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Fruit trees are prone to disease, and the apple tree is no exception. And if you are a responsible gardener, take care of your garden and want to get a decent harvest, then you should know about the diseases of apple trees and their treatment methods. The article will help you successfully diagnose the most dangerous of them and tell you what to do in each case.
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The causative agent of powdery mildew is a dangerous parasite called powdery mildew. The pest develops in the spring and affects the buds, leaves, shoots and bark of both young and adult apple trees. The main reason that contributes to the development and spread of the disease is excessive soil and air moisture.
On the leaves, shoots and sometimes on the fruits, a mealy coating of gray or off-white color is formed. Over time, this plaque becomes brown and multiple black blotches appear. In the initial stage, plaque can be easily removed, but over time it becomes more dense. Under its action, the foliage begins to curl, turn yellow, gradually dry out, and young leaves stop in their development. If the ovaries have formed, they can crumble. The disease leads to a decrease in yield, in severe cases – up to 50%. Even low ambient temperatures in winter do not affect the pathogen. It calmly overwinters in the buds of infected shoots. Even in the most severe and cold winters, the mycelium only slightly decreases, but still remains viable. The fungus can reduce the winter hardiness of the apple tree.
In autumn and spring, remove and be sure to burn shoots affected by powdery mildew. Use agrotechnical measures that can prevent excessive soil moisture.
In the prevention of this disease, the Topaz fungicide is successfully used. It is advisable to process the entire garden, especially if Semerenko, Boyken, White Rosemary varieties are present. To suppress the primary infection, treatment with this drug begins at the beginning of the growing season. Usually spend 4 sprayings per season.
After harvesting, the treatment is continued by spraying 1% Bordeaux mixture. A solution of copper sulphate is also perfect for this procedure. To cook in a bucket of water, add 2 tbsp. spoons of copper sulfate and 1 tbsp. a spoonful of liquid soap.
Also use a colloidal sulfur solution for spray control. It is recommended to use it at least 3 times. The first is when the buds begin to emerge. The second – after the flowering phase and the third – 2 weeks after the second spraying.
Know that the fight against powdery mildew is quite protracted – the fungus is very insidious and often relapses.
Video “Prevention and treatment of powdery mildew on apple trees”
This video will show you how to prevent and treat an apple tree suffering from such a common fungal parasite as powdery mildew.
Apple fungus – scab
This fungus mainly affects apple and pear trees. The disease is spread by spores with the help of water droplets. Ideal conditions for propagation are a rainy long spring.
The main signs of the disease are olive-brown plaque on the leaves. Later, dark gray spots and many cracks appear on the fruits. It is through them that all kinds of infection can penetrate, which will cause rotting of the fetus. Since the fungus infects the petioles of the leaves, after a while they fall off, but the parasite does not destroy the development mechanism – photosynthesis and the infected tree continues to grow, which is what the fungus uses.
The fight against diseases of apple trees, including scab, first of all begins with preventive measures in the fall – harvesting foliage, dried fruits and branches. In the spring, before flowering, it is advisable to use the Fitosporin M biofungicide or Bordeaux mixture.
To combat scab, fungicides “Gamair”, “Horus”, “Fitolavin” are used. Spraying is carried out both before flowering and after.
Mineral fertilizers have proven themselves well against the fungus, and this method can also be foliar top dressing at the same time. For treatment, solutions of 15% potassium salt, 10% ammonium nitrate, 15% potassium nitrate, 10% ammonium sulfate of high concentration are used. They can also be used for maintenance work, however, in this case, the concentration must be reduced.
Fruit rot or moniliosis
This disease traditionally manifests itself during fruit ripening, at the end of August. Especially if the weather is wet. If an apple tree is affected by scab or codling moth, then this will be enough for moniliosis to develop: rot develops on a fruit infected with a fungus and spreads to healthy fruits through contact (an example of infection in the photo).
First, a small spot appears on the apple, which progresses very quickly and occupies the entire surface of the fruit. The apple turns brown and becomes very soft. This apple should not be eaten. Moniliosis is much more insidious than powdery mildew or scab, since the symptoms do not appear immediately, but gradually. It is also dangerous after harvesting – the infection can easily spread to healthy fruits through contact.
The onset of cold weather calmly tolerates rot on diseased, mummified fruits.
First of all, as soon as you notice a diseased affected fruit, immediately remove it from the tree. Do not forget about the carrion, it should be collected and buried. Do not leave mummified fruits for the winter, they must also be disposed of. After you harvest, the places on the crown, where the main foci of rot were located, must be sprayed with a 5% solution of urea.
Do not allow the codling moth, sawfly, goose to spread in the garden. These pests contribute to the development of moniliosis. Carry out preventive spring spraying with a 0,3% solution of a suspension of copper oxychloride or 1% Bordeaux mixture. The first spraying – during the period of bud maturation, the second – immediately after flowering and the third – 2 weeks after the growing season.
To combat rot, the drug “Hom” is used. The drug is diluted in cold water according to the instructions and two sprays are carried out: during the appearance of new foliage and after flowering.
