General information

Dangerous fungal disease - pear scab


Since both apple and pear belong to the same fruit crop, namely, pome fruit, they have the same diseases. For example, such a disease, as scab of apple and pear, weakens trees, reduces the strength of their fruiting and resistance to winter frosts. At the same time, almost all parts of the tree are affected: flowers, ovaries, leaves, branches and fruits. But there are varieties of pears that have a relative "immunity" to this terrible fruit disease. Resistant to scab varieties of pear are: Bere Gardi, Sketch, Trembita, Bere Ardanpon, Vyzhnitsa, Bere Bosch and others.

But there are varieties that should be avoided if the scab information has scared you and you do not want to watch it in your garden. Varieties subject to the disease: Bere Ligel winter, Sapezhanka, Forest beauty and Bergamot mliyevsky.

What is scab on pear

This nuisance is caused by microscopic pathogenic fungi and bacteria remaining on the "wintering" in the garden in the fallen leaves or on the branches of fruit trees. The external signs of this dangerous infectious disease include the following:

  • Peeling of the skin.
  • The appearance of spots. They will be large if the infection occurred in early spring, or small in case of a later infection.

  • The appearance of ulcers and warts on all parts of the tree (up to the fruit).

On a note! If on the eve of the harvest there was rainy weather, then the appearance of late scab on a pear, which is visually almost imperceptible, is possible. It can appear only at the storage stage (that is, the stains will appear already in stock).

20-22 days after bud break, the first signs of the disease can be easily detected on the tree with the naked eye.

Shoots affected by scab

The first to take a "painful blow" shoots (especially young). Blisters appear on the cortex, as a result of cracking of which a large number of olive-colored spores can be seen with the naked eye. The bark becomes rough and begins to peel off.

Affected leaves

The leaves are the following to take the disease upon themselves: on their underside are spots of olive color with a velvety patina, which is nothing but a plantation of fungal spores. The foliage dies and falls as it is defeated, thereby weakening the tree and disrupting its water balance (and this, in turn, has a very negative effect on fruiting not only this year, but the next).

Flowers and ovaries affected by scab

If the spring was rainy, the first signs of the disease will appear very early: already on the flowers and the resulting ovaries. The disease is manifested by small dark spots covered with spores of fungi. Ovaries affected by the disease cease to exist: this, in turn, can lead to the loss of almost the entire crop.

On a note! The opinion of those who believe that the fall of the ovaries is caused only by bad weather conditions is erroneous.

Fruits, disfigured by disease

Fruits can get scab at any stage (and at the beginning of fruiting, and at the end of the season). A sign of the disease is the formation of gray-black spots (sometimes framed by a light rim) of a round shape, the size can vary (sometimes they can merge with each other and cover a significant part of the fruit). The scab affected fruit stops growing, its tissue hardens, it acquires an ugly shape and falls to the ground.

On a note! If the lesion occurred at late maturity, then during storage, stains may appear, which subsequently crack and cause pathogens to enter.

The causes of the disease

There are a number of factors leading to the appearance of scab on a pear:

  • High degree of soil moisture. The presence of moisture is a prerequisite for the development of scab. In the spring, water is formed due to the melting of snow, and in summer as a result of rains, dews and fogs.
  • Very dense planting of fruit crops. Disputes are very quickly transferred from one tree to another.
  • Genetic uniformity (when plants of the same species are fairly close to each other).

Tip! We strongly recommend to plant a variety of trees nearby. For example, next to a pear you can plant a plum: there is a chance that a scab will not infect a nearby tree. If you have planted a few pears in the garden area, which are in close proximity to each other, then infection of all trees (if one is sick) with scab is just a matter of time.

  • Incorrectly selected grade. It is more expedient to choose varieties resistant to scab (especially since breeders are constantly working in this direction).

Agrotechnical measures to combat the disease

Now you have the information that a scab on a pear. How to deal with it, tell you next.

