves, manifestations of the disease can be seen already at the beginning of summer:

At first, the leaf is covered with dark brownish spots.
In the center, necrosis acquire a black color with a yellowish border around the edges.
The spots are located along the veins, due to uneven tension, the sheet becomes bumpy, curl appears.
Then, the leaves crack.
The damaged areas dry out and fall off. When a leaf is badly damaged, it turns yellow all over and falls off.

Usually, the spread of infection captures the lower leaves, less often it falls on the whiskers and tops of the bunches. They also die off and turn black.

Ripe berries infected with the fungus:

first turn brown, their taste changes;
become dark purple in color, gradually wrinkle and rot;
most often, infection occurs during the flowering period, the process can also capture green fruits, at first it is invisible and manifests itself during ripening.

Many people confuse black spot with a pest, the phyllocoptis mite.

Distinguishing the disease is not difficult if you look at the leaf at the light. The insect leaves yellowish lesions, and the fungal infection stains them black.

Escoriosis leaves pronounced black spots on vines and leaves

How to get rid of

To cope with false spotting is possible only with comprehensive measures: competent agricultural technology and chemical protection. Care measures are aimed at improving the growth of the vine:

timely garter;
regular weeding;
infected shoots and leaves are necessarily removed and burned;
for better ventilation of the bush, pruning of non-fruiting shoots is carried out;
introduction of a balanced complex of fertilizers.

Chemical protection requires adherence to the fungicide spray pattern, otherwise it will be difficult to get rid of black spot. You should know that even modern drugs are not effective enough to destroy the mycelium of the fungus, so the fight must be directed against the spreading spores. Processing should be careful, especially the leaves and shoots are sprayed with high quality from below:

If the disease was previously noticed, the first spraying is carried out as early as possible, even before bud break. Bordeaux liquid is used, but Ridomil and Dron preparations are more suitable.
The next treatment is carried out when the buds have just swollen or one leaf has appeared on half of the vine.
Another sprinkling of the grapes is required when 3 or 4 true leaves appear.
When the berries are formed, processing is carried out almost every decade until mid-August.
For prophylactic purposes, contact fungicides are used: "Dithianon", "Folpet".

Black spot is a disease from which it is not easy to cure a grape bush, sometimes it is chronic; in case of severe infection, you will have to take measures to eliminate it within several years.

If the owner of the vineyard carefully examines the leaves, he will be able to understand why the leaf has turned black, identify the disease and eliminate problems at an early stage.

28.04.2018

Everyone's favorite fragrant and tasty grapes appear on the shelves closer to autumn. In order not to engage in a long wait for a juicy treat, gardeners grow grape bushes on their own. To maintain health and increase the yield, it is recommended to constantly monitor the bush, because one of the problems is the appearance of black dots on the berries, leaves, and stems.

Causes of the disease

The most common reason for the appearance of black dots on grapes is the defeat of the bush with a fungal infection. Depending on the site of localization, as well as additional symptoms and signs, you can independently determine the extent of the lesion and the pathogen. In order to inspect a grape bush, it is necessary to carefully examine the stem of the plant, its leaves on both sides, as well as the presence of new shoots. If the bush is already bearing fruit, it is necessary to carefully examine the berries for diagnosis.

The appearance of points on the berries

The appearance of an unpleasant symptom in the form of multiple small dots indicates that the plant is affected by a fungal infection. The most common type of such disease is anthracnose. At first, small blotches appear, which, as the berry develops, turn into brown or brown spots. Several additional signs of anthracnose:

It is important to know!

Black dots on the leaves

It is generally accepted among summer residents that the most beautiful and delicious grape varieties are prone to fungal attack. One of the common problems is black spot, which at the initial stage is characterized by the formation of black dots on the leaves of grapes. . The first signals arrive already in May and early June, when gardeners expect flowering.

The list of signs of excoriasis will help determine it with accuracy:

Excoriosis can be treated with chemicals if the disease was diagnosed on time.

Preventive measures and methods of control

Under the condition of prolonged ignoring of fungal infections, the bush begins to gradually die. At first, new shoots are not formed, the inflorescences dry up, and the fruits are not tied. The sooner the gardener takes measures to combat the pathology, the more chances there will be to save the bush.

To remove black dots on grapes, use the following techniques:

Among the preventive measures, it is worth highlighting the improvement of the ventilation of the bushes, the removal of stepchildren and excess shoots, the digging of row spacings, weed control, and the tying of the vines. Digging the ground between the rows is a must, because some types of fungi tend to overwinter between the bushes. All vines removed during pruning must be burned to prevent re-infection. From folk remedies against fungi, a lime-sulfur broth is used, which helps to destroy the infection.