Potato rot: why potatoes rot, protection and control measures

Wet rot of potatoes
Wet rot is caused by a number of bacteria that penetrate the tubers due to mechanical and fungal irritation of external tissues. This disease begins to develop on tubers even before or during harvest, but it develops most during storage. If stored improperly, bacteria quickly spread to healthy tubers. Thus, you can lose a significant part of the harvest. In this case, all healthy potatoes will be wet and covered with the remains of infected potatoes. Therefore, it is very important to know how to properly deal with wet rot of potatoes.

Potato rot: why do potatoes rot during storage, and how to avoid it?

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.

Infection and development of the disease

Why does dry rot appear on potatoes? The causative agent is the fungus Fusarium oxysporum. Its spores are easily carried by the wind. It also gets onto potato bushes from fresh manure. An excessive amount of organic matter on the site, as a rule, leads to the occurrence of dry rot.

Weedy soil around potato plants can also harbor Fusarium oxysporum spores. With excessive watering or due to frequent rains, spores of the dry rot fungus multiply rapidly. Their carriers are insects. The process is especially active when spores get to the site of damage to the stem or tuber.

Spores can quickly spread throughout the entire area. Dry rot affects not only potatoes, but also other garden plants. Most often it affects strawberries, peppers, and tomatoes.

Spores of this fungus also live in the soil. From it they move on to potato tubers. It is sad that after harvesting, the affected tubers end up in vegetable storage facilities, where the spores continue to multiply. It is enough for one tuber infected with spores to get there, and they will spread to all the vegetables in storage.

Late blight of potatoes

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.

Late blight of potato tubers.

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.

Basic preventative measures to combat rot

The most effective measure to combat the appearance and spread of rot is the use of potato varieties that are specially bred for planting in a certain climate and are highly resistant to disease. In addition, it is important to disinfect the soil and the tubers themselves before planting. When storing, you need to carefully prepare the storage area and sort the potatoes before storing.

It is best to plant the following potato varieties:

1. Treasures
2. Early lapis lazuli.
3. Spring.
4. Herald.

They are highly resistant 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.

Fungal diseases

These diseases are associated with the effects of fungal infections on potatoes. They can affect both tubers and other parts of the plant. Among fungal infections, several types are most common.

Late blight

This disease is one of the most dangerous. The fact is that it affects the tubers during storage and the crop itself during the growing season. A fungal infection can destroy most of the crop. You can tell that potatoes are affected by late blight by the appearance of gray hard spots.

When the first signs of potato late blight appear during the growing season, it is necessary to immediately treat with a two percent solution of Bordeaux mixture. In addition, the crop must be provided with the correct storage conditions. Temperature and humidity should not contribute to the spread of rot. It is also important to provide adequate ventilation and shade to the potatoes. Therefore, storing potatoes at home is not recommended.

Fusarium

A disease also known as dry rot. It is dangerous because it affects the entire plant, and not just the tubers. Fungal spores spread well at high temperatures and waterlogged soil. The appearance of fusarium can be determined by the appearance of gray spots on the leaves, wilting and drying of the potato bush. If blue-black rings are visible on the cut stem, this indicates that the crop has been infected by a fungus.

When tubers are damaged during storage, a white coating appears on their surface and the skin in this place becomes dry and wrinkled. In addition, you can see dark voids filled with mycelium in the section.

It is worth remembering that fusarium poses a serious danger to human health. If there is a suspicion that the crop is affected by this infection, then it is prohibited to use it for food. To save potatoes during the growing season, they need to be sprayed with biofungicide solutions. Measures to preserve crops in winter do not differ from those needed to protect against late blight. It is best to treat each potato with Fitosporin, and also carry out regular sorting in the future, since the infection quickly spreads from affected tubers to healthy ones.

Alternaria blight

The disease causes the same damage to the crop as late blight. Dry rot is most dangerous for middle and late varieties of the crop. It affects all parts of the plant. During the growing season, Alternaria blight can be identified by the appearance of large concentric spots on the leaves and stems. Over time, these spots become brown or dark brown. On tubers, Alternaria blight appears in the form of depressed, wrinkled spots. On the cut you can see that the flesh becomes black-brown.

To protect potatoes, during preparation for planting, tubers are treated with biological products. You can use Planriz or Integral. During the growing season, treatment is carried out by analogy with the prevention of other fungal infections. The same applies to the storage conditions of tubers.

All of the fungal diseases described above spread mainly through seed material. Therefore, to ensure the safety of tubers until the next harvest, it is recommended to grow varieties that are resistant to diseases.

Fusarium (dry rot) of potatoes

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.

Fusarium (dry rot).

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.

Description of potato rot

Rots can affect different organs of the potato plant and are provoked by various pathogens, which means they will require different treatment and prevention. We offer you to get acquainted with the description of the most common types of rot. In total there are about 20 of them.

Did you know? Potatoes were cultivated 7-9 thousand years ago in the territory that is today Bolivia. Residents of South America, in addition to eating the tubers, also worshiped this plant.

Wet

Wet or soft rot is caused by saprophytic bacteria that penetrate the tubers through damage. The fruits rot while still in the ground, or while already in storage. In the field, wet rot most often occurs during high and prolonged humidity, that is, during frequent rainfall, as well as on heavy soil. In storage - at high temperatures (above +5°C), high humidity, as well as during long-term storage in the temperature range -1°C...+1°C.

When affected by wet rot, the tuber becomes soft and produces an unpleasant odor. If you press on it, a yellow-brown liquid is released at the place of pressure. At first, the rot is white, but gradually turns black.

Dry

Dry or brown rot most often affects potatoes. It can ruin up to 40% of the harvest. The fungus that causes it damages the roots and tubers. Infection occurs through plant debris, soil, and infected fruits. The fungus enters through damage caused by late blight or harmful insect activity.

The fungus attacks the plant at any stage. The first symptoms become noticeable even during the release of flowers - the leaves of the upper tier on the bushes lighten and fade. Subsequently, symptoms appear on the stem - its lower part becomes brown and covered with a pinkish or orange coating. Depressed gray spots form on the tubers. When cut, you can find voids with white mycelium inside.

Did you know? In the Inca calendar, daytime was measured by the time period during which potatoes were cooked (about 60 minutes).

Fomoznaya

This type of disease develops if the plant was cool and had a lot of rain during the period of growth and growth of green mass. When infected, depressed round spots begin to appear on the fruit, reaching 2–5 cm in diameter. The peel remains intact, but the insides of the tuber can almost completely rot. Also, brown spots can sometimes form on the lower part of the stem of a diseased plant, and the tops can rot.

Ring

The bacteria that cause this type of potato rot affect only those tubers that begin to develop or are placed in storage. The development of the disease is provoked by damage during harvesting or when attacked by harmful insects. Once damaged, the entire potato rots, leaving only a white, foul-smelling mass.

Rubber

This variety received this name because when infected, spots appear on the fruits, the tissue under which resembles rubber. When cut, the tuber emits the smell of rotten fish. The disease can also affect the tops. Most often it develops at temperatures above +25°C.

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.

Is it possible to eat potatoes affected by rot?

The answer to this question is clear: rotten potatoes should not be eaten under any circumstances. You should not do this, even if not the entire tuber is affected by rot, and the affected part can be removed. Harmful bacteria and fungi that provoke the development of rot when entering the human body lead to acute poisoning, damage to the gastrointestinal tract and other negative consequences.

Important! It is forbidden to eat green potatoes - they contain large amounts of the toxic substance solanine, which can cause serious harm to human health.

So, rot is a dangerous potato disease that leads to massive crop loss. It can develop while the tubers are still in the soil, or affect them immediately after harvesting. To prevent this, it is necessary to apply preventive measures, create optimal conditions in the crop storage and carefully select fruits for planting and storage.

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.

Alternaria blight (dry spotting of potatoes).

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.

Manifestation of the disease

If there are spores of the dry rot fungus in the soil where potatoes grow, then sooner or later they, along with life-giving moisture, enter the structure of the plant. For this reason, small whitish spots appear on the tips of the leaves (you can see them in the photo).

After a short time, a pinkish coating appears on the potato stems. Next, the mycelium begins to grow and thereby block the access of beneficial substances to the stems and leaves of the potato. The development of the bush slows down, the tops fade, and then the leaves fall off. The bush soon dries out completely.

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.

Prevention of potato tuber diseases

To reduce the likelihood of potatoes getting sick with any diseases, you should follow certain rules:

1. Low-lying or marshy areas should not be used for planting potatoes.
2. It is advisable to use areas for planting where nightshades have not been grown during the previous 2 years: tomatoes, eggplants, potatoes, tobacco.
3. The area must be regularly cleared of weeds.
4. Seed material must be inspected, rejected and processed before planting.
5. It is advisable to use certified seeds from a trusted nursery for planting.
6. The soil for growing potatoes should be loose and well-drained.
7. You should not plant potatoes too early, trying to weed them out faster. Planting in soil that is too cold and wet can lead to disease.
8. 10-12 days before harvesting, you need to mow the tops. This will increase the density of the potato skin and increase its resistance to transportation.
9. Excess nitrogen fertilizers in the soil should be avoided, so fresh organic matter should be used with caution.

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.

Conditions of infection

Potatoes can become infected with wet rot in the garden or in storage. This requires special conditions:

1. Bacteria that cause wet rot usually enter tubers due to mechanical irritation of the skin by pests and other diseases. Ring rot and blackleg are most often the precursors of wet rot. Potatoes are also often infected as a result of irritation of the tubers by wireworms.
2. Wet rot develops best at storage temperatures above 5 degrees Celsius. If the potatoes are poured in large piles and in places where there is high humidity and air temperature, then the disease will spread very quickly throughout the entire potato. In places where there is an outbreak of the disease, the temperature, due to the activity of bacteria, can rise to 50 degrees Celsius. In such places, potatoes quickly rot.
3. When tubers are smothered, outbreaks of wet rot often occur. The tubers lack oxygen, and the high carbon dioxide content weakens the immune system. Therefore, in storage, potatoes should not be placed in large piles and reliable ventilation in the room should be ensured. Suffocation can also occur in the soil if the soil is wet and very dense.
4. Wet rot develops better in potatoes that have been supercooled at temperatures close to zero. Potatoes that have been stored at temperatures below 0 degrees cannot be stored; they must be isolated and used as soon as possible.

Black potato leg

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.

Potatoes affected by blackleg.

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.

Potato cancer

The disease is caused by a specific quarantine pathogen, chytridiomycetes. Therefore, the import of crop products from other countries must be strictly controlled. In addition to potatoes, carriers of this harmful organism are weeds - black nightshade, henbane, datura. Among the cultivated plants - physalis.

The growths of potato cancer are initially light, but over time they turn black and can cover the entire tuber. If saprophytic organisms join the soil, the crop rots while still in the garden.

Important! Potato cancer can develop on all plant organs and exists in various forms. Wilting, wrinkling and swelling on tubers is a corrugated and crater-shaped form of cancer.

Potato 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.

Ring rot of potatoes.

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.

Ways to combat fusarium

In former times, only thorough treatment with copper sulfate could stop the spread of gray rot. However, the modern chemical industry is producing more and more drugs to combat various potato diseases, including gray rot. They can be divided into biological and chemical.

Baktofit

This biological product is created on the basis of microorganisms that can suppress the growth of all fungal diseases of potatoes. It is available in the form of a suspension or powder. To prepare a working solution, dilute 1 gram of powder per liter of water.

Fitosporin-M

This product is more used as a prevention and control of all fungal and bacterial diseases of potatoes. It is used to treat the seed before planting in the following dosage: 3 tbsp. spoons per glass of water. All tubers are washed with the resulting solution before planting. After the tops appear, they are also treated with this drug at the rate of 10 grams per 5 liters of water.

Integral

A domestic product based on microbiological material. This drug not only suppresses the growth and development of pathogenic microorganisms, but also disinfects seed material, and also protects seedlings, stimulates the acceleration of their growth, and increases the productivity of young plants.

All these drugs are considered biological, so they do not harm either people or animals. But if they don’t help, you should use chemicals.

Titus

This is a herbicide for killing weeds, but it also perfectly disinfects potato plants from various diseases. Harmful fungi and bacteria die along with the weeds. You just need to use it carefully: one gram diluted in 6 liters of water is enough for two hundred square meters of potato field.

Maksim

A domestically produced fungicide is used both for processing planting material and for preparing potato tubers for storage. For this purpose, the drug is diluted at the rate of 8 ml per 4 liters of water. 3 kg of potatoes are disinfected in 1 liter of the resulting solution.

Colfugo is super

Appearing quite recently, this drug affects the division of fungal cells, but mutation does not occur and resistant forms of the fungus do not appear. To achieve the effect, it is enough to spray the above-ground part of potatoes (as well as eggplants and tomatoes) with a solution of 2 g per liter of water. This product is non-toxic to humans, animals and bees.

Potato 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.

Brown rot of potatoes.

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.

Viral diseases

This type of disease includes mosaics of various types:

• ordinary;
• banded;

  Black stripes and spots appear on the foliage and stems

• wrinkled.

  Affected plants appear to be stunted and do not bloom, and the leaves become corrugated.

This name of the disease is due to the characteristic signs that appear on the tops of the plant.

The virus penetrates inside the tuber through mechanical damage to the peel. Various pests act as carriers: aphids, Colorado potato beetles, cicadas. Therefore, such potatoes cannot be used for planting.

Rotting of the tuber begins from the outside and spreads inward

In such cases, resorting to some kind of therapeutic action is pointless. They pull out the tops along with the tubers and destroy them outside the garden. After this, neighboring plantings are inspected and, if damaged, they are also disposed of.

In the first year, the virus may not manifest itself, but the next season it will destroy up to 50% of the crop.

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.

Once again about the importance of prevention

It is important for vegetable growers to remember that the result of treating potato tuber diseases is unpredictable. Spraying may show its effectiveness, or its effectiveness will be minimal. Therefore, one should not neglect preventive measures that prevent the introduction of infections into the garden.

Breeders from all countries are actively working to develop new varieties that are resistant to tuber diseases.

Varieties Santana, Desiree, and Belorussky starchy show high resistance to fomosis.

You cannot plant potatoes brought from other regions without pre-treatment. The simplest means for disinfecting tubers is potassium permanganate , but it is not always effective against fungi.

Selecting a predecessor and observing crop rotation

Below is a comparison of potato predecessors.

Favorable predecessors

• cucumber
• radish
• zucchini
• peas
• alfalfa, clover, white mustard
• winter wheat as green manure
• carrot
• beet

Unfavorable Precursors

• tomato
• pepper
• eggplant
• physalis, strawberry
• cabbage
• sunflower
• linen
• nightshade

Please note that even proximity to crops that are undesirable predecessors is bad for potatoes. For example, tomatoes, peppers, and strawberries are heavily affected by late blight, which causes root rot. Having settled on a strawberry plantation, Fusarium and Phytophthora mushrooms are difficult to eradicate, quickly spread throughout the plantation and cause the death of the bushes.

In vegetable gardens, returning the potato crop to its original place is acceptable after 3 years. If any disease was detected, then after 4 years. It is preferable to apply manure in rotted or semi-rotted form under a predecessor, for example, cucumbers. Storing manure and bringing it to the required conditions must be done correctly in a closed area, where the manure mass is heated and disinfected naturally during the process of rotting.

In farms where potato harvesting machines are used, it is important to ensure that there is as little mechanical damage to the tubers as possible. An infection that gets into the wounds can destroy the crop in storage by half or more.

Since tubers become infected from tops, the practice of removing them 5-7 days before harvesting is fully justified. Removal of tops can be done manually by mechanical cutting, or with the help of chemicals - desiccants. Under no circumstances should tops with signs of fungal diseases be placed on the site.

Before each storage season, the room where potatoes or containers will be stored is thoroughly washed with the addition of soap, disinfectants and antifungal agents. It is good to whitewash the basement walls with lime, and sprinkle the floor with copper or iron sulfate. It is advisable to store a small portion of onions at the same time as the potatoes. Because the phytoncides secreted by this vegetable protect the storage from the outbreak of infections.

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.

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.

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.

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

Fulfilling the basic requirements for preparing tubers, planting them, caring for them and harvesting them will minimize damage to the crop during winter storage.

When planting several varieties on a site, each is harvested separately.

Causes and source of infection

As can be seen from the description of rot, the main reasons for their development are:

• poor-quality soil tillage before planting;
• prolonged precipitation;
• improper care (overfeeding with nitrogen, waterlogging);
• untimely treatment of diseases and pests;
• mechanical damage to tubers during harvesting;
• damage to the skin of the fruit by harmful insects, for example, wireworms;
• storage under conditions that do not meet the requirements (most often at warm temperatures combined with high humidity);
• storing the crop in bulk when the fruits warm up to +50°C;
• storing crops in stuffy conditions, in the absence of ventilation, poor ventilation and poor access to oxygen.

The source of infection is diseased tubers, soil, and plant residues.
It is in them that pathogens - fungi and bacteria - settle. Their development is provoked by favorable conditions (high or low temperatures, high humidity, stagnant air, dense soil). They penetrate plant organs damaged mechanically or otherwise and begin their harmful activities. Important! Potatoes that have been stored at 0°C for a long time must be used for their intended purpose as soon as possible. It is no longer suitable for long-term storage.

Rules for protecting potato tubers from rotting during storage

1. When planting several varieties on a site, each is harvested separately.
2. Only mid-season, mid-late and late potato varieties are stored for storage. Early varieties after December are no longer suitable for use as food and remain as planting material or are used for animal feed.
3. In order for the tubers to ripen well, the potato tops are mowed 10-15 days before harvesting.
4. Potatoes are dug up in dry, sunny weather. If the weather is rainy, then the potatoes are slightly dried and manually cleaned of adhering dirt (to avoid mechanical damage through which a fungal or bacterial infection can penetrate inside the tuber).
5. Mechanically damaged and diseased tubers are immediately put into a separate pile.
6. Healthy, undamaged potatoes are transferred under a canopy (covered from the sun) or in a dark room with good ventilation for 5-7 days to ripen (coarse) the upper skin. Protection from light is necessary to prevent the potatoes from turning green. Solanine is formed in light, and such tubers cannot be used as food.
7. Before storing, the storage facility is disinfected and dried.
8. To protect against rotting during storage, dried and cleaned tubers can be treated with the biological preparations “Fitosporin” and “Anti-rot”, which will reduce the infectious background. They are harmless to humans and animals.
9. If potatoes are stored in bulk, then it is advisable to place 1-2 rows of beets on top. It will absorb excess moisture, which will protect the potato tubers from rotting. The beets will not be harmed.
10. It is more advisable to store potatoes in boxes (each variety separately).
11. Once a month, the tubers are sorted, removing the diseased ones.
12. Good ventilation will protect stored products from infection and rotting.
13. The air temperature in the storage must be maintained at +2...+4°C, and humidity 80-91%. If the humidity in the room is high, you can place, in addition to ventilation, a container of quicklime and change the filler if necessary. With the arrival of spring, the temperature in the storage room may rise. Frozen water in plastic bottles with a capacity of 3-5 liters will help reduce it. Ice containers are placed in different places. Ice in closed containers will gradually melt and cool the room.

Rhizoctoniosis, or black scab

Rhizoctoniosis (black scab) is a fungal disease. A distinctive feature is flat black sclerotia that can be easily scraped off.

We have two news about this disease: good and bad.

Let's start with the good thing: black scab does not spread in the cellar during storage, is not transmitted from diseased tubers to healthy ones, and does not spoil the taste of potatoes. Bad: it can greatly harm next year’s plantings (for example, if you use seed potatoes affected by scab).

Remember: the development of the disease is facilitated by late cleaning, when it is already very cold and damp outside.

Preventative measures for potato fusarium

Symptoms of fusarium blight on potato leaves.
Photo: WikiGardener - Fandom The best prevention of fusarium is the cultivation of potato varieties that are resistant to fungal diseases, coupled with proper agricultural practices. Correct agricultural technology involves neutralizing acidic soil, fertilizing with potassium fertilizers, minimizing nitrogen fertilizers and treating tubers (before planting) and bushes with specialized fungicides (1% Bordeaux mixture, Kuproxat, etc.) and “introducing” saprophytic fungi, such as Trichoderma veride, to the fusarium. Compliance with crop rotation also contributes to the “recovery” of the soil from fusarium.

We recommend reading: Cereal feed

If, during the growing season, potato bushes sick with fusarium were noticed, then the best prevention of tubers dug up and placed for long-term storage would be to avoid injuries and cuts during the sorting and transportation process - you should not throw the tubers unnecessarily, and cut tubers should be immediately selected, not putting it in storage. In addition, it is recommended to keep the tubers for 2-3 weeks in a warm, dry place, as a quarantine, with subsequent inspection.

To prevent planting diseased tubers in the spring, it is recommended to germinate seed potatoes and carefully inspect the planting material before planting.

Phoma rot

In this case, the above-ground part of the plant is also affected. Symptoms:

• change in leaf color: brown, black spots appear on them, then concentric rings can be seen in these areas;
• As the disease progresses, the leaves fall off.

The causative agent of the disease is a fungus. It can also affect the underground parts of the plant - dark-colored depressions form on the tubers. As they grow, the tuber turns black. Infection of potatoes occurs for various reasons, since the fungus spreads from neighboring plants (for example, pepper). It is contained in the soil, affects healthy parts of plantings, and the source can be plant debris on the site. Because of this, the risk of infection is quite high.

Routes of penetration into plant tissue:

• points where pinching occurs;
• injury to the skin and green parts of plants by pests that feed on sap;
• natural or pathological process of cracking of the outer covering under the influence of various factors.

The spread of the fungus occurs at a temperature of +20°C. In this case, a large number of conidia are released into the environment. These are microscopic particles that can get into the soil or water, onto work equipment and clothing. The main preventive measure is a sufficiently low temperature in the storage (as far as possible). In addition, they use a method for treating potatoes against fusarium rot. The drugs are used simultaneously with measures to create unsuitable conditions for the spread of the fungus.

When harvesting, care must be taken, since any damage to the tubers opens the way for the penetration of microorganisms. Potatoes are harvested from the field and stored dry. High humidity and precipitation are favorable conditions for the spread of the disease.

Other measures:

• increasing soil fertility;
• compliance with the rules of crop rotation: annually change the location of the site where potatoes will be grown;
• Regular weeding of the area: weeds are removed, but plants of the nightshade family are more dangerous.

Dry, wet and other potato rots - methods of control

Wet rot is caused by a number of bacteria that penetrate the tubers due to mechanical and fungal irritation of external tissues. This disease begins to develop on tubers even before or during harvest, but it develops most during storage. If stored improperly, bacteria quickly spread to healthy tubers. Thus, you can lose a significant part of the harvest. In this case, all healthy potatoes will be wet and covered with the remains of infected potatoes. Therefore, it is very important to know how to properly deal with wet rot of potatoes.

Dry potato rot

One of the most common types of rot in the southern, southeastern regions and the Far East of Russia. Under favorable circumstances, it can destroy up to 40% of the crop. The causative agent of fusarium dry rot (another name is “brown”) is a fungus that attacks the root system and tuber. The disease spreads through contaminated soil, plant debris and infected potato tubers.

Symptoms. Dry rot can infect potatoes at any time during development; the first signs of the disease are noticeable during the flowering period. The upper leaves of the potato bush lighten and later begin to fade. The lower part of the stem turns brown, and when humidity is high, a pink or orange coating appears on it. The affected plant dries out; rings of individual vessels are visible in the section of the stem. Usually the disease appears in a certain area, spreading to several bushes at once.

On tubers infected with dry rot, dull, gray-brown, slightly depressed spots first appear. Then the flesh under the spots dries out, becomes dry and rotten, and the peel wrinkles. White voids appear in the tuber, which are filled with mycelium. Diseased tubers germinate poorly, usually thin thread-like sprouts appear from them.

Dry rot is the most common

Factors contributing to potato infection with dry rot:

• poorly sorted seed material (planting diseased potatoes);
• late blight and other diseases that make the tuber vulnerable;
• increased temperature and humidity during storage;
• excess nitrogen in the soil (including humus);
• damage to tubers by pests, such as wireworms;
• mechanical damage to potatoes during harvest.

Preventative measures for dry rot:

• apply fertilizers in a balanced manner, avoid excess nitrogen, add potassium fertilizers;
• use only healthy planting material purchased from reliable suppliers;
• do not plant potatoes on heavy soils and in lowlands with excess moisture;
• When harvesting, avoid mechanical damage to tubers (very important when using a walk-behind tractor), discard and do not place damaged potatoes in the cellar;
• observe crop rotation to destroy the pathogen in the ground (the fungus lives in the soil for 3-4 years);
• plant green manure - plants that act as organic fertilizer for the soil;
• Properly store harvested potatoes.

Treatment. There are no specific remedies that can completely get rid of dry rot. For preventive purposes, it is possible to treat planting material with phytosporin (40-50 grams per 100 kg) and bactofit (300-500 grams per 100 kg). Before storing the tubers, they are treated with Maxim KS (0.2 liters per ton of potatoes).