Many people know what potato scab looks like, but not everyone can get rid of it.

Scab develops on alkaline and neutral soils when the pH is above 5.5. Therefore, it is necessary to first conduct a soil analysis.

How to deal with scab on potatoes

If the acidity of the soil in your area is normal or alkaline, that is, pH 6.5 or higher, then it is necessary to acidify the soil by any possible means. But the main thing is not to overdo it, since potatoes grow poorly in very acidic soils.

You can go more the easy way and treat potato tubers before planting with a 1.5% boric acid solution. It is best to process potatoes in a solution of the following composition: boric acid(0.5 - 0.6 g), potassium permanganate (0.3 - 0.6 g), copper sulfate (0.4 - 0.8 g) - dissolve in one liter of water. The tubers are dipped into this solution, then laid out and covered with burlap, and kept for 2-3 hours. About 1 liter of solution is consumed per 10 kg of planting material.

Under no circumstances add fresh manure when planting potatoes! All organic matter added to the soil must be rotted.

You cannot grow potatoes in one place for many years in a row; you need to observe the so-called crop rotation.

If this is not possible, then after harvesting the potatoes, it is necessary to immediately sow rye or other grain crops, mustard, and soybeans. And in the spring, before planting potatoes, it is enough to plow the green mass with the soil - this will improve its health.

Briefly, we can say this: - Potatoes can be planted in the same place from year to year, if after harvesting the soil is “returned” to fertility through green manure, and before planting it is fertilized with rotted organic matter.

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This year I encountered the same potato disease; at first, (due to my little experience), I thought that the wireworm was working here, and only now it dawned on me that the wireworm was making moves inside the potatoes, and my whole potato was covered brown spots. So it turned out that this year not only did the wireworm spoil the harvest, but the scab also destroyed all the potatoes! Please tell me. What should I do and how to deal with this disease?

For a long time, I also could not find a remedy for treating soil scab after potatoes, since I had to plant potatoes in the same place for several years. And then I adapted to adding pine litter, that is, needles from pine trees, during autumn and spring digging, fortunately we have enough of this goodness in the forest. He collected it directly into bags and brought it to his dacha. scattered it on the soil and then dug it up. I read that many people do not dig, but add pine needles to the holes, which is also an option. This method helps very well against scab on potatoes and there is no need to use any chemicals.

Grow lupines in potato fields. The plowed plant mass of perennial lupine has a phytosanitary effect - potato tubers are less affected by scab.

Potatoes develop scab due to calcium deficiency.

You can also plant potato varieties that are resistant to scab, such as Belorussky, Detskoselsky, Starchy, Loshitsky, Temp. And of course, do not apply fresh manure under the potatoes, but only humus.

Now we have no scab on potatoes at all, although we have been fighting it in various ways for many years. Now we only apply mineral fertilizers to the soil, because organic fertilizers stimulate the development of scab. And in the fall, when we collect the harvest, we plow the field and sow mustard. In the spring we plow up the mustard greens and plant potatoes. It's simple.

If you water potatoes from the moment tubers form en masse until they reach 2-3 cm in diameter, the development of scab will be significantly reduced. During this period, soil moisture in the tuber formation zone should not be lower than 75–80%.

Gardeners often encounter a disease such as potato scab. This disease spoils the taste and appearance crops, which reduces the shelf life of tubers. To cope with it, you need to know how to treat it and preventive measures. Timely measures will help protect the crop from the disease.

Description and causative agent of the disease

Potato scab is a fungal disease that mainly affects tubers. In some cases, it spreads to the roots and stems of the crop. Spore fungi, the causative agents of the disease, constantly live in the soil. But they are activated and enter root crops under favorable conditions.

Affected potatoes are not poisonous to humans and can be eaten. But the value of such tubers decreases. They lose half of their starch, nutrients and vitamins. Due to the disease, the presentation of potatoes deteriorates and the shelf life of affected tubers is reduced, so it should be dealt with at the first sign.

There are several types of this disease, each with individual symptoms and course. A description of scab on potatoes will help you understand the type of disease and select effective treatment.

