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The apple tree is deservedly considered hardy and quite unpretentious in its care, but sometimes problems cannot be avoided when growing it. One of the most common symptoms of “ill health” is apple tree leaves curling up. The cause can be both diseases or pests, and errors in care.
Why are the leaves curling up on the apple tree?
Leaves can twist on both “age” and young apple trees. The list of reasons that cause such an unpleasant phenomenon for the gardener is quite long. It includes serious errors in agricultural technology, and diseases typical of the culture, and pest attacks. In any case, from the gardener, who discovered that the leaves of the apple tree began to curl up, it is necessary to quickly and correctly identify the problem.
aphid red gall
Despite the name, the red-gall aphid is a small, “translucent”, rounded insect of a grayish-green color. It got its name because of the most noticeable symptom: first, bright red or crimson “bumpy” swellings appear on the front side of the leaves, then they “go in folds”, curl up like a boat.
The red-gall aphid feeds on the sap of the plant, at the same time “poisoning” the tissues with the products of its vital activity. If nothing is done, the leaves on the apple tree not only curl, they quickly dry and die. Dry brown spots appear on the fruits, gradually turning into depressed “ulcers”.
If left untreated, apple trees, whose leaves curl up in the presence of bright “bloatings” on them, die in 2-3 seasons
common aphid
It is much easier to detect ordinary aphids, even without taking into account that the leaves begin to curl up – it “clumps” into large colonies, sticking mainly to the tops of the shoots, opening leaves, buds – the entire young growth.
The color of the pest can be different – from pale light green and yellow-green to dark brown and almost black. Ordinary aphids also feed on the juices of the plant, the leaves affected by insects first seem to be “crumpled”, then they curl up, the shoots are bent. As the deformity worsens, the tissues discolor almost to the point of transparency, dry out, and die.
The danger of aphids being affected is not only in the “failure” of the photosynthesis process. The sooty coating and sticky discharge left by her on the leaves of the apple tree, after they have curled up into a tube, is a very favorable environment for the development of pathogenic microflora.
Aphids carry pathogens of many diseases, including incurable ones.
Leaflet
After an attack on an apple tree by leafworm caterpillars, the leaves quickly and massively begin to curl up in a boat, turn black and fall off. This is due to the fact that the pest “injects” substances poisonous to the tree into the tissues. The peak of insect activity occurs at the end of spring. If nothing is done, by the middle of summer the apple tree has lost most of its foliage.
Leaves due to a leafworm can begin to curl up on any fruit tree, but most often it attacks apple trees and pears
apple moth
The adult is a rather small grayish-brown butterfly. Females lay their eggs in cracks and other microdamages on the bark. Caterpillars hatching from them “go” deeper under the bark and winter there. In the spring, when the leaves bloom, the pest “populates” in them. The leaves gradually curl up, the caterpillars of the apple moth braid them with cobwebs, turning them into a kind of cocoon. Then they dry up and fall off.
In severe cases of apple moth damage, the apple tree is almost completely covered with cobwebs, the leaves curl up en masse.
Mučnistaâ rosa
The first symptom of powdery mildew infection is a whitish or grayish powdery coating on the leaves, resembling spilled flour. As the disease progresses, it thickens and darkens, changing color to gray-lilac. Twisted leaves on the apple tree dry out or rot. It depends on the temperature and humidity of the air outside.
Outwardly, lesions from powdery mildew look insignificant compared to other diseases. However, a “harmless” plaque, due to which the leaves curl up, causes a loss of presentation in 30-50% of the apple crop.
Powdery mildew is one of the most common diseases
destroyed
Scab is a fungal disease that often affects apple trees. To a lesser extent, the pear is susceptible to it. The spread of the fungus, due to which the leaves curl up, is facilitated by strong winds and high humidity, therefore, if it affects one tree in the area, the others also “pick up” the pathogen quickly enough.
Before the leaves of the apple tree curl, a “velvety” olive-brown coating appears on them. If you do not fight the scab, it also affects the fruits. Apples crack, rot and fall before they are ripe.
Scab-affected apples are not edible
Micronutrient deficiency
Almost any apple tree is a fairly large and regularly fruiting tree. Accordingly, she needs a lot of macro-, microelements and other nutrients that she “pulls” from the soil. If the “stock” is not replenished, the appearance of a tree suffering from nutritional deficiency worsens. In particular, the leaves of the apple tree begin to curl up.
What kind of substance she lacks can be determined by the nature of the “twisting” and the accompanying symptoms:
- Nitrogen. The leaves of the apple tree curl up along the central vein, while discoloring to a pale green hue.
- Phosphorus. Especially often the deficiency of this macroelement is manifested in the acidification of the substrate. The leaves of the apple tree are folded into a very narrow tube, almost a tourniquet, while changing color. First, a bronze tint appears, then they successively become purple-red, inky purple and black.
- Potassium. Most often associated with an excess of calcium and manganese in the substrate. With its shortage, the edges of the leaves of the apple tree are wrapped down, they turn pale and fade, an unnatural bluish undertone appears in the color. The twisted “border” begins to dry out, the surface of the leaf plate goes “wrinkled”. New leaves of the apple tree develop incorrectly, all kinds of deformations occur. Many of them, not having time to blossom, are already folded into a tube or bent along the central vein.
- Calcium. With a lack of calcium, the leaf plates of the apple tree curl up, as if “twisting” upwards. At the same time, the growth point dies. Leaves that have retained their shape fall off en masse.
- Bor. First of all, boron deficiency manifests itself on the youngest leaves of the apple tree: they curl and dry from the tip to the petiole, change color to pale green or yellowish.
