Apple scabis one of the most common and oldest diseases of apple trees grown in our country. It causes numerous damages, including corking of the skin on apples. Symptoms of the disease appear every year and it is necessary to regularlycontrol scabSee how to overcome this apple disease, what sprays are effective against scab, and whether you can avoid chemicals and overcome scab by natural methods.
Apple scab - apple peel corking
Note!
At the end of this article you will find information about thenew, natural and ecological preparation for scab, which appeared in 2018Its use can completely change your approach to fighting apple scab and possibly allow you to give up chemical plant protection products used so far. Therefore, be sure to read this article to the end!
Apple scab - symptoms, harm description
Apple scabis caused by the fungus Venturia inaequalis. The fungus attacks all the above-ground and non-woody parts of the apple tree.Symptoms of scabare most seen on leaves and fruits, but the pathogen also infects petioles, flower parts, fruit stalks, shoots and buds.
On the upper side of the leaves, dark olive stains are formed, covered with a velvety coating. The spots are mostly round and can vary in size. Sometimes, under conditions conducive to the growth of the fungus, the spots may merge with each other, thus creating significant necrotic areas.In severe infection, the leaf tissue deforms and crumbles. Infected leaves fall prematurely.
Symptoms of scab on leaves and young fruits
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The most dangerous, however, is the infestation of the fruit buds.Symptoms of scabon fruits are dark, round spots in which the skin is necrotic. The plant, defending itself against excessive water loss, creates a layer of cork in these places, which is a kind of scar. In case of infection of older fruits, small, scabby spots appear on them. Such apples are not suitable for consumption.
Apples affected by scab
Fig. depositphotos.com
Apple trees are most often infected in spring, when the bag spores are released from the fruiting bodies under the influence of moisture from precipitation. Spores can travel several hundred meters with the air current.In our climatic conditions, the sowing of spores lasts from the beginning of spring to the end of June. The spore release process slows down at low temperatures and at night. The most intense release of spores occurs during the pink bud development and flowering of apple trees, which is the period of the greatest threat from apple scab.This disease also affects other fruit trees. In Polish orchards, apart from apple scab, pear scab can also appear.
Apple scab - spraying, chemical control
The control of apple scabcan be carried out by various methods, which can be divided into chemical and natural.
Chemical control of apple scabinvolves the use of chemical fungicides, i.e. fungicides.Apple scab sprayingfungicides applied before or at the time of infection inhibit the germination of fungus spores and create a protective layer on the surface of the protected parts of the apple tree.The durability of such fungicides is 6-8 days from the moment of treatment during the flowering period and 10-14 days after flowering. Provided that the fungicide has not been washed away by rain.
Scab sprayafter onset of disease symptoms destroys conidial spores or mycelium. With this type of fungicides, it is advisable to spray 2 sprays with an interval of 5-7 days.
Apple scab - spots on leaves
Apple scab sprayingis performed during the leaf emergence phase, green flower bud, pink flower bud, flowering and bud growth. For the earliest spraying, it is possible to use, among others, preparations Miedzian 50 WP, Syllit 65 WP, Carpene 65 WP or Score 250 EC, for later spraying of Kaptan suspension 50 WP or Merpan 80 WG. However, since the recommendations for the use of plant protection products change almost every year, you should read the current apple protection program for a given year before buying them.
Apple scab - prevention, combating with natural methods
In home and allotment gardens, however, we should limit spraying apple trees with chemical pesticides and use natural methods as often as possible.
These types of methods undoubtedly include mechanicaldestruction and removal fallen leavesas a source of infection. The potential number of sac spores is reduced, thus reducing the possibility of contamination in spring. This method, however, does not completely eliminate the risk of infection, as the bag spores are carried up to several hundred meters by the wind.
Scab hibernates on fallen leaves. It is worth removing them from under the trees
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Biological control of apple scabThis method of apple scab control consists in inoculating fallen apple leaves with antagonistic fungi.The advantage of this method is that it reduces the development of apple scab by 80%. The downside is the high price and the complicated way of applying antagonistic mushrooms. This method is used only in production orchards and does not apply to amateur crops.
Cultivation of apple varieties resistant to apple scabThe latest varieties showing resistance to apple scab are: Topaz, Rubinola, Florina . Older, highly resistant varieties are Antonówka or Costela. However, it should be remembered that such varieties are often more sensitive to other diseases, e.g. fire blight or bark diseases. However, it is worth taking an interest in them in areas where apple scab attacks the most.
In autumn we spray the trees with urea
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Urea spraying on scabThis is undoubtedly the most recommendable method forapple scab controlFor spraying, prepare a 5% urea solution .This urea solution can be obtained by mixing 0.5 kg of urea fertilizer with 10 liters of water. Spraying fruit trees with urea against scab should be done in the fall. It is best when there are still leaves on the apple trees. This time is at the end of October or the beginning of November, depending on the weather.The spraying treatment with 5% urea solution should be carried out very carefully. You have to spray all the leaves on the tree as well as those that have already fallen to the ground. The more carefully we perform the treatment, the greater the probability that apple scab will not infect our apple trees next year, in the spring. During several years of research carried out at the Institute of Pomology and Floriculture in Skierniewice, it was found that by spraying fruit trees in the fall with urea, up to 90% of fungal fruiting bodies formed on apple leaves can be eliminated. With the same spraying, we also fight pear scab.
How to spray urea against scab is also shown in the video. See it at a glance again. Thanks to this, you will remember better what and how to do it. We invite you to watch an inspiring video: -)
Ecological horsetail scab spraying
I am adding this fragment at the beginning of 2018, because thenew, phenomenal preparation for spraying against scabis now available for sale. It is completely natural and allowed to be used in organic farming: -)
Evasiol - is a natural preparation based on horsetail. The beneficial effects andhigh efficiency of spraying with horsetail preparationshave been appreciated by ecological gardeners for many years. Until now, however, you had to collect horsetail herb and prepare preparations based on it, which was quite time-consuming. As a result, many people gave up this valued method.Thanks to the appearance of Evasiol, we have a ready-made horsetail preparation Just dissolve it in water and spray is ready!
Ecological spraying against apple scabwith the Evasiol preparation we can perform from the flower buds cracking to drying up of flowers, performing a total of 2-6 treatments at intervals of 7 days. In the same way, we also fight apple mildew and peach leaf curl.
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