19 potato diseases: photos, descriptions, causes, treatment and prevention

Potato diseases can develop for various reasons. For example, with improper maintenance and care. In this case, it is enough to simply adjust them. It is much more difficult to cope with infections that are caused by pathogenic microorganisms; you cannot do without auxiliary means. In both cases, potatoes must be treated immediately, otherwise the vegetable crop will die or the root crops will lose their taste characteristics.

Causes of potato diseases

Non-infectious potato diseases manifest themselves under stressful conditions for the crop. For example, with sudden changes in temperature, frost, drought or high humidity, lack of mineral elements, etc. Because of this, the plant’s physiological processes are disrupted, which affects its development.

Diseases of potato tops and tubers are also caused by pathogenic agents: viruses, bacteria and fungi (the latter include ergot, smut, tinder fungus and others). The most favorable environment for their development is when the culture is under stress, as stated above.

Pathogens can spread on the legs of pests (for example, Colorado potato beetles, wireworms, etc.), on the body of birds and animals, with water and undisinfected garden tools.

The main reasons for the development of diseases

Potatoes, like other cultivated plants, are susceptible to various diseases. The reasons for their occurrence can be different, from unfavorable weather conditions and insect invasion, to violation of agrotechnical rules for growing crops. It is impossible to influence the weather, but violation of agricultural technology is the fault of the gardener. Among the most common agrotechnical errors leading to the development of potato diseases, the most common are:

• improper crop rotation;
• use when planting infected tubers;
• inaccurate choice of planting site, too acidic or waterlogged soils;
• lack of proper care (weed removal, pest control, fertilizing, loosening, hilling, etc.).

In order to avoid such mistakes, before starting to grow potatoes, it is necessary to study in detail information about the crop, consult with agronomists, and also do not forget about disease prevention measures.

All diseases of the crop in question, depending on the pathogen, are divided into three main groups: fungal, viral and bacterial. Regardless of the etiology of origin, all diseases lead to deterioration of tubers, their rotting, unsuitability for consumption and use as seed material. Methods of treatment and prevention are selected depending on the type of disease.

How to distinguish diseases from a lack of microelements and errors in cultivation and care

Potato diseases and the cause, which lies in insufficient care, are called physiological. They differ from infectious diseases in the following ways:

• no pathogen;
• Almost all crops in the garden are affected;
• the pathological condition can be stopped or the plant can be cured completely if the factor that caused its origin is eliminated.

Note! As a rule, the occurrence of physiological diseases occurs in all parts of the crop. But, despite this, the plant does not die; its leaves can only turn yellow and become deformed, and the ovaries die. The bush will lag behind in development.

Description of signs of nutritional deficiency:

What diseases of potato tops there are and what needs to be done to prevent the crop from dying, we will tell you in this article. In general, it is important to know the signs of fungal, bacterial and viral diseases. Based on the description, treatment should begin immediately.

What to do if you can’t understand what ails a culture?

If the gardener is unable to identify the type of disease, it is necessary to use methods for a comprehensive effect on the crop:

• Use wood ash. The substance is mixed with water in a proportion of 1 kg per 10 liters of water, and treatment is carried out.
• Fertilize with potassium and phosphate fertilizers.
• Treat the beds with a manganese solution.
• After harvesting, the planting material should be changed and treated with an antiseptic before planting.
• Remove damaged bushes to prevent further development of the disease.

Purchase drugs such as Maxim and Fitosporin in specialized stores and treat the beds.

Bacterial diseases of potatoes: photo, description, treatment and prevention

Infection can occur from the soil, from nightshade weeds, or through infected tubers.

Ring rot

Potato bushes begin to wither from the top to the roots. In hot weather this happens faster; moderate temperatures and high humidity slow down the spread of infection.

Prevention measures: soil disinfection and the use of varieties resistant to this disease: Lazurit, Rosinka, Skarb.

Brown rot (bacterial wilt)

An infection can be identified by the following signs:

• sudden withering;
• yellowing of leaves and their wrinkling;
• rotting of the root zone;
• putrid odor when pressing on the fruit;
• brown mucous discharge upon transverse incision.

The causative agent is Ralstonia solanacearum (Smith) Yabuuchi et al. Bacteria enter through mechanical damage to tubers, stomata, stolons, and roots.

