Black dots on apples - why they appear and what to do with them

Content:

How scab looks on an apple tree, signs of a disease
Ways of infestation of apples
Does scab pose a danger to people
Preventing dark spots
Autumn garden work
Scab resistant apple varieties
Treatment: use of chemicals

Black dots on apples are a situation faced by many gardeners. This symptom cannot be ignored, since it indicates a tree infection with scab. This disease is very common. By itself, it will not lead to the death of the plant, but suppression of immunity, a decrease in resistance to cold and other diseases will make the tree vulnerable to other viruses and fungi.

How scab looks on an apple tree, signs of a disease

The causative agent of the disease is the marsupial fungus Venturia unequal. The first signs of scab appear during the flowering period of the apple tree, around May. Description of the symptoms of pathology:

The foliage affected by the fungus are covered with specks of olive color. These spots are the breeding ground for conidia.
On the branches on which the fungus has settled, formations are formed that look like small blisters.
On fruits that ripen, parts of the tissues become dark and dense, like a cork. Under these lesions, the flesh of the fruit begins to crack.
If the fungus affects most of the leaf plate, it falls off prematurely.
Deformation of fruits, their loss of appearance, taste and benefit. Dark spots appear on apples, which gradually increase in size and number. Dark spots disappear over time, and through holes may form in their place.

Dots on fruit are a sign of scab

Additional Information! The scab does not apply to fruits that have been picked and are in storage.

Scab spoils fruit, cracks in them create a favorable environment for pathogenic microorganisms

Ways of infestation of apples

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The ways of infection of the tree are varied, which explains the wide spread of scab:

with water during irrigation, rain, fog;
by the wind;
with insects and animals;
through garden tools that have not been disinfected after handling other plants.

Provoking factors:

summer heat - the fungus actively develops at temperatures from +22 and above;
abundant and prolonged precipitation - fogs, rains, which lead to an increase in humidity.

Throughout the season, the fungus is actively developing, and wintering transfers in the shoots and in the soil, in fallen leaves.

Does scab pose a danger to people

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There is no unequivocal answer to the question of whether scab is dangerous for humans and whether it is possible to eat fruits damaged by the fungus. Many people eat fruits with black dots, because they are not there from the inside of the pulp, others prefer to refuse such a crop.

You cannot eat fruits that are heavily affected by the fungus.

The fungus that causes scab produces mycotoxins, substances that can have an extremely negative effect on the condition and functioning of internal organs. On the affected fruits, mycotoxins are present in a minimal amount that cannot harm. But these toxic substances tend to accumulate in the human body if they are supplied often and in large quantities. And then various diseases and irreversible pathological processes can occur.

Additional Information! If the damage to the fruit is insignificant, the dark lesions are single and small, you can use it after cutting off the peel.

Preventing dark spots

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Knowing why black spots can appear on apples, and that the fungal disease of scab is to blame, its appearance can be prevented if preventive work is carried out in a timely manner. Every gardener should know what to do to keep his orchard safe:

It is necessary to engage in prevention in the fall. This is necessary in order to prevent the wintering of the fungus in the foliage and the outbreak of the disease in the spring.
Strictly follow the rules of agricultural technology.
Apply the correct fertilizer regularly. If the tree receives a sufficient amount of nutrients and minerals, its immunity will be stronger and its resistance to fungal diseases and parasites will be higher.
Regularly carry out preventive treatments with specialized solutions. Biologicals are used. They must be used before the formation of the kidneys. Bordeaux liquid shows a good result as a prophylactic agent.
Every 5 years, it is recommended to add lime to the ground around the tree at the rate of 100 g per square meter. If the soil is acidic, you will have to apply lime every year in double the amount.

Additional Information! Carry out preventive treatment of trees it is necessary every 2 weeks until the onset of the kidneys.

Preventive and therapeutic measures should be started as soon as the first small blotches have appeared.

