Potatoes are capable of photosynthesis, like all plants. Usually potato tubers are in the ground, in almost complete darkness. However, if exposed to light, the chlorophyll in the skin will react with carbon dioxide and water, causing the potatoes to turn green.

On my own chlorophyll is harmless to health, but the concentration of solanine increases in green tubers. This substance is poisonous to humans, so it is dangerous to eat such potatoes. It will even taste bitter. It can be used for seedlings, but if potatoes were stocked as a food product, they will have to be thrown away.

To avoid this problem, potatoes must be stored in a dark place. Suitable cellar, pantry or insulated balcony. The main thing is to close it from the penetration of sunlight. A small amount of potatoes can be kept in the refrigerator, away from the freezer.

Why is it black inside?

There are a number of reasons why potatoes can turn black on the inside, from improper fertilization during cultivation to improper storage conditions. Blackness can be caused by various diseases that a plant can infect from the soil or from other plants.

Some varieties of potatoes, in principle, do not lie for a long time. They must be eaten in early autumn. If the potatoes have been watered too much, they may darken due to rot. Perhaps the crop was harvested too early, and the tubers did not have time to form a sufficiently dense crust that could protect against diseases.

If the cultivation and harvesting of potatoes took place in accordance with all the rules, then the happy owner a large number quality potatoes must be able to preserve it.

1. Potatoes require good ventilation and a temperature of +2 ... +6 degrees.
2. Before storing the tubers, it is recommended to clean them of soil residues in order to reduce the risk of infection with the fungus.
3. It is better to put the crop in boxes with gaps between the boards or boxes with holes.
4. It is recommended to install them on pallets to improve ventilation.

IMPORTANT! Regardless of whether the potatoes were washed or the soil was simply mechanically shaken off, they must be stored dry in storage. Sometimes it is recommended to dry it for some time in the sun for additional disinfection with rays.

Reasons for sprouting

A potato tuber is a variant of a kidney filled with nutrients. Its purpose is to germinate in the spring and form a new plant. This process starts when it gets warm enough. Sprouted tubers become less nutritious as the starch is used up for germination.

If the potatoes sprouted during storage, it means that the storage is too warm. Elevated temperatures can also form in the depths of stores if ventilation is inadequate. The sprouts are dangerous to eat, so they will have to be cut off. Potatoes must be sorted out and laid so that the optimal amount of air enters.

So, to prevent germination, the room with potatoes should be well ventilated and cool (but not too cold, otherwise the flesh will start to darken).

Diseases

There are more than 20 potato diseases caused by fungi and microorganisms. Infection can be transmitted through the soil, through proximity to diseased plants and through storage, if a crop affected by the disease was lying in it a year before.

Potato late blight, remedies

Potato late blight affects leaves, stems, peduncles and tubers. The development of the disease is favored by humid and moderately warm weather.

On the leaves brown growing spots are formed, on the underside of which, under conditions of high humidity (especially in the morning), a cobweb-like white coating is observed - these are spores of the fungus.

On petioles leaves, stems and peduncles, the disease manifests itself in the form of brown oblong spots, they become brittle. In dry weather, the affected tops turn brown and dry out, in wet weather, they turn black and rot. Slightly depressed lead-gray spots form on the surface of the tubers. The flesh under them acquires a rusty-brown color.

Primary sources of infection are diseased planting tubers and plant residues remaining in the soil. From late blight, the yield can decrease by 10-20%, and in the years of early and intensive development of the disease (rainy and moderately warm weather in the second half of summer) - by 50% or more.

How to deal with late blight of potatoes

For prevention plants are sprayed with fungicides during the appearance of buds, and diseased ones - when the first signs of late blight appear.

Then the effect of drugs will be more efficient. First, they are treated with one of the systemic contact fungicides, using 50 g of kurzat R, or 20 g of oxychoma, or 25 g of ridomil MC per bucket of water (10 l).

If repeated treatments are needed, they can be carried out after 7-10 days. To do this, use one of the contact fungicides. On a bucket of water, take 50 g of agiba-peak, or 40-60 g of cartocid, or 40 g of copper oxychloride. The last spraying is carried out 20 days before harvest.

Also, plantings can be treated with a solution of the agate-25K biofungicide, using 25 g per bucket of water.

Potatoes with brown veins - is it possible to eat this?

The first spraying is carried out when the tops are closed, the next - after 10-12 days.

Useful advice. To prevent late blight disease, the tops can be sprinkled with garlic and potassium permanganate. To do this, put 1.5 cups of garlic pulp in a bucket of water, insist for a day, then filter and add 1.5 g of potassium permanganate. Plants are treated in the evening so that drops do not drip from leaves and stems. The first time is sprayed 2 weeks after planting and the second time after 10 days.

What is alternariosis on potatoes

Alternariosis affects leaves, their petioles, stems and tubers of potatoes. Dry dark brown rounded or angular spots form on the leaves, then they merge together, and the leaf dies.

On stems and petioles the disease manifests itself in the form of oblong grayish-brown ulcers. Subsequently, damaged tissues turn brown, rot or dry out. On the surface of the tubers, several small (1-1.5 cm) black-brown spots pressed into the tissue appear.

Development of the disease occurs especially rapidly in hot weather. The pathogen persists on tops not harvested in autumn, on tubers remaining in the soil, and also on tubers stored for spring planting.

Means of protection against Alternariosis. When the first signs of disease appear, the plants should be immediately sprayed with one of the contact fungicides recommended against late blight. Repeated treatments are carried out after 7-10 days.

Rice. 2 Potato Rhizoctonia: 1 - affected shoots; 2 - affected plant; 3 - sessile small tubers; 4 - ugly tuber; 5 - sclerotia of the fungus on the tuber

Rice. 3 scab tubers on potatoes

Rice. 4 Black potato leg: 1 - affected plant; 2 - cork layer formed in the pulp of the tuber after the penetration of soil bacteria and fungi; 3 - cracking of the tuber peel; 4 - affected tuber in the context

Rice. 5 Potato nematodes, potato nematode: 1 - part of the potato root, heavily affected by the nematode; 2-female: 3 - male; potato stem nematode; 4 - male above, female below: 5 - affected tuber in longitudinal section: 6 - tuber severely affected by the nematode

What is rhizoctoniosis on potatoes

Rhizoctonia it affects stems, roots, tubers, but especially sprouts during germination of potatoes and during the emergence of seedlings. On sprouts, the upper part darkens and rots. Weeping brown ulcers appear on them, subsequently general rotting of tissues develops.

On the underground part of the stems elongated dark brown ulcers appear, the stem thickens in this place.

At high humidity underground and aboveground (at a height of 5-10 cm from the soil surface) parts of the stems are enveloped in a dirty white felt coating, which is why this disease is also called the white leg. Often the stem rots in the soil.

The upper leaves are covered with purple spots, the rest turn yellow or remain greenish. Then they curl up, the plant dries up and dies. On tubers, the disease manifests itself in the form of dark formations of various shapes and sizes.

The greatest harm this disease causes if at the time of its appearance it is cold and rainy weather. The source of infection are tubers, plant debris and contaminated soil.

Protection against rhizoctoniosis on potatoes

Tuber germination in the light and spraying them with a solution of biofungicide agate-25K before planting. 14 g of the drug is diluted in 1 liter of water, this amount is enough to process 100 kg of tubers.

To reduce the possibility of disease effective spraying with zircon growth regulator (0.3 ml per bucket of water) at full germination and repeated at the beginning of budding.

At the first signs of the disease, treatment with a fungicide solution of cuprosate (25-50 g per bucket of water). Repeated spraying can be carried out after 10 days, but no later than 20 days before harvest.

scab on potatoes remedies

Common scab. On potato tubers, scab appears in the form of scabs and ulcers, which reduces their commercial and seed qualities. Tubers up to 3 cm in size with a fragile skin are infected.

distribution dry weather contributes to the disease, especially during the formation of young tubers, as well as the introduction of fresh manure and high doses of lime under potatoes. The source of infection are soil micro-organisms that persist there for several years, infected tubers.

What to apply for scab on potatoes

Watering potatoes during drought, especially during the formation of tubers. When pre-planting soil preparation, the introduction of only rotted manure.

Liming carried out only in autumn. During germination, it is advisable to spray the tubers with boric acid and blue vitriol (1 tablespoon per bucket of water). Also useful is the preventive spraying of the tops with a zircon growth regulator (0.3 ml per bucket of water) at the full emergence of seedlings and again at the beginning of budding.

What is a black leg on a potato

Blackleg is a bacterial disease. It begins to appear soon after the emergence of seedlings. The leaves of such plants turn yellow, roll up into a tube along the main vein, and often dry up. The base of the stem and root system rot, turn black or remain green. The plant is easily removed from the soil.

Tubers become infected from diseased tops. Their pulp at the site of the lesion turns into a soft, dark-colored slimy mass with an unpleasant odor. The tubers become light, their peel darkens and becomes dull.

With insufficient soil moisture and warm weather, the development of the disease sometimes stops, and the tubers do not have external signs of damage. However, the infection remains in them and may appear during storage or the next year. It also remains in plant debris that has not been removed from the beds.

Blackleg Remedies

Before the autumn bookmark for storage, spraying tubers intended for spring planting with a solution of fungicide maxim (0.2 l per bucket of water) and subsequent drying.

diseased plants should be removed, and the hole should be powdered with a mixture of ash (1 cup) and blue vitriol (1 teaspoon). Before budding, the tops can be treated with copper sulfate (1 tablespoon per bucket of water) with the addition of 40 g of laundry soap. It also helps to powder the soil near the plants and their stems with crushed charcoal, chalk or ash.