Infection control measures:

• treatment of planting material with a fungicide;
• regular weeding;
• spraying with Baktofit before flowering;
• drying potatoes before storing them;
• disinfection of fruit storage areas.

Blackleg

It starts with the bottom greens and turns yellow. The upper leaves are angled and turn yellowish a little later. The shoots rot, become soft and easily break near the ground.

Mixed internal rot

With this disease, the tubers rot completely and crack. As a rule, the infection develops during crop storage. The peculiarity of this lesion is that the tubers are susceptible to two types of pathogens at once: bacteria and viruses. They get inside through damage on the surface.

Methods for treating and preventing bacterial infections

Affected crops must be destroyed immediately to prevent the infection from spreading to other plants. It is also necessary to promptly mow the tops and remove them from the territory.

Folk remedies for preventing biological contamination

Recipe for an effective folk remedy:

• Infuse 1 kg of dry bird droppings in a small volume of water for a couple of days.
• Boil 1 kg of dried wormwood in a small amount of water for 10-15 minutes.
• Add 1 liter of bird droppings tincture to the grass.
• Strain and add 10 liters of water.
• Add 10 g of laundry soap shavings to the solution.
• Treat potatoes with this fertilizer from the moment of budding 2-3 times at intervals of a couple of weeks.

Helpful information! Also, to stop diseases, you can spray with tobacco decoction, iodine solution or ammonia.

Chemicals to combat biological infections

Before planting, treat the tubers with the chemical TMTD (consumption 2.1-2.5 l/t). After harvesting, before sending it for storage, treat it with Maxim. To do this, dilute 5 ml of the chemical with 50 ml of water and spray the potatoes.

You can also use the biological fungicide Planriz. For 100 kg of crop, 1 liter of 1% solution will be required.

Fungal diseases

Fungal infection of potatoes is one of the most serious and dangerous diseases that destroys tops and tubers. Infection occurs through insects, from infected plants to healthy ones and under improper cultivation conditions. Mushrooms prefer a moist, cool environment. They actively reproduce in shaded and dense plantings.

Some fungal diseases, such as late blight, Alternaria and Fusarium, are described in this video:

Dry rot

The disease is characterized by damage to the root crop. Most often occurs in warm, dry conditions. Feature - if tubers that are at the growth stage are affected, the use of the site is allowed after at least 7-8 years.

The process of formation of dry (fusarium) rot:

• Initially, a dry spot forms on the surface.
• A mycelium with spores appears under it, which actively ripen.
• Next, the pulp dries out.
• After this, the fruit deteriorates.

To avoid dry rot, in addition to standard methods, it is necessary to treat the tubers with fungicidal agents before planting. This is Prestige, Maxim.

Potato cancer

Cancer affects tubers and above-ground parts of potatoes and spreads rapidly at high humidity. It penetrates into the soil through manure, animals, shoes, and garden tools. In case of cancer infection, there is a need to destroy the entire crop and soil, since the fungus remains viable for a long time. It is extremely dangerous to human life. It is prohibited to plant potatoes on affected soil for 5 years.

Symptoms:

• the appearance of tubercles on root crops in the eye area;
• formation of growths of arbitrary configuration;
• spread of formations to stems and stolons;
• blackening of plant surfaces in the affected area;
• slipperiness

It is impossible to destroy cancer, so the tops along with the tubers are burned, doused with kerosene, formaldehyde or bleach.

Late blight

This fungus is the most dangerous because it spreads with lightning speed through spores and is resistant to frost. The favorable environment is rain, but during drought, sporulation is inhibited. Characteristic features:

• the formation of dark-colored spots on the leaves;
• drying of the tops;
• the appearance of a brown tint on the stems;
• white coating on the leaves.

Methods of disposal:

• Late blight does not affect potatoes if mustard is planted nearby. If you do not need such a crop, you can plant it 2-4 weeks before planting potatoes. As soon as the shoots appear, the soil is carefully dug up along with the mustard, after which the potatoes are planted.
• You can use mineral fertilizers with potassium and phosphorus.
• Drugs used for prevention: Agat, Ridomil.

More is written about late blight on potatoes in this article.

