Apple scab - prevention, treatment

Unfortunately, the apple orchard, like other fruit orchards, suffers from pests, of which, by the way, there are many. These are such well-known diseases as rot, powdery mildew, cytosporosis... The most dangerous is the fungal disease of scab on an apple tree, how to deal with which, this article will tell.

What does scab look like?

The scab on an apple tree is easy to identify by its characteristic external features: first, olive green spots appear on the leaves, which eventually turn black and crack. The disease affects almost all trees: leaves, fruits, ovaries, petioles.

The fungus also affects young shoots, for which it can be a difficult test - often the diseased plant dies. The bark of diseased seedlings becomes covered with swellings, which burst after a while, and the bark itself cracks and flakes.

Preconditions for development and distribution

The development and spread of the disease is facilitated by a wet, rainy spring, as well as thickening of tree crowns in the garden. The greatest danger of tree infection occurs during the flowering period of the apple tree - the end of May, when the weather is humid and warm.

The causative agent of the scab is the unequal venturia fungus (Venturia inaequalis), and the fungus spreads through its asexual form - fusicladium dendriticum. In early spring, the spores of the fungus, thanks to drops of water, fall on the foliage of the apple tree, where they attach to the surface with the help of a mucous membrane and germinate.

Stages of the disease

The first signs of the disease are visible to the naked eye 2-3 weeks after the kidneys open. Olive spots appear on the leaves, where spores of asexual reproduction develop. The next stage of propagation: young branches and fruits are affected, on which dark areas of damaged tissue are formed, under which the pulp of the fruit is destroyed.

Due to the fact that the fungus does not interfere with the process of photosynthesis in the leaves of the plant, the tree continues to grow and develop, contributing to the spread of the disease. Leaves affected by scab fall off prematurely, the fruits shrivel.

The fungus enters the third stage, resistrophic, with the onset of autumn, when the leaves fall. The fungus hibernates in fallen leaves, infected fruits and tree bark. In the spring, spores mature again in the formed bags and the apple tree undergoes a new infection.

Prophylaxis

Autumn

Correct and timely care of your garden will become the basis of prevention and will help prevent the emergence and development of such illness, like a scab on an apple tree, the treatment of which is a rather long and laborious process. Prophylactic work aimed at preventing diseases should be started in the fall. Once the crop is harvested, immediately start removing the dried fruit. Trim dead branches, trim the trunks to healthy tissue where necessary, and remember to whiten them. Collect all the foliage that fell out in one place, and then take it out or burn it.

Spray the crown of the apple tree with a 5% solution of copper sulfate.

Spring

Disease prevention can be started in early spring, but only until the buds bloom... At this time, it is recommended to conduct the first sprinkling the apple tree bordeaux liquid 1%.If there is a need, then the second spraying is carried out immediately after the flowering process, again with Bordeaux liquid or solutions of zineb, captan, cuprozan.

15 days after flowering, a third spraying is carried out. If Bordeaux liquid is used for it, then you need to make sure in advance if the leaves will not get burned. To do this, conduct an experiment - select a couple of branches and spray only them. If, after processing, necrotic spots did not appear on the leaves, and a grid pattern on the fruits, the concentration of the solution is normal and the entire tree can be sprayed.

It is advisable to use immunostimulating biological products such as potassium humate or biofungicide "Fitosporin M" in the treatment before the scab appears (second half of May). ... This will make it possible to reduce the number of chemical treatments in the future.

In the event that the defeat is massive, then during the season it will be necessary to carry out at least 4 treatments, and in especially severe cases, all 6 times.

Spraying a tree in the green cone stage is also advised with such a preparation as "Raek". For preventive spraying in the spring, Skor and Vectra are also used. For repeated spraying of both young ovaries, and in the fall after harvest, use "Zircon".

Treatment

If preventive methods did not bring the expected results and turned out to be ineffective, then chemical preparations - fungicides - are resorted to to fight the fungus. But before applying, you need to familiarize yourself with their features.

Application of fungicides

Many of these drugs are available under different brand names. And, despite the fact that they have different names, the active ingredient is the same. Therefore, when choosing a fungicide, pay attention to the active ingredient. If you do not do this, then there is a high probability that you will constantly use the same drug and over time the parasite will develop resistance to it. Therefore, it is important not to constantly use a fungicide with the same active ingredient to combat infection during one season.

In suburban garden plots, drugs belonging to the 3rd and 4th hazard classes are used. They do not accumulate in fruits and are not dangerous for human skin, since they do not penetrate the skin. In no case do not use chemistry on your plots that is used to control pests in horticultural farms - such drugs are mostly dangerous to humans.

Fungicides copper sulfate and Bordeaux liquid should be sprayed more liberally, until large raindrops are present. Such spraying is also called "blue spraying" because the tree after the procedure acquires a blue color.

It is necessary to carry out processing in the morning or in the evening. The main thing is that the weather is calm. Since we use pesticides, it is necessary to use personal protective equipment (gloves, masks, glasses).

Spraying after rain is considered the most effective.

Video "Treatment of apple trees with fungicides against scab"

This video will show you how to treat scab-infested apple trees with fungicides.

Basic chemicals

Substances that contain hay sticks are considered to be less dangerous. It actively suppresses the pathogen fungus. For small subsidiary farms, "Gamair" is used, its 10 tablets should be dissolved in 10 liters of cold water. Spraying is carried out up to 3 times per season.

The "Horus" preparation is effective even at low temperatures of + 3- + 10 degrees. The spraying procedure is recommended to be carried out 2 times. Before bud break and after flowering. Its distinctive feature is that it is not washed off in the rain.

"Fitolavin" belongs to the group of streptotricin antibiotics. To prepare a solution, 20 ml of this drug is dissolved in 10 liters of water. They carry out 4 treatments per season, at intervals of 15 days.

Strobe. The drug is active not only against scab, but also useful in the fight against sooty fungus, powdery mildew. To prepare the solution, you need to dilute 2 ml of this substance in 10 liters of water. It is necessary to carry out at least 3 sprays per season.

Treatment with mineral fertilizers

It is believed that mineral fertilizers "work" no worse than chemistry in the fight against scab. In addition, they are at the same time foliar feeding. For treatment, highly concentrated solutions of 10% ammonium nitrate, 10% ammonium sulfate, 15% potassium salt, 15% potassium nitrate are used.

These fertilizers can also be used for prophylaxis, only in lower concentrations.

Scab on an apple tree is a dangerous enemy of our garden, but with proper care, and above all thanks to autumn preventive work, in most cases you can save your garden and infections.