Potato tuber rot

Potato tuber rot pathogens i are different kinds bacteria. Tuber tissues soften and turn into a slimy mass with an unpleasant odor. The development of rot is often a consequence of the defeat of potatoes by diseases during ripening, hypothermia and mechanical damage during harvesting, sharp fluctuations in temperature and air humidity during storage.

Means of protection against rot of potato tubers

Before laying potatoes for storage, spraying the tubers with a solution of fungicide maxim (0.2 l per bucket of water), followed by drying. Removal of all diseased tubers. Maintaining a temperature of 2-3 degrees and humidity of 85% in the place of storage of potatoes.

What is a potato nematode

potato nematode very often appears in areas where potatoes are grown for a long time in one place. Affected plants develop poorly, their leaves turn yellow, shrivel and dry out, starting from the bottom.

root system acquires a fibrous ("bearded") appearance, spherical white, yellow or brown formations with a diameter of about 1 mm appear on them (nematode females and cysts).

tubers small ones are formed. Eggs and larvae remain in the soil for more than 10 years. The nematode spreads with tubers, soil, equipment, containers, as well as water and wind.

Means of protection against potato nematodes

Cultivation of varieties resistant to the nematode. After 2 years, you need to change the place of planting potatoes. If a nematode has appeared on the site, then it is necessary to immediately inform the specialist of the nearest quarantine inspection. You cannot cope with this disease alone.

Return to the table of contents - Gardening

We try not to harvest large potatoes for the winter, fearing that they will be empty inside, that is, with a hole. Although outwardly it looks very good, and it is convenient to use such tubers. After all, it happens like this, they prepared potatoes for the winter and everything seems to be fine, they bought or grew them, they dug up potatoes, the tubers are large, good, but if you cut them, there is a hole inside the tuber - emptiness.

What are these voids in potatoes? Potato hollowness is the name given to such holes and voids in potatoes.

What should be the potato?

This is not spoilage and not a disease, and not even pests have eaten these holes in potatoes. The hollowness of the potato does not harm health when eating such tubers, but leads to losses, because sometimes most of the tuber has to be cut off.

Potato hollowness is most often manifested in large-tuber potato varieties. These varieties include potatoes: Lyubimets, Gatchinsky, Temp, Table 19.

Large potato tubers grow, and not only from varieties predisposed to this, but also for other reasons, this is mainly due to agricultural technology, with abundant fertilization causing the growth of tubers. Large tubers of potatoes grown on fertile soil enriched with organic fertilizers, compost, high soil moisture also matters.

The hollowness of potato tubers reduces its keeping quality, makes it inconvenient for cooking and leads to large losses. Planted large potatoes with signs of hollowness are often subject to rotting, which develops inside the tuber. Tuber walls become thin, and the tuber becomes vulnerable to mechanical damage during transportation. Microorganisms that cause rotting and, as a result, rotting of the potato tuber, penetrate into the damage. Microorganisms can get into the voids in the tubers and through the passages if the potato is affected by a dangerous wireworm pest.

The cause of potato hollowness and how to eliminate it

Compliance with agricultural technology will help grow healthy tubers, even large sizes, without damage by hollowness.

The reasons for the formation of emptiness in tubers are the uneven development of tops and tubers. The tops of potatoes lag behind in growth, and the tubers grow rapidly, however, the tubers lack nutrients and oxygen, which leads to poor development of tissues inside the tuber, metabolic processes are disturbed in it, starch is not formed, and hollow hollows form in the tubers.

It is necessary to loosen the row spacing after watering and rain. During the formation of tubers, carry out hilling potato bushes.

Too much organic matter in the soil frequent application of organic fertilizers, oversaturates the soil with nitrogen and minerals; for planting potatoes, organic matter should be applied no more than once every three years. Be sure to combine the application of organic fertilizers with mineral fertilizers, and when planting in the hole, add a tablespoon of wood ash.

Seed potato quality can also cause hollows in potatoes. For planting, use seed potatoes weighing at least 50g, select zoned potato varieties with high yield and average tuber size.

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Potato diseases

A) Potato diseases caused by fungi

PHYTOPHTHOROSIS. An infectious disease caused by the fungus Phitophtora infenstans.

The infection persists in tubers, in the soil and on plant debris. Leaves, stems and tubers are affected. As a rule, the disease is observed mainly in the second half of the potato growing season, first on the lower leaves in the form of dark brown spots with a grayish sporulation on the underside of the leaves. In the presence of favorable conditions, the disease passes to the stems. Optimal conditions for the development of late blight are created in cool and rainy weather (at a temperature of + 8 ... 100C and air humidity over 90%). Often the tops on the site die in 5 ... 10 days.

As a result of sexual reproduction, oospores are formed that can be stored in the soil for 4–5 years. Symptoms of the disease in this case often appear earlier than usual - before the budding phase. In this case, the first signs of the disease are often observed on the stems, which are easily broken and the tops die off. Sporulation of the fungus is noted on the lower and upper surfaces of the leaves, as well as on the stems. The harmfulness of late blight increases sharply due to the severe damage to tubers.

Control measures. Cultivate relatively late blight-resistant varieties. Cleaning and destruction of affected plant residues, landfills, waste from potato processing, timely and deep hilling before closing the tops, removal and destruction of the affected tops 7 ... 10 days before harvesting, drying the tubers before storing. Seed material dressing before planting with one of the following preparations: botran (20 g/c), polycarbocin (260 g/c), cuprosan (25...50 g/c), cineb (50...100 g per 1 c of tubers). The introduction of increased doses of potash and the use of copper-containing fertilizers.

At a plant height of 15 ... 25 cm, preventive spraying of plants is carried out with a 1% solution of Bordeaux liquid (100 g of copper sulfate and 100 g of lime per 10 liters of water). Consumption rate - 6 liters per 1 weave. Of the chemical means of combating late blight, systemic preparations are the most effective: ridomil and acrobat (a matchbox in a bucket of water). Also used are drugs of contact action polycarbocin, polychom (40 g per 10 l of water). The consumption rate is 6 liters per 1 weave.

Rhizoctonia manifests itself in the form of a “black scab” of tubers, rotting of the eyes and seedlings, they die without reaching the surface, and the roots die. In summer, after the tops close, with high soil and air humidity, the fungus begins to sporulate, forming an off-white coating at the base of the stems. This is the sexual stage of the fungus, called the "white leg". Its intensive development in the field indicates a severe damage to the underground organs of the potato. The resting stage of the fungus - sclerotia can persist in the soil for 2-6 years. Under conditions of monoculture and crop rotations with short rotation, the pathogen accumulates in the soil, which ensures a high level of the disease.

Control measures. Planting potatoes with healthy planting material is the main condition for effective protection against rhizoctoniosis. Seed treatment with fungicides. Cultivation of potatoes in crop rotation. Germination or heating of seed tubers, early dates and correct planting depth, destruction of the soil crust, timely care, etc.

POTATO CANCER. It is a quarantine object. All parts of the plant are affected, except for the roots, due to which the potato disease is most often detected only at the time of harvest. The disease manifests itself in the form of growths on tubers, stolons and at the root collar. The outgrowths are initially small, and then grow and often exceed the size of the tuber. As the growths age, their color changes from white to dark brown. In the future, the growths decompose at the same time, the tuber also rots, turning into a brown slimy mass with an unpleasant odor. The development of the disease is promoted by increased humidity and soil temperature in the range of + 16 ... 200C. The infection persists in the soil for up to 20 years, as well as on tubers.

Control measures. Plant resistant varieties. In the foci of the disease, potato harvesting should be carried out only in the presence of a representative State Inspectorate by quarantine. Sick tubers are placed in large pits and buried, the tops are dried and burned. Cabbage, cucumber and other crops are planted on the site. The soil from the cancer pathogen is cleared after 5 ... 6 years.

MACROSPORIOSIS. Appears on the leaves in the form of rounded concentric dry spots of various sizes, on the stems - in the form of oblong grayish-brown dry ulcers. Harmfulness increases in dry and hot weather. On the affected tubers, superficial black, slightly depressed spots of various configurations are formed; only the integumentary tissue of the tubers is damaged. But during winter storage, another infection occurs through these places, and the tubers, as a rule, rot by spring.

Control measures. Harvesting seed tubers only in a mature state, applying increased doses of potash fertilizers. Spraying potato plants and soil in dry hot weather with a (white) solution of chalk or lime (arbitrary norms), which significantly (up to 50C) reduces the temperature of the soil in the tuber formation zone and reduces overheating of the plant.

DRY ROT. Dry rot (fusarium) develops on tubers during storage. At first, grayish-brown, slightly depressed spots appear on the tuber, and the integumentary tissue is slightly wrinkled. The flesh under the spot becomes loose, acquires a brownish color. It forms voids filled with white, yellowish, reddish or dark fluffy mycelium of the fungus. Diseased tissues dry out quickly, forming peel folds around the site of the primary spot.

The pathogen fungus comes out and forms fluffy pads of mycelium of various colors on the surface of the tuber. The tuber becomes light and so hard that it is difficult to cut with a knife. The causative agent of the disease enters the tuber through wounds on the peel resulting from mechanical damage, as well as through places affected by other diseases or damaged by harmful insects. The disease is favored by high temperatures and high humidity during storage of potatoes. The infection persists in the soil.

Control measures. To prevent dry rot, do not allow mechanical damage to the tubers during harvesting and transportation: they must be poured into the container carefully, from a height of no more than 30 cm, you can not walk on the tubers. Planting with healthy seeds. Compliance with the modes of storage of potatoes. Reduction of autumn-winter bulkheads of tubers in order to reduce their re-infection.

