Mildew on grapes: how to treat the disease, control measures and processing

Grapes - a plant known for several millennia. Delicious fragrant clusters, which are quite difficult to grow, seem to be filled with the sun and have a huge amount of nutrients. The vine, like any other plant, can get sick. Mildew of grapes is a serious misfortune. Having discovered a problem, it is necessary to immediately begin the fight against the disease so as not to destroy the entire vineyard.

What is this disease?

Mildew - a fungal infection of grapes, ranks first among the diseases that European vineyards are exposed to. The disease was brought to Europe in the 19th century from North America along with infected vines of new varieties, and was first discovered in England.

Due to the peculiarities of the European climate, the disease began to spread rapidly, affecting the local vine, destroying the entire crop in a short time. Soon, mildew spread across the continent, the vineyards of France and other European countries were infected, significantly reducing the number of grapes and ruining winemakers.

Causes infection of omyocet - a fungus-like organism, a member of the Pyronosporaceae family, the disease is also called downy mildew of grapes.

First, the green leaves of the grapes are covered with light yellowish oily spots. In large leaves, yellowing may appear along the veins, under favorable conditions for the fungus (warm, humid weather), the disease begins to progress rapidly. On the back of the leaves, in spots, a barely noticeable whitish fluff appears.

If urgent measures are not taken, the shoots dry up, the ovary is quickly affected and the leaves fall off. Of course, in this case, you no longer have to wait for the harvest, the main thing is to get rid of mildew on the grapes as soon as possible and save the vine.

What is the difference between mildew and oidium?

If mildew is called downy mildew, then oidimum - the second frequent and very dangerous fungal disease of grapes - is simply called powdery mildew.

White smoky coating on the leaves (from a distance it seems that the plants are sprinkled with ashes), affected, bursting, juicy berries, as if powdered with flour, are all symptoms of odium. If the disease is not treated, a thick layer of plaque becomes like felt, cracked berries exude a smell of rot, the grape harvest is significantly reduced, it is no longer suitable for processing.

Important: mildew appears on the back of the leaves, a whitish fluff forms on the inside; oidium affects the outer part of the leaf, covering it with bloom.

For the treatment of odium from vineyards, preparations containing sulfur are used. The first treatment is carried out in the spring, after the shelter is removed, (the vine must first be ventilated for several days), the second time the plant is sprayed after harvesting. Azofos is used for processing. Sulfur should get not only on the bushes, the soil under the bushes and around the plant is covered with the fungicide.

If you do not take preventive measures and do not treat the diseases that have arisen in a timely manner, this dangerous "couple" can completely destroy the vineyard in a matter of days. Plants stop growing and fruiting, do not tolerate the coming winter, and are very likely to get sick next year.

Causes of occurrence

Spores of a dangerous fungus that causes mildew on grapes are resistant to cold. They overwinter safely in fallen leaves. The first spring rain, hitting the soil, raises them, fixing on the lower leaves, and the mildew quickly spreads throughout the plant.If this is accompanied by warm (+ 20-27 ° C) and humid weather, the rapid spread of the disease becomes almost inevitable. After 5-20 days, the first signs of infection are visible.

Wind promotes the transfer of the fungus to new areas. If the plants are planted too close together, the disease quickly covers the entire vineyard. Heat and humidity shorten the time it takes for mildew to develop; under favorable conditions, the fungus can reproduce up to 8 generations. In dry weather and air temperatures above +30 °C, the fungus does not survive, so it is not typical for Central Asia.

Possible symptoms

The main symptom and sign of the development of mildew is the appearance of yellowish oily spots on the front side of the leaf. From the inside, it is covered with a whitish fluff, better visible on young foliage. Then the spot grows, becomes red-brown, the leaf dries up, curls and falls off, allowing the spores to start a new cycle.

Young shoots and flowers of the plant are especially quickly affected. Berries infected with downy mildew become dark and shriveled, they dry out, crumble, giving the clusters an unattractive appearance. In severe cases, branches are affected.

Young shoots stop growing, diseased vines shed their leaves prematurely.

Mildew control measures

Treatment of mildew grapes is carried out with the help of chemicals and folk remedies. Detrimental to the fungus are preparations based on copper, lime and sulfur. Spraying is done several times per season, depending on the susceptibility of the variety to this disease.

Important: the fungus gets used to the drugs and develops resistance, so if the vineyard is sprayed more than 3 times per season, it is necessary to diversify the arsenal of funds.

Varieties most attractive to the fungus, such as Kishmish, are processed throughout the growing season, every 2-3 weeks.

