Grape chlorosis: causes and treatment with iron sulphate, what to do

Vine crops of different varieties can be resistant to fungal or infectious diseases. Lack of nutrients in the soil, sunny days, high humidity, fungal infections become the causes of grape chlorosis. It can be infectious and non-infectious, the way to deal with the indisposition of the fruit crop depends on the cause of its occurrence.

What is chlorosis

Chlorosis of grape leaves is manifested in the loss of chlorophyll - the leaves become translucent, discolored or turn yellow. This phenomenon is caused by a decrease in plant photosynthesis.The lemon-yellow hue in this disease of the plant is characteristic of both the foliage and the vine.

What is dangerous

When selecting seedlings of grape varieties with weak immunity to yellow mosaic and common fungal and viral diseases, even non-infectious chlorosis can lead to the death of the entire bush.

For disease-resistant shoots, a strong chlorosis lesion threatens:

• discoloration or discoloration of leaves;
• drying the tips of the shoots;
• lack of fruit.

Note! With repeated treatments of plants with chemical compounds with a high content of trace elements, the yield of plants affected by grape chlorosis will be lost or reduced due to crushing of berries and their shedding.

Types of disease

Purely schematically, chlorosis can be divided into three types:

• non-infectious due to iron deficiency;
• infectious, provoked by the yellow mosaic virus;
• edaphic, related to soil quality.

There are slightly more subspecies of chlorosis due to the different chemical composition of soils on which grape seedlings are planted, the climatic conditions of the regions where the vine grows.

Non-infectious

Non-infectious chlorosis is not associated with pathogens, it is caused by external adverse factors:

• high soil moisture;
• long rains, high rainfall;
• imbalance of the chemical (mineral) composition of the soil.

Non-infectious chlorosis of grapes is diagnosed by the initial stage of leaf color change. The first yellowness appears at the edges, gradually spreading to the veins, they are the last to lose their initial color.

Types of non-infectious chlorosis:

• nitrogen;
• iron;
• carbonate;
• magnesium;
• sulfur.

How to distinguish non-infectious from infectious chlorosis

For the diagnosis of non-infectious chlorosis, iron chelate is used as a tester. It is applied to the affected leaf in a stripe. A change in color within 24 hours - the return of a green color on the area treated with the composition indicates that the form of the disease is non-infectious.

Infectious

Infectious chlorosis develops on the background of a viral disease. Most often it is a yellow mosaic, panacheur, variegation, but other fungal infections of the vine can lead to chlorosis.

Change in the color of the leaf with an infectious form of the disease of the grape bush begins with veins (in the direction from small to large). The last to turn yellow or discolor are the areas as far as possible from the veins. The leaves of old shoots are the first to undergo infectious chlorosis, gradually the disease passes to young ones.

During the flowering period of grapes on infected plants, the color of the leaves is restored. The shape and size of berries, clusters, respectively, differs from those characteristic of a he althy plant of this variety.

Infectious chlorosis of the grape vine is not treated. The infected vineyard must be destroyed. Seedlings after vaccination are at high risk.

Note! Grape varieties growing in the European part that do not have a rootstock are not subject to infectious chlorosis.

Edaphic

A bush disease caused by adverse conditions associated with the soil - excessive moisture, lack of minerals and other nutrients, blocking them from the roots of seedlings with dense layers of soil is called edaphic chlorosis.

Excess lime in the soil is associated with a lack of iron, which causes the same signs of plant disease. The carbonate type of chlorosis also belongs to the category of edaphic.

Help! Edaphos - soil (translated from Greek). Edaphic - relating to the soil, generated by it or conditioned by its influence.

Carbonate

The carbonate form of the disease is often called iron chlorosis, the deficiency of the Fe element causes the disease. This subspecies of non-infectious damage is more susceptible to high yields and red-fruited varieties. For their high-quality fruiting, easily digestible forms of iron are required.

Excessive carbonate content of the soil is caused by natural factors:

• alkalinization of the soil;
• close to the surface of the aquifer;
• high s alt content;
• mixing the humus layer with others;
• density.

All these factors contribute to the imbalance of mineral nutrition, redox regime and water-air balance.

The imbalance of minerals supplied for plant nutrition is most often observed in humus soils, carbonate soils formed during the destruction of calcareous rocks and marls.

