Signs and treatment of scab on an apple tree, how to fight with drugs and folk remedies

The problem of many gardeners is pests and diseases of fruit trees. Apple scab is one of the most common diseases caused by the Venturia unequal fungus. The proposed material provides a description of the specified disease, chemical and folk remedies and treatment procedures.

Description of the disease and causes

Scab is one of the most common diseases of fruit trees, manifested by characteristic formations on the leaves of the apple tree. If timely measures are not taken, it leads to damage to the tree. An apple, after exposure to a fungus, looks wrinkled and significantly loses its taste.

The fungus is transmitted in the following ways:

• atmospheric moisture;
• by the wind;
• insects.

Scab allows the tree to grow and develop, facilitating the spread of the disease, since it does not disrupt the process of photosynthesis. The fungus overwinters in fallen leaves and tree bark, continuing its life activity with the onset of spring.

The appearance and development of the disease is facilitated by a large amount of rain in the spring and excessive shading of the garden. Like any fungus, Venturia unequal requires high humidity, warmth and shade to develop.

Lesions

Scab affects the tree completely, starting with the leaves, then moving to the bark, young shoots and fruits. The disease is especially dangerous for young trees - it can lead to the death of the apple tree.

Damaged foliage falls off, the disease spreads to the bark and young shoots, then to the fruits. The bark cracks and swells, the shoots begin to wither, and the fruits shrivel.

Signs of scab

Characteristic signs of the disease:

• first, small olive-colored spots with a greenish tint appear on the leaves of the tree;
• over time, the stains become more numerous, they turn black and crack;
• similar marks appear on young shoots and bark, in which cracks and swellings appear;
• with the appearance and growth of fruits, they also become covered with similar spots, wrinkle and lose their visual appeal.

The duration of the incubation period of the fungus, depending on the resistance of the variety and accompanying conditions, is from six to twenty days. The listed external signs begin to appear after a specified period after infection.

Chemicals

If timely measures are not taken to treat the disease, the productivity of the garden will significantly decrease, the size of the fruits will decrease, their appearance will deteriorate and the content of vitamins and other useful substances will decrease. In a short period, the disease can affect up to ninety percent of the garden, which is especially dangerous for young trees.

The following discusses the most effective chemicals for combating scab.

Abiga Peak

This is an antifungal fungicidal drug. Trees are treated with it not only for treatment, but also for disease prevention. The therapeutic effect is provided by active copper, which is formed after spraying and blocks spores, which creates obstacles to their reproduction and spread. This product has the following advantages:

• versatility of application;
• resistant to moisture, does not wash off when it rains;
• large distribution over the processing area;
• compatibility with other means;
• negligible environmental hazard.

The drug does not change the taste and appearance of the processed fruits. The product is available in bottles of forty to fifty grams.To prepare the mother solution, the contents of the container are diluted per liter of water. The resulting composition, for use, is diluted in a ratio of one to ten.

Oksikhom

This drug has a similar mechanism of action, but is characterized by the presence of two substances:

• copper ions, which cause the death of the pathogen;
• oxadixyl, absorbed by the foliage and blocking the synthesizing processes in the mycelium of the fungus.

Like the previous remedy, the use of oxychome helps to treat and prevent the occurrence of the disease. In addition to high efficiency, the drug has the following advantages:

• long period of protection;
• fast response time - within two hours after treatment.

However, there are also disadvantages. The medicine is not always compatible with certain drugs, especially with alkaline drugs.

Note! Oxychome is a substance of the first hazard class, therefore, when using, appropriate precautions and protective equipment must be used.

The drug is available in powder form, in five-kilogram packages. For use, up to fifteen grams of the drug is diluted in ten liters of water.

Kuprikol

Many gardeners prefer to get rid of scab using Cupricol. The product is produced in a colloidal solution containing two hundred grams of the active substance. This form allows the drug to be easily dissolved for use.

Cupricol is highly effective against fungal diseases, including scab, and does not affect the development of apple trees. During the season it is necessary to process the tree up to six times. The medicine is resistant to atmospheric moisture and is highly soluble when preparing the composition.Can be used in combination with other products.

Cuprostat

A similar remedy to save the garden from scab. The drug consists of:

• nineteen percent - from copper;
• sixteen - from ammonia;
• twenty-six - from acetic acid.

The medicine has similar benefits and mode of action as the above. An environmentally friendly product that does not pose a danger to humans and animals. Use with caution near stocked water bodies.

Produced in liquid form, in canisters of ten and twenty-five liters. More effective in the initial stages of the disease. As the disease spreads, the effectiveness is significantly reduced.

For spraying, you must choose a clear, quiet day, the wind speed should not exceed six meters per second. The frequency of treatment per season is about three times. The last spraying before harvesting should be done a month in advance to eliminate the presence of harmful substances in the fruits.

