Apples – a storehouse of vitamins. Almost no orchard in our latitudes can do without this tree. Apple trees bring a generous harvest that can delight us, ranging from mid-summer, and ending with the end of spring.
But how sad a gardener is if the tree starts to hurt. One of the diseases that has spread much lately is black cancer. This is nothing like a fungus that most often affects just apple trees. In second place for the defeat is a close relative – pear.
Almost all parts of the plant suffer from the disease – leaves and flowers, bark and fruits. If time does not notice the problem, do not start to deal with it, then the apple tree quickly loses strength. The most deplorable outcome is the death of the tree.
But do not hurry to get upset. First of all, you need to understand what black apple cancer is, where it comes from, and how you can overcome it.
Description of the disease, signs
The last stage of black apple cancer is considered incurable. That is why it is extremely important to monitor the condition of your trees. This will help in time to recognize the symptoms of the disease. So, how does black cancer manifest itself:
- Specks on leaves. This symptom can be seen on the tree at the beginning of spring. Namely – in the period when the leaves bloom. Spots appear on these young buttercups. They are small at first, have a purple hue. With the development of cancer, the spots are getting bigger.
- Pycnidas. These manifestations occur already in the case when the disease is in the last stage. Pycnids are directly the fruiting bodies of the fungus that hits the tree. You can see them on the crown.
- Leaves fall. This symptom occurs when the fruit is about to ripen. About 2-3 weeks before the apples ripen, the tree abruptly begins to drop foliage affected by cancer. This is quite noticeable effect on yield. Decreases as the number of fruits collected, and their quality.
- Fruit rot. At first on apples you can see small specks of brown shade. Over time, they not only become larger, but can fully embrace the fruit. Then it becomes clear that the apples are rotting. This is evident both in the consistency of the pulp and in the smell.
- Mummification. The disease is characterized by not completely dropping sick fruit. Sometimes some of them remain on the tree, although they are already completely amazed. Even after the leaves have fallen, these apples remain hanging – black, sometimes with a brown or bluish tinge, rough surface.
Causes of black cancer
Experts identify several major factors that provoke the occurrence of this disease.
- First of all, you need to understand: the older your garden is, the more trees in it are at risk of getting black cancer. Young strong and healthy trunks are more stable, their problem is very rare.
- The second cause of cancer is considered improper or poor care. For example, if apples do not water properly, this makes them more vulnerable. This also applies to dressings. The absence of these two factors can lead to the disease the next year, when the apple tree is depleted.
- The third cause is burns. We are talking about the influence of the sun and the effects of frost. Usually they arise like this. Sometimes with the onset of early spring too warm days are issued. Then the snow has not yet melted, and the bark has not yet been whitened. The tree heats up on those days. But in the evening it gets colder, and at night the frost can hit. These are too strong temperature fluctuations and lead to burns. And they, in turn, are wounds through which an infection enters the plant’s body.
- Violation of the rules of pruning is another reason for the appearance of black cancer. Infections are prone to trees that are pruned too late. Indeed, at high temperatures, mushrooms spread faster and grow. If the tool and wounds on the trunk are not properly processed, the risk of infecting the tree increases significantly.
To suffer from the disease risk and varieties that are not suitable for a particular region. Each variety of fruit trees has its own characteristics and requirements for climatic conditions. If they do not match, then the apple tree is more at risk of getting sick, including black cancer.
And the last reason is pests. Most often on bark beetles parasitize apple trees, glass-case. They are carriers of the fungus that causes black cancer. Insects live on a sick tree, and then fall on a healthy one, infecting it with this unpleasant disease.
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How to treat black cancer
Treating an apple tree for black cancer must be thought through, taking action in the correct sequence.
- All the bark that had suffered from the disease should be removed as soon as possible. With the help of a knife, the entire diseased area and about 2 cm of healthy wood are cut.
- Wounds resulting from the removal of diseased parts need to be properly treated. They, like cracks that have arisen on the bark, are covered with garden pitch, linseed oil, or simple oil paint. Gardeners use in such cases and Zelenka.
- Those parts of the tree that are not affected by black cancer should be treated with copper sulfate. The use of other products containing copper is also permitted.
- The trunk and branches of apple trees must be properly disinfected. To do this, use different means. The most reliable – solution of potassium permanganate. You can mix a little salt and a couple of drops of iodine. Some gardeners use ordinary laundry detergent as a disinfector.
- Only after cleansing the trunk of the tree, as well as complete disinfection of the plant, can physiological putty be used. It is best to cook it yourself. For this, clay and mullein are mixed in equal amounts.
- Leaves also require processing. If there are injured specimens, then after flowering of the apple it is necessary to treat with Bordeaux liquid.
- All cut bark areas, infected foliage, and fruits must be burned.
If the disease is not at the last stage, the pycnids have not yet grown, then all the measures described above should bring results. Following such instructions, you can save the tree.
Firstly, experienced gardeners do not recommend using cuttings from trees with black cancer for vaccination, even if they were cured. Also, planting of varieties resistant to this disease is considered one of the main preventive measures.
It is important to remember about the sanitary and hygienic measures that will help save the apple trees from black cancer. First, trees need additional feeding. It will help plants to maintain immunity, to obtain the full balance of the necessary substances. It is best to apply bormagnium fertilizer.
Secondly, special iron brushes need to clean the bark. This is done both in spring and in autumn. It is also necessary to regularly trim. Patients are removed, as well as dry branches. Do not forget the cleanliness of the tools. They must be treated with a liquid containing alcohol. Otherwise, you can infect trees with your own hands.
Do not forget about whitewashing. This, at first glance, such a simple event helps the trunks. If in time to whiten the apples, they will avoid infection. Also, whitewash helps protect trunks from burns in early spring.
It is important to pay attention to the soil under the apple trees. Even before planting, you need to ensure the correct balance of moisture and acidity. It is very important to ensure that there are no chemical, soapy substances under the apple trees. Promotes contamination and stagnation of water.
If there are compost heaps in the garden, you need to ensure that the roots of the apple trees do not touch them. The first need to be moved regularly, just so they will be useful.
With the help of different materials trunks must be protected from frost, sun. It is important to ensure that the apple trees are not injured. Cracks and other wounds are the gate for infection.
As already mentioned, pests are carriers of the causative agent of black cancer, so they must be regularly fought.
Weeds must be destroyed. Garbage in the garden should be cleaned regularly. Healthy waste goes to compost, and patients are burned without fail.
And remember, if a tree is hurt by the last stage of black cancer, it needs to be uprooted. Otherwise, you risk infecting your entire garden.
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Cancer resistant varieties
Fully resistant and relatively resistant varieties can be distinguished. The first are summer apple trees Malt Bagaevsky, Alva, as well as Papirovka. Relatively stable winter varieties, namely Jonathan, Bolotovskoye, Pashkevich Memory, Haralson, Zarya Alatau, Lobo. There are autumn varieties with relative stability. These include Cinnamon Striped, Freedom, Autumn Joy and Borovinka.