Scab: What To Treat, Preparations, How To Fight It On Apple, Pear Trees

Mumps is an infectious disease that poses a great danger to many crops. It is caused by pathogenic microscopic fungi, bacteria and actinomycetes. Plants affected by scab have deformation of the surface of leaf plates, tubers, stems and fruits, which has a very negative impact on the yield. The most widespread occurrence of this disease is observed in temperate climates. There are scab that affects shrubs and trees, and there are also types of this disease that affect beet and potato root crops.

Specialists have noticed that all crops are affected by different scab pathogens. For example, scab on an apple tree will never spread to a potato or pear tree. However, all types of such a disease have common symptoms. Examination of a diseased plant can reveal the following symptoms: peeling of the skin, pustules, spots, warts and sores on fruits, tubers, shoots, leaf plates, stems and flowers. If the plant is affected by scab very strongly, then drought and falling off of leaves, disturbance of crop water balance, and it very badly affects the fruiting of both the current and the next season can be observed.

Also, sick flowers and buds fall off, and the fruits become ugly because of this disease. In addition, such fruits begin to rot during storage, as it is very easy for the pathogens to penetrate them through the cracks formed on the peel surface due to scab.

The crop is affected by this infectious disease only under certain conditions. For example, high soil humidity. This disease cannot develop without moisture.

The fungus activates when the snow cover descends in the springtime, and the air temperature should be about 12 degrees. During the summer, scab begins to develop if it rains frequently or there are frequent fogs and dews. And also contributes to the development of the disease overly dense planting. In those garden plots with many trees of the same species, rapid spread of the disease is noted especially if the soil surface between the rows is overgrown with weeds, which, as a bridge, transmit spores from one plant to another. The rapid spread of scab scabs in an orchard is also observed in genetic uniformity, for example, when trees of the same species grow close to each other.

For example, if a plum or pear tree is planted near an apple tree affected by apple scab, it is unlikely to "catch" the disease from the apple tree. And if 2-3 more apple trees will grow near the diseased apple tree, then all these plants will be affected by apple scab after some time. Also, some plants are more often affected by scab because of the susceptibility of the variety. Thus, experts found out that some varieties are less often affected by apple scab and others more often (due to their high susceptibility). To date, breeders have succeeded in obtaining varieties that are highly resistant to scab.

Scab. How to fight apple scab.

For controlling apple scab

How to treat apple scab

Scab: what to treat, preparations, how to fight it on apple, pear trees

Chemicals are the most quick and effective way to treat scab. And in some cases, pesticides are the only hope of saving a sick plant. To treat trees, fungicidal preparations are used such as: Zato, Skor, Bordeaux mixture, Hom, Phytosporin, etc.

To get rid of scab, several treatments will be required, and it is extremely important to choose the right time for spraying plants. In order to do this, it is necessary to know at what time the beginning and end of the spread of the fungus ascospores occur. The first time plants are sprayed against this disease in the phase of the green cone, repeatedly - in the phase of the rose cone and the last most important treatment is carried out after the petals. In summer, crops are treated against the disease at intervals of 15-20 days. If the season is rainy and the humidity is rising regularly, the scab scabs must be sprayed at least 5 or 6 times.

Preventive treatment

Scab: what to treat, preparations, how to fight it on apple, pear trees

Many gardeners have learned through experience that it is much easier to prevent scab development by taking preventive measures regularly than by fighting the disease later.

There are certain agronomic practices that are very effective in controlling scab. For example:

  1. The soil surface under trees and shrubs should be cleaned of fallen leaves in good time, and the soil in stump circles should be recultivated.
  2. For early detection of the beginning of disease development, frequent and regular inspections of trees during the vegetation period should be made. Fruits and foliage that look suspicious are immediately cut off and destroyed.

  3. Don't forget to thin the crowns of shrubs and trees every year, as scab development occurs very quickly if they are overgrown.
  4. Fertilize plants foliarly with phosphorus, potassium carbonate and silica based fertilizers such as Opty Sil and Solfan PK.
  5. When the leaves fall off, spray shrubs, trees and the soil beneath with a solution of urea (7%), ammonium nitrate (10%) or Nitroammophoska (10%). When spraying plants with these preparations, the air temperature must be at least 4 degrees. Such a treatment will not only eliminate most pathogenic microbes and pests but also gives the bushes and trees additional nourishment.