The fight against scab is a very long process, since if it is present on neighboring trees, the risk of infection is very high. Proper agricultural technology will help reduce the likelihood of infection with a fungus:

Select healthy seedlings without signs of damage, with a well-developed root system.
Observance of the distance between seedlings at least 3 m. Due to densely planted trees, their crowns begin to intertwine, the sun's rays penetrate poorly, and air circulation decreases. This creates favorable conditions for the penetration and spread of the fungus.
Top dressing should be applied strictly in the dosages specified by the manufacturer.
Correct watering. It is impossible to allow both the drying out of the soil and the stagnation of water, because of which the roots begin to rot.

Careful maintenance of the garden will prevent the development of scab

Attention! If all preventive measures are taken, but the scab comes back anyway, most likely the matter is in the low pH level in the soil.

Autumn garden work

Why do spots on apples appear even though the gardener is doing preventive spraying on the tree? This is due to the neglect of proper cleaning in the garden in the autumn.

The reason for the black spots on apples lies in the fact that the spores of the fungus successfully hibernate in fallen leaves, in the spring they are activated on the tree with double strength. Rules and recommendations for autumn garden cleaning:

In the fall, it is necessary to remove all remaining fruits and other plant elements from the tree.
All foliage that has fallen naturally must be collected and must be burned. Leaving it on the site, especially using it for composting, is strictly prohibited.
It is necessary to collect all the fruits that have not fallen from the tree.
Shoots are subject to removal, they are also burned.
Dry or broken off branches don't just need to be removed from the plant, they need to be cut out.
The exfoliated bark is removed from the tree and burned, its remains are cleaned off the tree. Bare places on the trunk must be treated with a solution of copper sulfate - 1 tbsp for 1 liter of water. l. drug. The prepared product is used to whitewash the tree.

It is necessary to burn the material collected from the tree and under it outside the site so that the wind does not re-bring fungal spores to the plants

Scab resistant apple varieties

Before dealing with blackheads on apples, the likelihood of scab can be significantly reduced not only by proper tree care, but also by choosing varieties that have increased scab resistance. These trees include:

Zorenka.
Babushkino.
Antonovka.
Renet Russian.
Pepin is saffron.
Senap.
Orlik.
Scarlet anise.

Planting trees with a low susceptibility to scab does not provide a complete guarantee that the disease will not occur if the garden crops are not properly cared for.

Treatment: use of chemicals

It is necessary to treat the disease immediately, as soon as small black dots began to form on the foliage. The most effective are products with chemical components in the composition. Recommended fungicides for scab treatment:

"Raek". The components of the drug penetrate into all parts of the tree, destroying the fungus and its spores in them. The remedy works from 3 to 4 weeks. Does not wash away with rain. During the season "Raik" can be used up to 4 times.
Horus. The advantage of the fungicide is that it can be used at temperatures up to +30. It is not washed off by sediments. Duration of action is 3 weeks. Spraying with "Horus" is carried out twice - before the buds open and after flowering.
Strobi is a complex fungicide. Valid for a month. Protects the tree from scab and a number of other diseases.
"Speed" is valid for 2 weeks, during the season you can use the tool only 2 times.
"Fitolavin" is a drug with antibiotics in its composition. During the season, 4 sprays are allowed with an interval of 14-20 days.

The gardener should work with chemicals in personal protective equipment.

Fungicides must be used correctly, only then will they give the desired result:

The use of chemicals must be alternated, otherwise the fungus will develop resistance to the same fungicide over time.
On garden plots, it is allowed to use drugs of only 3 and 4 hazard classes. Industrial products are strictly prohibited.
Chemical mixtures should be evenly applied to trees using a special sprayer.
Spraying with chemicals is mandatory combined with preventive measures.
Spraying is carried out in dry, calm weather.

Black dots on fruits and leaves are a sign of scab. Getting rid of a fungal disease is difficult. An integrated approach is required with the use of a chemical and adherence to correct agricultural practices. Preventive work plays an important role, which can significantly reduce the likelihood of scab.