SCAB. There are several types of this disease. Common scab affects mainly young tubers, which are covered with a continuous crust, ulcers, and cracks may occur. Such tubers, as a rule, rot during storage. Powdery scab is characterized by the appearance of spots on the tubers, then brown warts, which rupture in a star-like manner and expose a dark, powdery mass of spores of the fungus. With tuberculous scab, the tubers near the eyes are covered with tubercles, which, merging, spoil a significant part of the tuber surface. Such tubers most often do not germinate, forming lunges of potato seedlings. Tubers infected with silver scab are distinguished by dark yellow rounded spots, first smooth, then depressed with a silvery sheen. The infection persists in the soil and on seed tubers.

Control measures. Planting healthy seed tubers, removing diseased tops before harvesting, using rotted manure rather than fresh, applying micronutrient fertilizers containing boron, copper, and manganese. Formalin treatment of tubers is effective against powdery scab.

B) Bacterial diseases

BLACKLEG. Plants and tubers are affected. Diseased plants are detected shortly after emergence. The leaves, starting from the top, turn yellow and curl into a tube along the main vein and dry out. The base of the stem, as well as the roots, rot and become intensely black in color. Diseased bushes or individual stems wither and are easily pulled out of the soil. Unlike rhizoctoniosis, the affected part of the stem is thinner than the healthy part.

The tuber is affected from the stolon end. In the place of its defeat, the pulp turns into a soft, dark-colored slimy mass with an unpleasant odor. On the border between the diseased and healthy tissue there is a darker band of corked cells. In the future, the tuber dies from wet rot. The disease is favored by high humidity, elevated soil temperature. The infection persists in the seed tubers.

Control measures. Warming up or germination of seed material. Treatment of tubers with a 5% suspension of TMTD. Planting only whole and healthy tubers. Removal of diseased bushes during cleaning: after germination, and during flowering - along with tubers. By careful cleaning, the harmfulness of the black leg can be minimized or completely eliminated. Tops mowing. Drying and greening of seed tubers after harvesting. Bookmark for storage of healthy tubers.

ROT ROTT. Plants and tubers are affected. On plants, the disease manifests itself in the form of bacterial wilt, which begins during the flowering of potatoes and continues until the end of the growing season. At the beginning, one or two stems wither, then all the rest in turn. Withered stems fall to the ground. With rapid withering, their color may remain green, with slow wilting, the diseased stem quickly turns brown.

The tuber is more often affected from the stolon end. The defeat of tubers begins in the soil. Part of the vascular system rots, softens, turns yellow, and when pressed, a rotting mass (from light yellow to brown) is released from it. Through the vascular system, rot spreads to neighboring tissues: there is a general lesion of the core of the tuber, which completely rots. In conditions of high humidity, the disease turns into a wet rot. Harmfulness during the growing season increases with high temperature and soil moisture. The infection persists in the seed tubers.

Control measures. The same as with the black leg, except for the disinfection of the seed.

WET ROT. The tuber tissue softens, at first it is light, then dark brown or pink. The tubers turn into a slimy rotting mass with an unpleasant odor. The development of the disease is facilitated by sharp fluctuations in temperature and high humidity during storage. Under unfavorable storage conditions, all potatoes can rot in 10-15 days.

Control measures. Germination of planting material. Planting potatoes only whole and healthy tubers. Prevention of the development of bacterial diseases. Compliance with optimal storage conditions. Damage, freezing of tubers should not be allowed. Timely removal of foci of rot.

B) viral diseases

Infectious diseases caused by phytopathogenic viruses. Virus diseases of potato are ubiquitous, in some cases they surpass fungal and bacterial diseases in terms of harmfulness. Every year, the global potato industry loses 15–20% of the crop from viruses. In addition, the nutritional value of tubers is significantly deteriorating: the dry matter content is reduced by 0.2 ... 1.5%, starch - by 0.5 ... 3.0%, vitamin C - by 1.5 ... 7.0 mg%. About 20 viruses cause harm to potatoes, often two or three of their species are found on one plant. The best known are wrinkled mosaic, striped mosaic, leaf curl, mottling, leaf curl, common mosaic, gothic (fusiform tubers), aucuba mosaic, variegation, yellow dwarfism, curly dwarfism, and apex panicle. The science of virology is the study of viruses.

All potato viruses are highly infectious, spread rapidly (mainly during the growing season, less - during the period of storage of tubers and their preparation for planting). Viral diseases are transmitted mainly by contact (by contact of the tops, roots, by sorting tubers, by hands, people's clothes, animals), as well as by living organisms: piercing-sucking insects (aphids, cicadas, bugs), mites, nematodes, soil fungi. Transmission of viruses by weed seeds is possible.

Viruses are closely associated with the plant cell. Penetrating into plant cells through damage and multiplying in them, viruses disrupt cell metabolism, reduce photosynthesis, increase respiration and transpiration, can inhibit plant growth and development, cause dwarfism, or selectively inhibit the development of some plant organs, cause increased growth of others. Viral infection can cause death of cells, tissues (necrosis) and the whole plant.

Often virus-infected potato plants look healthy on the outside (latent infection), but the yield is reduced even if there are no symptoms of infection. Signs of virus damage are different, depending on the duration of the infection, the type and strain of the virus, the external conditions that weaken the plants (high and low temperatures, excessive moisture or lack of moisture). The most typical manifestations of a viral infection on potatoes are mosaics, deformations, chlorosis, necrosis, yellowing of leaves. Tubers are small, often ugly, spindle-shaped.

Control measures. Sick plants are practically incurable. Therefore, a set of protective measures should consist mainly of techniques that prevent infection and the spread of a viral infection. These methods include. Cultivation of resistant varieties. Improvement of potatoes by methods of thermo- and chemotherapy and culture of meristems in research institutions and their subdivisions. Planting healthy tubers. Preplant warming and germination of tubers in the light. Improved selection, when only healthy ones are selected for seeds appearance plants with the highest tuber yield. Weed control - aphids (carriers of a viral infection). High agricultural technology. Crop rotation, spatial isolation. Balanced fertilization. Timely tillage. Optimal timing planting and harvesting. Wellness cleansing. The use of chemicals against insect vectors. Early removal of tops.

The first preventive spraying (on seed plots) against aphids is carried out 10-12 days after full emergence, subsequent (as needed) - at intervals of 10-15 days. The last processing is carried out no later than 30 days before harvesting. To destroy carriers of viral infections, the same drugs are used as against the Colorado potato beetle.

D) Mycoplasma diseases

Distributed in all zones of potato growing. They are caused by microscopic organisms - phytopathogenic mycoplasmas. Dramatically reduce the yield and quality of tubers. The most harmful are stolbur wilt (stolbur), purplish tops, "witch's brooms", and round leaves. The infection is not transmitted by contact. Mycoplasmas are spread by infected planting material, as well as by cicadas and mites. The source of infection is perennial weeds (field bindweed, sow thistle, chicory).

By clogging the vessels of plants, mycoplasmas cause wilting, dwarfism, yellowing of plants, shredding of leaf blades, and growth of flowers. The growth of plants is inhibited, the development of generative organs is disrupted (greening of flowers, the transformation of individual parts of the flower into leaf-shaped formations, the appearance instead of one flower of many of them with incorrect development). Mycoplasmas are one of the main reasons for the germination of tubers with filamentous sprouts.

Control measures. The fight against mycoplasmal diseases is reduced to planting healthy planting material, the destruction of weeds - the source of infection and the cultivation of resistant varieties. For the treatment of diseased plants, the use of antibiotics of the tetracycline group, as well as thermotherapy of tubers at a temperature of + 35 ... 500C, is promising.

BRONZE LEAVES. Occurs with insufficient intake of potassium in plants. The leaves are covered with small dots of dead tissue, wrinkled. In the future, tissues from the edge of the leaf blade partially die off, and the leaf acquires the color of oxidized bronze. The edges of the lobes are twisted down. Roots and tubers develop poorly. Plants often die prematurely.

Control measures. When the first signs of the disease appear, it is necessary to feed the plants with potash fertilizers. In areas where leaf bronzeness systematically develops, increased doses (by 25 ... 50%) of potash fertilizers are applied in the fall.

BROWN SPOT OF STEMS. At the beginning of growth, the tops have a lighter color than ordinary plants. Then, on the stems, starting from the bottom, brown dry elongated spots of dead tissue appear on the petioles of the leaves. The disease gradually spreads upward. The lower leaves wither, dry up, but remain on the stems. The upper leaves turn yellow, partially curled. They appear dark small angular necrosis between the veins. In contrast to the banded mosaic, blackening and death of the veins are not observed. The plant is stunted. The disease manifests itself on heavy acidic soils containing an excessive amount of iron and aluminum oxides.

Control measures. When digging a site in the spring, wood ash is added at the rate of 50 kg per hundred square meters or lime 15 ... 20 kg.

IRONAL SPOT (RUSTY) OF TUBES.

Note: potato tuber diseases

On the section of the affected tubers, red-brown spots of various sizes and shapes are visible. Unlike late blight, spots do not have access to the periphery of the tuber. The disease is caused by malnutrition of plants and elevated soil temperature, due to a decrease in the efficiency of photosynthesis and an increase in oxidative processes in tubers with a lack of nitrogen, calcium and magnesium in them, an excess of iron and aluminum, which activates this process.

Control measures. To prevent the disease, organic fertilizers must be applied under potatoes in combination with a complete mineral fertilizer. Liming of acidic soils.

GROWTH OF TUBES. The disease manifests itself in the form of the formation of nodules on the mother tubers of potatoes and the outgrowth of tubers during plant growth. Nodules are formed on the mother tubers in the soil in spring under adverse weather conditions (damp and cold, or, conversely, dry and hot), as well as in storage - at elevated temperatures and lack of atmospheric oxygen. The formation of nodules can occur due to damage to the eyes of the mother tuber by various diseases.