  • Fallen fruits are collected, we burn the fallen leaves.
  • Remove the affected shoots with a secateur and burn them.
  • We keep pristvolny circles in perfect purity: we weed out weed grass and also burn it.
  • In late autumn and early spring we dig the soil under the trees.
  • After autumn loosening, we feed the earth with a solution of urea (7%), nitroammofoska (10%) or ammonium nitrate (10% solution). In addition to food, the destruction of pests and pathogenic microflora occurs.
  • In early spring, we are obliged to carry out sanitary and thinning crown pruning.
  • Throughout the growing season, we carry out a visual diagnosis of trees in our garden: we immediately remove the leaves and fruits that cause suspicion.
  • Periodically we carry out top dressing (extra root) with potash and phosphate-silicon fertilizers.

Chemical processing of trees

In addition to agrotechnical measures, the fight against scab pears also involves chemical treatment. They resort to such cardinal measures when other methods no longer help. We carry out treatment in several stages:

  • First stage. We sprinkle fruit trees with Bordeaux liquid (3%) in the green cone phase (that is, before flowering).
  • Second phase. In the pink bud phase (just before flowering) we spray, for example, using the “Skor”, “Zineb” or “Xom” products in the proportion of 2 grams of the drug per 10 liters of water.
  • The third stage. We spend it after all the petals have fallen, and the leaves of pear have become coarsened. We process colloidal sulfur or other agents that have a similar effect.

Important! All spraying during the summer season is recommended at intervals of 2.5-3.5 weeks. Exceptions are periods characterized by high humidity: in this case, we increase the number of treatments (up to 5-6 pieces).

Pear scab can be avoided altogether if you strictly adhere to all our recommendations.

What is scab?

Scab- common fungal infection of pears and apples.

However, besides them, it easily affects other fruit trees.

It is so common that there are practically no areas where this disease is absent.

It is caused by the fungus Venturia pirina Aderh, which specifically affects the pear.

The apple tree also suffers from this disease, but the causative agent is another fungus.

The danger is that it can completely destroy the crop.

For the early diagnosis of plant diseases, it is important to know their symptoms. The disease on a pear has clear, isolated from other diseases, manifestations, not only on the leaves of the tree, but also on the pears themselves. It can be determined with high probability correctly.

For example:

  • brown spots on the fruit. The first manifestation of the disease, visible to the eye,
  • green spots with an olive tinge on the sheets. At first, such spots are not very noticeable, but with the development of the disease, they darken and turn brown,
  • the affected fruits cease to develop, acquire a strange, unaesthetic form,
  • any infected parts of the tree fall: leaves, fruits, ovaries, etc.

Further in the article photo and treatment of such a disease.

How to get rid of the disease?

Combating any plant disease requires comprehensive measures. It is important to combine all methods of struggle, otherwise the disease will continue to spread.

So how to get rid of scab on a pear?

Among the most effective ways:

  • Spraying In the fight against virtually any disease of trees, this method is the most correct. Spraying is carried out necessarily several times a year. Good results gives spraying of blue vitriol, as well as combining it with lime.Also, alternate spraying copper sulphate and bordeaux liquid proved its worth in the fight against this scourge. You can replace the Bordeaux mixture on copper chlorine or colloidal sulfur,
  • regular cutting and destruction of infected parts of the tree, especially young shoots,
  • destruction of infected fruit.

The combination of prevention and control measures gives good results. A disease is always easier to prevent than to cure. It is important, before planting trees or detecting the first symptoms of the disease, to remember about its threat.

When to do processing?

Special attention to the gardener should be paid to the processing schedule of trees. Spraying is carried out several times a year, depending on the weather and the degree of infection of the plants.

The most severe development of the disease requires about 5 procedures per year:

  • the first spraying - in the period of formation and swelling of the kidneys. Most often, spend his copper sulphate,
  • the second is during the period of bud formation. Suitable fungicide,
  • the third spraying is carried out after completion of flowering. It is advisable to treat again with a fungicide,
  • quadruple - 2 weeks after the previous one,
  • the fifth spraying is carried out on winter trees in the late summer - early autumn.

Disease prevention

Prevention should be carried out long before planting trees. The probability of the disease depends on the choice of the place of the future planting.

Among the main preventive measures:

  • careful selection of the location for the future garden,
  • observance of planting density. The thicker the trees are planted, the more likely the spread of the disease,
  • collection of fallen leaves. The disease is experiencing winter in the fallen leaves, so they must be destroyed,
  • spraying pear trees with Bordeaux mixture or copper oxychloride,
  • proper full fertilization of the soil.