Rhizoctoniosis

The main pathogens are fungi, deuteromycetes, and actinomycetes. Features of the manifestation of the disease:

• Sclerotia may appear and look like pieces of dirt.
• If the affected plant has already been sent for storage, then rot will form during this period.
• The root part and sprouts become covered with brown or black spots and ulcers up to 2 cm in size. Over time, these areas die off.
• On the surface of the root crop, a thin black mesh may form over the entire surface.
• The stolons decompose to a mushy state, forming weeping ulcers.
• With early damage, the shoots die.
• If the disease progresses during flowering, then rhizoctonia looks like a white leg with a felt coating.

How to get rid of:

• Adhere to common preventive measures for potatoes.
• Treat seed material with brown or boric acid.
• Spray the tubers with biological agents before planting (Baktofit, Agat-25, Planriz).
• Chemicals: TMTD, Maxim, Titusim, Tecto.

Alternaria blight

The fungus prefers young shoots during heat and drought. As it progresses, tubers are also affected. The main cause of infection is the absence and lack of mineralization. Method of spread - during windy weather, spores are spread across the field, settling on the shoots. Fruits can become infected only during digging, as there is contact with contaminated soil.

Signs:

• chaotic arrangement of brown spots on the leaf part;
• the same spots are observed on tubers.

Treatment and prevention:

• For 7 days, treat the bush with Bordeaux solution (1%) 4 times every day.
• Use copper oxychloride twice a day for a week.
• The drug Arcerid (follow the instructions).

Read more about the potato disease Alternaria blight here.

Fomoz

With Phoma, the fungus penetrates into stolons, stems, and roots. If the disease is detected during storage, the mycelium multiplies, affecting the entire crop. A favorable environment is considered to be weeds and other vegetation left in the garden.

How to identify:

• Shapeless, elongated spots appear on the plant. Most often they are covered with brown dots.
• Growth slows down as the fungus rings the plant.
• The saturation of the foliage shade disappears.
• The tops begin to fade.
• The tubers are affected by ulcers up to 6 cm in size, after which cavities form.

Root vegetables are not suitable for consumption, so they are disposed of. But it is extremely important to save the soil. To do this, before planting, the tubers are treated with Fundazol solution and all preventive measures are followed.

Scab

The most common potato pathology is scab, which affects fruits and tops. Divided into several types. In order to get rid of scab, you must adhere to standard prevention rules. Additionally, before planting, tubers can be treated with such agents as Ditan, Maxim, Prestige, Mancozeb.

Common scab. Potatoes with thin skin and red fruits are affected. If potatoes are planted at a sufficient depth, then infection is unlikely, since the fungus cannot exist without oxygen. To prevent infection, you will have to enrich the soil with boron, manganese and other minerals.

Symptoms:

• formation of dry ulcers on tubers;
• the color of the scabs is brownish-red;
• the size of the ulcers is average.

Silver scab. If affected by this fungus, it is undesirable to eat potatoes. The infection prefers a moist environment and warmth. Signs:

• drying of tubers;
• the formation of deep spots on the peel, the color of which is silver.

Black scab. The scientific name is rhizoctoniosis. The signs are consistent with silver scab.

Powdery scab. The only scab fungus that affects not only the tuber part, but the entire bush. Signs:

• the formation of white spots on the stems and root system;
• increase in size of spots, their darkening;
• ulcerative lesion of tubers, color – red, diameter – 5 mm.

Fusarium wilt

The infection occurs by spore fungi. The mycelium resembles spider threads, inside of which there are canodes. Location: soil.

Symptoms:

• discoloration of the upper leaves;
• curling of foliage along the vein;
• yellowing of the tops followed by falling off;
• staining the stem with a brown tint;
• rotting of the stem and tubers;
• formation of a putrid odor on tubers.

Verticillium wilt

The fungus penetrates the root system through insects and mechanical damage.

Signs:

• growth slowdown;
• death of roots;
• the formation of brown streaks of a slightly pressed elongated shape;
• the presence of pink or gray bloom on stems and foliage;
• on the cut there is a brown tint.

Powdery mildew

Infection occurs from different types of fungi, localization is foliage, young shoots. Initially, the color of the plaque is white, but as the spores spread (they have a brown tint), the plant darkens.

Characteristic manifestations:

• the formation of a powdery coating that is sticky to the touch;
• deformation of the root crop;
• growth arrest;
• death of the affected areas.

