Delicious amber grape berries, which absorbed a maximum of solar heat and rays, are a favorite delicacy of every person. Large clusters, hanging in the thick greens of the bushes, delight in their size and shape. To grow such beauty, it takes a lot of work and spend a lot of time. In addition, there is always a risk of damage to the bushes by pests and diseases, one of which, although quite rare, is anthracnose grapes. The photo fully conveys how dangerous this disease is for the plant.
Dangerous disease of grapes: anthracnose
Grape anthracnose is a fungal disease, the development of which largely occurs in the green aerial parts of the plant: leaves, shoots, inflorescences and berries (before they start ripening). The causative agent of the disease is the fungus Gloeosporium ampelinum. Sass, which at the initial stage forms a colorless mycelium, turning brown with time. Under the cuticle on the mycelium, short cylindrical conidiophores with colorless single conidia are formed. Forming throughout the growing season and growing, they tear apart the cuticle, with the result that conidia protrude. The incubation period at the optimum temperature for the development of the fungus - 23–32 ° C is 3–4 days. Vineyards that grow in areas of humid climate and high temperatures suffer most from anthracnose. The disease is particularly pronounced in wet rainy weather and can cause damage to the plant at the very beginning of the growing season.
Signs of Anthracnose
To determine the appearance of anthracnose can be on the leaves, which affects the disease in the first place. On them are formed spots of light gray color, the edges of which are surrounded by an uneven dark brown or reddish rim. Appearing in the form of small spots and dots, in the process of developing the disease, they increase, acquiring angularity. This leads to the destruction of leaf tissue in the affected areas and the loss of such areas causing the formation of holes.
Anthracnose grapes along with the defeat of the leaves covers shoots, appearing on them brownish small spots with uneven edges. As the bush grows, they are drawn out and pressed in, acquiring a coffee shade with dark purple edges. Such ulcers on the plant, which often merge into one whole spot, ring the shoots, can be very deep, besides the bark, seize the woody part, rather than disturb the supply of nutrients. Strongly affected parts of the grape bush become charred, black, easily broken. The leaves on them are small, often dried. How to treat anthracnose grapes? Photo of damaged shoots shows the danger of this fungal disease for the grape bush. It is obvious that it is impossible to let everything take its course.
Anthracnose grapes are particularly dangerous for young ridges, infecting them during flowering or earlier. As a result, the inflorescences dry out and die (partially or fully). Berries also fall under the anthracnose lesion. Deformed, with depressed spots and uneven growth on clusters, they represent a very sad sight, often torn and exposing seeds in the places of defeat.
Anthracnose resistant varieties
The strong development of the disease leads to browning and complete drying of the entire aboveground part of the plant, and, as a result, to its death. Anthracnose grapes can spread through raindrops, irrigation water, insects, and even working equipment. Most often, the disease occurs foci and mostly affects varieties such as Lydia, Husayne, Karaburnu, Isabella. Resistant to anthracnose are Tsolikouri, Riesling, Nimrang, Saperavi, Sauvignon.
The introduction of varieties resistant to anthracnose will be the most effective measure against this disease. But if the disease still hit the plant, how to treat the anthracnose grapes?
The fungus is able to overwinter on the remains of a vine and awaken along with the plant in the spring. Therefore, protective measures aimed at the prevention and control of the disease, include mandatory cutting and destruction of the affected shoots.
Preparations from anthracnose grapes
As a preventive measure, throughout the entire growing season, spraying with drugs such as Ridomil, Horus, Bordeaux Liquid is required, which should be used within a few hours after preparation. Processing is recommended to be carried out in calm weather in the morning or in the evening, without admitting fungicides to growing near crops. Such drugs are not washed away by rain, quickly penetrate the plant tissue and begin to act 2-3 hours after spraying.
Excellently proven in the fight against antrocnosis and microbiological preparations: "Gaupsin", "Planriz", "Mikosan", possessing powerful growth-promoting properties in addition to the protective action. The drugs are not toxic to humans and animals and do not affect the taste of the grown product. Efficiency in the fight against anthracnose is up to 94%. Also in the fight against fungal disease is recommended the use of drugs with a copper content, such as "Poliram", "Copper oxychloride", "Abiga - Peak", "Cartocid". Their use is made when vegetative shoots reach 10-15 centimeters in length.
