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Many gardeners traditionally grow potatoes in large quantities in order to stock up on vegetables for the whole winter. But, like many other crops, potatoes are susceptible to some characteristic diseases, which, despite the efforts of the farmer, reduce the yield and quality of the product and slow down the process of its ripening.
When signs appear diseases The gardener needs to take measures to treat potatoes to prevent the spread of infection and maintain the health of the fruit. A number of preventive measures will allow you to protect vegetable plantings in advance. Thus, the most common potato diseases and their control, as well as recommended preventive measures, are described below in the article. This information will certainly help novice and experienced farmers identify the problem and successfully cope with it.
Potato diseases and their treatment
Fungi, bacteria and viruses can cause potato diseases. They penetrate the plant body through the root, leaves, and damaged areas of the stem.For each disease there are a number of characteristic signs, in the presence of which the gardener must immediately take measures to treat the plants.
Fungal diseases
Spores of the pathogenic fungus can spread with air flow and water droplets. Moving in a dormant state, they attach themselves to the surface of potato leaves and wait for favorable conditions for development to occur. As a rule, these are high levels of humidity and low air temperatures. Having affected one plant, the fungal disease quickly spreads throughout the entire planting area. Broad-spectrum fungicides are often used to treat fungal diseases. In addition, in the fight against each individual disease, you can use special medications and follow some recommendations to eliminate the problem.
Late blight
This well-known fungal disease is characteristic not only of potatoes, but also of all other nightshade crops. Its first sign is the appearance of brown spots on the outside and a white coating on the back of the leaves of the plant. If you do not take appropriate measures to treat late blight at an early stage of the disease, then literally in a month all potato plantings may suffer from the fungus: the leaves of the plants will become brown, dry, and brown, dense, deeply penetrating spots will appear on the tubers. With high air humidity, the affected potato tops rot over time; during periods of drought, they wither and dry out.
The causative agents of late blight can be in the soil or move through the air.Planting material can also be infected with late blight spores. Among the preventive measures to combat the disease we can recommend:
- do not plant potatoes in the same place year after year;
- plant planting material only after treatment with antifungal drugs in germinated form;
- place potato plantings far from other nightshade crops;
- hill up bushes, forming high mounds near the trunk of plants;
- when potato seedlings exceed 20 cm, for preventive purposes the plantings should be treated with copper sulfate, adding 1 g of the substance per 1 liter of water.
Preventative protection of potatoes, as a rule, shows a high level of effectiveness. However, in some cases, weather conditions and the aggressiveness of the fungus still contribute to the development of the disease. To combat it, it is necessary to treat the potato tops with Bordeaux mixture, preparing a solution of 1% concentration. A single treatment with this product is not enough to completely destroy the fungus, so the event is repeated every week for a month.
IN fight against late blight You can also use other special preparations, you can learn more about them from the video:
Potato cancer
This fungal disease is one of the most dangerous, since eating damaged tubers can trigger the development of certain diseases in humans. Cancer appears only on potato tubers in the form of tuberous growths. They form mainly at the eyes of the potato and over time spread over its entire surface. In rare cases, you can see symptoms of the disease on the leaves and trunks of the plant.
Spores of the cancerous fungus are hidden in the soil and have high viability.If potatoes from one season show signs of cancer, then from now on only varieties resistant to the disease can be sown in this place, for example “Belorussky”, “Stolovy 19”, “Falensky”, “Lvovsky Bely” and some others. When growing such resistant varieties, it will be possible to completely clear the soil of this disease fungus within 3-5 years.
Often, potato cancer fungi are transferred from one piece of land to another through equipment. This spread of the disease can be prevented by disinfecting all instruments with a chlorine solution. Unfortunately, it is useless to treat the disease itself on the bushes while growing the crop.
Fomoz
This fungal disease, at first glance, may seem harmless. It develops in the second half of the crop growing period and the first signs of Phoma are dark, vaguely shaped spots on the leaves of the plant. Small ball-shaped growths can be observed on the stems.
When digging up potatoes, the farmer will not find signs of disease on the tubers, however, they will certainly appear during storage. This is the cunning of Phomosis. After harvest, dark spots with dry rot form on the tubers. Their diameter can reach 5 cm. Sometimes on each potato there are not one, but several spots at once. If you cut such a potato, you can see a clear border between the affected and healthy tissue.
It is recommended to combat the disease using preventive methods. To do this, seed potatoes are treated with special preparations, for example, “Maxim,” before planting in the ground.After processing, the planting material is dried and sown.