Macrosporiasis

Another name is patchy dryness. The causative agent is Macrosporium solani Ellis et Martin. Infection occurs during harvest through mechanical damage. The infection can be transmitted through the tops. Most often localized on nightshade crops. Tubers and stems may be affected.

Early symptoms:

• formation of spots up to 1.5 cm in size;
• color of spots – gray, brown, dark brown;
• the formation of a slight plaque with a black tint;
• clearly defined boundaries of defects;
• aridity of the tops.

Signs of late infection:

• round rashes along the edges of leaves;
• the color of the spots is dark brown with an olive tint of a velvety type;
• rolling leaves into a tube.

Stem form of the disease:

• spots on oblong-shaped stems;
• at a later stage, the rashes merge together;
• ringing of stems with spots;
• stem dying.

Tuberous form:

• the formation of brown or gray spots on tubers;
• presence of plaque;
• hardening of the affected area.

If you carefully monitor potatoes at each stage of growth and storage, you can promptly detect the first signs of disease, which will preserve the harvest. Do not neglect pre-planting treatment; leave the potatoes to germinate a month before planting. This will avoid illness.

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Potato viral diseases: features, photos, prevention and treatment

These diseases are incurable. Moreover, the infection is transmitted to the next generation of tubers. It spreads on the legs of insects, with nematodes, fungi, unsterile garden tools, and when stems and leaves come into contact with diseased specimens.

Speckled mosaic

Mosaic provokes a deterioration in photosynthesis. Because of this, light spots of various shapes and sizes appear on the foliage. The above-ground part grows slowly, the leaves turn yellow and fall off.

Striped mosaic

Necrotic stripes, spots, and mosaic-like patterns appear on the foliage. Brown streaks and stains appear on the underside of the plates. The veins become watery and the greenery dies. The lesion first affects the lower part, gradually spreading to the apexes. By the end of the growing season, the foliage falls off.

Wrinkled mosaic

Due to this disease, about 30% of the crop is lost. The greenery fades, the edges become deformed and become curled. The leaves die and hang on the shoots without falling.

The infection usually appears during hot weather in the middle of the growing season. The culture does not begin to bloom and stops developing 2-3 weeks earlier.

Gothic tubers

Pathogenic microorganisms penetrate the plant at the slightest contact. The pathogen can live in dry soil for about 2 months, and in dried tops for up to 2 years, so vegetation must be promptly removed from the site.

Signs of the virus:

• a large number of eyes located in the pits on the tubers;
• elongation of root crops;
• reduction of foliage;
• lumpy surface of potatoes;
• cracks and spots on the peel;
• leaves grow at right angles.

Important! Infection can occur at any stage of potato development.

Tuber necrosis

If you cut the root vegetables, you can see:

• dark stripes in the form of arcs;
• rings;
• necrotic inclusions with rot;
• rottenness of the frame;
• cream-colored mucus in spots.

It is difficult to detect this infection, because... There are no external signs on the tops.

Net necrosis of tubers

This disease causes leaf curling and reduces yield by 50%. The leaf plates at the bottom of the bush bend into a tube along the midrib and become hard and rustling. The disease is promoted by drought and lack of moisture.

Fighting viral diseases

As mentioned earlier, viral diseases cannot be cured.

The only way out will be preventive treatment with drugs:

• Agate 25 K;
• Biosil;
• Fitosporin-M;
• Gumi-20M.

You need to soak the tubers in fungicides for 60 minutes. This will develop resistance to viruses.

Fusarium dry rot of potatoes

If brown, slightly depressed spots appear on potato tubers, and then the flesh dries out in folds, the peel becomes covered with a white coating similar to mold, and cavities with mycelium form inside - this is fusarium, the second most widespread and harmful potato disease after late blight. Tubers infected with the fungus eventually dry out, becoming light and almost empty inside (hence the second name “dry rot”).

Unfortunately, signs of the disease appear only after 2-3 months of storage, when diseased tubers manage to re-infect the majority of the crop stored nearby - losses can be about 30%. Most often, fusarium occurs on tubers affected by other diseases or with mechanical damage. In some cases, fusarium is also accompanied by wet rot.