What is anthracnose?
The disease is not widespread, which, unfortunately, does not affect its harmfulness. Prone to damage varieties that are not treated with fungicides. The damage from grape disease such as anthracnose depends largely on climate. So, high humidity and temperature - the ideal environment for its development. The incubation period in such conditions lasts 4-5 days.
The causative agent is the fungus Gloeosporium ampelinum of the genus Melanconiales, which with the onset of spring affects all green areas of the plant. A characteristic is the fact that anthracnose "is interested" only in young, up to 25 days leaves, lignified shoots and unripe berries.
On the photo is damaged by anthracnose grapes. On the berries you can see the appearance of brown spots. They are rounded in shape and slightly impressed at localized areas, strictly delineated. After some time, the spots turn black and already occupy the entire area of the infected area, be it berry, leaf or vine. Of course, the berries do not ripen, the leaves fall, and the fragile vine freezes in the winter.
Causes of the disease
Many varieties are susceptible to grape anthracnose. Of the main reasons, the following are distinguished:
- mechanical damage to the bush,
- poor quality, or inadequate care of grapes,
- lack of macronutrients - potassium, phosphorus,
- high humidity and persistent hot,
- elevated pH in soil.
The disease spreads from damaged areas to still alive ones, and the fungus can remain on the garden tools and tools. Spores are transmitted through precipitation, downwind. And yet the root cause is insufficient care of the plant.
Ways to treat grape anthracnose
What is the treatment of the disease, and what are the ways? Professional gardeners recommend chemicals. This method of treatment is divided into two types - vegetative and eradicating.
The treatment should be carried out in the spring when the plant is not higher than 10 cm. In the morning or in the evening, in order to avoid burns on the shoots, the grapes should be sprayed with a 3% solution of Bordeaux mixture.
It must be cooked in plastic or glass containers, as iron utensils can be eroded. Copper sulphate is diluted separately, in warm water about 100 grams. It is required to gradually add water until the solution increases in volume to 5 liters. Lime is prepared in the same amount. The vitriol slowly flows into the lime, the mixture is filtered through cheesecloth. The result should be a liquid light blue color, this is evidence of its proper preparation. Store this drug is not recommended, it should be used immediately.
In working with chemicals, it is important to observe precautions. The use of a respirator and protective clothing will prevent liquid from getting into the lungs and onto human skin, which can lead to allergic reactions and toxic poisoning.
One week after the first treatment, the procedure is repeated. It is necessary to use a sprayer with a thin spray to cover a large area of damage.
Additional means of dealing with the disease
In the fight against anthracnose grapes use and agrotechnical measures. These include:
- removal of diseased shoots
- the creation of improved conditions for the growth of culture,
- garter bushes, weeding around them,
- removing weeds around grapes.
Remote crop parts and weeds must be burned. Heat treatment will prevent fungus from entering healthy plants.
Many gardeners are frightened by the prospect of treating grapes with chemicals. Unfortunately, folk remedies to combat anthracnose does not exist. And who would not say, the fungus must be treated with special means, otherwise there will be no sense. Launched forms of the disease are eliminated with fungicide preparations (Skor, Acrobat). To understand the dangers of the disease, you only need to look at the photo of anthracnose on grapes. How to treat the plant? How to save the harvest?
It is worth recalling once again that a well-groomed and strong plant can hardly undergo a similar disease.
Running a bush can get sick much faster and in some cases it will be impossible to cure it. By proper care include timely pruning, weeding, pasynkovanie. As a preventive measure using a solution of potassium permanganate. They are processed garden tools, tools, grape bush.
An excellent measure will be spraying a one-percent Bordeaux liquid in the spring. The soil must be loosened, watering should be moderate and timely. Be sure to make a complex of fertilizers containing calcium and phosphorus. If the bushes were exposed to heavy rain or hail, which caused damage to the grapes, the bush should be immediately treated with Bordeaux mixture.