Verticillium wilt
Sometimes at the end of the flowering period you can notice yellow leaves on potato tops. If yellowing begins at the top of the bush and rapidly spreads downwards, then we can conclude that the potato has contracted verticillium wilt, or wilt for short. Additional signs of the disease are symptoms:
- growth retardation of the diseased plant;
- As the disease progresses, the leaves and stems of the potato become brown and fade, die off;
- in wet weather, the leaves on the back side become covered with a pinkish or gray coating.
A fungal disease spreads in moderate temperatures from +16 to +250C. Its development is favored by dry weather and light soil. The peak of disease development often occurs at the end of flowering. In this case, symptoms of infection with the disease are initially observed only on potato leaves. As soon as the crop is placed in the cellar for storage, wilt fungi will manifest themselves, as a result of which the potatoes will quickly rot and become unusable.
It is useless to treat potatoes for verticillium wilt. Fungi are resistant to various chemicals. The development of the disease can be prevented by removing the diseased bush. Potato harvesting must begin with complete mowing of the tops and burning them. Only after removing the remaining vegetation can the tubers be dug up. This measure will reduce the likelihood of additional infection of vegetables. Next year, in the place where potatoes grew and signs of wilt were observed, corn, clover or green manure should be sown.
Fusarium wilt
The disease is often called dry rot. It develops in hot weather during intense evaporation of moisture. Excessive watering of plants can be a prerequisite for the development of the disease. Infection of the crop occurs during various periods of the growing season, but the probability of infection is highest during flowering.
Symptoms of Fusarium wilt on potatoes are:
- change in leaf color. The edges of the lower leaves become slightly purple, the top of the bush becomes lighter;
- the leaves of a diseased bush lose their elasticity and wither;
- the stem becomes brown in color;
- at high air humidity, the stem is torn by an orange or pink fungal coating and rots;
- spots appear on the tubers, covered with a fluffy coating of white or gray color. Over time, vegetables become rotten.
Unfortunately, the disease spreads very quickly from one bush to another. The spread can only be prevented by timely removal of the affected bush. After being infected by the fungus, the potato tops literally wither and die in 3-4 days. Leaves, stems and tubers from such plants are carriers of the disease, so they must be removed from the site.
Treating seed potatoes with fungicides before sowing will reduce the likelihood of disease development. The likelihood of tuber infection during harvesting can be reduced by pre-mowing the tops.
Alternaria blight
The fungal disease is sometimes also called potato dry spot. It often affects late-ripening crops. Under favorable conditions, the disease can destroy a significant amount of the crop, up to 30%.
Symptoms of Alternaria blight include brown, fairly large spots on the leaves. They can most often be observed 2-3 weeks after the start of flowering. Over time, the spots cover the entire leaf blade, causing it to die. A characteristic symptom of the disease on tubers are slightly depressed dark spots. The skin on their surface may wrinkle.
To combat Alternaria, fungicides and some other biological and chemical preparations are used. These include “Acrobat MC”, “Ditan M-45”, “Mankotsev”. Treatment of seed with fungicides can also be a preventive measure in the fight against the disease.
All of the listed diseases of fungal origin can be prevented by treating seed potatoes with fungicides before sowing in the soil. The most common preparations among fungicides are Fitosporin and Maxim. Proper care of potato plantings will also prevent the development of fungal diseases: regular and thorough weeding and hilling of plants will not allow harmful microorganisms to reach the surface of the tubers. Regular inspection of tops and timely destruction of diseased bushes will help avoid the spread of infection throughout all sown areas.
Potato scab
A disease like potato scab combines several different fungal diseases that appear on the skin of tubers and, less often, on the leaves and stems of the tops. Diseases of this type are not capable of destroying the crop completely, but the fungus still significantly deteriorates the presentation and quality of vegetables. The following types of scab are distinguished:
- Common scab develops on slightly acidic soils at air temperatures above +250With and unhindered access to oxygen. Well-earthed potatoes are rarely affected by this disease. A characteristic sign of the disease are rough dark spots on the skin of the tubers. Sometimes cracks appear in place of the stains. Such potatoes are edible, but do not have a very attractive appearance. Prevention of the development of common scab is the addition of manganese and boron to the soil, as well as the cultivation of potato varieties that are resistant to the disease and compliance with the rules of crop rotation.