Fusarium actively develops during periods of high humidity and cool weather. Its first signs can be noticed already during the potato growing season. Yellow spots appear on the leaves (starting from the apical part of the stem), then brown spots; along the edges of the leaves they often become reddish-purple and curl. With severe infection, the stems also begin to turn brown, and soon the entire plant dries out.

• Fusarium: signs and methods of treating a dangerous disease

  Your plants suddenly began to turn yellow and wither, although there were no prerequisites for this? Most likely, the reason is the dangerous influence of one of the “fusarium” fungi. What to do?

Measures for the prevention and control of potato fusarium:

• Selection of potato varieties resistant to the disease (for example, Detskoselsky, Berlichingen, Priekulsky early, etc.).
• Selection of healthy, undamaged tubers for planting.
• Harvesting tubers in dry sunny weather.
• Preventive treatment of tubers before storage with a fungicide (for example, Fitosporin-M, Kagatnik, Maxim, Baktofit).
• Drying the tubers before storing them in a dry, dark room with good ventilation.
• Storing whole, undamaged tubers in a layer of no more than 1 m.
• Creating the right conditions for storing potatoes - temperature about 2-3°C, humidity - 80-90%, no light, good ventilation.

• Why potatoes rot in the cellar - 6 most dangerous diseases

  Do you dream of eating potato pancakes and potato dumplings with meat all winter? Then immediately get on the warpath against dangerous potato diseases.

General preventative measures against all potato diseases

To prevent the development of diseases of any type, crop rotation must be observed. Potatoes cannot be planted in their original place earlier than after 3 years. The best predecessors will be legumes, grains (including wheat), and melons.

Before sending for storage or planting, the tubers need to be heated at a temperature of +14...+18 °C for 2-3 weeks. This is necessary to reject diseased potatoes and use only healthy ones.

Note! Early ripening varieties are more susceptible to diseases.

It is necessary to carry out pest control treatment, because... they are carriers of pathogens. Periodically it is necessary to clear the area of ​​tops and plant debris. Potato bushes that grew from tubers that were in the ground over the winter will have to be destroyed.

Non-infectious potato spots

This is a type of non-communicable disease caused by various reasons:

• Gray spotting - primarily, mechanical shocks and damage to potato tubers during harvesting or transportation are to blame for its appearance. During its storage, even in the absence of noticeable traces on the outside of the tuber, for these reasons, gray spots of different sizes may appear inside, which change color to black during heat treatment.
• Iron spot (tuber rust) appears for another reason, namely due to unfavorable soil and weather conditions during the growing season. During storage, brown spots of various sizes and shapes form in the pulp of diseased tubers. Externally, a diseased tuber is also no different from a healthy one.

Measures for the prevention and control of potato blight:

• Maximum care during harvesting, transporting and storing tubers.
• Harvesting potatoes in dry sunny weather.
• Drying the tubers before storing them in a dry, dark room with good ventilation.
• Storing whole, undamaged tubers in a layer of no more than 1 m.
• Creating the right conditions for storing potatoes - temperature about 2-3°C, humidity - 80-90%, no light, good ventilation.

Tips and recommendations from Mister Summer Resident

In conclusion, I would like to give a couple of useful recommendations from experienced gardeners:

Potatoes need to be inspected daily to detect infection early. If there are signs of ring rot, it is recommended to remove the bush and pour 1 liter of copper sulfate (100 g per 10 liters) into its hole.

Copper sulfate or copper oxychloride also helps against fungus (1 tablespoon per 10 liters of water, consumption 0.5 liters per 1 sq. m). After a few days, spray with Bordeaux mixture (0.5 l per 1 sq. m). Treatment is carried out before planting the tubers in the ground.

Following simple recommendations will help reduce the likelihood of developing potato diseases and get a rich harvest. The most important thing is to carry out preventive measures and detect the infection in a timely manner, carry out diagnostics and take immediate action, because in the initial stages it is easier to treat and it is still possible to save the crop.

Prevention measures

With timely implementation of preventive measures, the likelihood of the spread of diseases can be significantly reduced.

Preventative measures for potato diseases are as follows:

• Selection of varieties resistant to pathogens. It is best to choose varieties bred specifically for your region. They take into account the composition of the soil and the climatic conditions of the area.
• If signs of disease are detected, curly leaves and other affected parts should be destroyed by burning.
• Compliance with crop rotation rules. It is recommended to plant potatoes in places where cabbage, pumpkin, cucumbers, and legumes previously grew. It is prohibited to plant in beds where sunflowers and nightshade crops previously grew.