Bark scab on trees

Apple scab

Scab: what to treat, preparations, how to fight it on apple, pear trees

Apple trees are most often affected by apple scab. Initially, apple scab develops: Olive-colored spots appear on the front surface of the affected leaves, covered with a velvety film containing fungal spores. As the disease develops, the leaves begin to fall off. Later, the fruits are affected: brown speckles with lighter color fringes appear on their surface, covered with a velvety plaque. This plaque eventually disappears, and cork tissue can be found under it.

Further, there is an increase and cracking of such cork spots, and often they join each other. The shape of affected fruits becomes irregular and ugly, and they are very poorly stored.

The following apple varieties are most susceptible to scab: Moscow Grusovka, Slavyanka, Borovinka, Antonovka, Papirovka, and Bellefler-China. Varieties considered most resistant to the disease are such as: Saffron peppin, Jonathan, Chinese anise, Rodnichok, Union, Fortuna, Junona, Dawn, Fairy, Red amber, Golden summer, Lyubava, Vasilisa, Orpheus, Margo, Nocturne, Talida, Ekaterinodarskoye, etc.

To cure diseased apple trees, agrotechnical measures should be combined with spraying trees with special pesticides.

Diseased stems detected on the plant must be cut out, and also make sure that the root zone is always clean, for this purpose, remove and destroy the fallen fruits and leaves and remove weeds in a timely manner. In the autumn, there is a compulsory re-cultivation of the root zone. Thinning and sanitary pruning of trees is carried out in early spring.

For prevention of apple scab, apple trees are sprayed shortly before the sap starts to move, using a solution of Nitrafen emulsion (20 grams per 1 liter of water) or DNOC (10 grams per 1 liter of water). The first spraying of apple trees for medicinal purposes is carried out in the phase of the green cone with a solution of Bordeaux mixture (1%), and the second time the tree is treated in the phase of pink buds, for this use a solution of Skor (2 mg per bucket of water).

If you did not have time to spray the plant on dormant buds by Nitrafen or DNOC, then it is recommended to conduct in the phase of green cone "blue" spraying with a solution of Bordeaux mixture (3-4%), and if desired, the treatment in the phase of rosebud in this case can not be conducted. Then, apple trees are sprayed against scab at regular intervals of 15-20 days, for this purpose, alternately use such means as Cineb or Captan emulsion (5 g per 1 liter of water), Hom (4 g per 1 liter of water) and colloidal sulfur in suspension (10 g per 1 liter of water). When there will be at least 30 days before harvesting, you must stop all spraying with pesticides. In those years when mass scab infestation of apple trees is observed, plants are sprayed one more time after harvesting, using a solution of Cineb (0.5%) or Bordeaux mixture (1%).

Caution! Apple scab 🍏 How to Treat Apple Tree Diseases ✔️ orchard

Pear scab

Scab: what to treat, preparations, how to fight it on apple, pear trees

The signs of a pear scab are almost the same as those of an apple tree (see above). But pear leaves have spots on the lower surface, and besides fruits and leaf plate, young shoots of pear tree are also affected by this disease. The scab scab causative agent overwinters on the branches of the tree and also on the leaves falling off under the plant.

For 15-20 days after bud opening, the first scab symptoms appear. If the tree has been infected early (in the spring or the first few weeks of summer), the spots that appear on the leaves and fruits will be large.

And if the tree was infected with scab later, then the spots will be smaller. The late appearance of scab is observed when there is wet weather before the harvest. In this case, the spots that have appeared are very small and hardly visible, but they will definitely show up during storage. These fruits are called "storage pears". On infected stems, many very small blisters appear on the bark, with their surface becoming rough and beginning to peel.

Pears varieties most susceptible to scab include: Lesser Beauty, Bergamot Mleyevsky, Sapezhanka and Bere Ligel Winter. Relatively resistant to this disease are the following varieties: Bere Gardi, Bere Ardanpon, Bere Bosch, Mliyivska Autumn, Klappa Favourite, Vrodlyva, Vyzhnitsa, Etude, Trembita, Zolotovorotska, Stryiskia, etc.

To cure scab infested trees, it is necessary to clean the ground surface under them from the leaves and fruits in time. In spring time obligatory pruning is performed to thin the crown and remove all diseased and withered branches, which are destroyed by fire. In autumn, the site is cleared of the fallen leaves and fruits, which are also burned.

To destroy pathogens which overwinter in the soil of the tree root zone and in the bark, in late autumn and early spring the soil under the pear is plowed over, and the tree and soil under it is sprayed with a solution of Nitraphen (3%) or DNOC (1%). Two buckets of the solution are required to treat one sotka. In spring, the first treatment, called "blue" spraying, of scab pears is carried out in the phase of green cone, using a solution of Bordeaux mixture (3%). Then, the plant is sprayed in the phase of pink buds and at the end of flowering, for this purpose, a solution of the drug Skor (2 grams per bucket of water) is taken. When 1.