- Black scab - This is another type of fungal disease that develops in conditions of high temperature and high humidity. The disease can damage not only potato tubers, but also destroy young shoots obtained by sowing infected material. Signs of black scab, which is also called rhizoctonia, are ulcerative spots on potato tubers up to 2 cm in diameter, as well as dark brown spots on the leaves of the tops. Under the influence of the disease they become brittle and break. It will not be possible to store potatoes with signs of black scab for a long time, since the crop will quickly begin to rot. To prevent the development of this fungal disease, seedlings are treated with Mancozeb, Ditan M-45 or their analogues before planting in the ground.For preventive purposes to combat the disease, it is recommended to sow scab-resistant potato varieties and follow the rules of crop rotation.
- Powdery scab has a lot of characteristic features that appear on potato tubers, stems, and tops. Thus, characteristic growths can be seen on the stems and roots of diseased plants. Their color changes from white to dark as the disease develops. After the color changes, the growths disintegrate. Potato tubers are covered with red ulcerative formations, no more than 7 mm in diameter. The source of the disease is a fungus that can be on the surface of seed potatoes or in the soil. Therefore, before embedding into the ground, it is recommended to treat the planting material with a fungicide. Potato ulcers caused by this fungal disease do not pose a particular threat during crop storage, however, through them various putrefactive infections, fungi, and bacteria can penetrate into the cavity of the vegetable. Such potatoes must be stored in strict compliance with certain humidity and temperature conditions.
- Silver scab easy to distinguish from all other types of disease. It appears only on tubers during winter storage. Temperatures above +3 promote the development of fungus0C and air humidity more than 90%. Under such conditions, closer to spring, a gray sheen can be observed on the surface of the stored crop. The weight of such tubers decreases as they significantly lose moisture. Dry, depressed spots appear on the surface of the potatoes. The reason for such anomalies during storage is infection of potatoes during cultivation. The causative agent of the disease may be hiding in the soil or on the surface of seed potatoes.The development of silver scab can be prevented by treating potatoes with fungicides before storing. After processing, the tubers need to be well dried for 3 days, and then placed in a cellar with certain humidity and temperature characteristics.
You can fight various types of scab with the help of antifungal and some special drugs, you can find out detailed information about which in the video:
Storage rules and conditions also play an important role in the safety of the crop: optimal conditions are with a temperature of +1-+30C and humidity 80-85%. Before storing the crop for the winter, the cellar should be treated with a solution of copper sulfate (5%) or bleach (3%).
Bacterial diseases
Various bacteria can damage potatoes and cause significant crop damage. Particularly dangerous are rots that damage tubers, making them unfit for consumption. Bacterial diseases of potatoes, photo descriptions and their treatment are given below.
Bacterial brown rot
This disease is like a time bomb. It develops very slowly over several years, but at the peak of its development it can significantly damage the crop. As a rule, the source of the disease is infected seed potatoes. Once in the soil, the bacteria develop slowly and in the first year you may not notice any symptoms of the disease at all. In the second year, during potato flowering, wilting, yellowing and curling of the leaves are observed. The leaf blades of the tops sometimes wrinkle additionally.
On the tubers of diseased plants, you can observe a thick, growing layer of brown rot under the apparently healthy skin.It literally encircles the fruit and makes it inedible. It will not be possible to store such a crop for a long time. Sometimes rot grows through the surface of the tuber, which is indicated by dark, watery, loose spots on the surface of the vegetable.
Preventive measures to protect potatoes from disease include following the rules of crop rotation and growing resistant varieties. Before sowing the crop, it is recommended to treat seed potatoes with the biological product “Rizoplan”. Unfortunately, there are no special means and chemicals to combat the disease during potato growing.
Potato ring rot
This bacterial disease is widespread and can destroy up to 45% of crops grown annually. The disease is characterized by hidden symptoms. The presence of the disease can be suspected only by 2-3 wilted potato stems. In this case, internal damage occurs in all vegetative organs of the plant. On a cut of infected leaves, when pressed, you can see a light yellow or light brown liquid. This putrefactive formation turns the leaf veins yellowish.
Despite the name, rot can develop not only in a ring pattern, but also in spots. Spots and rings form under the skin of the tuber and may not be visible at all from the outside. Damaged areas of tubers are filled with an oily, viscous, cream-colored liquid. Over time, the internal spots and rings acquire a dark brown color.
Treat ring rot it is useless, you can only prevent the disease before planting seed potatoes. Thus, preventive measures include introducing a moderate amount of nitrogen and an increased amount of potassium fertilizers into the soil.After harvesting from the field, the potato crop must be carefully selected and dried.