With alternating dry and wet weather in the second half of the growing season, stolons develop from the eyes of young tubers, on which one or more additional nodules are formed. If the stolon leaves the soil, the tuber may grow with the formation of a shoot (stem).

In dry hot weather, the growth of tubers stops, as a result of which the peel becomes stronger. With the resumption of favorable conditions on tubers that have lost their ability to grow, new nodules (children) are tied or outgrowths are formed that disfigure the tubers, while the quality of the crop is noticeably reduced.

Control measures. To prevent the sprouting of tubers, germinated planting material is used, planting it in warm soil at the optimum depth. In dry periods, it is necessary to water the plants.

DARKENING OF THE PULSE. The flesh of the tuber on the cut acquires a dark color (gray, black or bluish). The cause of the disease is insufficient potassium nutrition of plants during the period of tuber formation, and a lack of oxygen and low temperatures during storage. Tubers with darkening of the pulp are of little use for nutrition due to a decrease in the content of starch and vitamins in them.

Control measures. Application of potash fertilizers, ensuring good aeration of the soil, preventing injury to tubers during harvesting, transportation and storage, compliance with optimal storage conditions.

HOLLOW TUBE. Inside the tuber, voids of various configurations and sizes are formed. The cavity of the hollow is covered with a thin skin of cream or light brown color. If the hollow does not have access to the surface of the tuber, then there is no decay of tissues and various kinds of raids. Hollowness is formed as a result of lagging behind the growth of internal tissues from the growth of external ones, due to an excess of nitrogen in the diet and a lack of potassium and phosphorus. Larger tubers are more commonly affected.

Control measures. Hollowness can be reduced by pre-harvest haulm mowing and the introduction of increased doses of potash and phosphorus fertilizers.

Judging by the photo, potato tubers are affected by glandular spotting. This disease is also called tuber rust.

Characteristics and causes of the disease

Glandular spotting appears as brown (rusty) spots on potato flesh. The color of the spots can vary and acquire different shades - from light amber to brown-red. Lesions are most often located around the circumference, closer to the core, but are scattered throughout the tuber. The spots do not have a clear shape, the edges are blurry. Further decay of the affected part of the pulp does not occur: it simply becomes hard, and the starch grains are destroyed.

A characteristic feature of the disease is that it is impossible to identify it during an external examination - rustiness is visible only when the tuber is cut.

The causes of the appearance of the disease are changes in the composition of the soil and weather conditions, which entail disturbances in the development of potatoes and their nutrition. These include:

• high air temperature;
• lack of moisture in the soil (drought);
• excessive amounts of iron and aluminum in the soil;
• lack of phosphorus.

Rusty tubers are not suitable for consumption, but they can be used for planting (the disease does not pass to the next crop).

Rusty spot appears and develops only during the period of growth of potato bushes; during storage, the disease does not spread further. Most often, rust affects plantings in hot and dry weather, but it can also be with sufficient soil moisture if the air temperature reaches 30 degrees Celsius. In cold summer, when the soil temperature drops to 18-11 degrees, the disease does not manifest itself.

How to protect potatoes from rust?

First of all, zoned varieties resistant to this disease should be used for planting.

Why does potato tops turn yellow, dry and wither

In addition, it is necessary to ensure proper nutrition of tubers during growth. To do this, periodically fertilize the soil with nitrogen fertilizers (organic, nitroammophoska), and also introduce phosphorus in a mobile form (superphosphate) throughout the entire period of development. The liming of the site works well against rust.
Do not forget about the timely watering of plantings on dry days, as well as a decrease in soil temperature.

It has been observed that rusty spots on potatoes appear less frequently if they are planted in an area where lupine, alfalfa, rapeseed or oil radish previously grew.

Protecting potatoes from other common diseases - video

Potato tubers affected by "hollowness" special conditions storage is not required and usually nothing special happens to such tubers during storage. In potatoes affected by "hollowness" - the structure of the starch grain is destroyed, the cells die off, form cavities.

With improper storage of potatoes, even unaffected tubers can turn into a completely unsuitable product for human consumption, even for cattle.

Another thing is when cavities are found when cutting the tuber, as a rule, such cavities are covered with a brown peel, which also needs to be cleaned. Which is often unexpected and not very pleasant. It happens that after cleaning such tubers nothing remains, since you have to clean both the outside and the inside. However, the "hollowness" of potato tubers does NOT affect the taste!

*** Only after the defeat of potatoes by fungal diseases, the tubers are UNSUITABLE for storage, as subsequently the tubers shrivel, dry out, become light and hard, sometimes completely empty inside.

As far as forage varieties are concerned, full responsibility I declare, such varieties do not exist!

There are technical varieties of potatoes.
Grown for processing for the production of potato starch!!! But such varieties, as a rule, are not available for sale in the form of seed potatoes in specialized stores "Seeds".

It is possible to distinguish technical varieties of potatoes only when peeling.
By removing the skin, by peeling, the pulp of technical varieties darkens immediately and when cooked, the tubers remain gray and, as a rule, no longer lighten.

If there is oily soil on the plot, scatter on the plot for potatoes IN AUTUMN: wood, peat ash, any potassium-phosphorus fertilizer.
And also, refrain from applying nitrogen fertilizers in SPRING.
Remember, you should follow the norms for applying organic and mineral fertilizers.
To reduce the "hollowness" of tubers during cultivation, you can "deceive" the plant!

* When planting, 1-2 handfuls of wood or peat ash are added to each well.
* Before harvesting, 2-3 weeks in advance, the tops should be removed.

The main diseases of the potato and the causes of its damage photo

"Hollowness" of potatoes are subject only to large-fruited varieties of potatoes:
Gatchina;
Giant / new variety /;
Radinka;
Pace;
Favorite; and etc.
! Choose zoned varieties for planting.
! Do not use for planting - potatoes bought in grocery store. Today, food potatoes of foreign selection are sold everywhere, which are not suitable for our latitudes and soils.

In addition, edible potatoes supplied to Russia from abroad are treated with chemical anti-sprouting agents, it is impossible to get a potato crop from it / even if the tubers germinate, the crop will be poor if the Colorado potato beetle does not eat the tops.
In the worst case, the tubers do not develop at all, since the germination time was late and the growing season conditions were short.

Beautiful and large potatoes are not always the best. Sometimes when cutting a tuber, a cavity is found inside, separated from the pulp by a creamy or light brown peel. In round potatoes, voids are more often spherical or cruciform, in oblong ones - oval. This disease is called hollowness of potato tubers and occurs as a result of adverse weather conditions or a violation of growing technology.

Is it possible to eat. Potatoes empty inside are edible, but when peeling, up to 50% of the tuber mass has to be thrown away. Hollow potatoes are stored worse than healthy ones, and if the tuber was damaged by a wireworm or potato moth larvae, pathogens penetrate into the cavity, which causes rotting.

Prevention of potato hollowness

While the potato is growing, it is difficult to determine whether it is sick with hollowness or not. Externally, hollow tubers are no different from healthy ones. Only indirect signs indicate whether there is a risk of voids in potatoes.

Causes of voids in potatoes

A void in a potato occurs when the outer tissues of the tuber grow much faster than the inner ones. Due to the strong tension, the intercellular bonds are broken. A wound is formed in the pulp, as the tuber grows, it heals and expands.

This happens if the root crop unevenly receives nutrients, mainly nitrogen and water. It has been noted that large potatoes are prone to hollowness, and voids appear extremely rarely in small ones. Accordingly, the disease often affects large-tuber varieties: Temp, Gatchinsky, Lyubimets, Tuleevsky, Yavir, Sineglazka.

Conditions under which the likelihood of voids inside the potato increases:

• after hot, dry weather, when the growth of tubers has slowed down, heavy rains begin. This is especially harmful if the soil is clayey: it retains excess moisture longer;
• in the southern regions, hollow potatoes are planted too late in light sandy loamy soil. Soils of this type dry out very quickly, and the tubers are constantly under stress, sometimes from a lack, sometimes from an excess of water;
• potatoes of ultra-early and early varieties are harvested one to two months later than the due date, expecting that the tubers will still grow. They really become larger, but lose their taste and burst from the inside;
• excessive fertilization of the soil with nitrogen fertilizers or organic matter;
• boron deficiency.

To find out if the tubers are sick with hollowness, immediately after digging, it is necessary to cut several especially large specimens. If the potatoes harvested in the fall are empty inside, then next season you need to change the fertilization scheme of the site. The amount of nitrogen fertilizers needs to be reduced, and phosphorus-potassium fertilizers need to be increased. A sign of "overfeeding" of potatoes with nitrogen is too thick and high tops. The full rate of nitrogen fertilizers should be applied only once every 3-4 years.

Another reason for hollowness is a lack of boron. This trace element is found in ash. It is best to apply it during planting, as well as during and after flowering, but not more than 20–25 g per bush. Excess ash provokes scab.

If hollow potatoes regularly ripen on the site, it is recommended to spray the tubers with a solution of boric acid (2 g per liter of water) before planting.

To find out if potatoes need additional feeding with boron, several grains of beets are sown on the edge of the plot: it is most sensitive to boron starvation. If the leaves of the beets grow deformed and curl up, then the potatoes also lack boron. In such cases, plantings are sprayed with a solution of 5 g of boric acid per 10 liters of water. By adding 10 g of copper sulfate to the composition, the gardener will receive an effective remedy against late blight. It is allowed to spray a potato plantation with boric acid up to 5 times per season (with an interval of 2 weeks).

Features of the prevention of hollowness of large-tuber varieties

So that potatoes of large-tuber varieties do not suffer from hollowness, they need to organize a constant humidity regime:

• thicken the plantings so that the tubers do not grow too large, and the soil shaded by the tops dries out more slowly. The maximum distance between bushes in a row is 30 cm;
• plant potatoes in double beds: bed width - 45 cm, distance between rows - 30 cm, between beds - 90 cm;
• hill bushes high, periodically loosen the soil;
• hilling can be replaced by mulching;
• be sure to water the plants when the soil at a depth of 5-6 cm dries;
• on a site with sandy soil, equip a drip irrigation system.

Storage of potatoes with hollowness

It does not make sense to cut all the tubers, but if at least a few hollow ones are found, it is better to select large potatoes before storing them and spray them with Fitosporin-M solution. The drug contains a strain of hay bacillus, harmless to humans, but protecting the roots from rot.

Large tubers should be stored separately from the rest and eaten first. If the potato is empty inside, it cannot be used for planting.

“My potatoes are blackening. You cut a potato tuber - inside is black and throw away half. Everything seems to be fine in my area. Seeds bought good, in a reliable place. What could be the reason for the blackening of potatoes?

Valery P., Chelyabinsk

Darkening of the pulp, or gray spotting of potatoes, is not a contagious disease, but a physiological one. The reason is a violation of agricultural technology for growing and storing potatoes. While the tubers grow and reach the kitchen, many such violations accumulate.

The main causes of browning potatoes (gray spot)

• 1. Lack of potassium in the soil or excess nitrogen during the period of growing potatoes. For example, they brought in a lot of fresh manure, mowed green grass, buckwheat husks, or dug up the land with a large crop of sederats and planted potatoes in the same year. Potatoes do not like fresh organics, because too much nitrogen is released and an abundance of fungi accumulates during its decomposition. As a result, tubers are affected by scab, and dark spots appear on the pulp during storage. Potato organic matter is essential, but not fresh, but rotted, 1-2 years after application.
• 2. During the formation of tubers, both a lack of moisture and waterlogging are dangerous. With a lack of moisture, the tubers overheat in dry, hot soil, and when waterlogged, they suffocate from a lack of oxygen.
• 3. Untimely harvesting. Early harvesting of unripe tubers results in darkening of the flesh. And vice versa, if the potatoes are ripe, the tops are naturally dried up or mowed, and the harvesting is delayed, then in warm sunny weather, the tubers are in dry, heated ground for a long time and overheat. Potatoes can go bad from long storage in bags without refrigeration. After digging, they were not cooled and laid in storage without ventilation. After 2-3 months after such harvesting, gray spots appear in the pulp. Potatoes are also “steamed” if, after digging, they are stored for a long time in bags without refrigeration.
• 4. Too late harvesting with the onset of light frosts is dangerous. In the cold ground, the tubers are supercooled. and the pulp darkens during storage. It is important to know that at a soil temperature of minus 1.5 - minus 1.7 degrees, the tubers freeze and rot during storage like wet rot.
• 5. An important cause of gray spotting is bruising and compression of tubers during harvesting, packaging in any container and transportation to the destination.
• 6. Violation of storage conditions when laying the crop for a long period. Optimum storage temperature plus 2 - plus 3 degrees C
  mandatory ventilation if the piles are high. At a temperature of 0 minus 1 degrees, the potato does not rot, but acquires a sweetish taste, and the flesh darkens. At a temperature of plus 7-12 degrees, the tubers quickly go through a dormant period (for different varieties it lasts up to 2-4 months), they germinate flabby, gray spots appear inside, taste and quality are lost.
• 7. Possible cause it may be that the selected variety contains too much starch. Such varieties are more likely to suffer from gray spotting.
• 8. Potatoes are often affected by an infectious disease - a black leg. The disease is transmitted with infected uterine tubers. From a diseased bush we get diseased tubers varying degrees defeat. The development of the disease continues in storage. The disease is different from gray spot. The tuber turns black from steel. Blackness captures the entire heart-shaped part up to the vascular ring, and then the entire tuber rots, emitting an unpleasant smell of rot. During growth, diseased bushes differ from healthy ones. They need to be seen in time, dug up along with the tubers and removed from the field before the main harvest.

How to deal with gray spot of potatoes?

During the growing season, planting potatoes are fed with potash fertilizers at the rate of 20 g per 10 liters of water.

“My potatoes are blackening. You cut a potato tuber - inside is black and throw away half. Everything seems to be fine in my area. Seeds bought good, in a reliable place. What could be the reason for the blackening of potatoes?

Valery P., Chelyabinsk

Darkening of the pulp, or gray spotting of potatoes, is not a contagious disease, but a physiological one. The reason is a violation of agricultural technology for growing and storing potatoes. While the tubers grow and reach the kitchen, many such violations accumulate.

• 1. Lack of potassium in the soil or excess nitrogen during the period of growing potatoes. For example, they brought in a lot of fresh manure, mowed green grass, buckwheat husks, or dug up the land with a large crop of sederats and planted potatoes in the same year. Potatoes do not like fresh organics, because too much nitrogen is released and an abundance of fungi accumulates during its decomposition. As a result, tubers are affected by scab, and dark spots appear on the pulp during storage. Potato organic matter is essential, but not fresh, but rotted, 1-2 years after application.
• 2. During the formation of tubers, both a lack of moisture and waterlogging are dangerous. With a lack of moisture, the tubers overheat in dry, hot soil, and when waterlogged, they suffocate from a lack of oxygen.
• 3. Untimely harvesting. Early harvesting of unripe tubers results in darkening of the flesh. And vice versa, if the potatoes are ripe, the tops are naturally dried up or mowed, and the harvesting is delayed, then in warm sunny weather, the tubers are in dry, heated ground for a long time and overheat. Potatoes can go bad from long storage in bags without refrigeration. After digging, they were not cooled and laid in storage without ventilation. After 2-3 months after such harvesting, gray spots appear in the pulp. Potatoes are also “steamed” if, after digging, they are stored for a long time in bags without refrigeration.
• 4. Too late harvesting with the onset of light frosts is dangerous. In the cold ground, the tubers are supercooled. and the pulp darkens during storage. It is important to know that at a soil temperature of minus 1.5 - minus 1.7 degrees, the tubers freeze and rot during storage like wet rot.
• 5. An important cause of gray spotting is bruising and compression of tubers during harvesting, packaging in any container and transportation to the destination.
• 6. Violation of storage conditions when laying the crop for a long period. Optimum storage temperature plus 2 - plus 3 degrees C
  mandatory ventilation if the piles are high. At a temperature of 0 minus 1 degrees, the potato does not rot, but acquires a sweetish taste, and the flesh darkens. At a temperature of plus 7-12 degrees, the tubers quickly go through a dormant period (for different varieties it lasts up to 2-4 months), they germinate flabby, gray spots appear inside, taste and quality are lost.
• 7. A possible reason may be that the selected variety contains too much starch. Such varieties are more likely to suffer from gray spotting.
• 8. Potatoes are often affected by an infectious disease - a black leg. The disease is transmitted with infected uterine tubers. From a diseased bush we get diseased tubers of varying degrees of damage. The development of the disease continues in storage. The disease is different from gray spot. The tuber turns black from steel. Blackness captures the entire heart-shaped part up to the vascular ring, and then the entire tuber rots, emitting an unpleasant smell of rot. During growth, diseased bushes differ from healthy ones. They need to be seen in time, dug up along with the tubers and removed from the field before the main harvest.

How to deal with gray spot of potatoes?

During the growing season, planting potatoes are fed with potash fertilizers at the rate of 20 g per 10 liters of water.

In dry weather, water and mulch, in wet weather - loosen, spud. ventilate. In the fall, they are cleaned and dried in a timely and accurate manner, without injury. When delivered to storage, they are not kept in bags for a long time, but scattered for quick cooling, ventilation is opened. If possible, keep the temperature 2-3 degrees.

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The quality of seed potatoes depends on the presence of tubers affected by pathogens and pests. The seed material must contain a minimum number of such tubers. Below is given short description possible damage to potato tubers.