Tsikhom

Another drug based on copper oxychloride. Another active ingredient is zineb. The principle of operation is similar to the above means. The effect appears immediately after spraying, the duration of protection is up to twelve days.

Combines well with other means. The treatment interval – taking into account the duration of protection – is about twelve days. When treating fruit trees for scab, the medication consumption rate is from six to eight kilograms per hectare.

Produced in ten-kilogram bags, in powder form. Not too dangerous for humans (second class), it poses a greater degree of danger to insects (bees and others).

A week after spraying, manual work in the garden is allowed, mechanized work after three days.

Colloidal sulfur solution

One of the most time-tested drugs. Unlike the means described above, it does not require penetration into the plant to obtain the desired effect.

The sulfur contained in the composition counteracts fungus, is beneficial for the growth and development of crops, and is one of the necessary components for plant vegetation.

Treatment with the solution should be carried out no more than five times during the season. From thirty to eighty grams of the drug is mixed in a bucket of water, depending on the stage and extent of the infection.

It is recommended to treat trees prophylactically and after the first signs of disease appear.

Note! Sulfur is a flammable substance, this must be taken into account when organizing the storage of the drug.

The composition is evenly distributed over the surface of the trees. Sulfur interferes with the respiratory function of the fungus, causing its death. Despite the relative safety for humans (third class), it is necessary to take appropriate precautions - work in respirators, do not eat or smoke during processing, do not spray in windy weather.

This remedy is one of the simplest and most effective against scab.

Cumulus

Cumulus is another name for the above drug, which is no different from it. The choice of the name of the medicine depends on the manufacturer, but the composition of these products is similar.

Tiovit Jet

Another contact fungicide with a wide range of applications. A Swiss analogue of colloidal sulfur, which has a more lasting effect and has proven itself well in Russian conditions.

The duration of action of the drug is up to ten days after spraying.The specified period may vary depending on the development of the disease, the level of atmospheric humidity, wind strength and other indicators.

The dilution ratio of the substance with water is similar to the above remedy. The solution is thoroughly mixed until completely homogeneous. The number of sprayings during the season is up to six times.

The product has a moderate degree of danger (class three), but getting the substance into the respiratory tract is undesirable.

The medicine is produced in granules, packaged in thirty-gram bags. For large scale use it is available in twenty kilogram bags.

Biological bacterial fungicides

Some soil bacteria counteract fungal pathogens. Therefore, scab can be cured using the following biological bacterial fungicides:

• Planriza is a product based on these microorganisms that effectively counteracts scab and destroys fungus, promoting plant development. During the reproduction process, bacteria protect crops from diseases and release nutrients that increase yields;
• Trichodermina is a biological remedy that uses the counteracting mushroom of the same name. By parasitizing the pathogen, it leads to its destruction; The effectiveness of the drug is not affected by the level of humidity, but the ambient temperature is important, it should be at least fourteen degrees;
• Phytobacteriomycin - produced in two-, five- and ten-percent powder with a high degree of antifungal effectiveness. Characterized by an average level of toxicity;
• Pentafage is a remedy based on a complex of five strains of bacterial viruses and biologically active components.During the decomposition of the drug components, new strains are formed that help destroy the fungus. Used in the form of an aqueous suspension, with a concentration of up to five percent, depending on the stage of development of the disease;
• Gaupsin is a universal remedy against fungal diseases and pests.

All biological products are characterized by the following advantages:

• high biological activity;
• increasing plant immunity against diseases;
• improving crop nutrition, soil structure and fertility.

Note! Unlike chemical agents, biological agents do not act as quickly, but the duration of protection is significantly longer, as is the accompanying positive effect from their use.

Systemic fungicides

By systemic action it is meant that the drug affects the fungus not only at the site of application, but is also redistributed throughout the tree, including inside the tissues. These products should be used until the disease has spread, but after treatment the drug continues to act, regardless of environmental conditions, without being washed off by rain or drought.

The duration of the effect is significantly longer compared to contact ones - up to three weeks. However, when re-processing, it is necessary to choose a drug from a different group, since the fungus adapts to the drug.

Next - more detail about individual chemical groups of systemic fungicides.

Preparations of the strobirulin group

The initial remedies of this group were derived from the fungus of the same name, which penetrates into the infection and prevents the pathogen from breathing, causing its death.

It is recommended to use these remedies before all others.To prevent adaptation of the fungus, no more than two treatments should be carried out during the season.

Triazole group drugs

The mode of action is similar to the above drugs. It is characterized by a rapid onset of effect from application, the product is instantly absorbed, so within half an hour after spraying, rain will not affect the result.

The medicine promotes plant growth by accelerating the process of photosynthesis. One of the few disadvantages is rapid addiction, so it is necessary to switch to other groups of fungicides.

Copper sulfate solution

The indicated remedy is copper sulfate. It is recommended to use it before the buds open, during primary treatment in early spring. Substance consumption – one gram per square meter; The solution is diluted at the rate of one hundred grams of the drug per ten liters of water. Processing is carried out from the bottom of the trunk to the top of the crown. The greatest effectiveness is observed when spraying once every five years.