Already in the autumn, after the harvest, you need to start fighting. The first spraying for prophylaxis is carried out immediately after the final harvest.

The weather should ideally be windless, dry. If it has rained after spraying, it is worth repeating it by choosing a sunny day.

Thus, pear scab is a disease that covers vast areas. It is dangerous for all gardeners, because able to completely destroy the crop.

The disease will recede only if to influence it with therapeutic and prophylactic measures. At observance of all rules of processing of trees, constant care for them, any disease will disappear, and the pear harvest will be rich.

Watch the video where you see a pear infected with a scab and immune to it.

The main signs of infection of pear

Having noticed spots on the lower part of pear leaves, you should take a closer look at them.

  1. At first they are whitish, then they begin to darken and become covered with an olive coating.
  2. The color of the spots gradually acquires a brown tint.

Photos of pears affected by scab are presented below.

Fungal infection does not linger only on foliage . Actively spreading along the shoots, the scab reaches the flowers and pear ovaries. At this point, we can assume that the harvest is already lost. Pears with scab have a non-marketable appearance, and their taste varies considerably. Spots on the skin not only spoil the appearance, but also lead to the stiffening of the pulp under them.

Scab can also infect pear fruit, then the crop will definitely not be.

Even if the spots on the harvested pears are few and harmless, after harvesting and storing it turns out that the spots begin to grow and cover the whole peel of the fruit. Storage of such pears is inexpedient, the harvest can be considered missing.

The defeat of pears by a fungus leads to the appearance of cracks in the fruit. Pears do not have a protective wax coating, so the cracks are significant, and the fruits are small.

Scab life cycle

Fungal disease develops in two stages - marsupial and conidial.

To the occurrence of scab on pears involved a fungus of the genus Venturia pirina aderh . Its life cycle is quite simple and goes through 2 stages:

The leaves in the garden are not collected in the fall - a great environment for wintering the fungus in the form of pseudo-events.

  1. With the first rays of the spring sun occurs spore aging and dispersion . Humidity contributes to the transition of the dispute appeared gentle foliage. The fungus begins to germinate inside the leaves and there is a noticeable spotting.
  2. Asexual motionless disputes appear with the arrival of the first summer days.
  3. Rainwater contributes to the spread of spores on the lower leaves, ovaries and shoots are affected.
  4. With the arrival of autumn on the fallen leaves appear pseudo-movements.
  5. The life cycle is repeated in the above scenario.. Human intervention can break this vicious circle and rid the tree of the disease.

Prevalence of scab

The condition for the development of the fungus is the increased humidity of the region.

The fungal infection is contagious and can affect other plants in your garden.

With scab in Russia are found almost everywhere. The exceptions are the following regions: North Caucasus, Stavropol, Krasnodar Territory. Dry summer prevents the spread of scab. Fungal diseases are also rarely found in the Astrakhan region.

With damp spring and heavy rains (from May to July) the risk of dispersion of fungal spores increases.

When choosing a seedling, it is necessary to take into account not only the resistance to diseases, but also the recommended growing conditions, otherwise you can not wait for the harvest.

Fungicides (chemicals)

The most effective method of dealing with scab will be the use of broad-spectrum chemicals.

  1. The broad-spectrum fungicides include Poliram D F, produced in granules. The drug is not toxic to trees, as well as bees and bumblebees.
  2. Another granular complex composition Tridex It is widely used to combat scab on fruit trees. The drug is harmless to bees. Components (manganese, zinc) in the processing of trees provide them with additional feeding.
  3. To combat scab there are special tools. One of them - Merpan . Use in a complex with other system structures is possible. The drug does not cause resistance in the fungus.
  4. Chorus refers to a wide range of active agents. Processing is allowed even on cold and wet days when the air temperature is about 10 ° C. The drug does not adversely affect the plant and is safe for insects that make pollination.

It is recommended to carry out treatment alternately with various drugs. Therefore, you should purchase several types of fungicides. Before harvesting (approximately 3 weeks), chemical treatment is stopped.

Natural remedies

Ordinary dry mustard - the most affordable means to fight scab on a pear.

