Potatoes are rotting in the cellar, what to do?

Despite the fact that potatoes are on sale in the markets all year round, you want your own - incredibly tasty, boiled and environmentally friendly potatoes. But often home-grown potatoes cannot be preserved until spring. After the New Year holidays, increased “spoilage” of tubers begins, an unpleasant odor appears in the storage facility and even (as they write in the newspapers) an explosive situation when gas accumulates in a closed room. What causes tuber rotting, and how to avoid it? Let's understand the reasons and develop a scheme for preserving the harvest of our favorite potatoes.

Why do potatoes rot during storage, and how to avoid it?
Why do potatoes rot during storage, and how to avoid it?

Fungal diseases of potato tubers during storage

Potatoes are affected during the growing season and during storage by fungal and bacterial diseases. Of the fungal infections, late blight, fusarium, and alternaria cause the greatest harm.

Late blight

Late blight is one of the most dangerous fungal diseases. The fungus infects the crop during the growing season (it can destroy up to 70% of the crop in a short period) and is transported with the tubers to storage areas.

Hard gray spots appear on the surface of the tubers, clearly visible on the pulp when cutting the potato. With the growth of the mycelium, the tuber begins to rot.

Protection and control measures

If plants are damaged during the growing season, it is necessary to spray the potatoes with a 2% raster of Bordeaux mixture. If a complex infection is suspected (that is, several types of fungal diseases), biofungicides “Fitohit”, “Fitosporin-M”, “Planriz”, etc. are used.

Optimal storage conditions are good ventilation, absence of light, air humidity within 80-90%, air temperature no higher than +2...+3°C. For late blight to develop, high temperatures are required (+20…+24°C). Therefore, storing potatoes in residential areas with high temperatures is not recommended.

The best potato varieties resistant to late blight are: “Lasunok”, “Temp”, “Scarlet”, “Aspiya”, “Vestnik”, “Golubizna”, “Lugovskoy”, “Resource”, etc.

Fusarium (dry rot)

Like late blight, it affects tops and tubers during the growing season. The rapid spread of the disease is facilitated by excessive soil moisture (long rains) at high temperatures.

During the growing season, external signs appear in the form of gray spots on the leaf surface, general wilting and drying of plants. The affected plant wilts literally in one day. A striking distinctive feature of a crop affected by fusarium is a blue-black ring on the cut of the stem (vessels clogged with fungal hyphae).

Tubers stored for storage become covered with a whitish coating, or the skin in places where gray-brown spots form wrinkles and becomes dry (without obvious reasons for violating the rules for storing products). The section shows dark voids filled with mycelium.

Protection and control measures

The level of harmfulness is very high. The mycotoxins of this disease persist not only on the crop, but also on processed products. They affect the human nervous system and cause the death of birds and animals. Tubers (like other products - flour, juices, jam, animal feed) affected by fusarium cannot be used for food.

During the growing season, plants are sprayed with a 1-2% solution of Bordeaux mixture, solutions of biofungicides (Fitosporin-M, Fitohit, Baktofit, Integral, Planriz).

Optimal storage conditions are the same as for protection against late blight. It is recommended to treat the tubers with “Fitosporin” when storing them (the biofungicide does not affect the health of humans and animals). Systematically sort the potatoes (carefully so as not to break the outer skin, as the infection quickly spreads to neighboring tubers).

The best varieties resistant to this disease are: “Detskoselsky”, “Priekulsky Ranniy”, “Berlichingen”, “Nevsky”, “Skarb”, etc.

Late blight of potato tubers. © IPM Images Fusarium (dry rot). © Government of Western Australia Alternaria (potato dry spot). ©omafra

Alternaria blight (potato dry spot)

In terms of the level of damage to potato yields, this disease is similar to late blight. It affects all parts of the plant (stems, leaves, tubers). Most often, dry spotting affects mid and late potato varieties, that is, those recommended for winter storage.

During the growing season, the lesion appears on leaves and stems in the form of large concentric spots. The spots gradually become brown or dark brown with a brown tint. Depressed spots appear on the surface of the tubers, which gradually wrinkle. On a section of the tuber, the affected areas are necrotic and differ from healthy tissue by hard, dense black-brown pulp.

Protection and control measures

When preparing for planting, treat the tubers with biological preparations “Planriz”, “Baktofit”, “Integral”, “Fitosporin-M” and others from the recommended list. During the growing season, carry out the same treatments as for previous diseases.

The optimal conditions for storing potatoes are the same as for protection against the previously listed diseases.

The best potato varieties resistant to this disease are: “Gatchinsky”, “Ogonyok”, “Zarevo”, “Lyubava”, “Bronnitsky”, “Sibiryak”, “Severyanin”, “Russian Souvenir”, “Effect”, etc.

The above-described diseases (late blight, fusarium, alternaria), as well as rhizoctonia, common scab, phomosis, and anthracnose spread mainly through seed material. Therefore, planting and growing disease-resistant varieties that are zoned to external conditions is a key basis for the preservation of tubers during winter storage until the new harvest.

Who's to blame: black scab

Rhizoctoniosis, which is popularly called black scab, is another popular fungal disease that deprives summer residents of their potato crop after digging it out of the ground. A distinctive feature of black scab is the sclerotia, which are colored black. They are located on the surface of the tubers and, if desired, can be picked off with a fingernail or scraped off with a knife.

So, regarding rhizoctoniasis, we have two news. One of them is positive, and the other is negative. Let's start with the positive: this disease does not jump from one tuber to another. If one tuber is infected with it and the rest are not, then the disease will not spread during storage of the vegetable. The bad news is that rhizoctonia can have a major impact on the crop you harvest next year. Unless, of course, you use the affected tubers as planting material.

Black scab does not in any way affect the taste of potatoes. The disease only spoils his appearance. And late harvesting contributes to the development of the disease.

What to do if you have scab

Measures for preventing black scab are in many ways similar to methods for preventing other fungal diseases.

  1. Carry out a cull. Although the disease is not transmitted from one tuber to another, do not store potatoes affected by black scab along with a healthy crop. Discard it and eat it as soon as possible.
  2. Treat the crop with Ditan M-45. To protect the crop from further development of fungal problems, be sure to spray it with a product diluted in a five-liter bucket. For the specified amount of water you will need 200 grams of the drug. The prepared solution is enough to spray a hundredweight of vegetables. After thorough drying, the tubers can be safely sent for long-term storage.
  3. Observe temperature conditions. Just in case, we remind you once again that the air temperature in the vegetable storage should fluctuate around 2-3°C. In this case, the hygrometer should constantly demonstrate a result approaching 90%.

And of course, harvest on time, do not delay this process. The dampness that comes with autumn and constant rains increase the risk of black scab infection tenfold.

black potato scab

Bacterial diseases of potatoes during storage - rot

In addition to fungal diseases, potatoes are susceptible to bacterial diseases. The source of the damage is putrefactive bacteria, which in 2-3 months can turn the tubers into a gray decaying mass with a sharp, unpleasant odor.

Bacterial infections develop when product storage conditions are violated (poor ventilation, high temperature and air humidity). Pathogenic bacteria penetrate into the tuber through external damage (cracks, cuts when digging potatoes, etc.).

The bacterial infection is transmitted mainly through seed material, but during the growing season it affects not only tubers, but also vegetative organs (stems, leaves, roots, stolons).

During epiphytotic years, up to 50% of the crop in the field and up to 100% during storage die from bacteriosis. Most healthy tubers become infected with phytopathogenic bacteria during preparation for planting, inaccurate harvesting (causing various types of mechanical damage) and sorting before storage.

Of the bacterial diseases, potatoes are most often affected by wet bacterial rot, button rot, ring rot, and blackleg.


Yield losses can range from 1-2% to 50-70%. Bacteriosis affects the vegetative parts of the plant and tubers. It is difficult to get rid of bacterial contamination, due to the fact that there are still no varieties resistant to this disease.

When planting infected material, many potato seedlings fall out or the seedlings are weak and develop poorly. With age, the lower part of the stem turns black (hence the name of the disease “black leg”), the leaves turn yellow, become brittle and hard. The leaf blades are curled in a boat, the leaf itself grows at an acute angle to the stem. When excavated, the mother tuber becomes rotten and slimy.

Ring rot

The bacterial infection affects all parts of the potato plant. The external manifestation of the disease during the growing season, like the black leg, is withering of the aerial part and rotting of the mother tuber.

A distinctive feature is a leaf mosaic in pale yellow tones and swelling of leaf nodes. 1-2 weak stems develop from the mother tuber. On diseased tubers during harvesting, pitting rot is visible; when cut, the diseased tuber tissue has an annular lesion of the vascular tissue or yellow subcutaneous spotting.

Brown rot

Mucous bacteriosis is one of the most severe bacterial diseases. It is distinguished by the rapid course of the disease. It affects about 200 plant species, including potatoes.

Distributed mainly in regions with warm climates. The source of infection is diseased tubers and soil, weeds, and irrigation water. The causative agent of the disease penetrates the tubers of the new crop through mechanical damage, stomata, and fills the vessels of the stems, stolons, and roots with a mucous mass, which causes wilting and death of the plant.

Symptoms of the disease appear externally during the flowering phase in the form of wilting leaves at the ends of the shoots. Green leaf blades acquire a brownish tint, curl into a half-tube and hang. The root part of the stems softens. The bacterial mucus accumulated inside (in the vascular ring) is released through breaks in half-rotten stolons, stems, and rotten tubers.

Potatoes affected by blackleg. © IPM Images Potato ring rot. © syngenta Brown rot of potatoes. © AgroFlora

Measures to protect and combat bacteriosis (rot)

All bacterial rots (as shown in the diseases described above) are characterized by a general wilting of underdeveloped potato bushes during the growing season and the rapid decomposition of tubers to a slimy mass during storage. A significant part of rots are soil pathogens and can persist in the soil for a long time, affecting planted healthy material.

Therefore, the main measures to protect crops from bacteriosis are the use of zoned, disease-resistant potato varieties, mandatory autumn-spring disinfection of the soil before planting, treatment of planting material to suppress soil infection during tuber germination, preparation of storage facilities, sorting of tubers before storage.

The best varieties are those resistant to this complex of diseases: “Skarb”, “Nevsky”, “Rosinka”, “Lazurit ranniy”, “Bronnitsky”. Mid-season varieties “Rodnik”, “Resource”, “Vestnik”, “Golubizna”, etc. are also resistant to bacterial rot.

Fusarium dry rot

First, dull depressed spots of gray-brown color appear on the tubers. After some time, the skin at the site of the spots wrinkles, the flesh becomes dry, and voids with mycelium often form in the affected parts of the tuber.

The infection penetrates along with lumps of wet soil - which is why it is recommended to harvest the crop in dry weather.

How to deal with Fusarium dry rot?
  • Do not store potatoes with mechanical damage, such as cracks or cuts, or tubers with signs of late blight or scab infection - such root crops are very vulnerable to dry rot.
  • Before planting, treat the tubers with the microbiological preparation Fitosporin (by spraying or dipping), follow the dosage indicated on the package. After this, dry them thoroughly in a dry room with good ventilation and send them to the cellar with a temperature of 2-3 ° C and a humidity of 80-91%.
  • There is no need to sort through the potatoes during the entire storage period - you can accidentally damage the tubers. But if you notice affected potatoes, be sure to remove them from the cellar.

The source of the disease is putrefactive bacteria that can turn beautiful tubers into gray porridge in a few months.

Symptoms of wet rot

First, the affected areas of the tubers darken, become covered with brown mucus, and become very soft. Such potatoes have a sad end - they rot, emitting an unpleasant odor.

The disease actively develops when storage conditions are violated (high temperature, humidity and poor ventilation) and when damaged potatoes are stored for storage. It is through cracks and microtraumas that bacteria penetrate the tuber, slowly destroying it.

How to deal with wet bacterial rot?
  • Before storing, be sure to sort out the potatoes: discard damaged tubers.
  • Follow the potato storage regime: the temperature in the cellar should be about 2-3°C (if the tubers freeze, they will be vulnerable to disease) and the humidity is about 80-91% (to reduce the humidity in the cellar, you can scatter ash on the floor, which absorbs moisture well) .
  • If you notice signs of bacterial rot and even identify the “sick” one, you need to continue to periodically review your potato bins, promptly removing diseased tubers that are dangerous to healthy ones. Otherwise, the entire harvest will be at risk - and instead of fluffy puree, you will get a gray, rotting mush. Not the most pleasant prospect, right?

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How to protect potatoes from rotting?

Based on all of the above, it is clear that the poor preservation of tubers during the cold period begins with a violation of the technology for growing and harvesting this crop. The following significant reasons are the unpreparedness of the storage facility (cellar, basement, vegetable pit, balcony, loggia, etc.) for storing products, incorrect selection of potato varieties, and violations of storage technology.

It is these reasons that cause damage to tubers by various fungal, mold and bacterial diseases; contribute to their rapid spread and loss of yield not only during cultivation, but also during storage.

To protect potatoes from rotting during storage, it is necessary to properly prepare the area for this crop. Apply fertilizers, fertilize, treat diseases and pests only in accordance with technology and recommendations.

Read our detailed materials Features of growing potatoes: preparation and planting and Features of growing potatoes: agricultural technology.

For planting (for the purpose of long-term storage of tubers during the cold period), it is necessary to use only zoned, medium and late varieties (in terms of ripening), resistant to fungal and other diseases. Before planting, the seed material must be processed.

Read our material Proper processing of potatoes before planting.

During the growing season, plant treatment must be carried out at the very beginning of the disease, and not wait for mass damage. It is more practical to carry out preventive treatments according to a previously worked out scheme.

Only absolutely healthy, undamaged tubers should be stored in prepared storage facilities.

Fungal diseases

Late blight - this disease is recognized without much difficulty: hard, brownish-brown spots of irregular shape form on the surface of the fruit. The cut of the tuber is rusty brown. These spots penetrate into the fruit, and then fungi and bacteria settle on the surface of the potato, and the potato rots. This disease is widespread everywhere.

Fomoz - Small depressed ulcers form on the tubers, which then crack and become covered with a gray coating. On a section of the fruit, the edges of the ulcers are clearly separated from the healthy part by a black border. It is found everywhere, but most of all in Siberia, the Central Black Earth and North-Western regions.

Fusarium (dry) rot - the potato skin wrinkles and becomes covered with grayish-white pads. Gradually they darken and the tuber dries out. With such a disease, the potatoes never get wet.

Rubber rot - on freshly dug up potatoes there are brown spots with a dark border, and underneath there is soft and elastic tissue. The spots gradually merge and become covered with a white coating. Then the tuber completely decomposes.

Bacterial diseases

Black leg - the skin of the tuber turns brown, then the tissues soften, rotting hollows appear, and become covered with foul-smelling rot. Most often found in the Central, Ural, North-Western and North Caucasus regions.

Ring rot – Light brown spots form at the base of the tuber. On the cut, there is first a yellow and then a dark ring, with rot inside. The tuber gradually completely decomposes.

Plants infected with bacterial diseases are very visible in the field; their stems dry out.

Causes of rotting

Why do potatoes rot immediately after harvesting, and why do they start to rot only towards the end of storage? The answer is simple - rot is caused by different types of infection.

Most often, the development of rot is caused by bacterial infections:

  • ring rot appears on potatoes when the first flowers appear.

The disease affects tubers, stems, leaves and stolons. When the tuber is cut, rot is visible, which is located around the circumference. The disease is widespread and destroys up to half the crop. Affected tubers can transmit the disease for several generations without symptoms.

A characteristic feature is a specific yellowish mucus that is released on the cut of wilted leaves; the plants grow dwarf. The disease spreads during harvesting through damage to the tuber skin.

  • Bacterial brown rot is a quarantine disease.

Potato brown rot destroys up to 70% of the crop in the countries where it is widespread. Since 2011, the pathogen has been detected on ware potatoes coming from warm countries. The disease is still not widespread in Russian planting areas. Infection occurs through the root system.

The first sign is the sudden wilting of leaves, branches and the entire plant. The tuber's vascular ring turns brown and softens. During storage, the pulp turns into dark mucus.

  • wet rot turns the tubers into a gray mushy mucus during storage. The disease develops with excessive watering and dense soil.

Wet rot of potatoes spreads quickly when stored in a warm and humid room with insufficient ventilation.

  • pitting rot is most often discovered at the end of March. When peeling potatoes, small oily yellow spots are visible. Over time, the affected area expands and the peel bursts in these places;
  • Fusarium develops especially actively in hot weather.

On potatoes, fusarium, or dry rot, appears at any time, but especially often during the flowering period, causing the plant to wither. Infection is transmitted through the roots and from one tuber to another during storage.

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Dry rot of potatoes affects tubers in the field, but the disease only appears during storage. First, grayish-brown folds appear on them, then the potato pulp becomes loose. And finally, the pulp dries out, cavities with fluffy mycelium appear inside. Fusarium disease of potatoes in storage is transmitted only to tubers with damaged skins.

Why do freshly harvested potatoes rot?

Late blight can be identified by the appearance of brown, blurry spots on the upper leaves, which appear during the period when the tops close. The plant either dries out or rots depending on the weather. Tubers become infected during the growth period; the spots on them are gray-brown, slightly depressed, dense.

Without protective measures, late blight can destroy an entire potato field in 3 weeks. The crop rots during storage.

In addition to the most common types of rot described above, pink, rubber, coal, white, stolon, wound, watery rot and fomoz can also be found.

Potatoes rot in the ground as a result of the following diseases:

  • Late blight. A very serious and dangerous disease of potato crops. If the infection is not detected in a timely manner, the fungus will infect the entire area in a short time. In infected plants, both tubers and tops rot. The most effective way to combat the fungal pathogen is to spray potato plantings with Bordeaux mixture 2%;
  • Alternaria blight. Potatoes rot in the ground as a result of a disease that affects potatoes and greens. Root crops are covered with dark spots that do not have a specific shape. Then the pulp rots. Favorable conditions for the development of the disease are waterlogging of the soil as a result of excessive watering or heavy rainfall, as well as a lack of nitrogen fertilizers. For prevention and control, Bordeaux mixture and special preparations “Integral” and “Baktofit” are used;
  • Rhizoctoniosis. The disease has a second name - black scab. It can be diagnosed by the presence of black bumps on the surface of potatoes. Then the peel cracks. The pulp turns into dust;
  • Fusarium or dry rot. The infection affects root crops during crop storage. The potatoes rot and turn into a mushy state. It dries out during long-term storage;
  • Fomoz or button rot. It develops with a sufficiently long storage period. In some areas of the root crop, fomoz turns into dry rot;
  • Blackleg. Quite a dangerous disease. Root vegetables acquire a general mass of wet mucus;
  • Ring rot. The name comes from the appearance of the disease (visible only after a transverse incision). The root crop is surrounded by a strip of rotten yellow tissue. It is very difficult to determine the infection, since the appearance of the tubers is very similar to healthy potatoes. Rotten pulp can be seen on the cut;
  • Wet rot. The fungus penetrates the tuber through small cuts and cracks that appear on the skin as a result of scab damage.

Why do potatoes rot immediately after harvesting, and why do they start to rot only towards the end of storage? The answer is simple - rot is caused by different types of infection.

The disease affects tubers, stems, leaves and stolons. When the tuber is cut, rot is visible, which is located around the circumference. The disease is widespread and destroys up to half the crop. Affected tubers can transmit the disease for several generations without symptoms.

Why do freshly harvested potatoes rot?

A characteristic feature is a specific yellowish mucus that is released on the cut of wilted leaves; the plants grow dwarf. The disease spreads during harvesting through damage to the tuber skin.

Potato brown rot destroys up to 70% of the crop in the countries where it is widespread. Since 2011, the pathogen has been detected on ware potatoes coming from warm countries. The disease is still not widespread in Russian planting areas. Infection occurs through the root system.

The first sign is the sudden wilting of leaves, branches and the entire plant. The tuber's vascular ring turns brown and softens. During storage, the pulp turns into dark mucus.

Wet rot of potatoes spreads quickly when stored in a warm and humid room with insufficient ventilation.

Dry rot of potatoes affects tubers in the field, but the disease only appears during storage. First, grayish-brown folds appear on them, then the potato pulp becomes loose. And finally, the pulp dries out, cavities with fluffy mycelium appear inside. Fusarium disease of potatoes in storage is transmitted only to tubers with damaged skins.

Late blight can be identified by the appearance of brown, blurry spots on the upper leaves, which appear during the period when the tops close. The plant either dries out or rots depending on the weather. Tubers become infected during the growth period; the spots on them are gray-brown, slightly depressed, dense.

In addition to the most common types of rot described above, pink, rubber, coal, white, stolon, wound, watery rot and fomoz can also be found.

Diseases due to poor care and improper storage

Wet rot - formed due to mechanical damage during harvesting. The peel is damaged, causing the flesh to soften and rot.

Smothering of tubers - appears due to a lack of air in the soil, either due to a large amount of precipitation, or due to poor ventilation in the cellar. The eyes of the tubers become like white pads. Then the pulp becomes soft, and the peel lags behind the fruit. The tubers rot quickly.

Hypothermia and freezing - appears if the cellar is too cold (0 degrees and below). The pulp of the tuber turns white, becomes sweetish in taste, then the peel lags behind the fruit, and the latter rots.

So how can you avoid all these diseases? First of all, you should grow keeping varieties, harvest them on time, and observe storage standards. But there are other rules:

  • About two weeks before harvest, completely mow the tops and remove them from the field.
  • If the soil is waterlogged, carry out deep loosening.
  • After you dig up the potatoes, dry them in the sun for 5-6 hours, and only then collect them.
  • If the weather is rainy, then it is advisable to wash the tubers from dirt, remove damaged and rotten ones, and rinse them in a weak solution of potassium permanganate. Then dry for several days under a canopy.
  • Before storing in the cellar, sort through all the potatoes again. Remove diseased and infected tubers.
  • Carefully lower the potatoes into the cellar so that they do not get beaten or damaged, which will later lead to rotting.
  • Before storing potatoes, dust the tubers with wood ash or chalk.
  • If you follow these simple rules, you can avoid most infections and keep your crop safe and sound.

Source: www.sad2.info

Why do potatoes rot in the basement?

Mold is a fungus that forms well-branched mycelia (vegetative bodies) without visible large fruiting bodies. Loose white, yellowish, black or other colors of plaque are fungal colonies. Reproduction occurs using spores. They can be constantly present in the cellar or basement, but active mold growth begins only when favorable conditions are created for their development.

The appearance of fungus on potatoes can be caused by the following reasons:

  • supply and exhaust ventilation is either completely absent or does not work well;
  • increased air humidity;
  • condensation on the walls of the storage facility;
  • poor air circulation in the room;
  • wooden structural elements are infected with fungus and were not treated with antifungal drugs;
  • there are rotting plant debris in the room;
  • poor waterproofing and, as a result, groundwater seepage;
  • early ripening varieties that are not suitable for long-term storage are stored;
  • Unripe potatoes cannot be stored for long.

First of all, you should fight the cause that caused the appearance of mold colonies. Without correcting this deficiency, all methods of combating mold will be temporary, since the fungus will reappear in the cellar.

Who's to blame: late blight

Late blight is one of the most common fungal diseases, which every summer resident is familiar with firsthand. If you don’t go into details and briefly answer the question of why this disease is dangerous, you’ll get something like this: late blight can destroy 70% of the crop. Impressive, isn't it?

You probably know what this sore looks like. Dark spots appear on the surface of potato tubers. If you cut a vegetable, you can see that these are not just surface defects: the blackness goes deep into the tuber and gradually grows. It is noteworthy that late blight infection can occur both during the growing season and during the harvest period. In the latter case, late blight from infected stems actually “jumps” to the tubers upon contact. Subsequently, during the period of storing the crop in the cellar, late blight can become more active. To do this, he only needs heat: if the air temperature in the storage facility is higher than necessary, trouble will not be avoided.

Please note: despite the fact that a fungal disease can “jump” from tops to tubers, the disease does not transfer from one potato to another during storage.

What to do if late blight

The first and most important thing to do in order to protect the potato crop from late blight is to thoroughly dry the tubers before storing them in the basement. Ideally, the potatoes should lie in the fresh air for some time, and then a few more weeks in a dark place with excellent ventilation.

  1. Sort through the harvest. After the potatoes are completely dry, be sure to sort out the tubers. This must be done as carefully as possible. Firstly, the potatoes will need to be cleaned of any lumps of dry earth adhering to them. And secondly, healthy fruits must be separated from those with suspicious spots on the surface.
  2. Observe temperature conditions. First, make sure that there is good ventilation and that sunlight does not penetrate into the potato storage room in any way. In order for root crops to be stored efficiently and not spoil, the air temperature in the cellar should not be higher than 3°C, and the air humidity should be at least 90%.
  3. Avoid storing potatoes in bags. This storage method is the most undesirable of all possible. It is considered ideal to store potatoes in wooden boxes. True, in this case it is extremely important that the layer of potatoes poured into the boxes does not exceed 100 cm.

Storing potatoes at home is strictly prohibited. As soon as the room temperature reaches 20°C, late blight begins to spread. After some time, you will find that your entire crop has rotted under the influence of a fungus.

potato late blight

Common diseases that cause rotting

The reasons why potatoes rot in storage may be the following fungal diseases:

  1. Late blight. The fungus appears during the growing season and infects the above-ground part (tops), then moves along the stem to the tubers. The disease can destroy up to 70% of the potato crop. It appears as blurry brown or gray spots extending into the root crop. This is clearly visible on the cut of the potato. Late blight develops most actively on potatoes at temperatures above +20°C.
  2. Fusarium (dry rot). Infection with fungal spores occurs when potato tubers come into contact with infected wet lumps of earth from the top layer of soil. It first appears in the form of small depressed spots of a gray-brown hue. Then, voids with colonies of fungi form in these places.
  3. Wet rot. Putrefactive bacteria cause darkening of some areas of the surface of the root crop. Then the tubers, covered with a coating of brown mucus, become soft and turn into a soft jelly-like mush.
  4. Fomoz. First, small depressed ulcers appear on the potatoes, then the skin in these places cracks and becomes moldy. On the cut of the tuber, the edges of the infected area are well separated from the healthy tissue.
  5. Spotting (rustiness). Brownish and gray spots of various sizes appear inside the tuber. This is not visible from the outside. The disease develops due to unfavorable weather conditions and improper harvesting, during which the potatoes were exposed to shock.
  6. Scab. It has several varieties: deep, convex, flat and mesh. It does not affect the taste of the vegetable; it is externally expressed by various dark brown spots on the surface of the potatoes. Diseased specimens cannot be used as seed material, because the disease affects the eyes and such tubers do not germinate well.

Who's to blame: common scab

Common scab is a collective name for similar painful conditions that are a common cause of potato rotting. Each of these conditions has distinctive features by which it can be recognized.

  • Flat scab is the presence of brown-colored abrasions on the surface of the tuber.
  • Net scab is cracks that partially or completely cover the potato skin, giving the appearance that the tuber is surrounded by a cloth mesh.
  • Convex scab is manifested by the presence of “warts” on the surface of root crops. Convex growths completely or partially cover the vegetable and look extremely disgusting.
  • Deep scab is depressed sores on the surface of tubers. As a rule, these dried wounds are surrounded by skin that has cracked.

Sores, which are a symptom of scab infection, destroy potato eyes. It will not be possible to plant these tubers next year: they are no longer suitable as planting material.

What to do if you have common scab

In order not to spread the scab throughout the harvest harvested and stored in the basement, under no circumstances leave affected potatoes in the general array of vegetables. Be sure to sort them. It is also advisable that, after harvesting and drying, the vegetables lie for a while in a dark room with good ventilation. The optimal short-term storage period is two weeks.

potato scab

Prevention of rotting when planting, growing and harvesting potatoes

To protect against mold, which covers potatoes during storage, it is necessary to carry out prevention. It is easier to prevent any disease than to deal with its consequences for a long time. Preventive measures include the following:

  1. It is necessary to select disease-resistant potato varieties. It is better to use local zoned varieties that are adapted to given climatic conditions.
  2. Prepare planting material in advance; to solve this problem, carefully sort the potatoes. Only healthy tubers are suitable for planting. White mold is especially carefully rejected.
  3. Pre-sowing treatment of vegetables is carried out with special means (copper sulfate, Fitosporin-M, Prestige, Quadris, etc.).
  4. It is necessary to regularly treat planted plants from pests that are carriers of infectious diseases.
  5. Maintaining crop rotation. Potatoes should be planted in one place no earlier than after 3-4 years.
  6. Cleaning work must be carried out in a timely manner. Unripe potatoes have poor resistance to disease due to their skin being too thin. Harvesting potatoes too late can provoke the development of fungal diseases on the tubers and their damage by insect pests.
  7. The potato crop must be dug up in dry and clear weather, then cleaned of dirt and dried well.
  8. Approximately 10-14 days before harvesting, it is recommended to cut and destroy the tops.
  9. Before storing in the cellar, potatoes are treated with special biological preparations (Gamair, Alirin-B).
  10. After harvesting, it is necessary to dig deep into the soil on the site, since fungal spores are stored in the top layer of soil.

Following these simple recommendations will help preserve the potato harvest.

Fighting methods

The main methods of combating wet rot of potatoes include:

  1. Only healthy and mechanically undamaged tubers should be stored. All potatoes should be dry and free of adhering soil.
  2. The storage must be well dried, with good ventilation and must be disinfected with a 3% lime solution or a 5% copper sulfate solution.
  3. Potatoes should be stored at a temperature of 1-2 degrees Celsius.
  4. Potatoes must be harvested and transported as carefully as possible to avoid a large number of damaged tubers that cannot be stored. It is better to store potatoes in boxes or in vegetable bags, rather than in bulk.
  5. In places where outbreaks of the disease have occurred, there is no need to sort through the potatoes, you just need to take all the potatoes from the infected area. After this, in another place, the potatoes need to be sorted and used in the near future. All potatoes that have been in contact with an infected person at a distance of 20-30 centimeters must be taken away. This is the only way to reduce losses and prevent further infection.
  6. Seed potatoes must be treated with antifungal and antibacterial drugs before storing.

Wet rot of potatoes is caused by bacteria, which most often only affect damaged or diseased tubers. Already in storage, the disease can spread to healthy tubers. The disease spreads especially quickly when potatoes are stored improperly.

Potato rotting is the result of exposure to pathogenic fungi or bacteria on the tubers. Mistakes made when planting, growing, harvesting and storing potatoes contribute to the rapid spread of diseases and loss of yield.

The main diseases that cause potato rotting are:

  • late blight One of the most dangerous potato diseases. If you do not immediately destroy the first affected bushes, then within a few days the epidemic will cover the entire area. Tubers and tops of plants affected by late blight rot. The most effective way to combat the causative agent of the disease is to spray potato plantings with a 2% solution of Bordeaux mixture;
  • Alternaria blight (early dry spot - a disease that affects tops and tubers). The peel becomes covered with dark, shapeless spots, and the flesh gradually rots. Excessive soil moisture and lack of nitrogen fertilizers contribute to the occurrence of the disease. It is recommended to treat potato bushes with Bordeaux mixture, Integral or Bactofit preparations;
  • rhizoctoniasis (black scab). Indelible black tubercles appear on the surface of the tubers, then the peel cracks, the pulp underneath turns into dust;
  • fusarium (dry rot) is a disease that develops during storage of tubers. The potatoes rot, the pulp turns to mush and dries out;
  • phomosis (button rot) - during long-term storage, certain areas on the surface of the tuber turn into dry rot;
  • black leg - tubers turn into lumps of wet mucus;
  • ring rot - the tuber is surrounded by a wide yellow ring of rotten tissue. The disease is dangerous because an externally diseased tuber is almost impossible to distinguish from a healthy one. Rotten areas of pulp are visible only on the cut of the potato;
  • wet rot - penetrates into tubers through cuts, scratches or cracks in the skin that occur when potatoes are affected by various types of scab.

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Sick tubers either do not produce offspring at all, or weak, stunted plants sprout from them. Therefore, only healthy root crops are selected as planting material.

Planted potatoes often rot in moist clay soil. Therefore, it is better to plant whole potatoes in such soil, rather than cut tubers or eyes. If, however, planting is done in slices or eyes, the potatoes must be cut a few days before planting so that the open “wounds” are covered with a protective crust.

If the potatoes are not cut in advance and you have to do this immediately before planting, then each slice must be dipped in sifted ash: the substance has an antibacterial and disinfecting effect.

Ash is the best natural disinfectant

To protect the seed material from rot, the tubers are sprayed with a solution of copper sulfate, Bordeaux mixture or Maxim fungicide. To prevent potatoes from rotting due to damage to the skin by insect pests living in the soil, it is recommended to treat the planting material with the complex-action preparation “Prestige” before planting.

No matter how healthy the planted potatoes are, if there are pathogenic fungi and bacteria in the soil, some of the tubers may rot. To prevent crop loss, it is necessary to follow the rules of crop rotation: plant potatoes in one place no more than once every 3-4 years.

In the vacated area, it is advisable to sow legumes, which saturate the soil with nitrogen. Exudations from the roots of winter rye, oats and white mustard have a depressing effect on pathogenic fungi and bacteria that cause potato rotting.

If, in the middle of a green potato field, the tops of several bushes begin to wither and the leaves turn yellow, this is a sure sign that the plants are affected by some kind of disease. You should immediately dig up diseased bushes and inspect the tubers.

If the cause of decay is an infection, the bushes are sprayed with a drug intended to combat pathogens. But tubers can also rot due to lack of oxygen. To provide the potatoes with air access, the tubers are planted shallowly and, as necessary, the seedlings are covered with well-loosened soil.

Potatoes are rotting in the cellar, what to do?

Bordeaux mixture is a universal spraying agent, it is only important to apply it correctly according to the instructions

Another reason for potato rotting is unbalanced fertilizing with mineral fertilizers. Excess nitrogen in the soil can cause voids to form inside the potatoes, the pulp around which begins to rot.

Potatoes often rot in the ground after flowering, when late blight pathogens get onto the tubers from the fading tops. To prevent this and allow the potatoes to ripen properly, the tops are mowed 1–2 weeks before harvest.

When digging up potatoes, severely damaged or diseased tubers are immediately set aside separately: they cannot be stored for storage, otherwise the entire crop may rot. The remaining potatoes are kept in a dark, well-ventilated place for 1–3 weeks so that all scratches heal.

Tubers with mechanical damage cannot be stored

Pathogenic fungi continue to live in storage even after all the potatoes are removed from there. Therefore, before storing new harvest potatoes, the cellar is whitened with lime with the addition of copper sulfate, and all shelves and drawers are disinfected with a solution of potassium permanganate. To get rid of mold, it is also recommended to use special smoke bombs.

Practice shows that the worst preservation is:

  • potatoes dug up during prolonged rains;
  • early varieties of potatoes.

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To protect against rotting, tubers are treated with a fungicide before storing them in storage. Previously, the drug "Maxim" was used, but due to its toxicity this drug must be used carefully. Modern bacterial preparations “Fitosporin” and “Anti-Rot”, which are safe for human health, very effectively prevent potato rotting.

Rules for storing potatoes

In most cases, potatoes begin to get wet and spoil in basements and cellars if the maintenance conditions are violated.

The rules for winter storage of potatoes in the cellar are as follows:

  1. The room must be prepared in advance. Storing is carried out only in a dry basement. To do this, it is left open for about 2 weeks. Particular attention should be paid to organizing good supply and exhaust ventilation and waterproofing. If the groundwater level is high, additional protection against moisture must be installed.
  2. It is necessary to clean the cellar or basement of old plant debris and carry out disinfection, which consists of disinfecting and antifungal treatment of the walls (apply a solution of Bordeaux mixture, lime and copper sulfate). Fumigation with sulfur bombs is effective. All boards and wooden parts need to be washed, dried and also treated.
  3. Before planting, potatoes should be sorted, discarding diseased and suspicious specimens.
  4. The temperature in the storage must be constantly maintained within +2…+7°C. Humidity should not exceed 70-80%. Conditions of detention must be regularly monitored and timely adjustments made.

What to do if the potatoes in the cellar are rotting

The crop can be saved only if the infestation area is small. The first and mandatory action is to sort through and throw out all the rot from the basement. After this, disinfection must be carried out.

Tubers that remain “alive” must be treated with contact fungicide Ditan M-45. Dosage - 200 g of product per 5 liters of water (the resulting mixture is enough for 100 kg of crop).

Next, the processed crop needs to be dried and storage continued. In the first 1-2 weeks, carefully monitor whether the rot is progressing. If signs of rotting are detected, the treatment can be repeated. But, if the potatoes continue to rot, they are subject to complete rejection.

Rotting potatoes in storage can take any summer resident by surprise. There are many reasons for it: unsuitable varieties or unripe tubers, failure to comply with storage conditions and much more. In relation to rot, it is easier to carry out prevention than to fight it later. Therefore, before storing for the winter, careful inspection and preparation is required - both the tubers and the cellar.

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Last year I planted 15 acres of potatoes. I took care of it on the advice of a summer resident friend, but the harvest was unsuccessful, the tubers rotted. I had to throw everything away.

I decided to figure out why potatoes rot in the ground and how to treat the soil to prevent disease.

How to get rid of mold on potatoes in the basement?

If the potatoes rot, then it’s too late to do anything. All effective methods of combating mold in the cellar come down to timely preventive measures.

Safe ways to remove mold in a basement or cellar include the following:

  1. The room is treated with an ultraviolet or quartz lamp, which is turned on for 5-6 hours.
  2. The walls are cleaned of mold and carefully treated with lime mortar (care must be taken that drops and splashes do not get on the tubers).
  3. Remove and destroy infected instances.
  4. Adjust the operation of supply and exhaust ventilation or take other measures to reduce humidity in the room. Dampness is often a trigger for the development of mold. It is recommended to place a container of quicklime on the floor, which absorbs moisture well. Potatoes in bins or bags are sprinkled with aspen chips, wood ash, etc.

All other disinfection methods pose some risk to the crop. They can only be carried out if there are no stocks in storage in the basement. If possible, potatoes, other vegetables and preparations are removed from the basement or cellar, then disinfected (treating the walls with special preparations, fumigating with smoke bombs, etc.). After some time, the stocks are lowered back.

Potato brown rot

Brown rot of potatoes is considered dangerous. a rapidly spreading disease that is subject to quarantine. The causative agent of the disease is the bacterium Ralstonia solanacearum, which actively reproduces in warm and humid conditions. More often found in warm regions and central Russia.

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This pathogen lives in the soil for a long time and is spread by insects and worms. After penetration into the underground part of the crop, it quickly affects tubers and tops. Brown veins appear on the stem in the root area and on the leaves. If you cut the stem of an infected bush, a gray, slimy, bacterial mass is released from the vessels of the plant, rapidly spreading through the internal vessels, the bacterial mucus literally kills the plant, the leaves begin to wither, turn yellow, and then dry out and turn brown.

Signs of infection appear during flowering. A distinctive feature is the longitudinal splitting of the stem. Penetrating into the tubers, a bacterial infection affects the vascular ring. The vascular area softens; if you press on such a potato, a dirty white mucous mass is released.

Methods to combat brown rot:

  • Planting material must be healthy, since the disease can appear in the second year after emerging from infected potatoes. Therefore, the seed mass is carefully sorted and heated for about three weeks. The disease manifests itself if seed potatoes are treated with a solution of succinic acid (0.002%) for half an hour.
  • Dried and undamaged tubers are treated with TMTD, SP (0.8 kg/t), and polycarbocin. SP (0.8 kg/t). Rizoplan is used not only for pre-planting treatment (20 ml of concentrate per ton), but also for spraying twice during the growing season, before flowering. Before planting, you can treat potatoes with the biological agent Planriz, consumption - 10 liters of substance per ton.
  • The area is cleared of weeds and all tops are removed before harvesting. Mechanical damage to tubers must be avoided during digging and transportation.
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