Potato diseases and control

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 subject to some characteristic diseases that, despite the efforts of the farmer, reduce the yield and quality of the product, slow down the process of its ripening.

When signs of a disease appear, 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 planting vegetables in advance. So, the most common potato diseases and their control, as well as recommended preventive measures are described below in the article. This information will surely help the novice and experienced farmer to identify the problem and successfully deal with it.

Potato diseases and their treatment

Potato diseases can be caused by fungi, bacteria and viruses. They penetrate into the body of the plant through the root, leaves, damaged parts 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 a pathogenic fungus are able to spread with a stream of air and drops of water. Moving in a dormant state, they are attached to the surface of potato leaves and wait for the onset of favorable conditions for development. As a rule, this is a high level of humidity and low air temperatures. Having struck one plant, the fungal disease quickly spreads over 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 drugs and follow some recommendations to fix the problem.

Fitoftoroz

This well-known fungal disease is characteristic not only for potatoes, but also for 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 appropriate measures are not taken to treat late blight at an early stage of the development of the disease, then literally in a month all potato plantings can suffer from a fungus: the leaves of the plants will turn brown, dry, brown, dense, deeply sticking spots will appear on the tubers. With high humidity, the affected potato tops rot over time, during the drought period it withers and dries.

The causative agents of late blight can be in the soil or move through the air. Planting material can also be infected with Phytophthora spores. Among the preventive measures to combat the disease, we can recommend:

• do not plant potatoes in the same place from year to year;
• plant planting material only after treatment with antifungal drugs in germinated form;
• place potato plantings far from other nightshade crops;
• hill bushes, forming high mounds at the trunk of plants;
• when potato seedlings exceed 20 cm, for preventive purposes, the plantings should be treated with copper sulphate, adding 1 g of the substance per 1 liter of water.

Preventive 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 tops of potatoes with a Bordeaux mixture, preparing a solution of 1% concentration. A single treatment with this agent is not enough to completely destroy the fungus, so the event is repeated every week for a month.

In the fight against late blight, you can use other special drugs, you can learn more about which from the video:

potato cancer

This fungal disease is one of the most dangerous, since eating damaged tubers can provoke the development of certain diseases in humans. Cancer appears only on potato tubers in the form of tuberculate growths. They are formed mainly at the eyes of the potato and eventually spread over its entire surface. In rare cases, you can see the symptoms of the disease on the leaves, trunks of the plant.

The spores of the cancerous fungus hide in the soil and have a high viability. If a potato of one season has signs of cancer, then from now on only varieties resistant to the disease can be sown in this place, for example, Belorussky, Table 19, Falensky, Lvovsky White and some others. When growing such resistant varieties in 3-5 years, it will be possible to completely clear the soil of the fungus of this disease.

Often, potato cancer fungi are transferred from one piece of land to another through inventory. This spread of the disease can be prevented by disinfecting all tools with a chloride solution. Unfortunately, it is useless to treat the disease itself on the bushes in the process of growing a 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 phomosis are dark blurry spots on the leaves of the plant. Small growths in the form of balls can be observed on the stems.

Digging up potatoes, the farmer will not find signs of disease on the tubers, however, they will definitely appear during storage. This is the insidiousness of phomosis. After harvesting, dark spots with dry rot form on the tubers. Their diameter can reach 5 cm. On each potato, sometimes there is not one, but several spots at once. If such a potato is cut, then you can see a clear border between the affected and healthy tissue.

It is recommended to fight the disease with preventive methods. To do this, seed potatoes are treated with special preparations, for example, “Maxim”, before embedding in the ground. After processing, the planting material is dried and sown.

Verticillary wilting

Sometimes at the end of the flowering period, you can see yellow leaves on potato tops. If yellowing begins at the top of the bush and rapidly spreads down, then we can conclude that the potato has fallen ill with verticillium wilt, or wilt for short. Additional signs of the disease are symptoms:

• lag of a diseased plant in growth;
• as the disease develops, the leaves and stems of the potato turn brown and wither, die off;
• in the presence of wet weather, the leaves on the back are covered with a pinkish or gray bloom.

A fungal disease spreads in conditions of moderate temperature from +16 to +25⁰C. Dry weather and light soil favor its development. The peak of the development of the disease often occurs at the end of flowering. In this case, the symptoms of infection with the disease are initially observed only on potato leaves. As soon as the crop is stored in the cellar, wilt fungi will show up, causing the potatoes to 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. Harvesting potatoes must begin with a continuous mowing of the tops, and its burning. Only after removing the remains of vegetation can you dig up the tubers. Such a 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 referred to as dry rot. It develops in hot weather during intensive evaporation of moisture. A prerequisite for the development of the disease can happen excessive watering of plants. Infection of a crop occurs during various periods of the growing season, but the infection is most likely 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 brightens;
• the leaves of a diseased bush lose their elasticity and wither;
• the stem becomes brown;
• at high humidity, the stem breaks with a fungal bloom of orange or pink color and rots;
• spots appear on the tubers, covered with a fluffy coating of white or gray. Over time, vegetables become rotten.