If the grapes grow in a humid and warm climate, the likelihood of getting sick with anthracnose increases. Here preventive measures and competent care will help, so that you do not have to resort to treatment with aggressive fungicides or destroy a bush at all. A well-kept vineyard is in itself the prevention of many diseases.
Winegrowers need to consider that endurance varieties may differ from those claimed by breeders. Having a basic knowledge of care and strict prevention will be the key to successful gardening. In the periods before and after flowering chemical treatments are carried out, this should be a prerequisite. The exchange of experience, communication on the forums and the acquisition of new knowledge about viticulture is necessary so that no problems and illness caught the husbandman unawares. Therefore, the information presented in this article will be very informative for everyone. Knowing how to treat anthracnose grapes, you can get a great harvest.
Causes of disease
Anthracnose is a fungal infection, which may be on the grape bushes and not to be felt until a favorable climatic conditions occur. Winter frosts do not affect his livelihoods. The fungus remains on the fallen leaves and sprouts, and in spring, with increasing temperature, it begins to act.
The optimal weather conditions for its development is the presence of temperature from 25 to 35 degrees at high humidity. The main reasons for the spread of the disease are:
- high rainfall, hail,
- improper trim bushes
- mechanical damage to the stems
- low levels of potassium phosphate fertilizers,
- sour or salty soil.
The danger of the fungus is that it is quickly transferred from one bush to another with the help of wind, rain, or special tools that are used in gardening.
Hot and humid weather provokes the development of anthracnose
Methods of struggle
If it was not possible to prevent the spread of anthracnosis, it is necessary to begin the treatment of the vines. First you need to get rid of the affected areas of the plant. To do this, remove the branches and leaves that have been exposed to the fungus, and burn them. Then it is recommended to treat the vineyard with a concentrated solution of the Bordeaux mixture.
The first treatment should be carried out when the length of young branches reaches 10 cm. After about two weeks, it is necessary to spray once more, but it is recommended to reduce the concentration of the substance.
In order for the treatment to be effective, it is necessary to ensure that the used remedy does not flow down to the ground, but falls exactly on the lower part of the leaf. Therefore the sprayer should be with small openings. Vineyard processing is recommended in the evening or early in the morning. This will help avoid sunburn, because this time of day is characterized by a decrease in its activity.
To consolidate the effect of treatment and as a preventive measure, after two weeks it is necessary to treat the grape bushes with copper sulfate solution.
Folk remedies and drugs do not differ in high efficiency especially in the final stages of the development of a fungal infection. In this case, for the treatment of vineyards, it is necessary to use systemic fungicides that perfectly eliminate the infection. A novelty in the field of gardening are biological products that more delicately cope with the disease.
Spraying of vines must be carried out systematically with an interval of ten days. It is recommended to minimize watering of plants. Do not forget about preventive measures. They can prevent the occurrence of infection, and in cases of its formation, it will be easier and faster to treat grape plants.
Copper sulphate solution is effective in preventing anthracnose
The main method of preventing anthracnosis is proper care. First of all, it should not be allowed to overgrow the bush. To do this, it is necessary to systematically prune and shoot the seedlings. You also need to disinfect garden tools, as well as grape leaves with a concentrated aqueous solution of potassium permanganate.
A few days before the start of active flowering of grape bushes, it should be treated with a solution of 1% bordovskoy mixture or chlorine dioxide. Repeat spraying should be two weeks later. An effective remedy is the pollination of bushes with sulfur powder.
In the fall, pruned grapes must be burned. The soil under the bushes must be well plowed, watered and mulched. The distance between plantings is dug up and weeds are removed. Such activities will help reduce the risk of spreading the fungus.
Potash-phosphorus fertilizers are recommended as vineyard fertilizers. With heavy and frequent rainfall, the number of sprays with a burgundy mixture or other preparation should be increased, especially when growing grape varieties that are vulnerable to infections.
Very often, those grape plants that are resistant to the infestation of mildew, gray rot, oidium are exposed to fungus. In this case, properly carried out prevention will help to preserve the crop and the grape bush itself.
The danger of anthracnose is that due to the rapid spread in a few days the whole vineyard can die. Therefore, it is important to properly maintain and carry out the necessary measures to prevent the spread of the fungus, especially in the presence of favorable weather conditions.