- Iron. Chlorosis is easy to identify by the bright yellow leaves of an apple tree with veins that have retained their natural color. If the lack of iron is not replenished, the leaves curl up and fall off.
- Manganese. The leaves of the apple tree turn pale, black dots appear on them – foci of tissue necrosis. They gradually expand, the leaf plates fold along the central vein and fall off.
- Copper. With a deficiency of copper, normal photosynthesis is impossible, the leaves become very pale. Only their ends curl up.
When carrying out top dressing, it must be taken into account that the needs for macro- and microelements at different stages of development in an apple tree differ.
Lack of moisture
Losing tone, sagging leaves are the first sign of moisture deficiency. If the “drought” continues, they curl up – in this way the plant tries to reduce the area of evaporation. When an apple tree is not watered for a very long time, it dries up completely, starting with the leaves and fruits.
An apple tree suffering from a moisture deficiency cannot normally absorb nutrients from the soil.
How to get rid of leaf curl on an apple tree
The method of “treatment” of an apple tree, in which the leaves are folded, directly depends on the cause that provoked negative changes in the state of the tree. If this is due only to improper care, it is enough to correct it. When affected by diseases and pests, a comprehensive fight against them is required, and in the future – the restoration of immunity and endurance of the tree, regular prevention.
Proper care
High-quality agricultural technology has a positive effect on the overall endurance, “stress resistance” of the tree. The main measures for caring for an apple tree to avoid the appearance of unpleasant symptoms:
- Watering. The substrate in the trunk circle in the first season should not be allowed to dry out. In the absence of rain, the soil is watered every 4-5 days. Mature trees often get by with natural precipitation, but during prolonged drought, the soil is moistened every 1,5-2 weeks. So that the leaves of the apple tree do not curl up, it is necessary to wet the soil in the near-trunk circle as evenly as possible.
- Top dressing. If the apple tree is planted in compliance with all recommendations, it does not need fertilizers in the first season after planting. Further fertilizing with nitrogen is carried out approximately in the middle of spring. At the stage of budding, the formation of ovaries, and about a month after the harvest, fertilizing with a content of phosphorus and potassium is applied. In principle, folk remedies are also suitable for an apple tree, but it is better to use complex store fertilizers.
- Pruning. The most suitable crown options for an apple tree are sparse-tiered and cupped. The formation begins immediately after planting, the whole process takes 4-5 years. Then you only need to maintain the resulting configuration. We must not forget about sanitary pruning. The experience of gardeners shows that in an “overgrown” apple tree, the leaves curl up more often. The crown is not blown by the wind, heat and light do not get inside. This is a very favorable environment for pathogens and many pests.
- Preparing for winter. Be sure to include top dressing and moisture-charging watering. It is also necessary to clean the trunk circle from plant debris and whitewash the trunk. The issue of the availability of shelter and its quality is decided based on the characteristics of the local climate and long-term weather forecast.
- Harvest regulation. The number of ovaries on an apple tree always exceeds the number of fruits that it can provide with nutrients for full ripening. Therefore, some of them fall off on their own. The task of the gardener is to “help” the tree by cutting off the most unsuccessfully located fruits after the final formation of the ovaries or their entire “bunches”.
The experience of gardeners shows that an apple tree, which is properly cared for, suffers from diseases and pests much less frequently.
Pest Control
To prevent the leaves from curling up on the apple tree, two broad-spectrum insecticide treatments are carried out at the beginning and at the end of the growing season. Having found insects on a tree, according to the instructions, the same preparations or “specialized” means are used.
Folk remedies are safe for the environment. But they will be effective against pests only if the attack is noticed at the very beginning. When the insects have managed to breed en masse, as evidenced by the leaves on the apple tree that have begun to curl and other symptoms, chemicals or preparations of biological origin are used. However, the former cannot be used during flowering and if less than a certain time is left before harvest.
Chemicals are more effective than biologicals, act faster, but work with them requires careful adherence to instructions.
Treatment of diseases
Only fungal diseases of the apple tree can be treated. If the cause of the leaves curling up on a tree is a bacterium or a virus, it remains only to uproot and destroy it.
Any copper-containing preparations are effective against fungi. Suitable as long-proven means (copper sulfate, Bordeaux mixture), and modern fungicides. Be sure to carry out two treatments (at the beginning of the season and in preparation for winter). When the leaves of the apple tree fold in the summer, the same preparations are used.
There are also folk remedies – natural “antiseptics” that destroy pathogenic microflora: a solution of potassium permanganate, table salt, food or soda ash, fermented milk products, iodine. But in advanced cases, they will not help, it is rather a prevention.
The frequency of spraying, their number and concentration of the drug solution is determined according to the instructions
Preventive measures
Simple preventive measures help to significantly reduce the risk of infection of the apple tree with diseases and pest attacks:
- sanitary pruning;
- crown thinning;
- annual cleaning of the near-trunk circle from plant debris, its timely burning;
- “cleaning” and whitewashing a tree trunk;
- disinfection of any sections and mechanical damage, their treatment with garden pitch;
- regular weeding of the near-stem circle, removal of basal shoots;
- timely renewal of the mulch layer;
- compliance with the regime of watering and top dressing;
- the use of biostimulants and other drugs to maintain the immunity of the apple tree.
Conclusion
If the leaves of an apple tree curl up, something is wrong with the “health” of the tree. There are a lot of reasons for this phenomenon, so it is necessary, given other symptoms, to identify the problem as soon as possible. If the gardener himself is “to blame”, allowing serious flaws in agricultural technology, it is enough to normalize care. When the leaves of an apple tree curl up due to diseases or pests, a “specialized” treatment is needed.