Many gardeners essentially do not use chemicals to process the garden. Indeed, excessive accumulation of chemistry adversely affects human health. And from your own site you want to collect everything fresh and natural.

There are several effective folk remedies that are successfully used in the fight against scab:

  1. Dry mustard powder . It will take 10 liters of warm water and 80 g of dry raw materials. Mustard is diluted in water and the tree is sprayed with the resulting solution. It is recommended to make several treatments: in the spring when the buds are blooming, during budding, after the flowers fall, during the ripening of the fruits (the phase of pear pouring).
  2. Medicinal plant - field horsetail will help to cope not only with human diseases. It is also used to treat the garden for fungal diseases. Freshly harvested grass is put in a bucket and poured with water (horsetail volume - 1/3 of the bucket). Insist 72 hours. Processing is done in the spring, after the appearance of foliage.
  3. Saline solution use even before the appearance of buds on the trees (in early spring). For 10 liters of water use 1 kg of salt.
  4. Manganese solution (per 10 liters of water - 5 g of potassium permanganate) process pears several times per season. The first time - during the blooming of the foliage, the second - after the fall of color, then the scab is treated in summer - during the ripening of the crop. For prevention, it is recommended that in spring, even before the kidneys awaken, the ground should be treated with the same composition in the near-trunk circle.

Step-by-step process

Spraying in the summer is done in dry weather in the morning or evening.

You can make a treatment plan for infected pears, so that the fight against fungus is effective. It is recommended to act as follows:

  1. Emerging leaves and shoots with scab pruned and burned away from the garden.
  2. Prepare a solution of any of the above chemical preparation and process the wood.
  3. After 2 weeks, re-treatment is carried out (you can use natural remedies).
  4. Через 10 дней провести комплексную обработку несколькими препаратами.
  5. После опадания листвы (осенью) обязательно собрать её и сжечь, чтобы споры грибка не смогли перезимовать.

Предупредительные меры

As an effective preventive measure, it is recommended to process the garden in early spring before bud break.

Timely preventive measures will help get rid of the extra hassle and costs associated with the treatment of fruit trees.

Prevention is carried out even when the trees look healthy and bear fruit well.

The probability of being infected with a fungus is very high. Indeed, in the area a lot of trees, for which they do not care. Wild plantations contribute to the transmission of disease.

Scab on plum.

The scab affects the plum under the same conditions and manifests the same symptoms as in the case of other stone-seed cultures. Therefore, the treatment is carried out on the same principle as the treatment of apricot: a “blue” spraying is carried out on the sleeping buds, and in the first decade of June the plant is treated with Skor or Horus. After two weeks, the treatment is repeated. The following spraying is carried out after leaf fall with one percent Bordeaux mixture.

Scab on cherry

Cherries, like other stone fruit types of fruit trees, are not so often affected by scab, however, if this happens, the plant is not as badly damaged by a scab as penetrating into cracks in the fruit produced by the development of the disease, pathogens of various rot. That is why measures to combat scab on cherries should be carried out from early spring in the same manner and using the same methods as we described in the section on scab on apricots.

Scab on fruit trees.

The scab often infects not only pome fruits and stone fruits, but also citrus fruits, but in our latitudes neither lemons, nor oranges, nor mandarins grow in gardens, but how to save homemade citrus from scab, we will tell in another article. With regard to crops such as peach, cherry plum, cherry and quince, then you can save them from scab in the same time and by the same methods as apples, pears and apricots. By the way, and preventive measures to improve the health of your garden for all fruit trees are the same.

Scab on gooseberry.

Powdery mildew is often called scab on gooseberries, although these are two different diseases, so before taking action, compare the symptoms of these two diseases and make sure that gooseberry is really a scab. How to treat gooseberries for scab? In order to minimize the risk of gooseberry disease with scab, in the form of prophylaxis in early spring, treat the still dormant buds with a 7% urea solution, trying to moisten the leaves, branches and soil under the bushes well with the preparation. In the autumn, after leaf fall, remove fallen leaves from under the bushes, dig the tree trunk and carry out the same treatment with urea. As a treatment for scab-afflicted gooseberry bushes, the swollen buds are treated with a two or three percent Bordeaux mixture or a mixture of the Aktar preparation with the Chorus preparation. After a month, the treatment with Horus and Aktaroy is repeated.