There is enough iron in these soils, but lime blocks the movement of zinc, boron, manganese ions towards the root system of plants. Nutrients remain out of reach.

Causes and signs of disease

Iron chlorosis can be diagnosed by the depletion of the vine and shoots, which is due to the deficiency of one or more nutrients.

With a lack of bromine, the following symptoms are characteristic:

• Spots with a low content of chlorophyll simultaneously appear on the entire leaf surface.
• Teeth of leaves dry out, crumble.
• Flowers fall without opening.
• Necrotic plaques appear on the berries,
• Fruits do not reach normal size.

Zinc deficiency is manifested in the insufficient development of petioles and leaf blades. The leaves of the upper shoots are covered with light green spots. Loose, light carbonate-type soils are predominantly zinc-deficient.

Manganese deficiency is diagnosed by the beginning of yellowing of the leaves from the serrated - extreme part, while the leaf areas adjacent to the veins remain green.

The most common nitrogen deficiency for the development of vineyards is observed on all types of soil during prolonged rains, washing out a useful element from the soil. This is a seasonal phenomenon. When planting vines in light sandy soils, nitrogen starvation of shoots causes causes:

• Stably cold days at the plant's vegetation stage.
• Excessive mulching with straw or sawdust.
• Lack of moisture - prolonged dry period.

Magnesium deficiency is observed in grapes growing on sandy and acidic soils, which is caused by an excess content of bromine, potassium, sodium. These chemical elements block magnesium ions, preventing them from reaching the roots of plants.

The rarest of chlorosis is sulfuric. It most often infects vineyards planted in areas with a low content of organic nutrients. Chlorosis is caused by phosphorus-nitrogen fertilizers used in excess of the recommended norms.

Chlorosis control methods

Annual top dressing is necessary for the vineyard. How to treat chlorosis before its first manifestations based on a visual analysis of the soil, every professional grower knows. To prevent disease associated with a lack of nutrients, root dressing is carried out in the spring before flowering, and foliar dressing, which is carried out in the fall.

Fertilizers to increase nitrogen levels:

• Urea is applied in liquid form, it is well absorbed. As the main root dressing is applied in the spring. In autumn, a liquid solution of urea is sprayed on the vine after harvest.
• Ammonium nitrate - ammonium nitrate is completely soluble in water, saturates the soil with easily digestible nitrogen. In the spring, it is applied as a root top dressing, in the fall as a foliar top dressing.
• Ammonium sulfate is recommended for application to soils with a high degree of moisture. This drug is practically not washed out of the soil by melt and rainwater.

Increase the level of phosphorus in soils superphosphates:

• Simple is for all soil types. The composition of the fertilizer includes gypsum - a source of sulfur.
• Double is a concentrated product, its dosage in solution is three times less than a simple one.

To increase the level of potassium suitable:

• Potassium chloride. The exception is acidic soils.
• Potassium s alt. High content of chlorine-containing substances. Used only in late autumn.
• Potassium sulfate shows the highest efficiency when enriching light soils.

Combined fertilizers to saturate the soil with nitrogen, phosphorus, potassium:

• "Nitrophoska".
• Nitroammophos.
• "Azofoska".

What to do with the vine affected by chlorosis, if the disease is detected after the flowering period? The answer to this question is ambiguous. If the disease is caused by an infection, then the leaves and vine should be treated with fungicides.

Universal in the fight against yellow mosaic, anthracnose, mildew and oidium are:

• Bordeaux blend.
• Iron vitriol.
• Colloidal sulfur.
• Lime-sulfur infusion.

The use of these products is recommended when the first signs of chlorosis are detected, they are applied to the entire surface of the bush - the vine, the leaves. Sprayed by them and a piece of land adjacent to the grape bush.

Preparations for non-infectious chlorosis are the same as those recommended for prophylactic treatment, only the dosage of active substances in the solution is higher. The fight against this type of chlorosis will be intense - from early spring to the middle of the growing season. Only in this way will it be possible to save the vineyard from death and return its productivity to the next season. This season, alas, it will not be possible to get a full-fledged harvest.

Using iron sulfate to treat grapes

Insecticide, fungicide - iron sulfate is not dangerous for plants, animals, humans. Ferrous sulfate, ferrous sulfate (FeSO4), is used for disinfection, plant treatment and as a fertilizer.It effectively fights non-infectious chlorosis, but is practically useless in the infectious form of the disease.

For each particular case of plant damage, there are recommendations on how to prepare the composition for processing in order to avoid burns of foliage and shoots. The versatility of the drug lies in the fact that it is used for:

• prophylactic seasonal treatment;
• in the fight against pests and their larvae;
• treatment of fungal infections;
• acceleration of tightening standard damage;
• soil enrichment with iron;
• storage processing.

There are several disadvantages of ferrous sulfate. They are expressed as follows:

1. During the spring processing of the plant, young leaves and shoots can get not only help in the fight against chlorosis and pests, but also burns.
2. The product does not penetrate deep into the tissues, the fight against fungal infections is superficial.
3. The disinfecting effect lasts no more than 14 days, which implies that in summer the treatment of shoots affected by the fungus should be carried out at intervals of 10-14 days.

Advice on how to treat grapes with iron sulfate in spring:

• The first treatment and preventive spraying is carried out between the onset of stable positive temperatures until the appearance of leaves.
• The concentration of the fertilizer is less (10-20 g per 10 liters of water), respectively, the processing time increases from the moment the snow melts to the appearance of 4-5 leaves on the shoot. Processing is carried out in calm, dry weather.
• The introduction of a 0.5% solution into the soil is carried out when digging. The recommended rate is 100 g for every 1m^2.

How to prepare a ferrous sulfate solution

To get a solution with a strength of 0.5%, you need to dissolve 50 g of concentrated fertilizer crystals in 10 liters of water. Dissolve the drug in cold water, heated in the sun. Subject to this rule, the characteristics of the fertilizer will not deteriorate, and a cold shower will not be a shock for the plant. Grapes do not tolerate cold watering.

Note: With a severe iron deficiency that caused grape chlorosis, the concentration of the ferrous sulfate solution also rises to 0.5%.

The composition prepared in this proportion can be used for spraying, which will protect the grapes from infection by diseases of nearby fruit trees and their parasites.

Autumn treatment with iron sulphate

In anticipation of winter, vine bushes are also treated with iron sulphate.This is a necessary measure of protection against cold weather, temperature fluctuations. A high concentration of ferrous sulfate provides a reliable covering of the plant with a protective film that prevents not only the freezing of the bush, but also the penetration of pests and fungi into it.

After the vegetative period until mid-November, spraying is carried out with a solution made in the proportion of 500 g of fertilizer per 10 liters of water. This is the norm for an adult plant.

For seedlings, the fertilizer rate is reduced to 300 g FeSO4. The same solution that is prepared for the treatment of the vine is used to treat the land adjacent to it.

Attention! Before autumn spraying, pruning and removal of foliage remaining on the branches is performed. This increases the efficiency of processing each branch.

Prevention

Preventive work to restore vines affected by chlorosis in the previous season:

• While the kidneys are in a state of sleep, the bushes are sprayed with copper sulfate or Bordeaux mixture. Root dressing - mineral fertilizers.
• After opening the buds, empty shoots are removed, nitrogen-containing compounds are introduced.
• At the stage of shoot development, a weak solution of Bordeaux mixture and lime sulfur is treated with foliar top dressing with mineral fertilizers.
• At the stage of formation of the ovary, spraying with solutions of colloidal sulfur and copper sulfate is carried out.
• The next treatment, repeating the previous one, will come only after harvesting and thinning the bushes.

Protection of a vineyard with calcareous soil begins with the selection of seedlings that can withstand the complexity of the soil.

For your information. Parsley is not tolerated by pests of grapes, this is the most favorable neighborhood.

Resistant varieties

Breeders are constantly improving the quality of the vine, using different combinations of rootstocks and scions, but no one has yet managed to achieve 100% resistance to chlorosis. To date, varieties are highly resistant to the disease:

• Alexa;
• Venus;
• Delight;
• Zaporozhye sultana;
• Pink Timur;
• Eastern Talisman;

To minimize the risk of damage to grapes by chlorosis, you should take a comprehensive approach to plant protection, without neglecting any of the stages of spring and autumn spraying and fertilizing.

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