Reasons for appearance

The main source of the disease is fungal spores. They enter healthy tubers through contaminated soil, while the pathogens live in the soil for a long time and do not manifest themselves. They enter the ground through infected planting material. If you plant potatoes in one place for several years, spores accumulate and attack the tubers. To avoid this, it is important to follow the rules of crop rotation.

Fertilizing the soil is the key to a good harvest, but you should not overdo it with fertilizing. Soil with excessive nitrogen content is a favorable environment for the development of spores. Do not exceed the dosage of medications. Incorrect application of organic fertilizers also contributes to the development of the disease. When growing potatoes, you cannot use fresh manure.

Types of disease and signs of damage

There are five varieties of potato scab, and each manifests itself differently. Forms of scab and main signs of damage:

• Ordinary. Irregular ulcers form on diseased tubers. As they develop, they increase in size and harden. Sometimes cracks appear on root vegetables.
• Powdery. The disease manifests itself on tubers and stems. The green part of the plant is covered with white growths. Red-brown warts appear on root crops.
• Black. The disease is recognized by the appearance of dark brown sores on the peel. As the fungus develops, they merge into powdery, black spots and tuber necrosis occurs. The sprouts and eyes of root crops rot.
• Silver. Pale growths with a small black dot in the middle appear on the tubers. As the lesions develop, they grow and become silvery-powdery in color. The spots occupy 40-50% of the root area.
• Tuberous. Symptoms of infection appear during potato storage. Dark tubercles with a diameter of 1–4 mm are formed on the tubers. The lesions transform into black-brown pustules with depressed edges and a convex center.

The spores of the pathogenic fungus are activated in slightly acidic and alkaline soil at temperatures from +25°C and lack of watering. The disease develops in areas where liming of the soil was carried out. The fungus is transmitted only through soil, and is not dangerous on potato tubers. Storing healthy and damaged root vegetables does not lead to the spread of the disease. But it is not recommended to plant diseased tubers. This is how the disease will spread.

Caused by a mobile fungus that can move underground and directly throughout the plant, but is also transmitted by air. Spores live in the soil for 5–7 years and become active at soil moisture levels of 80–100%. The disease develops in heavy soil after prolonged rains. During storage, affected potatoes shrink and rot.

This disease, known as potato rhizoctonia, is dangerous to the crop. It completely affects the plant: tubers, stems and leaves. This makes the diagnosis easier, but if the disease has spread to the entire crop, it will not be possible to save the potatoes and the crop will have to be destroyed. The disease develops in conditions with high humidity. Potatoes are often attacked if the spring is cold and rainy.

Fungal spores are transmitted through soil and damaged root crops, so healthy and diseased tubers cannot be stored together, otherwise the disease will spread. Pathogens are activated in sandy and loamy soils with high humidity. Fungal spores survive at temperatures from +6 to 32°C. During storage, the affected potatoes do not rot, but gradually dry out. By spring, half the crop is lost due to the disease.

The disease develops at a temperature of 12–16°C. When raised to +25°C, the growth and development of fungi stops. Tubers become infected through the soil. The fungus prefers sandy and soddy-podzolic soils. Less common in peat-bog substrates. The risk of developing the disease increases with late harvest. In storage, the fungus is activated at low temperatures (1°C and below) and increased levels of formaldehyde, carbon dioxide and sulfur dioxide in the air.

How to get rid of scab on potatoes

Control measures include dressing the tubers before planting and storing. To counteract the disease, varieties that are resistant to fungal spores can be grown. There are several medications available to help treat scab. These include:

• Zircon. This remedy is used during bud formation. Effective against all types of disease.
• Fitosporin. A safe new generation drug that kills fungi and mold. The tubers are treated with it before planting and the bushes are sprayed 2-3 times a season for preventive purposes.
• Maksim. The drug copes with all types of scab. To get rid of the disease, planting material and bushes are treated with the solution.