Unfortunately, the disease spreads very quickly from one bush to another. It is possible to prevent the spread only with the help of the timely removal of the affected bush. After the defeat of the fungus, the tops of the potatoes 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 developing the disease. It is possible to reduce the likelihood of infection of tubers during the harvesting process by pre-cutting the tops.

Alternaria

The fungal disease is sometimes also called potato dry spot. It often affects the culture of late ripening. Under favorable conditions, the disease can destroy a significant amount of the crop, up to 30%.

Symptoms of Alternariosis are brown, fairly large spots on the leaves. They can often be observed after 2-3 weeks from the beginning of flowering. Over time, spots cover the entire leaf plate, as a result of which it dies off. A characteristic symptom of the disease on the 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. Among them it is necessary to include “Acrobat MC”, “Ditan M-45”, “Mankotsev”. The 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 ground. The most common drugs among fungicides are “Fitosporin” and “Maxim”. Proper care of potato plantings will also help prevent the development of fungal diseases: regular and thorough weeding, hilling plants will not allow harmful microorganisms to get on the surface of the tubers. Regular inspection of the tops and timely destruction of the diseased bush will help to avoid the spread of infection throughout all sown areas.

potato scab

A disease such as potato scab combines several different diseases of a fungal nature at once, which appear on the skin of tubers and less often on leaves and stems of tops. Diseases of this type are not able to completely destroy the crop, but the fungus still significantly worsens the presentation and quality of vegetables. There are the following types of scab:

1. common scab develops on slightly acidic soils at an air temperature of more than +25⁰With and unhindered access to oxygen. Well-hilled potatoes are rarely affected by this disease. A characteristic symptom of the disease are rough dark spots on the skin of the tubers. Sometimes cracks appear in place of spots. Such potatoes are edible, but do not have a very attractive appearance. Prevention of the development of common scab is the introduction of manganese and boron into the soil, as well as the cultivation of potato varieties that are resistant to the disease and the observance of crop rotation rules.

   

2. 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 rhizoctoniosis, are ulcerative spots on potato tubers up to 2 cm in diameter, as well as dark brown spots on leaves of 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, as 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. As a preventive measure to combat the disease, it is recommended to sow scab-resistant varieties of potatoes and follow the rules of crop rotation.

   

3. Poroshistaya parsha has a lot of characteristic features that appear on tubers, stems, tops of potatoes. Thus, characteristic growths can be seen on the stems and roots of diseased plants. Their color in the process of development of the disease changes from white to dark. After the color changes, the growths disintegrate. Potato tubers are covered with ulcerative formations of red color, with a diameter of not more than 7 mm. The source of the disease is a fungus that can be found on the surface of seed potatoes or in the soil. Therefore, before planting in 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 at the crop storage stage, however, various putrefactive infections, fungi, and bacteria can penetrate into the vegetable cavity through them. It is necessary to store such potatoes with strict observance of certain humidity and temperature conditions.

   

4. silver scab easy to distinguish from all other types of the disease. It appears only on tubers during winter storage. Contributes to the development of the fungus temperature above +3⁰C and air humidity over 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 sunken spots appear on the surface of potatoes. The reason for such anomalies during storage is the infection of potatoes during cultivation. The causative agent of the disease can hide in the soil or on the surface of seed potatoes. You can prevent the development of silver scab by treating potatoes with fungicides before storing them. After processing, the tubers must 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 them on the video:

The rules and conditions of storage also play an important role in the preservation of the crop: conditions with a temperature of +1-+3 are optimal.⁰With and humidity of 80-85%. The cellar before laying the crop for the winter 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 unsuitable for human consumption. Bacterial potato diseases photo description and treatment are given below.

Bacterial brown rot

This disease is like a ticking time bomb. It develops very slowly over several years, but at the same time, at its peak, 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 the flowering of potatoes, wilting, yellowing and twisting of the leaves are observed. The leaves of the tops sometimes wrinkle additionally.

On the tubers of diseased plants, a thick growing layer of brown rot can be observed 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 the disease are the observance of crop rotation rules, the cultivation of resistant varieties. Before sowing the crop, seed potatoes are recommended to be treated with the Rizoplan biopreparation. Unfortunately, there are no special means and chemicals to combat the disease in the process of growing potatoes.

