If a white coating appears on grape leaves, immediate action must be taken.
The color of the spots corresponds to some disease. There are diseases that are caused by viruses, bacteria and fungi.
Yellow spots
This is a sign of powdery mildew and mildew. The disease affects the upper part of the leaves, and a white coating appears on the bottom.
The leaves die off very quickly and the berries become wrinkled and dark. The disease spreads very quickly.
Spray the leaves with "Schirma", "HOM", "Kurzat", "Oxyhom", "Proton Extra".
For prevention, spraying is carried out at the beginning of bud break and at the beginning of flowering. Then spray the grapes once every two weeks - 1% Bordeaux mixture.
Brown and tan spots
This is an anthracnose infection. The leaves become darker and then fall off. The stem turns brown and begins to rot. If the humidity is high, the disease quickly affects the entire bush.
If the peduncle is affected, the berries will fall off. The bushes are sprayed with 3% Bordeaux mixture or "Agrolekar", "Fundazol", "Medea", "Abiga-Peak". After 14 days, the treatment is repeated. If the bush is half affected, the shoots are removed and burned. For prevention, the bushes are treated with 1% Bordeaux mixture three times a week.
Ash and greyish spots
This is an infection with powdery mildew, oidium. The berries turn grey and the leaves dry up and fall off. The reason is an abundant planting. Dissolve 3 tablespoons of colloidal sulfur in 10 liters of water and treat the grapes on the vine when three leaves grow on it.
During the entire growth period, sprinkle the bushes with sulfur three times. 2 grams are required per 1 m2. For treatment, use: "Hom", "Fundazol", "Medea", "Kurzat", "Albit", "Sporobacterin".
Black spots
This is an Alternaria infection. The leaves darken and become covered with a coating at a very fast rate. The reason is hot and humid weather.
Or the bush is affected by excoriosis, which is noticeable between the nodes of shoots and legs. The reason is dense plantings, damp and humid weather.
The bushes are sprayed with 3% Bordeaux mixture or "Trichodermin". In the fall, the affected shoots are removed and burned. The leaves under the bush are also collected and burned. For prevention, 1% Bordeaux mixture is used during budding. Spraying is repeated after a week.
Red spots
This is a rubella infection. The cause is improper cultivation, lack of potassium, prolonged drought, low temperatures outside, felt or spider mites. Yellow spots appear on white grapes.
If humps are visible on the outside of the leaves and holes are visible on the inside, the grapes are affected by phytoptus. Treat the bushes with 1% potassium nitrate. Spray the vines with Antikleshch, Apollo, Fufanon-Nova or colloidal sulfur. In the fall, remove the affected leaves and shoots.
Rusty spots
This is a rust infection. Humps appear on the leaves, where fungal spores live. Treat the bushes with "Profi", "Agrolekar" or "Prognoz". Repeat the treatment after three weeks.
The main rule is timely inspection of bushes for diseases and preventive measures.