You can fight scab on potatoes with a 1% solution of copper sulfate. It is worth considering that bushes of the crop are treated with the drug. Vitriol should not be allowed to come into contact with the soil, as the solution is toxic and poisons the soil.

Resistant varieties

There are no varieties that are completely immune to the disease. But breeders have developed several varieties that are resistant to pathogens. These include Aspia, Bryansk novelty, Vilna, Rodnik, Ostara, Nikola, Lyubimets. If agricultural technology, cultivation rules and processing of planting material are followed, these varieties rarely develop scab.

Preventive measures

Compliance with crop rotation is the main rule of agricultural technology. You cannot grow potatoes in the same place for two years in a row.

It is advisable to alternate vegetables with planting legumes. If this is not possible, after harvesting it is recommended to plant the area with green manure: rye, wheat, lupine. These crops saturate the soil nutrients and destroy pathogenic fungi.

When green manure reaches 10–15 cm, they are mowed down and the area is dug up along with plant remains.

Prevention methods:

• Affected root crops should not be planted.
• Before planting, seeding material should be processed.
• It is not recommended to fertilize the soil with fresh manure.
• Planting material is stored in a cold, dry, ventilated area.
• During the flowering period, the crop is provided with regular watering.
• The tops are removed 2–3 weeks before harvest.
• The crop should be dried before storage.

Before planting potatoes, acidify the soil if it is alkaline. To do this, dilute 2 tbsp in 10 liters of water. l. ammonium sulfate. Each bush is watered with 400–500 ml of solution.

One of the common diseases is common scab. Scab is a very rare and common fungal disease of potatoes. It is known in all areas where this vegetable is grown. All gardeners and farmers know about it, because everyone directly encounters it almost every year, and the fight against scab is an annual process.

Scab ruins the potato crop

Common potato scab affects the underground organs of the crop. Brown outlines, cracks or bulges appear on the tubers. The appearance of cracks is the most intense form of scab. It deforms the potato to the greatest extent. But the disease does not infect one bush, it moves from one to another, infecting the entire plantation.

Subtleties of growing potatoes

Almost everyone grows potatoes, because dishes made from this vegetable are everyday and familiar to us. Its large-scale production also occupies one of the leading ranking positions in the country. Therefore, all gardeners are concerned with increasing the yield. It is paradoxical that every year, with the advent of new technical means and processing technologies, the annual harvest, on the contrary, decreases. Diseases and insects, getting used to and adapting to new ones strong poisons, poisons, are becoming more resistant and harmful. The fight against them is not always effective.

They are destroying larger and larger plantations, and it is becoming increasingly difficult to stop the invasion; the fight is bringing less and less results. For many, success will already be getting what was planted from the harvest, at least not going to a loss and growing a minimum supply for the winter for yourself and your family. And even if you get at least some harvest, there is a huge percentage that it will be damaged by some kind of insect or disease. Which leads either to complete utilization of potatoes, or to a significant reduction in its species and taste qualities.

If the potato is slightly affected by scab, it is not necessary to destroy it, but its taste and external qualities are hopelessly deteriorated.

Why does the disease appear and how does it develop?

The causative agent of common scab is a microorganism from the category of actinomycetes. This microorganism is found in earthen soil, so it is impossible to completely get rid of it. Factors that contribute to the spread of scab are determined by temperature and soil condition. The temperature that will be most optimal for the development of the disease is approximately 25-30 degrees.

Average humidity also contributes to the development of scab. But still, sandy, loose soil is most prone to scab. Organic fertilizer has a beneficial effect on the spread of the disease. Humus, if not allowed to rot, will be a catalyst that contributes to the growth of scab on your plantations. Even the type of potato plays a role; some are less susceptible to this disease. These are varieties that have been germinating for a long time in a certain area and already have some immunity.

Scab is very easy to spot. When you harvest your potatoes, pay attention to the hole. You will see what looks like white mycelium on the potatoes. It will cover the fruit, but in the sun the coating will quickly disappear.

Immediately after digging, a white coating is noticeable on scabbed potatoes.