Potato ring rot

This bacterial disease is widespread and can destroy up to 45% of the grown crop annually. The disease is characterized by latent symptoms. The presence of the disease can be suspected only by 2-3 withered potato stalks. In this case, internal lesions occur in all vegetative organs of the plant. On the cut of infected leaves, when pressed, you can see a liquid of light yellow or light brown color. Such a putrefactive formation stains the veins of the leaves in a yellowish color.

Despite the name, rot can develop not only according to the ring principle, but also in spots. Spots and rings form under the skin of the tuber and may not be visible at all from the outside. The damaged areas of the tubers are filled with an oily, viscous cream-colored liquid. Over time, the inner spots and rings acquire a dark brown color.

It is useless to treat ring rot, you can only prevent the disease until the seed potatoes are planted. So, preventive measures are the introduction of a moderate amount of nitrogen and an increased amount of potash 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 the stems and tubers of potatoes. The stem in the lower part begins to rot, rotten wet spots can be seen on the tubers. Potato rot occurs during growing and storage. An additional symptom is hard leaves twisted in a boat. When trying to pull the plant out of the soil, the tops come off at the bottom of the stem, where rotting was observed. Symptoms of the disease on potato tubers can be seen closer to autumn. The tubers rot, become soft and at the same time exude an unpleasant odor.

You can prevent the onset of the disease by treating seed potatoes before planting with Maxim. Tubers and tops of diseased plants must be removed, as they can be a source of disease for the next year.

Bacterial diseases pose the most serious threat to potatoes, since there are no effective treatments for 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.

Virus diseases of potatoes

The well-known mosaic belongs to the category of viral diseases. There are three varieties of this disease, depending on the strain of the virus that provokes it. In addition to the 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 a pronounced symptomatology on the leaves of the plant. Different strains of the mosaic virus are characterized by certain features:

1. Wrinkled mosaic does not damage potato tubers, however, its detrimental effect lies in the fact that diseased bushes finish their vegetative process for several weeks, and sometimes months, earlier. At the same time, potato tubers ripen smaller. Weight loss can be up to 30%. The main symptom of the disease are leaves 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.

   

2. The banded mosaic of the potato shows its symptoms on the leaves of the plant. When infected, spots and stripes of excellent color appear on the leaf plates and stems of the potato. On the underside of the leaf, one can also observe a clear symptom of the disease: brown or purple strokes on the veins. Such spots in the process of development of the disease spread throughout all the vegetative organs of the potato. Under the influence of the disease, the crop yield is significantly reduced.

   

3. The speckled mosaic is especially pronounced on young potato leaves. A sign of the disease are light green and yellow spots of various sizes and shapes. On older leaves, the spots that appear are brown in color. Diseased potato bushes lag behind in growth, the process of photosynthesis in the vegetative organs of the plant is disturbed, and chlorosis occurs. As a result of exposure to this virus, potato tubers grow underweight.

   

The source of the mosaic virus may lurk on the surface of seed potatoes or on the bodies 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 soon it will be possible to observe the mass spread of the disease.

Rolling leaves. PLRV virus

This viral disease is most often transmitted by aphids, however, there are cases when the planting material itself is the custodian of the infection. The disease affects the leaves and tubers of potatoes. Its main symptoms are:

• leaves twisted in a boat along the central vein;
• signs of net necrosis on tubers;
• vegetables are practically devoid of starch.

A prerequisite for the development of the disease is very dry and hot weather. When spreading, the virus can infect more than 50% of the crop.

You can prevent the occurrence of the disease by soaking seed potatoes before planting in a 1,5% boric acid solution.

Spindle tubers

This disease is often referred to as 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.

Gothic symptoms in potatoes can be observed on the tops and its tubers. So, when plants are infected, a purple color appears along the edges of the leaf plate and veins. Young leaves on the bush grow narrow, small. Tubers of diseased potatoes have an elongated, bizarre shape. In the section, the infected vegetable has no defects and signs of the 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: a change in shape, their lightness, a decrease in the amount of starch. If symptoms of viral diseases are found on single bushes, the damaged plants are removed. If the virus has already affected large areas of crops, then it is recommended to use the preparations Camposan, Efeton, Krezatsin and some other antiviral substances.

Conclusion

When growing potatoes, you can encounter many diseases. Their symptoms and treatments are different, which means that the farmer must accurately diagnose the problem in order to competently eliminate it. The article shows each of the most common potato diseases in pictures, in order to make it easier for the gardener to navigate the whole variety of diseases. For more information on potato diseases, see the video: