Rotting potato tops near the ground. Potato diseases - photo, description and treatment of scab, dry rot

Potato rot is the result of exposure to tubers of pathogenic fungi or bacteria. Mistakes made when planting, growing, harvesting and storing potatoes contribute to the rapid spread of diseases and loss of crops. However, with the help of simple preventive measures, mass rotting of tubers can be prevented and damage minimized.

The main diseases that cause potato rot 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. In plants with late blight, tubers and tops 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;
Alternariosis (early dry spotting - a disease that affects the tops and tubers). The peel is covered with dark shapeless spots, 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 a Bordeaux mixture, Integral or Baktofit preparations;
rhizoctoniosis (black scab). Indelible black tubercles appear on the surface of the tubers, then the peel cracks, the pulp under it turns into dust;
Fusarium (dry rot) is a disease that develops during storage of tubers. The potato rots, the pulp turns into gruel and dries up;
phomosis (button rot) - during long-term storage, individual sections on the surface of the tuber turn into dry rot;
black leg - tubers turn into lumps of wet mucus;
ring rot - the tuber surrounds a wide yellow ring of rotten tissue. The disease is dangerous because an outwardly diseased tuber is almost impossible to distinguish from a healthy one. Rotten areas of the pulp are visible only on the cut of the potato;
wet rot - penetrates the tubers through cuts, scratches or cracks in the skin that occur when potatoes are damaged by various types of scab.

Preplant preventive measures

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 are more likely to rot in moist clay soil. Therefore, it is better to plant whole potatoes in such soil, and not cut tubers or eyes. If, nevertheless, the planting is done with slices or eyes, the potatoes must be cut a few days before planting so that the open “wounds” are covered with a protective crust. Before cutting the next tuber, the knife must be disinfected in a concentrated solution of potassium permanganate.

If the potato is not cut in advance and you have to do it immediately before planting, then each slice must be dipped in sifted ash: the substance has an antibacterial, 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. So that the potato does not rot due to damage to the skin by insect pests living in the soil, it is recommended to treat the planting material with the Prestige complex preparation 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. In order 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 that saturate the soil with nitrogen. The secretions of the roots of winter rye, oats and white mustard have a depressing effect on pathogenic fungi and bacteria that cause potato rot.

Prevention of rotting of tubers during the growth of bushes

If in the middle of a verdant 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. Diseased bushes should be immediately dug up and tubers inspected. Withered tops and rotten tubers are burned, healthy ones can be eaten, but they cannot be stored for storage. You need to figure out why potatoes rot.

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

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, around which the flesh begins to rot. If in the fall it turns out that some of the tubers are rotting from the inside, then next year the amount of nitrogen fertilizers applied to the soil should be reduced, and potash fertilizers should be increased.

Prevention of tuber rot during harvest

Potatoes often rot in the ground after flowering, when pathogens of late blight fall on the tubers from the withering tops. To prevent this and allow the potatoes to ripen properly, the tops are mowed 1-2 weeks before harvest.

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 rest of the potatoes are kept in a dark, well-ventilated place for 1-3 weeks so that all scratches are healed.

Tubers with mechanical damage should not be stored

Protecting potatoes from rotting in storage

Pathogenic fungi continue to live in the storage even after all the potatoes are taken out. Therefore, before storing potatoes of a new crop, the cellar is whitewashed with lime with the addition of copper sulfate, and all shelves and boxes 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 is preserved:

potatoes dug up during heavy rains;
potatoes of early varieties.

To protect against rotting, tubers are treated with a fungicide before being stored in storage. Previously, the drug "Maxim" was used, however, due to toxicity, this remedy must be used with caution. The modern bacterial preparations "Fitosporin" and "Antignil", which are safe for human health, are very effective in preventing the decay of potatoes.

Potatoes are carefully sorted and placed in boxes. For additional protection against fungi and bacteria (especially when the crop is stored in an apartment), layers of potatoes are interspersed with rowan, fern or wormwood leaves. If rotten potatoes are found in a box in winter, the spoiled tuber is thrown away, and the neighboring ones, even if outwardly healthy, are primarily used for food or pet food.

So that the tubers do not rot from a lack of oxygen, ventilation should be arranged in the cellar. The ideal temperature at which pathogenic microorganisms do not develop is from +2 to +4 °C. In the spring, when it gets warmer, it is recommended to freeze several 5-liter plastic bottles of water in the freezer and put them in the cellar: the ice will slowly melt, cooling the room.

Vegetables on top of potato tubers absorb moisture well

Excessive moisture also leads to rotting of potatoes. If water droplets settle on the ceiling in the cellar, it is recommended to lay 1-2 rows of beets on top of the potatoes, which will absorb excess moisture condensing on the tubers. Another option for dehumidifying the air in too damp cellars is to install a container with quicklime in the corner.

Almost everyone grows potatoes in their garden. It is no coincidence that this vegetable is planted, because it is one of the main components of traditional Russian dishes. Potato grows well in almost all regions, including the northern ones, and belongs to unpretentious plants. But, like any other species, it happens to him. Fruits can rot, causing the entire crop to suffer. Why is this happening, and is there any remedy?

The main causes of rotting potatoes in the ground

The vegetable itself is hygrophilous. He demands.

Potatoes need abundant watering only during the formation of tubers, the rest of the time, excess moisture will only bring harm.

Yet if moisture limit exceeded , then this may affect the quality of the crop, rot may appear on the potatoes. Today, any regions are not immune from this, as summer is increasingly rainy. The northern, northwestern and even southern regions are especially affected by heavy rains today. At the beginning of summer, half a month or even a month's rainfall often falls in one day, which cannot but affect the harvest.

So, the following reasons for rotting potatoes in the ground are distinguished:

It is worth noting that all diseases in potatoes, accompanied by the appearance of rot, occur due to improper planting, abundant moisture and rain, as well as improper storage.

Potato rots in the ground from the rain: how to save the crop in a rainy summer?

After heavy rains, the ground often becomes covered with a crust. Because of it, the root crops do not receive enough air, as a result of which the potatoes receive little air and can deteriorate. For a vegetable, it is important that the earth breathes.

Potatoes need to be spudded at least 3 times per season!

If you notice a rotten root crop, then it is better to remove it so that it does not infect the nearest roots.. In its place, you can plant a new plant.

It is very important to control humidity during growth. After the flowering of the plant is completed, the infected tops can be removed. The fruit will ripen well, in this case, summer residents should not worry. This procedure will protect the plant from various fungal infections and rot.

This bush must be dug up and see why it died.

If the tops are not removed in a timely manner, then all the infection will be washed away from her after another rain into the ground, as a result of which even more root crops may suffer.

Security measures

To protect the potato crop from spoilage and rotting, adhere to the following safety measures:

Potatoes are planted not in the lowlands, but on relatively high beds . It is advisable to choose a well-lit place where enough sunlight will fall. So, the earth will dry out faster from moisture.
Good place for potatoes.
Potato should not be adjacent with tomato, eggplant and pepper. Good neighbors for potatoes: radish, corn. For potatoes, the land on which corn, beets, rye, and flax grew is ideal.
Plants are best planted at a temperature of +15 degrees. The optimal landing time is the end of April and until the middle of May.
If potatoes are planted in a region where there is often a rainy summer, then it is planted in high double beds . Planting depth can be up to 8 cm. Between rows there should be at least 30–40 cm. As a result, the potatoes will always be above the level, and moisture will immediately flow down.
On moist soils, potatoes are planted in high beds.
So that potatoes grow better next season, in autumn, it is recommended to plant rye or oats on the site under it. With the onset of spring and after the snow melts, the earth is dug up and seed potatoes are planted. When planting, the bed is made high so that the root crop receives enough air.
Area with planted potatoes sure to weed . Remember that due to weeds, moisture stagnation often occurs.
The crop rots more often in clay soil. If you are going to plant potatoes in this type of land, then first use top dressing, then plant plants. It is better to choose a high type of landing.
Seed potatoes can be planted whole or in slices.. If you choose the second method, then a few days before disembarking, give the slices time to dry. It is advisable to cut seed potatoes with a disinfected knife. It can be washed in a solution of potassium permanganate. If you still plan to plant the slices immediately after cutting, then use ash to prevent rotting. Roll them in ashes and place them in holes.
Treatment of seed potatoes with a pink solution of potassium permanganate.
To prevent rot, planting material is advised to be treated with Bordeaux liquid, a solution of a copper case or a fungicide.

Diseases and protection against them

In summer, potatoes can also rot due to fungal infections caused by heavy rains, moisture, improper planting in clay soil, etc.

There are several types of rot. It can infect stems, leaves, root crops, infect neighboring plants. What to do in this case?

If you notice that the fruits are rotting in the ground, then you can try the drug " Prestige". It provides comprehensive fruit protection.

Bushes wither

If you notice that the bushes began to wither, and their leaves turned yellow, then the plant must be dug up and the tubers inspected. When rotten roots and tops appear, they should be burned immediately.

To avoid rotting potatoes, be sure to use mineral supplement . In this case, in no case should the fertilizer be exaggerated, since an excess of top dressing can also cause a fungal infection.

Preparations

Sick bushes should be removed, and healthy ones should be treated with a special tool.

If you find damage to plants after flowering, you notice late blight or other disease , then the tops must be mowed. You can treat it with a special preparation " Ridomila". Follow the instructions on the packaging.

There are other ways to help:

Appin;
Efal;
Revus;
Ditan.

After harvest, each potato is carefully checked. Rotten fruits should be thrown away or burned immediately.

Damage to the skin of tubers can become a place for infection.

If there is at least one rotten fruit among healthy potatoes, then it can eventually infect the entire harvest.

conclusions

So that the potatoes do not rot in the ground, they should be planted correctly, choose a well-lit place for planting, and properly feed the ground.

Potatoes can rot for various reasons, we hope that they have passed you.

Simple precautions can help you avoid fungal infections. If, nevertheless, the plant began to rot, then special preparations can be used.

The lush greenery in the beds with potatoes darkens and begins to dry out. Quite normal at the end of the growing season. If the tops of potatoes turn black, which are far from ripening, this is a pathology, and it must be dealt with.

A bush with stunted shoots will not be able to provide tubers with good nutrition. Consequently, the formation of fruits will occur with a lag or stop altogether.

Favorable conditions for their reproduction are created under such circumstances as:

violation of the rules of agricultural technology in the cultivation of land;
lack of moisture or its excess;
lack of oxygen in the soil;
lack of nutrients;
low resistance of varieties;
mechanical damage caused by pests.

These factors weaken the immunity of plants, increasing their susceptibility to diseases. Fungal spores are transferred from a diseased area to a healthy one by birds, insects, through the gardener's clothes, as well as working equipment.

During irrigation or rain, pathogens seep deep into the ground and infect root crops. There is another way of infection: the use of unhealthy maternal tubers.

After planting potatoes in the ground, the mycelium that had been dormant before that begins to grow, moves to the tops and forms spores.

Some damage to potatoes is caused by pathogenic bacteria.

Major infections

What diseases do farmers face?

Potato leaves turn black with pathologies such as:

late blight;
alternariosis;
fusarium;
rhizoctoniosis;
blackleg.

The infection can be diagnosed by the first changes in the color, structure and shape of the aerial part of the tuberous fruit.

Late blight (V. Phytophthora)

If the tops turn black after prolonged rains, prolonged cloudy weather and noticeable temperature fluctuations, most likely this is late blight (potato rot).

Most often, late blight manifests itself during budding and flowering bushes. Under favorable conditions, the disease may appear earlier.

The infection spreads rapidly, and its initial stage is easy to miss. It's like an epidemic: leaves and stems can become spotted and then turn black in just one day.

Phytophthora is a common disease and a real scourge for farmers. Phytophthora can destroy up to 20%, and with intensive development, in warm rainy weather, up to 80% of the crop. The larger the landing area, the more difficult it is to stop the spread of infection.

Alternariosis (v. Alternaria solani)

The second name of the disease is dry spotting. The fungus damages plantings 2-3 weeks before flowering. In terms of its harmfulness, Alternaria is related to late blight, reducing the yield of tubers by 20-30%. The risk zone includes mid-season and mid-late potato varieties.

Hot weather (from 26 ° C), as well as the presence of moisture (raindrops or heavy dew) for at least 2 hours are optimal conditions for infection of the bushes. Alternariosis pathogen produces alternariic acid, which leads to necrotic damage to the aerial part of the plant.

The incubation period lasts 3-8 days, then the tops, starting from the lower leaves, are covered with rounded dark spots.

The same damage is observed on the stem. With a strong degree of the disease, the spots merge with each other, the leaves turn yellow and dry out. Root crops are affected less often, however, one cannot count on a good harvest.

Fusarium (c. Fusarium oxysporum)

The disease is known as Fusarium wilt or dry rot. Fusarium fungi form arachnoid mycelium and contain a huge amount of spores.

They multiply very quickly in the soil, contributing to the growth of colonies. The pathogen enters the plant through the root system and disrupts the absorption capacity of the bush. As a result, the plant receives less moisture.

Infection of potatoes occurs during the flowering period, but the necrosis of the tops appears after 20-25 days. The leaves, starting from the bottom, discolor, curl and fall off.

Stems acquire a brilliant blackish color and, in high humidity, begin to rot. In the affected areas, there is a white coating in the form of a web. Yield losses in case of Fusarium disease are up to 50%.

Fusarium spores germinate slowly on tubers. The product begins to rot 1-2 months after storage. The flesh of the potato softens, the smell of moldy rot is felt.

Rhizoctonia (v. Rhizoctonia solani Kuehn)

Another name for rhizoctoniosis is black scab. The fungus infects all parts of the plant. The pathogen is widespread in all areas of potato cultivation and is very tenacious. In the soil, in a dormant state, he is able to stay without harm to himself for up to a year and a half.

The pathogen goes through 3 stages of development:

Optimal conditions for the activation of rhizoctoniosis: humidity - from 65%, temperature - no more than 18 ° C, soil acidity - 6.0 pH.

Black leg (c. Erwinia carotovora)

The causative agent of the disease is able to develop in a wide temperature range - from 2 to 32 ° C. The source of infection is the remains of vegetation in the soil and on its surface, as well as diseased seed material. Infected tubers may look healthy, but under favorable conditions, the infection will manifest itself by blackening of the basal part of the stem.

Diseased bushes are visible shortly after emergence. Distinguish between slow and rapid development of the disease. With a slow flow, the tops turn yellow and fade.

Circumstances under which the infection progresses rapidly are hot weather and high humidity. The black part of the stem softens, and it breaks under its own weight.

Penetrating into the underground part of the potato, the bacteria destroy the tubers, turning them into a rotting mass.

Treatment of infected plantings of potatoes

Disease prevention is the best opportunity to get a good harvest. But what if the tops of the potatoes have already turned black? It is necessary to identify the pathogen and take therapeutic measures.

You can use the following drugs:

Ridomil Gold MC;
Oksikhom;
Arcerid;
Acrobat MC.

The course of treatment consists of 3-4 treatments with an interval of 7-14 days, according to the manufacturer's instructions. Eradication fungicides are effective against most types of fungi and the diseases they cause, but they do not guarantee a 100% cure. If the bushes do not respond to treatment, you will have to destroy them and thus stop the epidemic.

In case of bacterial diseases, treatment is carried out with any of such drugs as: Fitosporin, Gamair, Fitolavin.

How to prevent blackening of haulm?

The fight against diseases must be carried out constantly, without waiting for surprises in the form of black spots on the foliage.

Sick tubers should be discarded, and healthy tubers should be treated with an insectofungicide before planting. The most common: Maxim 25, Fludioxonil, Prestige. Opponents of chemistry can be advised bioactive drug Agat-25.

After the potato seedlings reach a height of 20-25 cm, the first spraying is carried out using fungicides Thanos, Oksikhom, Ditan M-45, Boxwood.

The next treatments are performed at intervals of 7-10 days - at least 5 times per season. Leaves and stems are covered with a solution not only from above, but also from below. Among the biological preparations are popular: Acrobat MC, Fitosporin-M, Ecopin.

Other protective measures

The best result can be achieved with an integrated approach to solving the problem.

If late blight has already settled on potato beds, the following measures should be taken:

Change the seed material, giving preference to varieties that are resistant to late blight and other types of fungi.
Choose another place for potatoes - isolated from planting tomatoes, peppers and eggplants.
Remove the tops in a timely manner after digging up the potatoes, without leaving them on the beds.
Weed regularly, keeping the potato bushes well ventilated.
Dry tubers well before storage.
After harvesting, sow the area with green manure.

These measures will avoid infection of the plots and keep the tops green throughout the growing season.

Sometimes potatoes give gardeners surprises in the form of rotten tubers in the spring, when their stocks are sorted out before planting. Rotten potatoes smell disgusting and cause nearby vegetables to rot. How to prevent spoilage of tubers and keep the seed material intact? To answer this question, you need to understand the causes of rotting potatoes.

Causes of decay

How to deal with rot

Potato storage rules

Conclusion

Causes of decay

Why do potatoes rot immediately after harvesting, why does it begin 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 provoked 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 of the crop. Affected tubers can transmit the disease for several generations without symptoms.

A characteristic feature is the specific yellowish mucus that is released on the cut of wilted leaves, the plants grow dwarf. The disease spreads when harvesting through damage to the skin of tubers.

brown rot is a quarantine disease.

Brown rot of potatoes destroys up to 70% of the crop in the countries where it is common. Since 2011, the causative agent has been found on ware potatoes from warm countries. The disease is still not widespread on the landing areas of Russia. Infection occurs through the root system.

The first sign is the sudden withering of leaves, branches and the whole plant. The tuber turns brown and softens the vascular ring. During storage, the pulp is converted to dark mucus.

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

Potato wet rot spreads rapidly when stored in a warm, humid and poorly ventilated area.

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

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

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

Fungal disease in the form of rot - late blight, the most harmful and common.

Late blight can be identified by the appearance of brown blurry spots on the upper leaves, which appear during the closing of the tops. The plant either dries up 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 the entire potato field in 3 weeks. The crop rots during storage.

Important! From one tuber to another, the infection is not transmitted.

In addition to the most common types of rot described above, pink, rubber, coal, white, stolon, wound, watery rot and phomosis can occur.

How to deal with rot

It is impossible to instantly cure any potato disease. The source of infection is located both on the tubers and in the ground. Therefore, for the prevention of diseases and the destruction of infection, an integrated approach is always used:

pre-sowing treatment of tubers with protective agents;
dressing beds;
spraying tops;
processing of the harvested crop;
disinfection of storage areas;
constant monitoring of stored potatoes.

Important! In the case of bacterial diseases, the best protection is prevention, as there are no complete measures to eradicate the infection.

Only healthy seed material should be planted, weeds should be destroyed, tubers should be dressed before planting, crop rotation should be observed, and the optimal amount of fertilizer should be applied.

How to deal with rot, gardeners knew back in those days when chemical methods of protection were not invented. To suppress fungal microorganisms, leaves of plants that prevent the process of decay were placed between the layers of potatoes: mountain ash, elderberry, bitter wormwood, and goutweed.

Methods of struggle in our time have expanded through the use of chemicals. Before planting tubers or laying them in storage, processing is applied:

1% solution of Bordeaux mixture or copper sulphate;
Maxim KS;
Titus;
Aktofit;
Planriz;
Bitoxibacillin.

When wondering how to get rid of dry rot, one must remember that infection often begins when damaged tubers come into contact with wet soil. Therefore, potatoes should be harvested on dry and warm days, dried before storage, and damaged tubers should be discarded.

The number of manifestations of various infections is significantly reduced when potatoes are treated before storage with the microbiological preparation Fitosporin.

Potato storage rules

Before laying potatoes for storage in the cellar, so that it does not rot, preparatory work is carried out:

remove all the remaining last year's vegetables and fruits;
the walls are whitewashed with slaked lime;
shelves and drawers are treated with a 2% solution of copper sulfate;
at the entrance they put a rug treated with a 5% solution of copper sulphate.

The air temperature in the cellar with the onset of cold weather gradually decreases. But the optimum should be kept at +13 ° C in the early days. During winter, it should not fall below +2–3 °C at an air humidity of 80–85%. The freezing temperature of the tubers occurs at -1.5 ° C, at 0 ° C, the starch in the potato begins to turn into sugar and the taste of the vegetable becomes sweet.

Important! As a layer of thermal insulation, you can use beets, which better tolerate lower temperatures and protect potatoes from frost.

If during the inspection of stocks an infected potato is detected, then all the tubers will have to be sorted out and the damaged ones mechanically separated.

Conclusion

Knowing why the harvested potatoes rot, you can and should try to prevent the infection during storage and get rid of it at the first sign of occurrence. Fortunately, the harsh climate of Russia does not allow many diseases to spread throughout the country. However, the mandatory implementation of preventive measures does not negate this.