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White, pink. Black people use grapes for different purposes. In the countryside, grapes are mainly grown for fresh consumption, juices and fragrant house wine. To get a good harvest, you need to study not only the rules of planting and care, but also to learn the weak places of plants, their enemies and disease. To the attention of visitors to the site, we offer a series of articles on pests and diseases of grapes to help learn how to prevent diseases in time and to help your garden pets. Each article details several diseases and ways of effective struggle.
Non-contagious diseases
These are grape diseases caused by poor growth conditions, and not by the vital activity of harmful living organisms.
Chlorosis
There is an infectious (about this below, in another section). With chlorosis, the leaves lose their green color due to a violation of the synthesis of chlorophyll, a green pigment. Other pigments in chromoplasts persist, so the leaves acquire a light yellow, creamy, whitish color. It is caused by a lack of iron in the plant. The plate itself turns yellow, the veins remain green for a while. To check the diagnosis, we apply a strip of iron chelate solution (lemon-acid iron) to the sheet, a sign or symbol. After a few hours at the application site, the leaf turns green.
The most common causes of non-infectious chlorosis are as follows:
- Soil salinity.
- Excessive moisture.
- Excessive, in comparison with iron, the content of copper, manganese, phosphorus, and lime in the soil.
Under such conditions, the absorption of iron from the soil is disrupted, which leads to chlorosis. Chlorosis of grapes is treated with 3-4 foliar dressings solutions of iron preparations, the cheaper than all - iron vitriol. It is convenient to combine top dressing with the addition of other trace elements, stimulating and therapeutic drugs.
Drought
In the viticulture zone, there is not always a proper amount of moisture for plants. The lack of water is expressed so.
Shoots -dramatically slowed growth and development, crowns fade, wither, wither.
Antennae -rusty, wither, beginning with the ends, fall away.
Leaves -massively yellow, beginning with the margins of the lower leaves, can thicken, curl, fall off.
Berries -Early in the spring, the ovary falls off. When drought in a pea phase - wither and dry up, starting from below the bunches. Drought in the phase of filling causes a characteristic defeat: darkening and the acquisition of a brown color of a part of the berry, as if pressed by a fingernail. When peeling, the inside is healthy. As a result, berries dry out like raisins, but alas, they become inedible.
Winter drought is accompanied by soil cracking, while small roots are torn.
Control measures- irrigation and preservation of moisture in the soil: mulching; shelter for the winter by soil; small loosening in order to disturb the capillaries of the upper soil layer, which makes evaporation difficult. Watering in the root zone on specially dug pipes is preferable: more economical and more efficient.
Sunburn
In the hottest months, grape clusters can overheat under the sun's rays. In appearance, the berries are like scalded boiling water, later on they frown and dry up. When touched, they are noticeably hot. Leaves as under the warmed-up iron visited: wither green, with time buret. Leaves with damaged petioles suffer first: they have a water supply to reduce the temperature is difficult. All damage is only on the sunny side of the bush, while there are no such pictures with infectious diseases. The bush tries to protect, intensively evaporating water for cooling. It does not grow, does not accumulate nutrients.
Control measures.The main thing is the presence of a sufficient amount of water, so - watering, mulching, the destruction of the soil crust of fur. processing. In the heat, we throw all the freshly grown shoots "visor" on the sunny side. You can cover the affected clusters with everything that is available: newspapers, leaves, etc. Intercropping is not obkashivaem, wait with the guidance of beauty before the weather is cooler. When bookmarking, we select the row spacing so that the rows sufficiently obscure each other.
Infectious diseases of grapes
Mildew, (false-mouthed dew, pernosporosis)
Perhaps the most common disease. The causative agent winters in soil and plant residues, is resistant to any weather, persists for 2-5 years, and spores are carried by the wind to 100 km. In the spring oospores germinate, with the help of juggles in the smallest drops of moisture (dew, watering, rain) swim to the stomata and germinate into plants, where it is introduced into living cells, destroying them. Treatment with contact fungicides after germination of the fungus inside the plant is ineffective.
After the introduction of the inside of the plant, thin filaments of the fungus develop - the hyphae, at night spore-forming organs extend outward. There are so many that for a person it looks like an easily erasable gray coating on the bottom surface of the sheet. The upper part of the leaves acquires an oily shade, initially small, with a bright center, the spots on the leaf increase, gradually merging.
On the shoots appear yellowish elongated spots, gradually acquiring a brown color. Affected berries in dry weather - dry up, in wet - rot and mold. With the late infection of berries near the stems, bluish gray dents appear, at the end of the berry, they crumble, decay, fall off. Full loss of crop is possible.
Control measures- repeated treatment with fungicides.
The first is conducted before the appearance of signs of the disease!
We use the rule of 3 dozens: temperature 10 ˚С, shoot length 10 cm, fallout 10 mm precipitation. Conditions are met - it's time to process. Subsequent treatments - depending on the weather. In a year favorable for the disease, the number of treatments can reach 6-8 ...
Prevention.First of all, the selection of resistant varieties. But do not rely too much, it does not completely solve the problem: in bad years the development of the disease on stable and unstable varieties differs in the speed of spread, a little more - the severity and percentage of the destroyed harvest. So, you probably will have to process it.
Oidium, or powdery mildew of grapes.
With the beginning of the growth of the grapes, shoots, leaves, which lag behind in growth, appear. Such leaves are curled. Leaves, berries, bunches look like sprinkled with flour, hence the name of the disease. This scurf is the finest thread of the fungus. To the plant it is attached by special suckers, called appressoria. Of these, haustoria, through which the fungus feeds, is embedded in the berries. Growth of berries with simultaneous destruction of the walls leads to ruptures, seeds are bare. At the edges of the hyphae, constrictions appear, these pieces are easily detached and carried by the wind. After falling on other vines, sprout and infect new bushes.
With partial damage, when part of the grapes are used for wine, sorting is necessary with the selection of damaged berries. Otherwise, the wine will have a taste of mold, completely invaluable connoisseurs ...
Measures to control the oidium of grapes.Proper, well-ventilated formation of grapes, destruction of vegetation in the aisles helps prevent or ease the disease. Fungicides and copper preparations that help against mildew are not suitable for treating powdery mildew of grapes. Excellent effect is given to sulfur preparations. The smaller the sulfur particles, the better. Powdered sulfur for pollination should be stored correctly, so that it does not stick together in the breasts, always in a dry place. The temperature during processing is important. Air should be warmed up to 20 ˚С, otherwise it will not work. At the same time, with severe heat, burns are possible, in the hot summer we process the plantings in the morning or evening hours. It is good to use special pastes from colloidal sulfur, making tank mixtures from milodyu and oidium. In this case, we save time and effort, reducing the number of treatments.
Anthracnose of grapes (bird's eye, hail disease).
The disease is activated after heavy rains with hail, hence one of the names. On the leaves it is manifested by the appearance of small dry brown spots, surrounded by a darker border. Later, the middle of the spot dies off, acquires a gray color, is often torn. Leaves become leaky. On the shoots appear dents with a dark border, shoots dry up, break. Similar spots, gray-brown, dented, with a dark border appear on berries. A bit like the image of a bird's eye, which causes one more of its name.
Control measures.When anthracnose grape infection is treated, treatment is carried out with copper preparations or systemic fungicides. The disease is not in vain called the disease of hail, after a heavy rain with hail immediately perform treatment. Not postponing and despite the time after the previous one.
Grapes need our care, otherwise it's hard to hope for a good harvest. Clearly, this includes only spraying with drugs. Correct planting, pruning, fertilizing, watering - everything matters. A strong, nutrient-rich plant better resists any disease.
