Content
Apple chlorosis is a disease that disrupts the formation of chlorophyll in the leaves and reduces photosynthesis. A number of reasons can provoke its development. But if the problem is identified in a timely manner and measures are taken to eliminate it, the tree quickly recovers without losing productivity. Therefore, every gardener should be able to determine apple tree chlorosis at an early stage of development, as well as know the possible causes of its occurrence.
With chlorosis, the leaves become unnaturally light in color.
Description of apple tree chlorosis with photo
This disease occurs against the background of metabolic disorders in the tissues of the apple tree. This is reflected in the appearance of the tree, primarily in the leaves. The plates become noticeably lighter, but the veins remain a rich green hue. Subsequently, black dots appear on the affected areas.
Also a sign of chlorosis is a decrease in the size of young leaves. The edges of the plates curl and the shoots dry out. Chlorosis negatively affects flowers, ovaries and fruits. With this disease they become deformed. Apples lose their presentation, and their taste decreases.
In this case, the disease disrupts the development of not only the crown, but also the root of the tree.
Causes of apple tree chlorosis
Apple tree chlorosis can be viral and physiological. In the first case, the disease is carried by pests. The virus can also be transmitted through young seedlings. And when purchasing, you should carefully inspect them, and also pay attention to the condition of the root system.
In the second case, the reason is a violation of the rules for caring for the apple tree, as a result of which the bush lacks nutritional components. This occurs in the absence of timely fertilizing and the inability of the roots to absorb them from the soil.
Physiological chlorosis occurs against the background of a lack of the following elements:
- Gland. The disease develops when there is a lack of this component in the soil, which provokes an excess of lime. As a result, the alkaline reaction of the soil is more than 7 pH. This turns the iron into a form that is unavailable to plants. This type of chlorosis occurs in spring and the first half of summer. It manifests itself as yellowing of the leaves, which begins at the top of the shoots. If left untreated, the frost resistance of the apple tree decreases and the fruits fall off.
- Boron, magnesium, manganese. With this type of disease, the plates between the veins lose their shade. Moreover, the lightening of the leaves occurs unevenly. In addition, the development of the seedling slows down, the fruits decrease in size, and their color fades.
- Nitrogen. With a lack of this element, the branches dry out from the bottom up. First, the old leaves evenly lighten, and only subsequently do the young leaves lose their rich color. The rate of development of the apple tree also decreases, the shoots grow thin.With this type of chlorosis, the tree blooms earlier than usual, but the buds become smaller and their number decreases. Additional signs: the petioles of the plates acquire a red tint, early leaf fall occurs, the fruits ripen prematurely, but they are tasteless.
- Potassium. The lack of this element is manifested by light spots between the veins of the leaves and a brown tint to their edges. Subsequently, the plates curl, young branches dry out, and shoots grow thin and short. Most often, potassium chlorosis develops on sandy soil.
- Calcium. The disease manifests itself on young leaves, marginal necrosis forms, and the fruit pulp hardens. With a long-term deficiency of this element, the development of the apple tree slows down, and the root system begins to die off. Also, the fruits become smaller, ripen earlier than expected, and their shelf life is reduced.
In spring, chlorosis of an apple tree after pruning mainly occurs due to sudden changes in night and day temperatures, which reduces the tree’s resistance to unfavorable external factors. In this case, the roots of the tree are still in the cold soil, and the leaves are well heated under the influence of the active spring sun. This leads to metabolic disorders in tissues and slows down the process of photosynthesis.
Heavy rains in the fall or at other times of the year can also provoke chlorosis of the apple tree. In this case, prolonged stagnation of moisture in the soil contributes to the leaching of nutritional components from the soil, which leads to their deficiency. As a result, the apple tree does not receive enough nutrition, which leads to disruption of metabolic processes in tissues.
Heavy, compacted soil as a result of prolonged drought can also cause the development of chlorosis. In this case, the root system of the apple tree experiences oxygen starvation.As a result, the functionality of the underground part of the tree is reduced, and it cannot absorb nutrients from the soil in the required volume.
This infectious disease cannot be treated
What can be confused with
Chlorosis can be confused with other apple tree diseases. To be able to recognize it, you need to become familiar with their characteristic differences.