Fungal diseases

late blight- is the most common and dangerous potato disease in most countries of the world. On the affected tubers, brown or grayish (depending on the variety and color of the peel) slightly depressed hard spots are formed, extending inward in the form of uneven brown smudges (“tongues”).
Most often manifested in areas with high humidity, where precipitation often falls, fogs, heavy dews are observed. Infection with late blight of plants proceeds at a tremendous speed, from single diseased bushes in 10-15 days the entire field can become infected, and in 2-3 weeks the plants can be completely destroyed. Alternariosis is a widespread potato disease. On the surface of the tuber, clearly visible, sharply different from the healthy part, depressed spots of irregular shape are formed, darker than skin. On the surface of large spots, wrinkles often appear, arranged in a circle and directed in parallel. On the section under the spots, the tuber tissues form a dense, hard, dry blackish-brown rotted mass, which differs sharply from healthy tissue.
The disease manifests itself in the budding phase of plants and develops throughout the summer. The fungus mainly infects leaves, sometimes stems and rarely tubers. First, dry brown spots appear on the lower, and then on the upper leaves. Dark brown or black spots of affected tissue may also appear on the stem. Fusarium dry rot- manifests itself throughout the entire period of storage, reaching its maximum development by the middle or end of storage. At first, grayish-brown, dull, slightly depressed spots appear on the tuber. In the future, the flesh under the stain becomes dry, rotten, the skin wrinkles, voids filled with mycelium form in the affected part of the tuber. On the surface of the tuber, sporulation develops in the form of convex pads of white, yellowish or pink flowers. Black scab (rhizoctoniosis)- black flat ones are formed on the tubers, resembling dried lumps of soil, difficult to scrape off the sclerotia of the fungus. With severe damage, almost the entire tuber is covered with sclerotia. This disease is especially harmful in cold, rainy springs. Severe defeat leads to attacks of plants, their oppression, deterioration of the presentation of tubers. Yield losses from rhizoctoniosis reach up to 20-25%. Important conditions that determine the development of rhizoctoniosis on potatoes are the temperature and humidity of the soil and air. The optimum soil temperature for the development of the disease is about 17 degrees, the humidity is 60-70% of the total moisture capacity. Optimum conditions for infection of plants are created on heavy (loamy) soils. Acidity in the Ph range from 4.5 to 8 is not significant. Rhizoctonia develops somewhat better at Ph 5.5 - 6.5, which coincides with the optimal acidity for potato growth. common scab- there are several types of manifestation of common scab - flat, reticulated, convex and deep. In the first type, the affected area remains flat, with brown indurations or abrasions (scabs) forming on the skin surface. With a net type of scab manifestation, the tubers are covered with cracks and "grooves" intersecting in various directions. Convex scab is characterized by the fact that the affected areas of the peel rise above the surface of the tuber in the form of warts or wart-like growths with cone-shaped depressions in the center. A distinctive feature of deep scab is depressed brown sores up to 0.5 cm deep, surrounded by a torn peel. Powdery scab- rounded light closed pustules in the form of warts up to 5 mm in size are formed on the surface of the tubers. When the tubers ripen, often after harvesting, the spots are rounded, become embossed, dry up, their peel bursts and ulcers are formed, filled with a brown dusty mass, consisting of fungal spores and destroyed tuber tissues. The remains of the peel remain for a long time along the edges of the pustules, giving them a star shape. The disease develops more strongly on waterlogged (70% of total moisture capacity) heavy soils at moderate temperatures (12-18 C). From the moment of infection to the appearance of the first signs of sporulation, 12 days pass, and until the full formation of spores - 29 days. The presence of open lenticels and wounds contributes to the penetration of the amoeboid into the tissue. Dry rot and late blight often develop on infected tubers in storage. scab silvery- brownish spots form on the surface, in severe cases they can cover a significant surface of the tuber. Under humid conditions, the skin of the stain can flake off, causing air to enter under it and the stain takes on a silvery tint. In red-skinned varieties, the appearance deteriorates significantly. Sometimes on the affected areas of the tuber you can see small black dots or soot deposits - sporulation of the fungus. The lesions are best seen in the spring, on green tubers. Often there is a wrinkling of the tuber and the death of the eyes. Oosporosis (lumpy scab)- on a diseased tuber, small ones are formed, about 1 mm. in diameter, dark pustules. On a dry tuber, their color approximately corresponds to the color of the tuber, but when wetted, they become dark brown on the outside and grey-violet on the inside. Oosporosis can be confused with the initial stage of common scab. Infection of tubers with oosporosis occurs in the field during the period of tuber growth, but signs of damage are found only during storage (2-4 months after harvesting) and are especially intensified towards the end of storage. The pathogen affects the eyes on the seed tubers, which leads to a strong thinning of crops and a decrease in yield up to 35%. In addition, the content of starch, protein, vitamin C decreases in infected tubers, and the amount of monosaccharides increases. They are more susceptible to damage by rhizoctoniosis, silver scab, wet and dry rot, and nematodes. rubber rot- on tubers, the disease manifests itself in the form of irregularly shaped superficial brown spots with a dark border. The texture of the affected tissues under the spots is elastic, rubber-like. If such a tuber is cut, then after 15-20 minutes the infected tissue turns pink, and then becomes gray-brown, to black. However, in some cases, the color may not change. During further storage, depending on the conditions, the affected tubers may become mummified or, conversely, mummified. The disease has a significant impact on the germination of seed tubers, the formation of stems, the height and productivity of plants, and the safety of tubers.

fomoz- on the surface of the tuber, small round depressed spots with clear boundaries first appear. Subsequently, the spot darkens, increases and deepens, turning into an ulcer with a tightly stretched paper-like peel. Soon the peel is torn and holes are obtained, similar to buttonholes. The affected tissue is dark gray, dry and dusty. Phomosis is one of the most dangerous potato diseases. Focal infection under certain conditions quickly acquires the scale of epiphytoties. The most active development of the infection is observed at 8-10 C. The air temperature below +3 C and above + 13 C slows down the development of the disease. The damage from phomosis is manifested in a significant reduction in yield as a result of the premature death of the affected tops and an increase in the loss of tubers during storage. The disease is especially harmful during storage of tubers. Tubers and stems are affected. Signs of phomosis on the stems are found during the flowering period of potatoes. The disease on the stems manifests itself in the form of elongated blurry spots, on which numerous small pycnidia from light to dark brown are subsequently formed. Spots are mainly located at the bases of leaf petioles - over the entire surface of the stem, pycnidia - over the entire surface of the spot. In wet weather, the pycnidia on the stems open and the spores spread with the help of rain and wind, causing new infections of the stems. Affected stems die prematurely.

Bacterial and viral diseases

ring rot- on a tuber, the disease is detected with a longitudinal section. The vascular ring is soft and has a yellowish color. When squeezing the cut half of the tuber, a light yellow mass protrudes from the affected vessels, representing destroyed cells along with bacteria. Later, the lesion may spread to adjacent tissues, including the core. The entire inner part of the tuber rots and turns into a viscous, unpleasantly smelling mass. Blackleg- tuber rot almost always starts from the place of attachment to the stolon, through which the infection penetrates from the stem affected by the pathogen of the black leg. Decay then captures the heart-shaped part, which quickly decomposes and turns first into a light, and then darkening in the air, mushy mass with a specific putrefactive (musty) smell. In the future, rot covers the entire tuber. Brown bacterial rot- the first symptoms on the surface of the tuber are not noticeable, but brown circles can be seen on the cut. At the initial stage of infection, sticky white mucus is released from the affected areas on the cut of the tuber. During storage, the affected tubers rot with an unpleasant odor. The main source of bacterial brown rot is infected soil, in which the pathogen is able to persist for a long time. The bacterium enters the tubers of a new crop through lesions on the roots and stems, as well as through stomata and stolons. Insects and nematodes contribute to the spread of the disease in the field. The disease develops especially intensively in conditions of high soil moisture. Having penetrated into the aerial parts of the plant, the bacteria multiply rapidly in them, penetrate into the vessels and fill them with a brown mucous mass, which causes wilting.

If the affected stem is placed in a jar of water, it is noticeable how brown bacterial mucus flows out of it - this way you can quickly distinguish bacterial wilt from fungal wilt in the field. Mixed internal rot- usually develops as a secondary phenomenon against the background of damage by pathogens of the black leg, ring rot and other diseases. Depending on the types of fungi or bacteria that develop on the rotting tissue, the rot can be different - wet or dry, with a coating of brown, gray or another color. Tuber spindle viroid- tubers are small, spindle-shaped, many-eyed, with clearly defined "eyebrows" of eyes and irregular outlines.

Other types of damage (non-infectious)

gray spotting- manifests itself if the tubers are impacted during harvesting, transportation or storage. Gray spots can form in potato tissues. On the outer surface of the tuber, such blows do not leave traces. Too early harvesting of potatoes, insufficient provision of plants with potash fertilizers, and an overdose of nitrogen also predispose to a significant development of gray spotting. Gray spotting is more pronounced in varieties rich in starch. When cooked, the gray spots turn black. Glandular spotting, or rustiness- in the pulp of the tuber, rusty-brown spots of various sizes and shapes are formed. Most of them are located near the vascular system (along the periphery of the core). The main cause of rusty tubers should be considered a lack of phosphorus in the soil. Iron spot is especially often observed on sandy soils, in years with dry and hot weather. Tuber rust develops only in the field, during the period of tuber growth, and does not progress during storage. Tuber hollowness- voids of various sizes and configurations are formed inside the tuber. The cavity of the hollow is covered with cream or light brown skin. The main reason for hollowness is the uneven growth of tubers with an excess of soil moisture and nitrogen fertilizers (rapid growth of external and weak growth of internal tissues, as a result of which they break and form a hollow). Larger tubers are more commonly affected. Tuber deformation (twin growth, malformations)- deformation usually occurs as a result of unfavorable weather conditions during the growing season, when the premature ripening of tubers that began as a result of drought is interrupted by heavy rainfall and the tubers begin to grow again. In such tubers, the starch content is reduced, they are poorly stored, as they easily break and rot. However, if they lay until spring, then they are suitable for planting. secondary growth- secondary growth is often observed when during the growing season there is a long drought, ending with heavy rains. Secondary tubers are formed in places of eyes. Tuber greening- occurs due to the action of light on the tuber. The degree of greening depends on the amount of light that enters. Chlorophyll and solanine are formed in the pulp and peel of the tuber under the influence of light. Due to the toxicity of the latter, the green parts of the tuber should not be eaten or fed to livestock. Green potatoes are ready for sowing. Red or blue staining of tuber pulp- on the cut, a red or bluish coloration of the pulp of the tuber is found - a feature inherent in some varieties with a pink or bluish color of the skin. It is connected with the fact that the dye contained in the peel extends to the inside of the tuber.

Potatoes turn black inside - why do potatoes darken during storage

Such staining does not affect the quality of tubers - they are suitable for both food and sowing. Cracking of tubers (growth cracks) and reticulation of the peel- during the growing season of potatoes, relatively deep cracks appear as a result of violations of the growth of tubers during
uneven supply of nutrients due to sharp fluctuations in soil moisture (heavy rains or watering after a long drought). Such tubers quickly rot during storage. With net cracking, small cracks or a network of shallow cracks are formed on the surface of the tuber, affecting only the cork peel and adjacent tissues. This type of lesion appears on certain varieties with a thick skin. It is caused mainly by soil and weather conditions: fertile and nitrogen-rich soil, a sharp change in its moisture content, etc. It does not cause much harm to tubers.

Good quality (І class)

The tubers are whole, clean, healthy, dry, unsprouted, unfaded.

Potato diseases - description and photo

Uniform in shape and color, mature with a dense skin, characteristic of this variety, without foreign smell.

When determining the quality of potatoes, tubers with mechanical damage no more than 5 mm deep and no more than 10 mm long (cuts, tears, cracks, dents) no more than 2% of the batch are subject to acceptance.

Inadmissible defects:

• Potatoes affected by late blight, rot: wet and dry, ring-shaped, button and others;
• Frozen and steamed tubers, with signs of "suffocation";
• Crushed, damaged by rodents;
• tubers are uterine;
• Tubers with the presence of organic and mineral impurities are not subject to acceptance: straw, tops, stones, etc.

Serious Defects:

• Minor dry mechanical damage, cracks;
• Mechanical damage more than 20 mm long (cuts, tears, cracks, dents);
• Dry scars over 30% of the surface;
• Slight greening on tubers (not more than 1/8 of the surface, dark green coloration, light green or green color penetrating deep into the tuber and not removed during normal cleaning);
• Sweet-tasting tubers withered and slightly wrinkled;
• Halves or parts of tubers with brown spots from exposure to heat, with internal voids, black core and other internal defects;
• Tubers are “small”, less than 30 mm;
• The presence of deep potato scab, spots of ordinary scab more than ¼ of the surface;
• With fragile skin (for late potatoes);
• Affected by rusty (glandular) spotting;
• Withered with slight wrinkling (when selling the harvest of the previous year).

Minor Defects:

• Dry scars on the peel of 10-30% of the surface (up to 10 pieces in one packaging unit of 25 kg of potatoes by weight and up to 2 pieces in packs of 2-2.5 kg packed);
• Tubers of another variety or variety (no more than 2% by weight of potatoes, not allowed in packaged);
• Single small scars on the peel, tubers with a slight light green tint no more than 1/8 of the surface, with single small healed cracks, provided that these minor defects do not impair the general presentation and do not affect storage, taking into account the dynamics of sales.

Potato diseases

A) Potato diseases caused by fungi

PHYTOPHTHOROSIS. An infectious disease caused by the fungus Phitophtora infenstans.

The infection persists in tubers, in the soil and on plant debris. Leaves, stems and tubers are affected. As a rule, the disease is observed mainly in the second half of the potato growing season, first on the lower leaves in the form of dark brown spots with a grayish sporulation on the underside of the leaves. In the presence of favorable conditions, the disease passes to the stems. Optimal conditions for the development of late blight are created in cool and rainy weather (at a temperature of + 8 ... 100C and air humidity over 90%). Often the tops on the site die in 5 ... 10 days.

As a result of sexual reproduction, oospores are formed that can be stored in the soil for 4–5 years. Symptoms of the disease in this case often appear earlier than usual - before the budding phase. In this case, the first signs of the disease are often observed on the stems, which are easily broken and the tops die off. Sporulation of the fungus is noted on the lower and upper surfaces of the leaves, as well as on the stems. The harmfulness of late blight increases sharply due to the severe damage to tubers.

Control measures. Cultivate relatively late blight-resistant varieties. Cleaning and destruction of affected plant residues, landfills, waste from potato processing, timely and deep hilling before closing the tops, removal and destruction of the affected tops 7 ... 10 days before harvesting, drying the tubers before storing. Seed material dressing before planting with one of the following preparations: botran (20 g/c), polycarbocin (260 g/c), cuprosan (25...50 g/c), cineb (50...100 g per 1 c of tubers). The introduction of increased doses of potash and the use of copper-containing fertilizers.

At a plant height of 15 ... 25 cm, preventive spraying of plants is carried out with a 1% solution of Bordeaux liquid (100 g of copper sulfate and 100 g of lime per 10 liters of water). Consumption rate - 6 liters per 1 weave. Of the chemical means of combating late blight, systemic preparations are the most effective: ridomil and acrobat (a matchbox in a bucket of water). Also used are drugs of contact action polycarbocin, polychom (40 g per 10 l of water). The consumption rate is 6 liters per 1 weave.

Rhizoctonia manifests itself in the form of a “black scab” of tubers, rotting of the eyes and seedlings, they die without reaching the surface, and the roots die. In summer, after the tops close, with high soil and air humidity, the fungus begins to sporulate, forming an off-white coating at the base of the stems. This is the sexual stage of the fungus, called the "white leg". Its intensive development in the field indicates a severe damage to the underground organs of the potato. The resting stage of the fungus - sclerotia can persist in the soil for 2-6 years. Under conditions of monoculture and crop rotations with short rotation, the pathogen accumulates in the soil, which ensures a high level of the disease.

Control measures. Planting potatoes with healthy planting material is the main condition for effective protection against rhizoctoniosis. Seed treatment with fungicides. Cultivation of potatoes in crop rotation. Germination or heating of seed tubers, early dates and correct planting depth, destruction of the soil crust, timely care, etc.

POTATO CANCER. It is a quarantine object. All parts of the plant are affected, except for the roots, due to which the potato disease is most often detected only at the time of harvest. The disease manifests itself in the form of growths on tubers, stolons and at the root collar. The outgrowths are initially small, and then grow and often exceed the size of the tuber. As the growths age, their color changes from white to dark brown. In the future, the growths decompose at the same time, the tuber also rots, turning into a brown slimy mass with an unpleasant odor. The development of the disease is promoted by increased humidity and soil temperature in the range of + 16 ... 200C. The infection persists in the soil for up to 20 years, as well as on tubers.

Control measures. Plant resistant varieties. In the foci of the disease, potato harvesting should be carried out only in the presence of a representative of the State Quarantine Inspectorate. Sick tubers are placed in large pits and buried, the tops are dried and burned.

Methods for combating potato diseases

Cabbage, cucumber and other crops are planted on the site. The soil from the cancer pathogen is cleared after 5 ... 6 years.

MACROSPORIOSIS. Appears on the leaves in the form of rounded concentric dry spots of various sizes, on the stems - in the form of oblong grayish-brown dry ulcers. Harmfulness increases in dry and hot weather. On the affected tubers, superficial black, slightly depressed spots of various configurations are formed; only the integumentary tissue of the tubers is damaged. But during winter storage, another infection occurs through these places, and the tubers, as a rule, rot by spring.

Control measures. Harvesting seed tubers only in a mature state, applying increased doses of potash fertilizers. Spraying potato plants and soil in dry hot weather with a (white) solution of chalk or lime (arbitrary norms), which significantly (up to 50C) reduces the temperature of the soil in the tuber formation zone and reduces overheating of the plant.

DRY ROT. Dry rot (fusarium) develops on tubers during storage. At first, grayish-brown, slightly depressed spots appear on the tuber, and the integumentary tissue is slightly wrinkled. The flesh under the spot becomes loose, acquires a brownish color. It forms voids filled with white, yellowish, reddish or dark fluffy mycelium of the fungus. Diseased tissues dry out quickly, forming peel folds around the site of the primary spot.

The pathogen fungus comes out and forms fluffy pads of mycelium of various colors on the surface of the tuber. The tuber becomes light and so hard that it is difficult to cut with a knife. The causative agent of the disease enters the tuber through wounds on the peel resulting from mechanical damage, as well as through places affected by other diseases or damaged by harmful insects.

The disease is favored by high temperatures and high humidity during storage of potatoes. The infection persists in the soil.

Control measures. To prevent dry rot, do not allow mechanical damage to the tubers during harvesting and transportation: they must be poured into the container carefully, from a height of no more than 30 cm, you can not walk on the tubers. Planting with healthy seeds. Compliance with the modes of storage of potatoes. Reduction of autumn-winter bulkheads of tubers in order to reduce their re-infection.

SCAB. There are several types of this disease. Common scab affects mainly young tubers, which are covered with a continuous crust, ulcers, and cracks may occur. Such tubers, as a rule, rot during storage. Powdery scab is characterized by the appearance of spots on the tubers, then brown warts, which rupture in a star-like manner and expose a dark, powdery mass of spores of the fungus. With tuberculous scab, the tubers near the eyes are covered with tubercles, which, merging, spoil a significant part of the tuber surface. Such tubers most often do not germinate, forming lunges of potato seedlings. Tubers infected with silver scab are distinguished by dark yellow rounded spots, first smooth, then depressed with a silvery sheen. The infection persists in the soil and on seed tubers.

Control measures. Planting healthy seed tubers, removing diseased tops before harvesting, using rotted manure rather than fresh, applying micronutrient fertilizers containing boron, copper, and manganese. Formalin treatment of tubers is effective against powdery scab.

B) Bacterial diseases

BLACKLEG. Plants and tubers are affected. Diseased plants are detected shortly after emergence. The leaves, starting from the top, turn yellow and curl into a tube along the main vein and dry out. The base of the stem, as well as the roots, rot and become intensely black in color. Diseased bushes or individual stems wither and are easily pulled out of the soil. Unlike rhizoctoniosis, the affected part of the stem is thinner than the healthy part.

The tuber is affected from the stolon end. In the place of its defeat, the pulp turns into a soft, dark-colored slimy mass with an unpleasant odor. On the border between the diseased and healthy tissue there is a darker band of corked cells. In the future, the tuber dies from wet rot. The disease is favored by high humidity, elevated soil temperature. The infection persists in the seed tubers.

Control measures. Warming up or germination of seed material. Treatment of tubers with a 5% suspension of TMTD. Planting only whole and healthy tubers. Removal of diseased bushes during cleaning: after germination, and during flowering - along with tubers. By careful cleaning, the harmfulness of the black leg can be minimized or completely eliminated. Tops mowing. Drying and greening of seed tubers after harvesting. Bookmark for storage of healthy tubers.

