How to deal with oidium on grapes

Grapes, like other cultivated plants, can have various diseases. They infect leaves, inflorescences, thereby harming the plant. Oidium (another name is powdery mildew) is one such common disease. In this article we will discuss the oidium on grapes: consider the treatment of this disease, as well as discuss the best way to handle the plant.

Description of the disease

Oidium is a fungal disease.affecting shoots and leaves. If the conditions are favorable, then it goes to the inflorescences and does not allow them to fully develop and mature.

Powdery mildew does not spread on dried shoots and leaves, but lives only on living tissues. In the form of mycelium, oidium is located in the cracks of the bark, on the kidneys and winters there. The spores of this disease persist on the leaves and shoots all season. It multiplies very quickly, forming new spores, and spreads throughout the bush, and then moves to neighboring plants.

In regions where spring is early and warm, powdery mildew is activated very early and affects newly grown young shoots. In colder climates, this disease wakes up when leaves appear on a bush.

Causative agent

The causative agent of oidium is a fungus of the genus Uncinula. This parasite develops on the surface of grapes. A gray-white patina on a plant is formed using extremely thin hyphae attached to the plant surface by suckers called appressoria. To absorb food, this mushroom implants its haustories into the epidermis. The affected cells die, forming a dark brown mosaic.

With the help of wind, conidia of the fungus are transferred to areas of grapes that are not yet infected. The best conditions for the development of this disease are dampness and humidity above 80%, as well as poor ventilation of the site.

Oidium incubation period is 7-14 days, depending on air temperature.Conidia develop best at +20 ° C, but their growth can begin at +5 ° C.

Signs of infection

Mealy dew of grapes appears on all of its above-ground parts:

• a gray-white patina appears on the leaves, which spreads to both sides of the leaf;
• leaves are bent at the edges, curled, turn yellow;
• plaque appears on the clusters, flowers, as if they were sprinkled with flour;
• dark spots are formed on the shoots;
• tissues shoots turn black and die in some places.

If the fungus continues to actively develop, this can lead to the fact that:

• infected inflorescences die off;
• grapes affected by the disease, dry up earlier;
• small fruits crack and dry, the seeds are exposed.

Control measures

To get rid of oidium on grapes, you need to take the necessary measures to combat the disease.

Prevention

To avoid the appearance of powdery mildew, you need to carry out prevention. Good care will help reduce the chance of powdery mildew to a minimum. In the fall and spring it is useful to dig up the ground under the grapes. It is also good to feed the bushes with potash-phosphate fertilizers.

To protect the grapes, they are treated with fungicides.Many prefer the tool "Tiovit Jet." If the grape variety is susceptible, it is better to use Topaz.

Useful tips to help avoid disease:

1. The soil under the grapes must be kept clean, dry leaves and branches clean in time.
2. Tools should be disinfected after trimming.
3. The plant is not worth overfeeding. It is best to use balanced blends.
4. When watering it is undesirable to allow water to enter the part of the bush that is above the ground.
5. Do not allow thickening landings.

Biological methods

The biological method of struggle consists in preparation in the spring of saprophytic microflora from humus.

This is done like this.:

1. In a 100-liter barrel to pour humus, so he took her third part.
2. Fill with water heated to +25 ° C.
3. Cover with sacking and, regularly stirring, wait 6 days.

The substance, which turned out, must be filtered with gauze. Pour the liquid into the sprayer and spray it on the young leaves of the vine and the shoots for prevention. Spraying is desirable in the evening or on cloudy days. Spray such microflora should be twice a season, observing an interval of one week. If the disease has spread much, you need to spray it even after flowering.

Potassium permanganate

During the ripening of berries, chemical agents are best not to apply. Therefore, a solution of potassium permanganate (5 g per 10 liters of water) will help to stop the disease for a while.

Sulfur-containing drugs

Sulfur is fatal to the parasite. The fungus absorbs it and dies. From the oidium on the grapes for the treatment dissolve 100 g of sulfur in water (10 l), and for the prevention - 40 g. This is best done in the morning or in the evening, as in the heat of sulfur burns leaves and fruits. This method works at temperatures above +18 ° C. If the temperature is lower, you can use sulfur-containing drugs, such as "CabrioTop."

Drugs from oidium

After flowering, use such drugs from oidium on grapes: "Skor", "Rubigan", "Topaz", "Bayleton". There is also "Fundazol", but it is effective only for young seedlings. From last year's oidium, Horus or Strobe helps best.These drugs are used in cold weather.

Folk remedies

There are also popular methods to combat the disease.:

1. 3 tbsp. l soda mix with 4 liters of water and add 1 tbsp. l liquid soap. Spray grapes immediately.
2. Stir 1 kg of sifted ash in warm water (10 l). Need to insist 5 days, stirring occasionally. Before processing, add grated soap (30 g).
3. 2 tbsp. l dry mustard diluted in 10 liters of boiling water. After cooling with this mixture, water and spray the grapes.
4. 25 g cloves garlic chopped and diluted with 1 liter of water. A day to put on the grapes.
5. Korovyak need to fill with water 1: 3. After 72 hours, filter the slush and dilute with water 3 times.

Resistant varieties

There are grape varieties resistant to fungal diseases. These are Aligote, Rkatsiteli, Kishmish, Merlot, Sauvignon.

Oidium - a malignant fungus, quickly spreading over all above-ground parts of grapes. If you take timely action, the risk of disease can be significantly reduced.