Ways to fight

A positive fact is that potato scab is still being eradicated, although it must be fought with effort and diligence. This must be a planned, precise and thoughtful set of measures and actions for treating potatoes.

What do you need to do, what control measures to use in order to get rid of the disease forever:

• Choose a potato variety that is resistant to scab. It should be familiar to your area, suitable for it, and natural conditions should be conducive to cultivation. If you have dry, sandy soil, choose a variety that doesn't need a lot of moisture;

• sandy soils are susceptible to the progression of bets; in nutritious, moist soils it develops with difficulty;

• Since the pathogen lives in the very soil where potatoes sprout, change its location. For about five years, scab microorganisms live in one place, but after two years they are not so dangerous and are easier to fight. Remember that other root vegetables, beets, and carrots are susceptible to the same disease; do not place a potato plantation in the place where these vegetables sprouted;

• It is better to choose fertilizers with an acidic environment; they inhibit the development of common scab. You need to be as careful as possible with organic fertilizers, since it is with them that you can introduce a pathogen into the soil; you should take rotted manure, where the presence of microorganisms is less possible;

• The undeniable method is always poisons and pesticides. If production allows, treat potatoes before planting.

Use all these tips, and you will at least slightly improve the condition of your plantings, even if you are not able to completely eradicate the scab, it is worth constantly fighting it. Healthy potatoes mean good appearance, high taste, and therefore a high price.

Therefore, do not spare work, it is worth working for a good result, control measures must be regular and targeted.

Potatoes are still popular among gardeners and grow in almost every garden. It happens that such a problem appears, we will look at it in the article. .

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What is scab?

This is a fungal disease, the pathogens of which live in the ground for a long time and most often infect tubers through thin cracks. Sometimes the root system and even stems are affected, but this happens rarely.

Affected tubers lose a third of their starch, their taste is much worse, the yield is reduced, and they are poorly stored. There are no completely scab-resistant varieties. Therefore, it is important to carry out preventive measures.

Signs of defeat

There are several types of scab, differing in shape and color. This is ordinary, silver, powdery, black.

Common scab

A very common form. The pathogen prefers soil with an alkaline reaction and high humidity. The introduction of fresh manure provokes an increase in the pathogen.

The fungus can be introduced with tubers; it is present in the soil and in plant residues. Infection of potatoes during storage does not occur, since there is no necessary conditions, and the pathogens are in a dormant state.

It has been noticed that varieties with red thin skin are infected with this form. Planting tubers at greater depths and abundant watering during fruit formation reduces the likelihood of infection.

The disease manifests itself in the form of a hard plaque various shapes on root vegetables. Sometimes the entire tuber is covered with these ulcers and cracks.

The Priekulsky, Berlichingen, and Kameraz varieties are less infected with common scab.

A preventive measure is Polycarbacin, Nitrafen. And mandatory germination of planting material in the light.

silver scab

Silver scab

It appears on potatoes as brown spots or specks of “black soot”; over time, the spots become gray warts. With increased humidity, the fungus begins to actively multiply and infect neighboring root crops, which will negatively affect the harvest. During storage, the affected tubers shrink, and gray warts become gray rot. This disease occurs more often on sandy and loamy soils.

If you notice symptoms of this disease, it is important to treat the potatoes with chemicals Botran, Nitrafen, Titusim before planting.

Powdery scab

This species is quite common, especially in moist soil. Interestingly, the fungus in the form of a lump of mucus itself moves in the soil and finds tubers, infecting them and the root system of the plant. Affected potatoes dry out during storage and rot when exposed to high humidity. Infected tubers have white growths, which then turn brown and burst, and the ulcers contain dust - fungal spores. The seed from such beds often suffers from late blight and dry rot. It is better to soak it in a formaldehyde solution for 7 minutes before planting and then cover it with a thick cloth for 4-6 hours.

The disease spreads through soil, planting material and fresh manure. Spores spread well in damp, heavy soils. They live in the soil for up to five years.

The varieties Yubel, Cardinal, Lorch, and Majestic are less susceptible to this disease.

Black scab

It is also called rhizoctoniasis. Spores are activated by high humidity, especially in late rainy spring. Pathogens attack a young plant. Infection is indicated by the affected stem and curled upper leaves; during the day, such a bush withers and is small in stature. In warm weather, the stem looks like a “white stem”. Most often, the disease manifests itself on loam.

There are no crop varieties resistant to the disease. It is necessary to treat the planting tubers with Integral, Vivatax, Baktofit.

Preventive measures

The first measure is healthy planting tubers, which must be treated with preparations to prevent soil contamination with scab. When planting, use mineral fertilizers containing copper, boron, manganese, which suppress the spread of the disease.

You should observe crop rotation and do not plant potatoes in one place, but alternate crops. If, with a small area of ​​land, it is impossible to change the place for potatoes, then there is no need to fertilize the garden with fresh manure.

If the soil is alkaline, you should use ammonium sulfate (2 g per bucket of water) when planting the crop and water the bushes when flowering. Application rate – 0.5 l.

Two weeks before harvesting, squeeze the tops so that the skin on the root crops becomes stronger.

After harvesting, it is advisable to sow the area with green manure (mustard, rapeseed), legumes (peas, lupine) or grain crops (rye, wheat).

The storage must be dry and with constant temperature 1-5 degrees.

The disease can be reduced by treating potato plantings just before flowering with Zircon, which will also enhance the growth of bushes and contribute to an increase in yield. You can also treat (spray) the plants with FitoPlus.

So we figured out what’s wrong with her. There is no need to leave everything to chance, it is better to apply all preventive measures and then you will have a good harvest of healthy and tasty tubers.

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When affected, brown ulcers form on the stolons, roots, roots and tubers various sizes and shapes (flat, deep, convex, mesh), in all cases cracking.

A cobwebby coating is noticeable on freshly dug roots and tubers, which disappears when they dry out. With severe damage, the ulcers merge, forming a continuous crust in the form of scabs.

The disease is widespread in potato growing areas. Among other crops, it affects beets, carrots, turnips, turnips, rutabaga, radishes, radishes.

The harmfulness of scab lies in reducing the food and seed qualities of roots and tubers. When table potatoes are damaged, the taste of the tubers deteriorates, they acquire an earthy smell, and the starch content decreases. When the eyes are damaged, the seed quality of the tubers deteriorates, growth energy and yield decrease (up to 15-40%).

The pathogen penetrates into the underground organs of host plants (mainly into the periderm) through lentils or wounds. Its development is possible in a wide range - from 3 to 33°C with an optimum of 24°C. Infection of plants occurs at temperatures above 10°C, reaching a maximum at 13-15°C; a further increase in soil temperature inhibits the infection process, and at temperatures above 26°C it practically disappears. Infection is more effective when host plants are grown on dry, aerated sandy soils, since the pathogen is aerobic.

In infected cells, the pathogen multiplies: the mycelium grows, spore carriers are formed from the mycelium threads, and spores (conidia) are formed on them. When the periderm ruptures, the spores enter the soil, where they remain long time. This fact can be considered as an evolutionary adaptation of the pathogen to a reliable, albeit primitive, transmission mechanism over time.

N.A. Naumov considered the main role of soil in the life cycle of the pathogen, and considered tubers as an additional factor in the transmission of the pathogen. Subsequently, this position was confirmed in the works of S. M. Tupenevich, who studied the development of the disease in field conditions with different methods of pathogen transmission. In his experiments, potatoes were grown according to potatoes and in crop rotation; In the first case, pathogen transmission through soil was modeled, but in the second case, relatively healthy soil was modeled.

Analysis of the data obtained quite convincingly reflects the main trends in the development of the disease, although direct accounting of the number of the pathogen in the soil was not carried out. It is also known that when potatoes are replanted, the concentration of the pathogen in the soil quickly increases. Moreover, 1 g of dry soil contains up to 1 million propagules of actinomycetes, of which approximately 27% are scab pathogens. The scab pathogen cannot withstand competition in the soil with saprotrophic species of the same order, and its numbers sharply decrease.

Transmission of the pathogen is also possible through tubers. The idea in the literature that tubers serve as a source of infectious agents is erroneous, since all attempts to experimentally infect young and mature tubers separated from the stolons were unsuccessful. This is explained by the fact that formed tubers cannot be a source of infectious agents. Moreover, as tubers are stored, the population of the fungus on them decreases sharply. These data indicate that soil and formed tubers are factors in the transmission of the pathogen.

Tubers can be a source of infection only during the growing season, and mainly in the initial phases of their formation. The information available in the literature about the infection of potato tubers with a pathogen throughout the entire growing season is associated with a vague idea of ​​the specifics infectious process diseases. According to S. M. Tupenevich, the development of the disease until the end of the growing season is practically at the same level as at the beginning of this year. Moreover, when statistically processing the data, it turned out that the seasonal dynamics of the disease has a negative rate of increase in infection. At the same time, an almost identical slope of the curve of the dynamics of scab infestation was noted on both large and small tubers. It is possible that when tubers are affected by common scab, the clarity of perception of external signs of the disease decreases by the end of the season, and perhaps processes of tuber healing take place as a result of protective reactions of plants -owners We can only state that by the end of the growing season, the development of the disease not only does not increase, but even decreases. This indicates that the initial supply of the pathogen in the soil and on tubers is decisive in the seasonal dynamics of the epiphytotic process.

Tactics P is characterized by the pathogen being confined to reproduction in the surface tissues of underground plant organs, mainly in tubers and root crops rich in organic matter in the initial period of their formation. Thanks to their use as planting material, tubers become a factor in the mass transmission of the pathogen in agroecosystems, although evolutionarily it (the pathogen) is adapted to transmission over time through the soil.

Integrated protection against the disease should include the prevention of pathogen transmission through soil and planting material. At the same time, its weak competitiveness towards soil saprotrophs makes the biological method of protection promising.

The main role in the fight against scab is given to agrotechnical measures - crop rotation with the return of potatoes to their original place after 4-5 years, the introduction of the best predecessors from a phytosanitary point of view: winter rye, grain legume mixtures, sunflower, soybeans, lupine, sainfoin, cabbage, cucumber.

They practice the use of rotted organic fertilizers or composts (with bark, sawdust, garbage) and trichodermin; Fresh organic fertilizers are applied only to the previous crop, as they enhance the development of the disease. A combination of organic matter with high doses of mineral, mainly phosphorus-potassium fertilizers is effective. It is recommended to apply nitrogen in ammonium form; physiologically acidic forms of nitrogen and phosphorus fertilizers are added to the rows during planting: ammonium sulfate and superphosphate (1-1.5 c/ha), especially with a neutral and slightly alkaline reaction of the soil solution.

It is effective to combine the application of organic and mineral fertilizers with liming of the soil in small doses. On Sakhalin, for example, lime in a dose of no more than 2 t/ha is usually applied in combination with manure (10 t/ha) and complete mineral fertilizer with the addition of boron-magnesium (60 kg/ha) and boron-lime (1 t/ha) fertilizers. In all cases, doses of mineral fertilizers are adjusted according to the data of agrochemical soil cartograms.

Before planting, it is recommended to treat seed tubers with nitrafen, floor with carbacine or 40% aqueous solution formaldehyde. Treatment of tubers with a 2% borax solution reduced the number of non-standard tubers among those affected by common scab by 5.4 times. At the same time, the number of tubers with rhizoctonia sclerotia decreased by 2.3 times.

Pre-sowing treatment of tubers, as well as the use of green fertilizer as the most rational ways to improve the health of the soil and planting material, provides a high effect. The complex of these methods practically eliminates the possibility of transmitting the pathogen with tubers of a new crop.

Varieties that are relatively resistant to scab are Northern Rose, Phytophthororesistant, Moskovsky, Borodyansky, Agronomichesky, Lyubimets, Olev, Stolovy 19, Kameraz, Berlichingen, Yubel, Woltman; stable - Adretta, Arina, Paul, Wagner.

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