ROT ROTT. Plants and tubers are affected. On plants, the disease manifests itself in the form of bacterial wilt, which begins during the flowering of potatoes and continues until the end of the growing season. At the beginning, one or two stems wither, then all the rest in turn. Withered stems fall to the ground. With rapid withering, their color may remain green, with slow wilting, the diseased stem quickly turns brown.

The tuber is more often affected from the stolon end. The defeat of tubers begins in the soil. Part of the vascular system rots, softens, turns yellow, and when pressed, a rotting mass (from light yellow to brown) is released from it. Through the vascular system, rot spreads to neighboring tissues: there is a general lesion of the core of the tuber, which completely rots. In conditions of high humidity, the disease turns into a wet rot. Harmfulness during the growing season increases with high temperature and soil moisture. The infection persists in the seed tubers.

Control measures. The same as with the black leg, except for the disinfection of the seed.

WET ROT. The tuber tissue softens, at first it is light, then dark brown or pink. The tubers turn into a slimy rotting mass with an unpleasant odor. The development of the disease is facilitated by sharp fluctuations in temperature and high humidity during storage. Under unfavorable storage conditions, all potatoes can rot in 10-15 days.

Control measures. Germination of planting material. Planting potatoes only whole and healthy tubers. Prevention of the development of bacterial diseases. Compliance with optimal storage conditions. Damage, freezing of tubers should not be allowed. Timely removal of foci of rot.

B) viral diseases

Infectious diseases caused by phytopathogenic viruses. Virus diseases of potato are ubiquitous, in some cases they surpass fungal and bacterial diseases in terms of harmfulness. Every year, the global potato industry loses 15–20% of the crop from viruses. In addition, the nutritional value of tubers is significantly deteriorating: the dry matter content is reduced by 0.2 ... 1.5%, starch - by 0.5 ... 3.0%, vitamin C - by 1.5 ... 7.0 mg%. About 20 viruses cause harm to potatoes, often two or three of their species are found on one plant. The best known are wrinkled mosaic, striped mosaic, leaf curl, mottling, leaf curl, common mosaic, gothic (fusiform tubers), aucuba mosaic, variegation, yellow dwarfism, curly dwarfism, and apex panicle.

The science of virology is the study of viruses.

All potato viruses are highly infectious, spread rapidly (mainly during the growing season, less - during the period of storage of tubers and their preparation for planting). Viral diseases are transmitted mainly by contact (by contact of the tops, roots, by sorting tubers, by hands, people's clothes, animals), as well as by living organisms: piercing-sucking insects (aphids, cicadas, bugs), mites, nematodes, soil fungi. Transmission of viruses by weed seeds is possible.

Viruses are closely associated with the plant cell. Penetrating into plant cells through damage and multiplying in them, viruses disrupt cell metabolism, reduce photosynthesis, increase respiration and transpiration, can inhibit plant growth and development, cause dwarfism, or selectively inhibit the development of some plant organs, cause increased growth of others. Viral infection can cause death of cells, tissues (necrosis) and the whole plant.

Often virus-infected potato plants look healthy on the outside (latent infection), but the yield is reduced even if there are no symptoms of infection. Signs of virus damage are different, depending on the duration of the infection, the type and strain of the virus, the external conditions that weaken the plants (high and low temperatures, excessive moisture or lack of moisture). The most typical manifestations of a viral infection on potatoes are mosaics, deformations, chlorosis, necrosis, yellowing of leaves. Tubers are small, often ugly, spindle-shaped.

Control measures. Sick plants are practically incurable. Therefore, a set of protective measures should consist mainly of techniques that prevent infection and the spread of a viral infection. These methods include. Cultivation of resistant varieties. Improvement of potatoes by methods of thermo- and chemotherapy and culture of meristems in research institutions and their subdivisions. Planting healthy tubers. Preplant warming and germination of tubers in the light. Improving selection, when only healthy-looking plants with the highest tuber yield are selected for seeds. Weed control - aphids (carriers of a viral infection). High agricultural technology. Crop rotation, spatial isolation. Balanced fertilization. Timely tillage. Optimum planting and harvesting times. Wellness cleansing. The use of chemicals against insect vectors. Early removal of tops.

The first preventive spraying (on seed plots) against aphids is carried out 10-12 days after full emergence, subsequent (as needed) - at intervals of 10-15 days. The last processing is carried out no later than 30 days before harvesting. To destroy carriers of viral infections, the same drugs are used as against the Colorado potato beetle.

D) Mycoplasma diseases

Distributed in all zones of potato growing. They are caused by microscopic organisms - phytopathogenic mycoplasmas. Dramatically reduce the yield and quality of tubers. The most harmful are stolbur wilt (stolbur), purplish tops, "witch's brooms", and round leaves. The infection is not transmitted by contact. Mycoplasmas are spread by infected planting material, as well as by cicadas and mites. The source of infection is perennial weeds (field bindweed, sow thistle, chicory).

By clogging the vessels of plants, mycoplasmas cause wilting, dwarfism, yellowing of plants, shredding of leaf blades, and growth of flowers. The growth of plants is inhibited, the development of generative organs is disrupted (greening of flowers, the transformation of individual parts of the flower into leaf-shaped formations, the appearance instead of one flower of many of them with incorrect development). Mycoplasmas are one of the main reasons for the germination of tubers with filamentous sprouts.

Control measures. The fight against mycoplasmal diseases is reduced to planting healthy planting material, the destruction of weeds - the source of infection and the cultivation of resistant varieties. For the treatment of diseased plants, the use of antibiotics of the tetracycline group, as well as thermotherapy of tubers at a temperature of + 35 ... 500C, is promising.

BRONZE LEAVES. Occurs with insufficient intake of potassium in plants. The leaves are covered with small dots of dead tissue, wrinkled. In the future, tissues from the edge of the leaf blade partially die off, and the leaf acquires the color of oxidized bronze. The edges of the lobes are twisted down. Roots and tubers develop poorly. Plants often die prematurely.

Control measures. When the first signs of the disease appear, it is necessary to feed the plants with potash fertilizers. In areas where leaf bronzeness systematically develops, increased doses (by 25 ... 50%) of potash fertilizers are applied in the fall.

BROWN SPOT OF STEMS. At the beginning of growth, the tops have a lighter color than ordinary plants. Then, on the stems, starting from the bottom, brown dry elongated spots of dead tissue appear on the petioles of the leaves. The disease gradually spreads upward. The lower leaves wither, dry up, but remain on the stems. The upper leaves turn yellow, partially curled. They appear dark small angular necrosis between the veins. In contrast to the banded mosaic, blackening and death of the veins are not observed. The plant is stunted. The disease manifests itself on heavy acidic soils containing an excessive amount of iron and aluminum oxides.

Control measures. When digging a site in the spring, wood ash is added at the rate of 50 kg per hundred square meters or lime 15 ... 20 kg.

IRONAL SPOT (RUSTY) OF TUBES. On the section of the affected tubers, red-brown spots of various sizes and shapes are visible. Unlike late blight, spots do not have access to the periphery of the tuber. The disease is caused by malnutrition of plants and elevated soil temperature, due to a decrease in the efficiency of photosynthesis and an increase in oxidative processes in tubers with a lack of nitrogen, calcium and magnesium in them, an excess of iron and aluminum, which activates this process.

Control measures. To prevent the disease, organic fertilizers must be applied under potatoes in combination with a complete mineral fertilizer. Liming of acidic soils.

GROWTH OF TUBES. The disease manifests itself in the form of the formation of nodules on the mother tubers of potatoes and the outgrowth of tubers during plant growth. Nodules are formed on the mother tubers in the soil in spring under adverse weather conditions (damp and cold, or, conversely, dry and hot), as well as in storage - at elevated temperatures and lack of atmospheric oxygen. The formation of nodules can occur due to damage to the eyes of the mother tuber by various diseases.

With alternating dry and wet weather in the second half of the growing season, stolons develop from the eyes of young tubers, on which one or more additional nodules are formed. If the stolon leaves the soil, the tuber may grow with the formation of a shoot (stem).

In dry hot weather, the growth of tubers stops, as a result of which the peel becomes stronger. With the resumption of favorable conditions on tubers that have lost their ability to grow, new nodules (children) are tied or outgrowths are formed that disfigure the tubers, while the quality of the crop is noticeably reduced.

Control measures.

To prevent the sprouting of tubers, germinated planting material is used, planting it in warm soil at the optimum depth. In dry periods, it is necessary to water the plants.

DARKENING OF THE PULSE. The flesh of the tuber on the cut acquires a dark color (gray, black or bluish). The cause of the disease is insufficient potassium nutrition of plants during the period of tuber formation, and a lack of oxygen and low temperatures during storage. Tubers with darkening of the pulp are of little use for nutrition due to a decrease in the content of starch and vitamins in them.

Control measures. Application of potash fertilizers, ensuring good aeration of the soil, preventing injury to tubers during harvesting, transportation and storage, compliance with optimal storage conditions.

HOLLOW TUBE. Inside the tuber, voids of various configurations and sizes are formed. The cavity of the hollow is covered with a thin skin of cream or light brown color. If the hollow does not have access to the surface of the tuber, then there is no decay of tissues and various kinds of raids. Hollowness is formed as a result of lagging behind the growth of internal tissues from the growth of external ones, due to an excess of nitrogen in the diet and a lack of potassium and phosphorus. Larger tubers are more commonly affected.

Control measures. Hollowness can be reduced by pre-harvest haulm mowing and the introduction of increased doses of potash and phosphorus fertilizers.