5-2 weeks pass after foliage coarsening and again after 20 days, pears shall be sprayed with a solution of Hom, Captan, Skor, Cyneb, colloidal sulfur and other preparations of similar effect.

Peach and Apricot

Scab: what to treat, preparations, how to fight it on apple, pear trees

Bolls are affected by pears less often than pears, but this disease is still dangerous for them. Increased humidity on the background of moderate air temperature increases the probability of scab of apricots and peaches. When air temperature rises up to 30 degrees, the disease begins to develop much slower.

The first symptoms of scab on apricot and peach fruit are spots with indistinct contour of greenish-brown color.

Over time, there is a darkening and proliferation of spots, on their surface appears a black or olive shade of velvet, with their boundaries becoming clearer. If the plant is affected very strongly, then the spots join together and form a crust. Fruit growth slows down, and ulcers and cracks form on its surface, through which the fruit rot pathogens can penetrate. Often, the affected fruits fall off. Diseased stems show retardation in development, and many fuzzy spots of greenish or brown color appear on the lower surface of the affected leaves.

The greatest susceptibility to scab are such varieties of apricots as: Red-cheeked, Shalah and the whole "pineapple" group.

Bordeaux mixture solution (3-4%) or other agent containing copper is used for tree spraying on dormant buds for prevention. Directly from scab spray the plant in the first decade of June, and use for this purpose Skor, Horus or Captan (strictly follow the instructions on the package). After 15 days, spray again. Later treatments will not have the expected effect, but after the apricot leaves have fallen off, it can be sprayed with a solution of Bordeaux mixture (1%).

Fungicide preparations containing copper are most effective against scab on apricot. And to save the plant from this disease one also should not forget about the rules of agrotechnics of this crop.

Plum

Scab: what to treat, preparations, how to fight it on apple, pear trees

Plum scab affection occurs under the same conditions as in the case of other stone fruits, the same symptoms of the disease also occur. For this reason plum trees are treated in exactly the same way as apricots:

  • the first time the plant is treated in spring on dormant buds ("blue spraying");
  • the first decade of June the plant is treated with Chorus or Skor Solution, 15 days later it needs to be sprinkled again;
  • when all leaves are shed in autumn the plant is treated with mildew (1%).

Cherry

Scab: what to treat, preparations, how to fight it on apple, pear trees

Cherry, like other stone crops, is relatively rarely affected by scab.

But if, however, it is infected with this disease, the most harmful to the plant is not the scab itself, but the causative agents of various rots that can easily penetrate into the cracks formed due to the disease in the fruit. That is why prophylactic treatments shall not be neglected in order not to lose the harvest and to save cherry trees from diseases, starting from early spring by the same means and following the same principle as in case of apricot.

Fruit trees

Citrus cultures also can be affected by scab, but in middle latitudes gardeners do not plant oranges, lemons and mandarins in their garden plot. Also can be scabbed cherries, quince, peach and bird cherry, and cope with the disease in the same ways and within the same time frame as in the case of pear, apple and apricot. Do not forget about preventive measures, which are virtually the same for all garden trees.

Bush scab treatment

Gooseberry

Scab: what to treat, preparations, how to fight it on apple, pear trees

Gooseberry is also susceptible to scab. However, gardeners often confuse symptoms of this disease on such a shrub with signs of powdery mildew, but these are completely different diseases. That's why before treating the bush, try to compare all existing signs of the disease in order to be sure that it is scab.

To prevent scab, don't forget to treat regularly in spring the buds, which have not yet swollen. A solution of urea (7%) is used for this procedure, and make sure that after spraying, the branches and buds as well as the soil surface under the plant should be well moistened.

When fall of leaves in autumn time is over, the ground near gooseberry is cleaned from decayed leaves and recurrent spraying with urea solution is carried out.

If a shrub was nevertheless affected by scab, then it is sprayed on swollen buds with mixture of such means as Horus and Aktara or with solution of Bordeaux mixture (2-3%). After 30 days, spray again with Actara and Chorus.

Carberries

Compared with gooseberries, currants are affected by scab much less often. However, experts do not advise to take any risks and recommend taking all necessary preventive measures.

Since gooseberry and currant are related crops, the same methods and preparations are used to combat scab. But even in this case, before you start treatment you must make sure that the plant is definitely affected by scab and not by powdery mildew.

