Grapes are one of the most common crops grown in most areas. As a rule, this plant pleases gardeners with an excellent harvest. But sometimes the appearance of colored spots on the foliage leads to a decrease in the yield of bushes or even to their death. To protect his vineyard, the gardener needs to learn how to notice diseased plants in time and treat them.
Appearance of yellow spots
The appearance of large yellow spots on the grape foliage indicates infection of the plant with mildew. This disease is also known among gardeners as downy mildew. It spreads very quickly. If treatment is not started in time, the disease will affect not only the vineyard, but also other plantings. The foliage of diseased plants begins to die and fall off. If there are already berries on the grapes at this time, they will darken and wrinkle. To combat this disease, plants are treated with drugs such as Arceride or Kurzat.
Spring treatment of the site with Bordeaux liquid will help prevent infection of vine bushes.
Brown and brown spots
Unpleasant dark brown spots can appear both on the bottom of the foliage and along the edges. Most often, their presence indicates infection of the plant with anthracnose. If the vineyard is affected by this fungal disease, over time, dark spots will begin to appear not only on the foliage, but also on the stems. This disease spreads most quickly during rainy summers. Its spread is facilitated by high humidity. To combat this disease, it is recommended to spray the bushes with Bordeaux liquid. After two weeks, the treatment must be repeated.
There are other reasons for the appearance of brown spots on the surface of the foliage.
- Bad weather conditions. Very often, sudden changes in temperature negatively affect the condition of the plant. To prevent this from happening, seedlings for planting on your site should be chosen, taking into account the climatic features of the region.
- Wrong place to land. The appearance of dark spots on the foliage may contribute to the lack of sunlight. In order for the plant to develop normally, it must be under the sun most of the time.
- Lack of nutrients. In order for grapes to develop normally, they need to be fed regularly. If dark brown spots appear on the surface of the leaves, which eventually turn into holes, then the plant does not have enough potassium. With a lack of calcium, the leaf plate first brightens. Only then do dark spots appear on it. If the foliage turned yellow and large brown spots appeared on it, then the grapes need iron.
If you feed the vineyard in time, dark spots will not actively spread. In order for the plant to have enough nutrients, it is best to cut the diseased leaves.
White spots
The appearance of light spots on the foliage is the first sign of infection of the grapes with powdery mildew.. Spots can be not only white, but also ashy or even grayish. Foliage, on which such spots appear, quickly dries out and crumbles. Over time, the fruits, like the leaves, are also covered with a light bloom. This leads to the death of the crop. As a rule, this disease develops in thickened vineyards, which are very rarely pruned. To protect your plants from this disease, excess shoots must be cut off in a timely manner.
If white spots still appear on the foliage, they must be treated with a solution of colloidal sulfur. To do this, 10 grams of the product is diluted in 90 liters of water. It is recommended to spray the bushes in the early morning or evening. It is worth doing this several times a season.
The appearance of spots of other colors
Spots of other colors may well appear on the surface of the foliage. They also need to be fought by all available means.
Black
The appearance of large black spots on the foliage indicates infection of the bush Alternariosis. The foliage of a diseased plant eventually becomes covered with a dense layer of fungal plaque. Over time, it spreads to the vine. If the plant bears fruit at this time, the berries will also be affected. The active spread of the disease is usually promoted by high temperature and high humidity.
To combat this disease, it is recommended to spray the bushes with Bordeaux liquid.. All infected branches should be removed. If dark spots appear on the foliage, this may also indicate that the black spot struck the grapes. This disease is called escoriosis. Not only foliage suffers from it, but also shoots. They also have black spots on them. If the plant is affected too much, its shoots begin to break over time, and the fruits fall off.
Since this disease most often affects dense plantings, extra shoots of grapes are recommended to be trimmed regularly. It is also important to remove all fallen leaves from the site in a timely manner. If the disease still struck the bushes, they should be treated immediately. The first step is to remove all affected shoots. After that, the vineyard must be treated with Bordeaux liquid. After a few days, this procedure will need to be repeated. In order not to lose your harvest, plants should be regularly inspected in the summer. Particular attention should be paid to the vineyard in August.
Red
Large red spots that appear on the foliage are indicative of site infection. rubella. This disease usually affects plants that lack potassium. In addition, signs of the disease may appear after a prolonged drought. To protect plants, potash fertilizers should be regularly applied to the soil. In addition, the bushes in case of drought should be well watered.
Another reason for the appearance of red spots on the foliage is activity of a spider or felt mite. In green grape varieties, yellow spots appear on the leaves in this case.
To protect plants from pests in spring and autumn, the site should be treated with fungicides. In the process of preparing the site for winter, you need to remove all plant debris from there.
rusty
The appearance of rusty spots on the foliage indicates infection of the plant. rust. They grow in size very quickly. Infected leaves dry in a short time and fall off the bushes. The disease spreads rapidly, infecting not only the vineyard, but also other green spaces. Therefore, you need to start the fight right away. Noticing the affected foliage, the grapes must be treated with fungicides. After 2-3 weeks, this procedure must be repeated.
By learning to deal with the most common diseases, the gardener can count on a good harvest.
