Grape chlorosis is a disease that affects the plant due to a lack of iron. In the common people, it is called pale infirmity. It is characterized by a decrease in the yield of grapes, and in the absence of timely treatment, it can even lead to the death of the plant.
Features and danger of the disease
Chlorosis provokes a violation of the production of chlorophyll by the plant, due to which the activity of photosynthesis, which is one of the main elements of the vital activity of representatives of the flora, decreases. Lack of minerals, improper soil composition or infectious lesions also lead to a slowdown in the production of chlorophyll. As a result, the leaves become discolored or turn yellow. Shoots become lemon-colored.
If chlorosis has been detected in grape varieties that are highly resistant to viral infections, then the shrub may slow down growth, the leaves will turn yellow, and the tops of the shoots will dry out. If the disease has befallen grape varieties with a weak immune system, then there is a high probability of death of the shrub.
Untimely treatment of the disease can cause the death of entire vineyards.
Types and signs of the disease
Among the characteristic signs of the disease are the following:
- shedding and yellowing of foliage;
- cessation of shoot growth;
- reduction in fruit size;
- looseness of grape brushes.
These or other signs of the disease are manifested to a greater or lesser extent depending on the type of disease.
- noninfectious chlorosis. It develops due to improper saturation of grapes with minerals in the soil. It is distinguished by yellowing of foliage in the vein area, shedding of flowers and clusters, the plant stops growing.
- infectious chlorosis. This type of disease develops due to fungi, viruses and microorganisms and dies at a temperature of + 58 ° C. Signs of the disease: yellow spots are randomly scattered on the green foliage. The shoots change shape, the size of the clusters decreases. It is recommended that such shrubs be uprooted immediately, since it will be difficult to cope with the disease, and there is a risk of infecting other plants.
- Carbonate chlorosis. It is considered the most common and develops on grape bushes growing on dense land with poor gas exchange. As a result, the plant does not receive the proper amount of carbonate and alkali. In most cases, the disease is local. The plant turns yellow, then dries up and dies.
Causes of appearance
Chlorosis develops due to viral damage or lack of nutrients. A non-infectious variety of the disease can be caused by the following points:
- excessive soil moisture;
- prolonged rainfall;
- unbalanced supply of chemical elements to the earth.
Most often, non-infectious chlorosis is caused precisely by a lack of iron and an excessive content of lime in the soil.
Therapies
The treatment of a disease such as chlorosis is directly related to the cause of its occurrence. A non-infectious type of disease is treated by performing agrotechnical work and using chemical components. The viral type of the disease is treated with fungicides, but the infected areas must first be removed, since viral infections spread quite quickly and are very difficult to treat.
Among the agrotechnical manipulations required to get rid of chlorosis, the following are distinguished:
- light, well-ventilated soils are selected for growing grapes;
- improve air and water permeability;
- the soil is mulched;
- preventive land drainage.
Medicines are also required. Among the most effective means are noted:
- chelates and ferrous sulfate;
- sulfate ammonium and iron;
- sulfuric acid.
You can also additionally use mineral supplements with magnesium and zinc.
But when fertilizing, you must strictly follow the dosages indicated on the preparations, since a deficiency or excessive use of trace elements can adversely affect the general condition of the plant.
If the soils are prone to alkalization, then iron sulfate is necessarily mixed with citric acid. If the use of products containing iron did not give the desired result, then most likely the disease is infectious.
The use of fungicides is also effective only in non-infectious form of the disease.. In the case of infectious chlorosis, the only correct solution is to remove the affected plants in order to prevent infection of other shrubs.
In the case of carbonate chlorosis, folk remedies are most often used. These include cultivating the land with a solution of iron sulfate and rubbing iron salts into grape shoots.
Tips and Prevention
The fight against chlorosis is a complex and lengthy process, therefore, in order to prevent the development of the disease, it is recommended to pay attention to preventive measures.
- Immediately before planting grapes, manipulations should be performed to improve the condition of the soil, its water and air permeability. This is especially important in areas where the soil is heavy and groundwater is close to the surface. You can improve the soil by creating drainage from crushed stone (it will prevent stagnant water) and 10-15 centimeters of slag. An additional bonus in this situation will be the suppression of the growth of weeds and the absence of the need to cultivate the land.
- The introduction of organic components into the ground: peat, compost, humus. But the use of manure should be abandoned, because when it is decomposed, carbon dioxide is released. And this provokes the dissolution of lime and an increase in the carbonization of the earth.
- Planting plants such as clover, cereals or alfalfa next to grapes contributes to the constant sodding of the soil. These plants change the chemical composition of the earth and make it favorable for grapes. In addition, the soil is enriched with nitrogen and is not washed out.
- Every spring and during the growing season grapes are treated with a solution of ferrous sulfate and iron chelate.
- Should be regularly apply potassium fertilizers, even the non-root method is allowed.
- The soil is regularly loosened and mulched, especially if it is dense or heavy. If the soil is loamy, then sand should be added to the ground before planting grapes.
- The use of mineral fertilizers should be completely abandoned.
- In the autumn, the earth must be dug up with high quality.
- Moderate watering even in dry weather conditions.
But the main preventive measure is the selection of grape varieties that are not susceptible to chlorosis. Among these varieties are the following:
- “Alexa”;
- “Eastern talisman”;
- “Zaporozhye kishmish”;
- “Muscatel”;
- Elbling.
It should be understood that each type of chlorosis requires an individual approach for more effective treatment. Therefore, choosing methods of treatment, it is necessary to accurately determine the type of disease.
And it’s even better to think in advance about preventing this disease and purchase a grape variety that will not be afraid of chlorosis, then you can be sure of a high-quality and plentiful harvest.
You can learn how to deal with grape chlorosis without spraying from the video below.