Currant scurf.

The currant is not affected by the scab to the same extent as the gooseberry, but in order not to risk the harvest, measures to combat the disease must be taken already in early spring. Since currant and gooseberry crops are related, the scab on currants is destroyed in the same way as the gooseberry scab, you just need to make sure that you are dealing with scab, not powdery mildew.

Scab potatoes

Potato scab most often affects the surface of tubers, causing the appearance, seeds and taste of potatoes to deteriorate and their ability to be stored for a long time. With a strong defeat, the potato becomes unsuitable for eating. In areas infected with scab, you can not grow potatoes for at least 4-5 years.

Potatoes affect these types of scab: common, lumpy (oosporosis), black (rizoktonioz), silver and powdery. The common scab is manifested by small and shallow ulcers of irregular shape on the surface of the tubers. With the development of the disease, the spots grow, and sometimes merge, and become covered with cork formations. When digging up potatoes on tubers, you can see spider webbing, which disappears as soon as they dry out.

Powdery scab occurs when the pathogen is infected by tubers, roots and stolons through the eyes and wound areas. On the roots, galls form in the form of white outgrowths of irregular shape, darkening with time, and the surface of the tubers becomes covered with warty pustules, which, when ripe, turn into potatoes with a dusty mass of brown color. During storage, diseased tubers are often affected by late blight and dry rot.

Silver scab can be recognized on tubers during harvesting or already in storage. It looks like unobtrusive matte light brown spots of various shapes and sizes. The development of the disease occurs closer to spring: the affected tissue becomes as if depressed and acquires a metallic luster. In case of severe damage, the skin is wrinkled due to loss of tuber.

Lumpy scab, or oosporosis affects the potatoes in the field, during the growth of tubers, but the symptoms of the disease can only be detected during storage. On the surface of tubers are formed round pustules, not differing in color from the peel. They may be depressed, bulged or flat. Pustules grow and form areas resembling the defeat of late blight, but only without rot under the peel.

Black scab, or rhizoctoniosis - the most dangerous of all types of potato scab, causing a decrease in yield by 20%. It destroys the tubers, twists the apical leaves, molds the root parts of the plant with mold and causes decay and subsequent death of the shoots.

To avoid contamination of potatoes with scab, you should use only high-quality and healthy planting material, which should be treated with Phyto Plus, Rovral or Aquaflo before planting. If you add boron, manganese and copper to the soil, this will greatly reduce the risk of potato scab. Crop rotation is an important preventive measure: alternate the cultivation of potatoes in the area with the cultivation of legumes, and if you do not have the opportunity to change the area for potatoes, then at least do not use fresh manure as a fertilizer.

The soil with a shift to the alkaline side must be acidified with a solution of 2 tablespoons of ammonium sulphate in 10 liters of water - this part is watered the plot with potatoes during flowering, spending on each bush a liter of solution. Two weeks before harvesting potatoes, mow the tops - this will allow the tuber skin to become stronger.

In order to increase yields and suppress the development of scab, during the budding period, process the potatoes with Zircon solution. After two or three weeks, spray the potatoes with a solution of one packet of Phyto Plus drug in 3 liters of water - this will reduce the degree of tuber infestation with scab.

And, of course, it is better to grow varieties resistant to the disease: Aspia, Skoroplodny, Alpha, Lady Rosetta, Mentor, Nicolas, Prevalent, Patrons, Element, Glade, Yavir, Vesta, Dara, Rakurs, Tiras, Riviera, Favorite, Reserve Spring, Herald, Varmas, Ramensky, Vilnya, Vyatka, Zhukovsky Early, Bezhitsky, Bryansk New and many others.

Scab Remedies

For the treatment of plants from scab, fungicides that belong to the third or fourth class of danger are used, since they do not form persistent compounds that penetrate through the skin and accumulate in the fruit. Which one to choose depends on many factors, so everyone decides for himself this question on his own. We remind you that in the fight with scab they use drugs Horus, Scor, Raek, Strobe, Abiga-Peak, Fitoflavin, Bordeaux mixture and copper sulphate.