Remember that the key to an effective fight against this disease is not periodic, but regular spraying and constant care of the garden.
Cytosporosis – a disease of the cortex
This parasitic fungus infects the bark of the apple tree. The main reason for the development is non-compliance with the irrigation regime, as well as heavy or poor soil. Weak specimens or those that have damage to the integrity of the bark are mainly affected.
The main symptom of the lesion is the appearance of dark ulcers on the branches and trunk. Ulcers progress over time, become deeper and affect an increasing area of the cortex. The bark, and then the affected branches, begin to die and fall off. If prompt assistance is not provided, a sick specimen, as a rule, does not survive.
Make sure that there are no mechanical damage to the bark. After pruning, treat wounds with clean drying oil or garden pitch.
Successful treatment of cytosporosis can be achieved if it is started in the early stages of development, while the wood and cambium have not suffered from deep penetration of the fungus.
First, spraying with the Hom preparation is carried out. It is advisable to do this as soon as the kidneys begin to swell. Solution: dilute 40 g of the drug in 10 liters of cold water.
Then use copper sulfate. To prepare it, dilute 10 g of the drug in 50 liters of cold water. The resulting solution is treated with a garden before flowering. After flowering, it should be treated again with Hom.
Be sure to fertilize with potash and phosphorus-containing fertilizers on the eve of winter cold weather.
Bacterial burn (bacteriosis)
The causative agent of the disease is gram-negative bacterium. They are able to infect not only young, but also mature fruit-bearing trees. Bacteriosis spreads from top to bottom. Basically, this disease penetrates the territory of the garden with newly acquired cuttings or young seedlings. The main development factors are high ambient temperatures and warm rains. In most cases, a bacterial burn is the main reason that an apple tree loses its flowers.
The main signs of a bacterial burn are the presence of black spots on the entire fruit tree. If branches and shoots are affected, they become covered with dark watery spots. Affected foliage has a charred, burnt appearance. Over time, it will begin to specifically bend. But, despite its non-viability, it does not fall off, but rests on the branches.
If a bacterial burn affects the flowers, then they change their color from white to dark brown and fall off the tree. In the event that the fruits suffer, they also become an unhealthy dark color, stop growing, but remain on the branches until late autumn arrives.
When buying a new seedling, carefully inspect all planting material so that it is healthy. Timely destroy all kinds of small parasitic pests in the garden. After all, many of them freely spread the disease throughout the garden. Disinfect the soil with blue vitriol (60 g of vitriol per bucket of cold water).
Thanks to preventive measures, it is possible to successfully fight this disease. Use agricultural techniques in the fight. First, remove (cut) the affected branches. It is better to carry out the procedure at the end of autumn or with the onset of winter. The cutting site should pass 20 cm below the necrosis. Be sure to disinfect the tool that you will use, do not forget to do this with saw cut places. Sawn diseased branches should be burned without fail. To increase the overall immunity of the plant, carry out repeated spraying with Bordeaux liquid. It is advisable to do this at the very beginning of the vegetative process. These activities will help increase resistance to all kinds of fungal diseases.
Milky luster
The disease affects leaves and twigs. The causative agent is a basidiomycete. An infected tree, if left untreated, will slowly die.
The main symptom is that the affected area becomes milky, silvery in color with a characteristic pearly sheen. Branches sick with a milky sheen cease to bear fruit. The fruits develop poorly, crumble, and the branches dry up and die after a few seasons. This disease manifests itself at the height of summer, in mid-July. It starts with the defeat of several branches, but quickly spreads along the trunk and leads to the non-viability of skeletal branches, and sometimes can lead to the death of the entire apple tree.
The main reasons contributing to the appearance and development of the disease are the lack of minerals in the leaves and new shoots, improper watering, freezing of the bark. It is not necessary to plant seedlings on wet land plots located in the lowlands.
First of all, preventive actions are aimed at increasing the winter hardiness of the apple tree. Conduct timely fertilization. Sick branches must be cut and burned. When cutting, the cut is made 5 cm below the change (browning) of the wood. The resulting sections are disinfected with 1% copper sulphate. On the day of pruning, the wounds must be covered with oil paint or garden pitch.
If there are severely damaged and drying apple trees in your garden, they must be dug up and burned.
Whitewashing of skeletal branches and boles helps with diseases of the bark of apple trees, which is carried out twice a season – at the end of winter and in autumn. To do this, use 20% milk of lime (dilute 10 kg of milk of lime per 2 liters of water). 500 g of 5% copper sulphate is added to the prepared mixture.
If you are the owner of a large garden and the trees in it are very dense, then the site is treated with a 2% solution of milk of lime using hose sprayers.
In dry and hot summers, make sure that watering is regular and sufficient. Do not forget to apply potash and phosphorus-containing fertilizers in sufficient quantities. Monitor the condition of the soil, apply lime and drainage.
Perhaps this material will help you in the fight against diseases of apple trees. After all, timely, and most importantly, qualified assistance can save your green fruit plantations. The gardener must know the diseases and treatment of apple trees, otherwise he risks being left not only without a crop, but also without his garden.