Chlorosis can be confused with:
- Apple tree mosaic. With this disease, light areas appear on the leaves in the form of spots and stripes. Initially they have a bright yellow tint, subsequently turn pale, and then necrosis appears. As a result, the affected plates crumble. The causative agent of mosaic is the Apple mosaic virus. The clarity of the pattern during the disease may vary, depending on the type of pathogen strain. Lightened areas during mosaic appear not only on leaves, but also on shoots and apples. Due to the disease, fruiting occurs later, and the yield of the apple tree decreases sharply.
The mosaic virus is transmitted during budding and grafting of cuttings
- Chlorotic ring spot. A common disease that manifests itself as light spots on the leaves and dark ring-shaped areas on the fruit. The growth of young shoots also slows down. The causative agent is the Apple chlorotic leaf spot virus. The disease begins to develop in the second half of summer. Moreover, the likelihood of its occurrence during dry seasons increases significantly.
Chlorotic ring spot affects not only apple trees, but also pears and quince
How and with what to treat chlorosis of apple leaves
As soon as the cause of chlorosis is established, it is necessary to begin its treatment.Because the sooner the apple tree receives the missing element, the less harm the disease will cause to the tree.
For iron deficiency
In this case, you can use iron sulfate. This is an affordable remedy, but in order for it to give the desired result, you must first convert the necessary component into a chelated or available form for the apple tree.
To do this, you will need to add citric acid (5 tsp) and iron sulfate (25 g) to settled water (10 l). Mix all ingredients and leave for an hour.
You can prepare an effective remedy using another recipe. In this case, you will need to dissolve 100 g of iron sulfate and 200 g of ascorbic acid in 10 liters of water. Mix all ingredients until smooth. After this, you can use iron sulfate in this form to water apple trees in the garden that suffer from chlorosis.
Iron sulfate increases the immunity of trees
For nitrogen deficiency
To make up for the missing component, urea or carbamide should be used. To treat chlorosis, you need to add 35 g of fertilizer to 10 liters of water and water the apple tree. If necessary, the procedure must be repeated after ten days.
Urea contains more than 40% nitrogen
With oxygen starvation
To eliminate this cause of chlorosis, it is necessary to loosen the root circle and add 10-15 kg of rotted organic matter to it, depending on the age of the apple tree. Subsequently, it needs to be embedded in the ground and the tree should be watered abundantly. This will attract worms into the root circle, which form tunnels during their life, which improves oxygen access to the roots.
With a lack of magnesium
Magnesium sulfate helps to compensate for the deficiency of the element. To prepare the solution, add 20 g of the drug to 10 liters of water and spray the apple tree. The procedure should be repeated 3-4 times per season every ten days.
Watering an apple tree with magnesium sulfate will give results only after a few years
If there is a lack of boron
Boric acid helps correct the situation in this case. To treat chlorosis, you need to prepare a solution at the rate of 5 g of the product per 10 liters of water, and then spray it on the tree crown. It is recommended to carry out the procedure before the apple tree blooms.
Boric acid improves fruit set
With a lack of potassium and calcium
If there is a shortage of this element, the acidity of the soil should be checked. To reduce it, you need to add 1 kg of wood ash to the root circle and then incorporate it into the soil.
If, if there is a shortage of these elements, the acidity is within normal limits, then you should feed the apple tree with calcium or potassium sulfate. To make up for the deficiency, dissolve 20 g of the drug in 10 liters of water and spray the crown with the resulting product.
Calcium and potassium sulfate quickly eliminates signs of chlorosis
Preventive measures
To avoid having to deal with apple tree chlorosis later, you need to follow simple preventive measures. This is especially important for preventing the viral form of the disease, since, unlike the physiological form, it cannot be cured.
Preventive measures:
- Promptly treat trees against pests that can be carriers of viral chlorosis.
- Do not plant apple trees in areas where water stagnates.
- Regularly loosen the soil in the root circle and remove weeds that can take away the necessary nutritional components.
- Feed the apple tree in a timely manner at least three times a season and add organic matter.
- During hot periods, mulch the top layer of soil to prevent excessive evaporation.
- Control the acidity level.
- Maintain a distance between trees of at least 3-4 m.
Conclusion
Apple tree chlorosis occurs due to improper care and inappropriate growing conditions. This disease can not only reduce the yield, but also cause the death of the tree. And only timely control measures can minimize the damage from defeat.
