Oidium grapes: what is this disease and how to treat it?

When growing grapes, special attention should be paid to measures to protect against diseases and pests.When the plant is already affected, it is necessary to cure it promptly, otherwise you can lose the entire crop. One of the common diseases of grapes is oidium. What is this disease and how to treat it, we consider in more detail in this article.

Oidium grapes is a fungal disease that affects all the green parts of the plant and spoils the fruit, making them unsuitable for human consumption. The disease has a second name - powdery mildew. The fungus is most actively distributed in the hot season. However, disputes can easily endure winter.

Humid environment also creates favorable conditions for the progression of the disease. With a high level of humidity, the mushrooms spread on the dry tissues of the plant. Oidium prefers moisture and heat, but not water. Therefore, in the period of frequent rains, the fungus can stop multiplying.

Powdery mildew infection for the most part does not depend on the plant itself. Fungi can move to the vineyard from the neighboring plots. This is due to the fact that with the onset of heat, the parasite forms spores that can be picked up by a strong wind and transferred to other territories.

Getting even a small amount of spores on the grapes already creates big problems for the plant. The first stage of the disease is not expressed in anything. The first signs of damage appear in one to two weeks.

The first signs of the disease may appear in the spring, if the disease struck the plant in the previous season. Young stems are covered with a bloom of white or light gray.

Externally, the plaque resembles flour or ash. Over time, shoots begin to turn yellow. On the leaves of the plant spots are formed. Gradually, the sheet begins to curl and dries.

You can make sure that the grapes are affected by powdery mildew, you can also use a peculiar smell, which will come from the raid, if you rub it with your fingers a little. The aroma will resemble the smell of rotten fish. If the spread of the fungus is not stopped in time, the grapes will slow down and may die.

In summer, powdery mildew infects berries. Fruits may not form at all on the hands, and if the grapes appear anyway, then dark-colored spots form on their surface, which over time begin to crack and rot.

Preventing the appearance and spread of powdery mildew is very important when growing grapes. The fact is that in the initial stages the disease develops without visual manifestations. The appearance of plaque already speaks of the spread of fungi. The most effective way to prevent the spread of this disease is to plant grape varieties that are highly resistant to oidium.

It is worth remembering that the parasitic fungus quite easily endures wintering, hiding in the tissues of the vine or in plant waste, such as fallen leaves. For this reason, in the fall, after harvesting, it is always necessary to harvest in the vineyard. It is necessary to collect garbage, remove it from the site or burn it.

Do not forget about the proper care of the vineyard. The plant should receive a sufficient amount of sunlight and be well ventilated. Therefore, it is necessary to conduct timely pruning of the stems and use trellis to grape the garter.

During watering should carefully pour the water, not falling on the leaves of the vine. At the end of autumn, it is recommended to treat the plant and soil with iron sulphate. Also next to grapes you can plant crops such as onions, garlic and dill.

Particular attention should be paid to the feeding of grapes. From nitrogenous fertilizers, it is best to refuse or limit their use as much as possible, since these drugs create favorable conditions for the spread of powdery mildew.

For prevention, you can also use drugs that are intended for the treatment of grapes.

To date, there are quite a number of methods to combat powdery mildew. With advanced forms of the disease is best to apply an integrated approach.

Chemical compounds are quite effective in dealing with powdery mildew. However, during the collection of berries it is better not to use them, so that large amounts of harmful substances do not remain on the fruits. The best option is processing during flowering or after harvesting. It is best to treat the plant with products that contain sulfur and a fungicide of organic origin.

Such drugs as “Caratan EC” and “Caratan LC” have proven themselves well. Caratan EC is a narrowly targeted drug. The remedy is mainly used to treat powdery mildew plants. This composition can be used if the air temperature does not exceed 30 degrees. Otherwise, the product may damage the leaves of the vine.

"Caratan EC" does not have the ability to penetrate into the tissues of plants, therefore, when precipitation falls, it will completely wash off from the grapes. The drug "Caratan LC" is resistant to water and does not dissolve in it. It is believed that "Caratan EC" is better to use for the prevention of powdery mildew, and "Caratan LC" - for treatment.

In addition to the preparations of the Caratan group, such agents as Triadimefon and Rubigan will help with oidium. "Triadimefon" is also known as "Bayleton." The drug affects the grapes through the roots and tissues. In soil, the substance remains active during one vegetative period.

The greatest effect of the processing of such a tool is observed when spraying grapes in the early stages of oidium. The healing process of the plant begins on the third day after treatment. The protective properties of the drug persist for a month from the time of spraying.

