Almost every year, gardeners encounter oidium on grapes, due to which their yield deteriorates significantly. This disease is considered one of the most common pathologies appearing on grape bushes. To save the plant, you should familiarize yourself with the description of the disease and methods of eliminating it in advance.
Description of the disease
Fungal-type infectious diseases often affect grape fruits.Because of this, they cannot be further processed or consumed fresh. Among the common infections are powdery mildew or oidium.
Plants become infected with oidium disease after exposure to pathogens that live in the vine. In spring, when the air temperature warms up to 15-20 degrees, the fungus begins to actively develop and infect nearby vineyards. Most often, bushes become infected in the second half of spring or early summer with high air humidity. However, with daily rains, the humidity level reaches too high levels, which leads to a slowdown in the development of the disease.
It is difficult to determine the presence of oidium at the initial stage of its development, since it practically does not manifest itself in any way. Only after 5-6 days can you notice the first symptoms of pathology. First, it affects the lower leaves of grape bushes and gradually spreads to the upper leaves and fruit clusters.
Causes
It is recommended to study the main causes of powdery mildew in advance. This will help to understand why grape bushes can become infected with such a dangerous disease.
The causative agents of oidium are quite often found in the upper layers of the soil. However, optimal conditions are required for their development. For example, if the weather is sunny and warm outside, and a person follows all agrotechnical cultivation rules, then the fungus will not develop.
There are a number of conditions that contribute to infection of grape bushes and further development of the disease. These include:
- Regular cloudy weather with increased air humidity. Lack of sunlight and high humidity levels are very dangerous for grapes.It is under such conditions that the causative agents of most fungal infections are activated.
- Increased nitrogen levels in the soil. When growing grape bushes, some summer residents add too much nitrogen fertilizer to the soil, which contributes to the development of powdery mildew.
- Dense plantings. Bushes that are planted too close to each other are susceptible to infection with oidium.
- Incorrect watering. Sometimes plants are watered very often, which is why the soil does not have time to dry completely. This significantly worsens the protective functions of grapes, which leads to infection with fungal diseases.
Signs of infection
In order to promptly identify oidium on a plant, you should familiarize yourself with the main signs of the occurrence of pathology. There are a number of symptoms that appear only with this disease.
The first signs of oidium disease appear in the form of small white spots that appear on the surface of the lower leaves. After 1-2 days, the size of the spot increases, due to which the leaves are completely covered with a white coating. With further development of the pathology, the spots progress, become denser and almost completely cover the grape seedlings. Because of this, upon external examination of infected plants, it seems as if they are completely covered with cobwebs or sprayed with lime liquid.
However, in fact, the surface of the leaves, fruits and stems is covered with fungal epithelium, which consists of many conidia.
If the grapes are not cured in time, their leaves will begin to become covered with yellow spots and dry out. Also, due to the disease, the growth of bushes slows down and their immune system weakens. Because of this, grapes cope much worse with temperature changes and even minor frosts.
How to deal with oidium on grapes?
It is necessary to combat the disease when its first symptoms appear. This will stop the further development of the pathology and prevent the grapes from dying.
Any control measures are aimed at the complete destruction of fungal infection pathogens. There are various methods of combating oidium that will help cure the bushes. To increase the effectiveness of each of them, you will have to engage in complex treatment. However, before this you will have to familiarize yourself with the main methods of combating fungal disease:
- Sulfur solution. Experts advise treating powdery mildew using sulfur liquid. It is better to carry out the procedure in the morning or evening, when there is no bright sunlight. When spraying the liquid, make sure that it gets to all affected areas of the grapes.
- Colloidal sulfur solution. Treatment with this remedy is considered quite effective, as it helps to quickly get rid of fungi on the bushes. Experienced gardeners recommend spraying once a week.
Effective chemicals
There are several effective chemicals that can help cure infected grapes. However, before using the drug to combat oidium, you will have to familiarize yourself with each of them in more detail:
- "Topaz". Among gardeners and lovers of growing grape bushes, the Topaz product is popular. The drug effectively fights many fungal infections, and powdery mildew is no exception. To get rid of the symptoms of pathology and save the plant, you will have to spray at least three times a month.
- "Vitaros". To prevent and eliminate signs of powdery mildew, you can use Vitaros.This fungicidal drug should be used in early spring, when pathogens are just beginning to become active.
- "Skor." To quickly eliminate the symptoms of infection, you should use the solution from Skor. When preparing it, a glass of the drug is mixed with 10-12 liters of water. Plants are treated at least twice a month.
Folk recipes
Folk remedies are also used to eliminate oidium. The most effective include the following:
- Serum. Fans of folk remedies often use whey, which can save grapes from infectious diseases. Such a solution can not only eliminate signs of the disease, but also improve the functioning of the immune system. To create a solution with your own hands, you will have to mix part of the whey with two parts of heated water. Treatment with the resulting mixture is carried out every two weeks for three months.
- Iodine. A solution prepared from medical iodine also effectively fights oidium. When creating a mixture for spraying, 10 ml of iodine is added to a container with ten liters of water and mixed thoroughly. Then, using a spray bottle, the grape brushes and leaves, which are covered with a white coating, are sprayed with liquid. The procedure is carried out twice a week.
- Ash. A product made from ash can prevent the death of plants infected with powdery mildew. To prepare a medicinal liquid, a kilogram of sifted ash is mixed in 7-8 liters of water and left for 20-30 minutes. After this, 200 grams of soap is added to the solution. Infected grapes are sprayed with the solution three times a month.
Prevention measures
When growing grapes, be sure to take care of disease prevention, since by taking preventive measures in a timely manner, you can protect the plants from death.Experienced gardeners consider the best prevention to be proper care of the plant they grow. By following all agrotechnical cultivation rules, the likelihood of becoming infected with oidium is minimized.
To prevent the grape bushes from getting sick, you will have to water them correctly. You should moisten the soil no more than twice a week. At the same time, you should not over-water the bushes, as this will increase the humidity of the soil and air. During prolonged droughts, watering becomes more frequent, since the soil dries out faster in such conditions.
Grapes also need regular feeding, which will increase its protective functions. In summer, the soil is fed with potassium fertilizers at least three times.
The most resistant varieties
Some gardeners are growing grape varieties resistant to oidium. These include:
- Aligote. This variety is popular among winemakers, as it belongs to the wine grape varieties. It is grown in open ground only in the southern or central regions. In cold climates, it is better to grow in greenhouses for higher yields. The advantages of Aligote include not only its resistance to powdery mildew, but also the taste of the crop.
- Sauvignon. A common variety that many grow to make aromatic white wine. The distinctive features of Sauvignon include small clusters of grapes with small berries, as well as resistance to many common diseases.
- Savraska. A well-known Altai variety with early harvest ripening. It is distinguished by huge tassels, the length of which reaches 35 cm, and delicious berries.
Conclusion
Powdery mildew is a common disease that affects many grape varieties.To get rid of it and protect the planted grape bushes, you will have to familiarize yourself with the basic methods of combating oidium and preventive measures.