Preparations of benzimidazoles groups

Drugs in this group interfere with the process of nuclear division of the fungus, preventing its reproduction and development of the disease. These are broad-spectrum agents characterized by a long period of protection. Not only trees, but also collected fruits are treated with medicine to prevent the development of the disease during transportation.

Horus

A relatively new drug that has gained popularity among gardeners. It is distinguished by its ability to prevent the development and occurrence of infectious plant diseases, protects and heals trees.

The disadvantage of the medicine is low effectiveness with a severe degree of disease development - for mature trees.It is characterized by local impact, therefore, to ensure the effectiveness of the drug, it must be applied, distributed over the surfaces being treated.

Spraying should be done at the beginning of the growing season. Effective in a temperature range from three to twenty-five degrees.

Fitosporin M

The newest remedy, effective at any stage of the disease. Created on the basis of a spore culture that suppresses the reproduction of pests. The main disadvantage of the medicine is the instability of the bacterium in natural sunlight, so cloudy weather should be chosen for treatment.

Folk remedies

Many gardeners fight scab using traditional methods, which include:

• timely removal of fallen leaves and fruits to prevent the spread of infection. They are buried in the ground or used to make compost;
• spraying with mustard solution - eighty grams of powder is dissolved and added to ten liters of water. The tree itself and the area around the trunk are processed. Several applications are required starting in May;
• treatment with potassium permanganate - five grams of powder per bucket of water. The method is identical to the previous one;
• spraying with saline solution - based on a bucket of water - one kilogram of salt; produced in early spring, before the buds swell;
• use of horsetail tincture - a kilogram of fresh grass is poured with five liters of boiled water, infused for three days. The resulting composition is diluted in a ratio of one to ten. Treatment is carried out after the first leaves appear;
• use of whey - the composition is filtered through gauze, the whole tree is sprayed, a very effective remedy at any stage of the development of the disease.

Note! Folk remedies are effective in the initial stages of the disease or as preventive measures, but are not effective in cases of serious infection.

Features of wrestling at different times of the year

Primary treatment of trees is carried out in early spring, before the beginning of the growing season. In the summer, in June and July, the garden is repeatedly sprayed with chemical and biological preparations. Substances are combined to prevent the fungus from becoming addictive. It is necessary to observe the frequency of treatments, taking into account the validity period of a particular drug.

An important factor in the development of the disease in the summer is the weather. If low humidity is established, accompanied by high air temperature, the development of the disease is stopped. This should be taken into account when determining the frequency of treatments.

Summer spraying must be done in the early morning or late evening to prevent the leaves from being burned by the preparation and its premature evaporation without having an effect.

In autumn, treatment is carried out after picking the fruits; To consolidate the achieved effect, it is necessary to remove the affected branches and leaves.

When fighting the disease, it is necessary to take into account that infection is possible from untreated trees located in a neighboring area. Fungal spores can be carried by the wind from the affected garden.

An important measure to counteract scab in the autumn is the fight against insects that carry the disease. They overwinter in the area around the trunk, with the onset of spring penetrating trees and spreading the infection. A circle around a tree, up to two meters in diameter, must be cleared of pests and treated with pesticides before the onset of cold weather.

How to treat during fruiting

Control measures during the fruiting period include the use of folk methods or environmentally friendly biological preparations to prevent the accumulation of toxins in the fruits.

Two weeks before harvesting, treatment should be avoided. Immediately after picking the fruits, the trees are sprayed.

Consequences

If timely measures are not taken, the development of the disease leads to reduction and wrinkling of the fruit, and a decrease in the content of useful substances in them. The growth and development of the tree slows down. Intensive infection can destroy young shoots, including the death of seedlings.

Preventive treatments for apple trees

The development of the disease is easier to prevent by taking appropriate preventive measures.

Spring treatment

In the spring it is necessary to produce:

• applying organic fertilizers to the tree trunk circle, up to one meter in diameter, in accordance with established standards;
• digging up the soil in the garden with preliminary cleaning of last year's leaves and fallen branches;
• abundant watering - at least fifteen liters for one tree;
• treating wet soil with urea, potassium chloride or ammonium nitrate;
• whitewashing trunks with lime to a height of up to one meter;
• spraying the branches and trunk with Bordeaux mixture.

The listed activities are carried out before the first buds bloom.

Autumn processing

Before the start of winter, it is necessary to remove dry branches and leaves from trees, collect and bury or burn fallen leaves to prevent overwintering of spores with subsequent infection in the spring. Trees are treated with chemical, bacteriological or folk remedies.

As can be seen from the presented material, apple scab is a serious disease that negatively affects the development of trees and leads to complex damage to the crop. Therefore, adequate measures must be taken to prevent and treat the disease to ensure high yield and normal development of trees.