Blackleg
This disease is one of the most insidious, as it can destroy almost the entire seasonal crop. More often, the disease parasitizes in places in close proximity to cabbage. Symptoms of the disease appear on potato stems and tubers. The stem at the bottom begins to rot, and rotten wet spots can be seen on the tubers. Potato rotting occurs during cultivation and storage. An additional symptom is hard leaves that are curled into a boat. When you try to pull the plant out of the soil, the tops come off at the bottom of the stem, where rotting has been observed. Symptoms of the disease on potato tubers can be seen closer to autumn. The tubers rot, become soft and at the same time emit an unpleasant odor.
The occurrence of the disease can be prevented by treating seed potatoes with Maxim before planting. Tubers and tops of diseased plants must be removed, as they can be a source of disease the following year.
Bacterial diseases pose the most serious threat to potatoes, since there are no effective drugs to treat plants, and the damage from infection is significant. That is why it is important to pay special attention to the choice of planting material and methods of its preventive disinfection.
Viral diseases of potatoes
The well-known mosaic belongs to the category of viral diseases. There are three types of this disease, depending on the strain of the virus that provokes it. In addition to mosaic, the PLRV virus can cause great harm to potatoes.A detailed description of common viral diseases is given below.
Mosaic
A feature of this viral disease is its pronounced symptoms on the leaves of the plant. Different strains of mosaic virus are characterized by certain characteristics:
- Wrinkled mosaic does not damage potato tubers, however, its harmful effect is that diseased bushes end their vegetative process several weeks, and sometimes months, earlier. At the same time, potato tubers ripen smaller. Weight loss can reach 30%. The main symptom of the disease is the leaves of the tops with a characteristic corrugated surface. Their color is slightly lighter than the color of healthy potato leaves. To prevent the disease, it is recommended to sow resistant crop varieties.
- Potato stripe mosaic shows its symptoms on the leaves of the plant. When infected, spots and stripes of distinct colors appear on the leaf blades and stems of the potato. On the underside of the leaf you can also observe a clear symptom of the disease: brown or purple streaks on the veins. During the development of the disease, such spots spread throughout all vegetative organs of the potato. Under the influence of the disease, crop yields are significantly reduced.
- The speckled mosaic appears especially clearly on young potato leaves. A sign of the disease are light green and yellow spots of various sizes and shapes. On old leaves of the tops, the spots that appear are brown in color. Sick potato bushes are stunted in growth, the process of photosynthesis in the vegetative organs of the plant is disrupted, and chlorosis occurs. As a result of the influence of this virus, potato tubers grow light in weight.
The source of the mosaic virus may be hidden on the surface of seed potatoes or on the body of insect vectors. When signs of disease appear, the infected plant must be removed from the furrow along with the tubers. If this is not done, then a massive spread of the disease will soon be observed.
Curling of leaves. PLRV virus
This viral disease is most often transmitted by aphids, however, there are cases when the planting material itself is the keeper of the infection. The disease affects the leaves and tubers of potatoes. Its main symptoms are:
- leaves curled like a boat along the central vein;
- signs of reticular necrosis on tubers;
- vegetables are practically devoid of starch.
A prerequisite for the development of the disease is very dry and hot weather. Once the virus spreads, it can affect more than 50% of the crop.
The likelihood of the disease can be prevented by soaking seed potatoes before planting in a 1.5% boric acid solution.
Spindle-shaped tubers
This disease is often called potato gothic. Its characteristic feature is the altered shape of the potato: the tubers are smaller, their presentation is lost under the influence of the disease.
Symptoms of gothic disease in potatoes can be observed on the tops and tubers. Thus, when plants are infected, a purple color appears along the edges of the leaf blade and veins. Young leaves on the bush grow narrow and small. Tubers of diseased potatoes have an elongated, bizarre shape. When cut, the infected vegetable has no defects or signs of disease.
Viral diseases, as a rule, cause less harm to potato plantings than fungal and bacterial diseases. Viruses spread more slowly and rarely infect tubers. The greatest harm of diseases lies in the deterioration of the commercial qualities of tubers: change in shape, their lightness, reduction in the amount of starch. If symptoms of viral diseases are detected on single bushes, the damaged plants are removed. If the virus has already infected large areas of crops, it is recommended to use the drugs Campozan, Efeton, Krezacin and some other antiviral substances.
Conclusion
When growing potatoes, you can encounter many diseases. Their symptoms and treatment methods are different, which means the farmer must accurately diagnose the problem in order to correctly eliminate it. The article lists each of the most common potato disease in pictures, so that it is easier for the gardener to navigate the whole variety of diseases. Additional information about potato diseases can be found in the video:
