Content
The apple tree is deservedly considered hardy and quite unpretentious in care, but sometimes problems when growing it cannot be avoided. One of the most common symptoms of “deteriorating health” is the leaves of the apple tree curling. The cause may be diseases or pests, or errors in care.
Why do apple tree leaves curl?
Leaves can curl on both mature 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, diseases typical of the crop, and pest attacks. In any case, a gardener who discovers that the leaves of an apple tree have begun to curl must quickly and correctly identify the problem.
Red gall aphid
Despite its name, the red gall aphid is a small, “translucent”, round insect of a grayish-green color.It received its name because of the most noticeable symptom: first, bright red or crimson “lumpy” swellings appear on the front side of the leaves, then they “go into folds” and curl up into a boat.
The red gall aphid feeds on the sap of the plant, while simultaneously “poisoning” the tissue with the products of its vital activity. If nothing is done, the leaves on the apple tree not only curl, they quickly dry out and die. Dry brown spots appear on the fruits, gradually turning into depressed “ulcers”.
In the absence of treatment, apple trees whose leaves curl up due to the presence of bright “swells” on them die within 2-3 seasons
Common aphid
It is much easier to detect ordinary aphids, even without taking into account that the leaves begin to curl - they “clump” into large colonies, clinging mainly to the tops of shoots, opening leaves, buds - all young growth.
The color of the pest can vary - from pale light green and yellow-green to dark brown and almost black. Common aphids also feed on the juices of the plant; the leaves affected by insects first appear “crumpled”, then curl up into a tube, and the shoots become bent. As the deformation worsens, the tissues become discolored almost to the point of transparency, dry out, and die.
The danger of aphids is not only a “failure” of the photosynthesis process. The sooty coating and sticky secretions it leaves on the leaves of the apple tree after they have curled up into a tube are a very favorable environment for the development of pathogenic microflora.
Aphids carry pathogens of many diseases, including incurable ones.
leaf roller
After the attack of leaf roller caterpillars on an apple tree, the leaves quickly and en masse begin to curl up, turn black and fall off. This occurs due to the fact that the pest “injects” substances that are toxic to the tree into the tissue. The peak of insect activity occurs at the end of spring. If nothing is done, by mid-summer the apple tree will lose most of its foliage.
The leaf roller can cause leaves to curl on any fruit tree, but most often it attacks apple and pear trees.
Apple moth
The adult is a fairly small grayish-brown butterfly. Females lay eggs in cracks and other microdamages on the bark. The caterpillars hatching from them “go” deeper under the bark and overwinter there. In the spring, when the leaves bloom, the pest “settles” in them. The leaves gradually curl up, and the apple moth caterpillars entwine them with a web, turning them into a kind of cocoon. Then they dry out and fall off.
In severe cases of apple moth infestation, the apple tree is almost completely covered with cobweb “cocoons”, the leaves curl up en masse
Powdery mildew
The first symptom of powdery mildew infection is a whitish or grayish powdery coating on the leaves, reminiscent of spilled flour. As the disease progresses, it thickens and darkens, changing color to gray-purple. Curled leaves on an apple tree dry out or rot.It depends on the temperature and humidity outside.
Externally, damage from powdery mildew appears insignificant compared to other diseases. However, a “harmless” coating, due to which the leaves curl, causes loss of presentation in 30-50% of the apple crop.
Powdery mildew is one of the most common diseases
Scab
Scab is a fungal disease that often affects apple trees. Pears are less susceptible to it. The spread of the fungus, which causes leaves to curl, is facilitated by strong winds and high air humidity, so if it infects one tree on the site, others will also “pick up” the pathogen quite quickly.
Before the leaves of the apple tree curl, a “velvety” olive-brown coating appears on them. If scab is not dealt with, it also affects the fruits. The apples become cracked, rot and fall off before they have time to ripen.
Apples affected by scab are unfit for food
Lack of microelements
Almost any apple tree is a fairly large tree that bears fruit regularly. Accordingly, it requires a lot of macro-, microelements and other nutrients, which it “pulls” from the soil. If the “reserve” is not replenished, the appearance of a tree suffering from nutritional deficiency deteriorates. In particular, the leaves of the apple tree begin to curl.
What kind of substance it lacks can be determined by the nature of the “twisting” and accompanying symptoms:
- Nitrogen. The leaves of the apple tree curl up along the central vein, simultaneously discoloring to a pale green hue.
- Phosphorus. Especially often, a deficiency of this macroelement manifests itself when the substrate is acidified. The leaves of the apple tree curl into a very narrow tube, almost like a rope, simultaneously changing color. First a bronze tint appears, then they successively become purple-red, inky violet and black.
- Potassium. Most often associated with an excess of calcium and manganese in the substrate. With its deficiency, the edges of the apple tree leaves turn down, they turn pale and dull, and an unnatural bluish tint appears in the color. The twisted “border” begins to dry out, the surface of the leaf plate becomes “wrinkled.” New leaves of the apple tree develop incorrectly, and all sorts of deformations occur. Many of them, before they have time to bloom, are already curled up 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” upward. At the same time, the growing point dies. Leaves that have retained their shape fall off en masse.