The fight against mildew is a whole range of measures to save the crop. In this case, the affected leaves and clusters must be cut off and destroyed (buried or burned) - they cannot be used as compost.

Pruning the old vine and disposing of the leaves can prevent the development of the disease in the new season. Mulching the ground around the plant is also a measure to protect the vineyard.

Too much nitrogen in the soil and too little potassium can trigger an outbreak.

Methods and means for processing grapes

Compounds based on copper (copper sulfate, Bordeaux liquid) are effective as a preventive measure. Such treatment was ubiquitous, so today its effectiveness has decreased somewhat - fungi have simply developed resistance to drugs.

Processing grapes from mildew is carried out in several stages.

For the treatment of disease-affected vineyards, complex fungicidal agents are used, which allow you to deal immediately with mildew, odium, spider and felt mites. Steps of protective measures:

1. The first processing of grapes is carried out in the spring, after the temperature rises to +8 °C. Plantings are treated for prophylactic purposes with a 3% solution of copper sulphate or Bordeaux liquid.
2. The next mildew treatment is done after the appearance of the first leaves, used: Delan, Horus, Hom.
3. In the flowering phase, the plant is treated twice: the first time - before flowering, the second time - after the grapes have faded. Use Delan, Strobi and other suitable drugs.
4. During the ripening of berries, when they gain juice and grow intensively, the grapes are not sprayed with fungicides. During this period, to protect the grapes, it is possible to use Baikal and Fitosporin, but it is still better not to use chemicals.
5. The last treatment of grapes with drugs is carried out for preventive purposes, after harvest, in August. Processing is carried out with copper or iron sulphate, fungicides can be used.

When choosing how to treat plants, it should be remembered that when using chemicals, the preparation of working mixtures is carried out in strict accordance with the manufacturer's instructions on the package, outdoors or in a well-ventilated area.

All work (solution preparation, spraying) is carried out using protective equipment: glasses, rubber gloves, protective apron. After processing the plants, you should take a shower.

Folk recipes

Not everyone wants to treat their own vineyard with fungicides, especially if there are not very many grapes in their summer cottage. In this case, the processing is carried out by folk remedies.At the same time, not only the vine is disinfected, but also the ground under it, because there may be spores of the fungus.

For the purpose of prevention, the soil under the grapes is treated with a decoction of tansy.

300 grams of a fresh plant or 30 grams of a pharmaceutical preparation are poured into 10 liters of water and infused for a day, then boiled for 2 hours, and after cooling, the earth around the plant is poured with undiluted infusion.

To protect against mildew, the vine is sprayed with an extract of wood ash with the addition of laundry soap. To prepare a working solution, a kilogram of ash is dissolved in a large bucket of water and infused for 1-3 days. The mixture is diluted 1:10, 3 tablespoons of liquid laundry soap must be added to each bucket of the finished solution. The vineyard is sprayed with this mixture.

Another method is to spray the grapes with a solution of potassium permanganate. To do this, a teaspoon of the product is thoroughly dissolved in 10 liters of water.

In addition, solutions of soda ash or baking soda are often used for processing.

Experienced gardeners spray grapes with an infusion of rotted straw, which is infused for a week - this is one of the oldest folk ways to protect grapes from mildew.

Of course, folk remedies are most effective in the initial stages of infection, and they have to be used much more often than fungicidal preparations, but they can be used without fear of the content of toxic substances in the berries.

Mildew resistant grape varieties

Thanks to the work of breeders, mildew-resistant grape varieties have been obtained today, which develop well in the Russian climate. Examples of such plants are: Timur, Rapture, Agat Donskoy, which, moreover, have excellent resistance to frost. The Monarch variety is also resistant to mildew, but it is often affected by oidium.

When laying a vineyard, to avoid trouble, you should choose zoned varieties, bred taking into account the climate and humidity in a particular area.

What to do for prevention

There are several rules that help prevent losses from mildew. To prevent the disease, you should:

• Don't space plants too often. The distance between rows of plantings is 3 meters, between adjacent bushes - 1.5-2 meters ;
• regularly mulch the soil under the vine;
• use drip irrigation;
• prune grapes, remove fallen leaves and dead old branches;
• after harvesting, before winter shelter, treat plants.

Simple recommendations for protection and timely prevention can reduce the risk of developing a disease not only with downy mildew, they will help resist oidium and other ailments, and protect plantings from pests.

Growing good grapes is not an easy task. Preventive plant treatment measures will reduce the likelihood of disease. The vine requires careful careful care, however, if you manage to do this, when you look at the brushes filled with juice, your mood is sure to rise.

And the he alth benefits of quality grape juice or homemade wine can be talked about for a long time in superlatives.

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