Sooty fungus on an apple tree: how and how to treat it

Sooty fungus on apple trees is a rather dangerous infectious disease caused by microscopic organisms. Outwardly it manifests itself as a black coating, reminiscent of soot. For treatment, it is necessary to use not only antifungal drugs (fungicides), but also insecticides (insecticides). To prevent the disease, it is permissible to use folk remedies.

Reasons for the appearance of black plaque on the leaves, branches and trunk of an apple tree

Sooty fungus is an infectious pathology that affects apple trees and other fruit crops. The disease is widespread. The following reasons contribute to its development:

1. If an apple tree is infected with aphids, honey beetles, bark beetles and other insects that leave sugary mucus, the fungus feeds on these secretions and penetrates the plant tissue.
2. Warm and humid weather is the optimal environment for spore germination.
3. Sooty fungus is activated by excessive watering, when the soil and air around are too wet.
4. Shading, as well as a dense crown and lack of regular pruning, contribute to the proliferation of the pest.

The described reasons lead to the appearance of a black coating on a young apple tree. If trees have not previously had this infection, they can cope with it, especially if treatment is started as early as possible. If the seedling is initially affected by spores, it will begin to lag behind in development and may die over time.

Signs and development

The main sign of sooty fungus is the appearance of a black coating on different parts of the apple tree:

• bark;
• shoots and branches;
• leaves;
• fruits, including unripe ones.

In appearance, this plaque resembles soot or ash, which is why the disease got its name. Unlike scab, the affected areas have different sizes and shapes, they are quite easily erased. The leaves gradually dry out and die, and the fruits become small and covered with an unsightly coating.

Sooty fungus attacks apple trees with wounds on the bark, damaged due to recent pruning. In these places, plant juices are released, which the pathogen feeds on. It multiplies quickly, producing numerous hyphae that cover the tree bark and clog the pores.

Apple trees affected by sooty fungus require treatment

As fungal microorganisms develop, they feed on honeydew - the sweet secretions of aphids and other insects, as well as the plant juices of the apple tree itself. This leads to adverse consequences:

• pores become clogged with viscous liquid;
• tissue metabolism and respiration of leaf cells are disrupted;
• the process of photosynthesis stops;
• tissues die;
• the apple tree becomes less winter-hardy.

How to deal with sooty fungus on an apple tree

You can fight black plaque on an apple tree in different ways. The most effective option is to treat with fungicides. It is also recommended to use folk remedies and mechanical methods.

Fungicides

Fungicides are special antifungal agents. They are produced in the form of solutions with chemicals or strains of bacteria. The main drugs against sooty fungus:

• "Fitosporin";
• "Bordeaux mixture";
• "Strobe";
• "Skor";
• "HOM";
• "Abiga Peak";
• “Respect 25%” and others.

When preparing the solution, you must carefully observe the dosage. You should also take into account the waiting period - the minimum period from the date of the last spraying to harvest. For many drugs it is 15-30 days. Therefore, the procedure is planned in advance.

"Strobi" is one of the effective fungicides against sooty fungus

Insecticides

Since the spread of disease on an apple tree is often associated with insects (aphids, honey beetles, bark beetles and others), it is necessary to treat with insecticides simultaneously with the use of fungicides. The most effective means are:

• "Biotlin";
• "Decis";
• "Fitoverm";
• "Aktara";
• "Inta-Vir";
• "Agravertine";
• "Fufanon"; and others.

Mechanical methods

If black plaque appears on the trunk of the apple tree, treatment can be carried out mechanically. Affected leaves are removed. The shoots are also pruned. The trunk and skeletal branches are carefully cleaned to a healthy place. After this, they are washed with solutions of special preparations:

• copper or iron sulfate;
• caustic soda.

If there are more than two weeks left before harvest, fungicides can be used. If the apples are almost ripe, then after cleaning the sooty fungus, the affected areas are washed with baking soda (150 g per 10 l) with shavings of laundry soap (100 g for the same volume). After harvesting, you need to repeat the treatment. They use not only folk remedies, but also fungicides.

Folk remedies

Folk remedies can only be considered as an additional method of treatment. They are quite effective in the early stages of infection, for prevention, when used simultaneously with fungicides. Experienced gardeners recommend using the following recipes:

1. Processing the apple tree with fresh beer - “live” (on tap) or homemade. Take a clean rag or gauze, soak it in the drink and wipe the affected branches, foliage and fruits.
2. Treatment with an aqueous solution of ethyl alcohol at a concentration of 60%. The method of application is similar - wiping the branches, fruits and foliage of the apple tree with a dampened rag.
3. To combat sooty fungus, use a solution of copper sulfate (5 g) with laundry soap (150 g). Both components are dissolved in 10 liters of water and mixed thoroughly. Then they begin to spray the apple tree.
4. Take dry potato tops (800 g) and pour 10 liters of warm water and leave for four hours. Then strain and add 40 ml of liquid soap and begin treating the apple tree from sooty fungus.
5. You can grind 400 g of dandelion roots and leaves, pour in 10 liters of warm water and leave for three hours, then strain and spray the crown. You can start working immediately after the buds open, at the end of flowering (for prevention), and when the first signs of pathology appear.

Treatment with folk remedies helps only in the early stages of the disease.

Boosting immunity

When a black coating appears on the apple tree, this already indicates the development of sooty fungus. To prevent the progression of the disease, it is recommended to take measures to increase the plant’s immunity. To do this, apple trees are regularly fed with mineral fertilizers. They should be applied using the root method (watering the tree trunk):

1. Ammonium nitrate - take granules in an amount of 30 g and dissolve in 10 liters. Watering is carried out annually in early spring, when the snow melts.
2. Ammonium sulfate – solution 20 g per 10 l. Water the tree trunk circle in early spring. Can be used simultaneously with ammonium nitrate.
3. Potassium chloride against sooty fungus - in April, water with a solution of 20 g per 20 liters.
4. Potassium salt - you will need 20 g per 30 liters. Watering is carried out in the fall.
5. Potassium sulfate – 50 g per 10 l. The product is effective in the autumn.
6. Urea (100 g per 10 l) and nitrophoska (50 g per 10 l) are suitable for application at the root. Used in autumn.

To increase the resistance of the apple tree to sooty fungus and other pests, it should be treated with special preparations (one to choose from):

1. “Stimix Concentrate” – dissolve 100 ml in 10 liters. Apple trees are watered after harvest.
2. “Stimix Standard” – 50 ml per 10 l. Treatment is done up to seven times per season with breaks of 14 days.
3. “Stimix Fitostim” - 50 ml per 10 l, spraying is carried out once a month. 3-4 treatments per season are enough.
4. “Baikal EM-1” - the drug is diluted in a standard bucket of water (10 ml per 10 l). Three treatments are done per season with an interval of 1-1.5 months.
5. “Shine-1” - dissolve 10 ml in 10 liters and water the apple tree in April.

Preventive measures

A black coating of sooty fungus on the bark of an apple tree is a symptom of a rather dangerous disease that can lead to the death of the tree.Eliminating the consequences of this pathology is much more difficult than preventing it. Therefore, experienced gardeners recommend following basic preventive measures:

1. In the spring, regularly do sanitary pruning, and then treat the apple tree with a fungicide.
2. Always follow the watering norm, especially in cloudy and rainy summers.
3. Be sure to thin out the crown.
4. When planting apple trees, place seedlings at a distance (at least 4 m).
5. Throughout the season, use special products to boost immunity.
6. To prevent sooty fungus in the fall, after pruning, carefully dig up the tree trunk, remove all foliage and other remains, take them away and burn them.

To keep the apple tree healthy, preventive treatments must be carried out every spring.

Conclusion

Sooty fungus on an apple tree can lead to a decrease in yield, winter hardiness of the tree and immunity to other diseases. Often the infection spreads along with aphids, suckers and other pests. Therefore, for treatment it is necessary to carry out several treatments with fungicides and insecticides. It is equally important to follow preventive measures. They will prevent the spread of sooty fungus and other dangerous pathologies.

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