- Bor. Boron deficiency first appears on the youngest leaves of the apple tree: they curl and dry from tip to petiole, changing color to pale green or yellowish.
- Iron. Chlorosis is easy to identify by the bright yellow leaves of the apple tree with veins that have retained their natural color. If the lack of iron is not replenished, the leaves curl and fall off.
- Manganese. The leaves of the apple tree turn pale and black dots appear on them - areas of tissue necrosis.They gradually expand, the leaf blades curl along the central vein and fall off.
- Copper. With copper deficiency, normal photosynthesis is impossible and the leaves become very pale. Only their tips are curled.
When feeding, you need to take 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 into a tube - 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 out completely, starting with the leaves and fruits.
An apple tree suffering from moisture deficiency cannot normally absorb nutrients from the soil.
How to get rid of leaf curl on an apple tree
The method of “treating” an apple tree whose leaves are curling directly depends on the reason that provoked negative changes in the condition of the tree. If this is due only to improper care, it is enough to correct it. When affected by diseases and pests, comprehensive control is required, and in the future, restoration of the tree’s immunity and endurance, and regular prevention.
Proper care
High-quality agricultural technology has a positive effect on the overall endurance and “stress resistance” of the tree. Basic measures for caring for an apple tree to avoid the appearance of unpleasant symptoms:
- Watering. The substrate in the tree trunk circle should not be allowed to dry out in the first season. In the absence of rain, the soil is watered every 4-5 days.Mature trees often make do with natural precipitation, but during prolonged drought, the soil is moistened once every 1.5-2 weeks. To prevent the leaves of the apple tree from curling, it is necessary to wet the soil in the circle around the trunk as evenly as possible.
- Feeding. If the apple tree is planted in compliance with all recommendations, it does not need fertilizers in the first season after planting. Next, fertilizing with nitrogen is carried out approximately in mid-spring. At the stage of budding, formation of ovaries and about a month after harvest, fertilizing containing phosphorus and potassium is applied. In principle, folk remedies are also suitable for apple trees, but it is better to use complex store-bought fertilizers.
- Trimming. The most suitable crown options for an apple tree are sparsely tiered and cup-shaped. Formation begins immediately after planting, the whole process takes 4-5 years. Then you just need to maintain the resulting configuration. We must not forget about sanitary pruning. The experience of gardeners shows that the leaves of an “overgrown” apple tree curl 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 fertilizing and moisture-recharging watering. It is also necessary to clean the tree trunk circle from plant debris and whiten the trunk. The question of the availability of shelter and its quality is decided based on the characteristics of the local climate and long-term weather forecast.
- Harvest rationing. 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 gardener’s task is to “help” the tree by cutting off the most poorly located fruits after the final formation of the ovaries or their entire “bundles”.
The experience of gardeners shows that an apple tree that is properly cared for suffers from diseases and pests much less often.
Pest Control
To prevent apple tree leaves from curling, two treatments with broad-spectrum insecticides are carried out at the beginning and end of the growing season. Having discovered insects on a tree, according to the instructions, use the same preparations or “specialized” products.
Folk remedies are environmentally friendly. But they will be effective against pests only if the attack is noticed at the very beginning. When the insects have managed to reproduce en masse, as evidenced by the leaves on the apple tree beginning to curl and other symptoms, chemicals or preparations of biological origin are used. However, the former cannot be used during flowering and if there is less than a certain time left before harvesting.
Chemicals are more effective than biological products and act faster, but working with them requires careful adherence to instructions
Treatment of diseases
Only fungal diseases of the apple tree can be treated. If the reason that the leaves on a tree are curling is a bacteria or virus, all that remains is to uproot and destroy it.
Any copper-containing preparations are effective against fungi. Both long-proven means (copper sulfate, Bordeaux mixture) and modern fungicides are suitable. Two treatments are required (at the beginning of the season and in preparation for winter).When the leaves of an apple tree curl up 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, baking soda or soda ash, fermented milk products, iodine. But in advanced cases they will not help; it is rather prevention.
The frequency of spraying, their number and the concentration of the drug solution are determined according to the instructions
Prevention measures
Simple preventive measures help to significantly reduce the risk of apple tree infection with diseases and pest attacks:
- sanitary pruning;
- crown thinning;
- annual cleaning of the tree trunk circle from plant debris, its timely burning;
- “cleaning” and whitewashing the tree trunk;
- disinfection of any cuts and mechanical damage, treating them with garden varnish;
- regular weeding of the tree trunk circle, removal of root shoots;
- timely renewal of the mulch layer;
- compliance with the watering and fertilizing regime;
- the use of biostimulants and other drugs to maintain the immunity of the apple tree.
Conclusion
If the leaves of an apple tree curl, there is something wrong with the “health” of the tree. There are many reasons for this phenomenon, so it is necessary, taking into account other symptoms, to identify the problem as quickly as possible.If the gardener himself is “to blame” for making serious mistakes in agricultural technology, it is enough to normalize the care. When the leaves of an apple tree curl due to disease or pest damage, “specialized” treatment is necessary.