• Treatment of tubers before planting. The use of special preparations makes it possible to destroy the sources of the disease living on planting material. Fitosporin, Prestige or Maxim are suitable for these purposes. First, a working solution is prepared according to the proportions indicated on the package. Potato tubers are dipped into it for 15 minutes.
• Timely care of plantings. This includes hilling the plants, watering and fertilizing.

Damage caused by weed killers

Often, gardeners approach the choice of chemical preparations for weed control without appropriate caution. This leads to two symptoms:

• pronounced curling of the leaves of the plant;
• characteristic increase in volume, black spots.

This entails stopping the development of tubers. Their number may be less than that of a healthy potato bush. When choosing high-quality preparations for eliminating weeds, you should not rush into irrigation.

Important! It is dangerous to do this in the first stages of tuber formation. Untimely use of aggressive drugs, the wrong dose for application and treatment of the area for each bush leads to curliness and entails problems with the harvest.

Why do potato tops still curl?

1. Potatoes often suffer from various viral and infectious diseases.
2. More often, the crop suffers from mosaics, which lead to deformation of the leaf, yellowing of the tops, and their twisting towards the vein, which is located in the center.

After this, the moment of plant growth stops. The bushes cannot grow to the size that they are supposed to have according to their variety. Those leaves that appear to be unaffected by the disease remain small. When digging, gardeners find a small number of tubers, many of them are small or deformed, and are not suitable for consumption or for selection for planting next year.

Mosaic may not appear the same in different varieties. It works on some with minimal losses to the crop, and the quality of the tubers remains high. But if potato leaf curl is neglected and treatment is delayed, the disease will progress. Even those crops that were immune to mosaic viruses will begin to lose tuber quality. The difference between the healthy and the affected will be noticeable.

The viral infection can accumulate in planting material, which leads to gradual degeneration of potatoes. It may appear slowly or quickly. At the time the symptoms of viruses, which differ in nature and structure, method of action, on fungi and bacteria, are detected, it is impossible to save the plant.

Viruses do not have the ability to penetrate shells of any density due to the lack of cellular structure. This does not prevent them from infecting crops through living organisms that are susceptible to infection by viruses.

Before understanding why potato tops curl, it is important to understand how the virus gets onto the crop. More often, this is facilitated by a living organism that feeds on potato leaves. A striking example of a virus carrier is aphids. Why potatoes curl, what kind of disease it is and how to treat it are important questions. When delving into the topic of why potatoes curl, it is important not to forget that early identification of signs of the virus can play an important role in the rehabilitation of the crop to preserve fruits and yields.

It is necessary to take into account the timing of the spread of the aphid, taking into account its cycle. Potato leaf curl occurs soon after this period, which means it is important to know in advance what to treat the crop with and when.

Types of mosaics that cause leaves to curl

People often ask themselves why potato tops are curly, without thinking that the plant could have been infected a long time ago. The virus often hides in the plant, is in a latent state, without showing the usual symptoms.

1. Ordinary and folded. The disease can be caused by three different viruses or a combination of them. Spots of different shades appear on the leaves, from dark to light. The disease is also provoked by strains of viruses. Signs of the disease may be masked if the air temperature is high and the potatoes are exposed to direct sunlight for a long time.
2. Speckled. Potato curl raises many questions, among which the most pressing is how to treat the plant. But determining the type of disease plays an important role. Soil fungus is often the culprit of speckled mosaic, which may not be noticed due to mild symptoms. You can notice the signs at the beginning of the growing season, by the characteristic light spots.
3. Wrinkled and striped. Curly potato tops can be caused by various reasons. Often the culprit of potato curl is the Y-virus or S-virus, which is capable of causing the disease independently and in combination with other pathogens, photos can be seen on the Internet. These mosaics are characterized by angular spots. Necrotization of veins is possible. The damage to the leaves is so severe that they become fragile and vulnerable. Necrotization can destroy the stems of the crop and affect the petioles. Wrinkled mosaics show a delay in the formation of new leaves and bush growth. The stems become weak.