"Rubigan" has a high rate of penetration into the tissue of grapes. In contrast to “Bayleton”, the drug has a protective effect not so long (up to two weeks). The product can be mixed with other fungicides and fertilizers of mineral origin.

Biological methods of combating fungal disease are the use of products of organic origin. In order to independently prepare a solution for processing the vineyard, you will need humus. Preparation of the composition should be carried out in the spring, in time to process the plants.

In addition to humus, you need a capacity with a capacity of one hundred liters and water. In the container is laid humus on one third of its volume. Then warm water is poured into the container (not lower than 25 degrees). On top of the container to cover with a strong durable cloth. This composition must be sustained for a week, daily removing the fabric and mixing the contents of the container.

At the expiration of the specified period, the present mixture must be passed through cheesecloth. The resulting liquid sprayed the vineyard in the afternoon.

For the prevention and treatment of oidium, you can use not only special-purpose chemicals, but also use traditional recipes. The simplest option is soda solution.For its preparation, you will need six tablespoons of baking soda, eight liters of warm water and two large spoons of liquid soap or dishwashing detergent. All components are mixed to obtain a homogeneous mass, which must be processed bushes immediately after preparation.

Another effective option is to make a composition based on Bordeaux liquid and sulfur. The components are mixed with each other in equal quantities. It is necessary to process grapes with such composition in dry weather, since precipitation will reduce the effectiveness of this product.

Eco-friendly means for processing bushes is the usual ash. Microfertilizer must be sieved beforehand and then mixed with water. For ten liters of fluid will need one kilogram of ash. It is desirable to insist the solution for five days, periodically stirring it.

Another harmless means for processing grapes from oidium is a decoction of tansy ordinary. To prepare the solution will require 300 grams of crushed flowers of a fresh plant or 30 grams of dry mix, which can be purchased at the pharmacy. Raw materials need to pour ten liters of water and leave to stand for one day.

After a day, the mixture must be boiled over low heat for two hours. Then the broth must be cooled and passed through cheesecloth. The resulting liquid is watered at the roots of the plant and between the rows in the vineyard.

If signs of the disease appear on the grapes just before picking the berries, the solution of potassium permanganate will stop the spread of the fungus. To prepare the product, it is necessary to dilute five grams of the substance in ten liters of water and spray the bushes with the resulting composition.

There are a few simple recipes that can be used to treat powdery mildew grapes:

• A solution of mustard powder (two large spoons) and hot water (ten liters). Such structure can be used both for spraying, and for watering. Before use, the solution must be cooled.
• One hundred grams of minced garlic cloves must be mixed with four liters of water. The mixture is allowed to brew for 24 hours, after which the plant is treated with it.
• Cow manure is mixed with water in a ratio of one to three. Insist the resulting mass for three days, then filter and pour in water. The amount of water added should be three times the volume of filtered infusion.

Sulfur has proven itself in the treatment of grapes from oidium. The fact is that this substance penetrates the body of the fungus and completely destroys it. The first treatment is best done in the spring when the first buds appear on the bushes. Even if the plant has no visual lesions to prevent the spread of the fungus, the treatment is recommended to be mandatory.

In order to result from sulfur spraying, it is necessary to take into account the air temperature during the procedure. On the street should not be below twenty degrees Celsius, otherwise the effect of the substance will be insignificant. Sulfur is not recommended for processing during the flowering period.

In order to sprinkle sulfur easily onto all parts of the vineyard, the substance must be the smallest fraction. To prepare the solution will require 100 grams of colloidal sulfur per ten liters of water.

If there is a need to urgently process the bushes when the air temperature outside exceeds 35 degrees, it is better to make a weaker solution. In this case, the proportions will be as follows: 60 grams of sulfur per ten liters of water. To prepare the mixture does not need to pour the contents of the sulfur package immediately into all the water.

From the total volume, it is necessary to pour a small amount of liquid into a convenient container, pour the substance there and stir until complete dissolution. The resulting mass is added to the remaining water and mix well. The solution is not suitable for long-term storage and should be used immediately after manufacture.

Processing must be carried out with special care so that the solution gets even on hard-to-reach areas. Leaves must be sprayed not only from the front, but also from the back.

To grow grapes on your plot, it is advisable to study in advance the characteristics of the available varieties and choose the most sustainable option. Since oidium is one of the most common plant diseases, the variety must be as resistant to this disease as possible.

Despite all the efforts of breeders, today there are no varieties of grapes that are one hundred percent protected from fungal diseases. Among the most resistant varieties are the following grape varieties:

• "Kishmish Zaporizhzhya";
• "Hope Azos";
• Pleven;

• "Bogatyanovsky";
• "Arched";
• "Anthony the Great";
• "Laura".

How to protect grapes from oidium, see the following video.