Potato scab

Scab: what to treat, preparations, how to fight it on apple, pear trees

Potatoes can also be affected by scab, just like fruit trees. In this case, the surface of the tubers is most often affected, causing them to become ugly, and the seed quality and taste of such potatoes are severely deteriorated. At the same time, the affected root-crops cannot be stored for a long time.

If the potatoes are severely infested, they cannot be used for food.

Potato plots with scab are not recommended for potato cultivation for 4 or 5 years (not less). This crop can be affected by the following scabs: Scabies, Ultrasonic (Oosporosis), Black (Rhizoctonia), Herringbone and Powdery mildew. More about each species:

  1. Common scab. Not very deep small irregularly shaped ulcers are formed on the tuber surface.

    Over time, the spots increase, they join each other, and cork formation appears on their surface. If the diseased potatoes are dug out, a cobwebby growth may be seen on their surface, but as soon as the tubers have dried, it disappears.

  2. Powdery scab. It appears if pathogens enter roots, tubers and stolons through mechanical damages or eyes. On the surface of the roots, formation of galls is observed, which are irregularly shaped white growths, which become darker as the disease develops.

    And many warty pustules appear on the tuber, which eventually become ulcers with a dusty brownish mass. During storage, diseased potatoes are often affected by dry rot or phytophthora.

  3. Silver scab. Potatoes can be recognized as diseased during harvesting or during storage. On diseased tubers, poorly visible matte spots of varying size and shape and a brownish hue are formed.

    The disease starts to develop actively closer to spring. At this time, the affected tissue on the tuber acquires a metallic sheen, and it looks slightly pressed inside. If the potato is very diseased, it loses a large amount of moisture, causing the rind to become wrinkled.

  4. Bugworm scab (oosporosis). The tubers are affected in the ground, during their active growth, but it is not until they are in storage that one realizes that they are diseased.

    Round pustules appear on the potatoes, which are the same color as the rind. These pustules can be convex, depressed or flat. With time, they enlarge and form areas similar to Phytophthora, but in this case there is no rot under the rind.

  5. Black scab (Rhizoctonia) . This type of scab that affects potatoes is the most dangerous.

    The grower can lose up to 20 percent of the crop because of it. Because of this disease, the tubers die, the apex leaf plates curl, and mold appears on the root parts of the bush. And it can also cause the stems to rot and die.

To prevent potatoes from being affected by this disease, only fully healthy, high quality planting material should be planted. Just before planting, do not forget to treat the tubers with a solution of Rovral, Fito Plus or Aquaflo.

To help reduce the likelihood of scab infestation of the plant can contribute to the introduction of manganese, boron and copper in the soil. It is also very important not to forget about the rules of crop rotation in order to prevent such a dangerous disease. So, on the site it is recommended to grow potatoes and plants belonging to the family of legumes alternately. And in case you can not plant potatoes on a new plot every year, be sure to refrain from adding fresh manure to the soil.

Alkaline soil on the plot is recommended to acidify with a solution of ammonium sulfate (2 tbsp.

per bucket of water). Such a solution is poured over the soil on the plot during the flowering period of bushes, and 1 liter of the mixture is used per plant. When up to harvesting will be about 15 days, it is recommended to mow the tops, so the skin on the tubers will be stronger. During the formation of buds, spray the bushes with a solution of Zircon, this will not only stop the development of scabs, but will also help to increase the yield. After 15-20 days, the processing of plants Phyto Plus (per 3 liters of water 1 sachet), thanks to this will reduce the degree of defeat of the tubers scab.

And still experts advise, choose to grow those varieties, which are most resistant to scab, such as: Aspia, Skoroplodny, Alpha, Lady Rosetta, Mentor, Nicolas, Prevalent, Patrones, Element, Polyana, Yavir, Vesta, Dara, Rakurs, Tiras, Riviera, Favorite, Reserve, Rodnik, Vestnik, Varmas, Ramensky, Vilnia, Vyatka, Zhukovsky early, Bezhitsky, Bryanskaya novina, etc.

T8 PARSHA on potatoes. How to fight scab and other fungal diseases

Particles remedies

Scab: what to treat, preparations, how to fight it on apple, pear trees

Fungicide preparations of the 3rd-4th class are used for treatment of scab infested plants as they cannot form stable compounds, penetrate through the skin or accumulate inside the fruit. Which remedy to choose in this or that case depends on various factors and personal preference of a dacha grower. But the most common remedies against the disease are: Chorus, Scor, Rayek, Strobi, Abiga-Pic, Fitoflavin, Bordeaux liquid and copper sulfate.

Treating apple trees with biopreparations

Treatment of apple trees against the disease.
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