Contents
Potatoes have many diseases. Almost all of them have manifestations on tubers, and it is important to correctly recognize the infection in order to understand how to deal with potatoes. And most importantly, what to do for the future to prevent the development of the disease.
Fitoftoroz
Oh, this ubiquitous phytophthora! She harms tomatoes, and does not leave potatoes alone. This disease is considered the most harmful in most countries of the world, and its main danger is that it spreads very quickly – in 2 – 3 weeks it can completely destroy all plants.
The disease affects leaves, shoots and tubers. On leaves and stems, it appears as dark spots. Depressed brown or lead-gray spots form on the tubers, and brown smudges are clearly visible in the pulp under them on the cut (1).
Dangerous outbreaks of the disease occur in years with cool and rainy summers.
Is it possible to eat. It is possible – spots in the pulp do not affect the taste of tubers.
Is it possible to store. Sick tubers are best eaten as soon as possible – in the cellar they re-infect neighboring ones. But if everyone is sick, then there is nowhere to go, you can send them for storage, but the temperature in the cellar should be low – 0 – 2 ° C.
Methods of treatment
Update planting material. In no case should tubers infected with phytophthora be left on seeds – in recent years, strains of this pathogen have become aggressive and the main source of infection is now not the soil, where fungus spores usually overwinter, but tubers – in the cellar, the disease continues to breed on them. Buy new, improved ones.
Observe crop rotation. Potatoes can be returned to their original place no earlier than after 4 years.
Pull out the weeds. Especially from the Nightshade family, the most common of which is black nightshade. They are disease carriers.
Use fungicides. In summer, the tops of potatoes need to be treated with drugs against phytophthora – Abika-Peak, Revus, Bordeaux mixture are recommended for summer cottages (2).
Plant resistant varieties. Resistant to phytophthora: Nikulinsky, Nevsky, Luck (3).
destroyed
Potatoes are affected by several types of scab, but the common scab is the most common. This disease has 4 variants of manifestation:
- flat – when brown scabs and abrasions form on the peel;
- mesh – in the form of numerous cracks on the peel;
- convex – warts and growths with a depression in the center;
- deep – with brown ulcers, which are pressed into the pulp to a depth of 5 mm, and the peel around them is torn.
The disease is caused by a group of similar fungi-pathogens. Their spores hibernate in the soil and partly on seed tubers. Scab affects only tubers (4) and begins to appear as soon as they are formed. With a strong defeat, the potatoes are almost completely covered with growths, the yield is reduced by 15 – 40%, and the starch content can be reduced by 30%.
The most severe scab affects potatoes on light sandy and sandy loamy soils. It also provokes excessive application of organic fertilizers – potatoes do not like them at all.
Is it possible to eat. You can, but, of course, you need to cut off the affected areas from the tubers.
Is it possible to store. During storage, diseased tubers do not infect healthy ones, but they themselves deteriorate rather quickly – they begin to rot. Therefore, you can store them, but not for long – you need to eat them first.
Methods of treatment
The most important thing is to prevent an outbreak of infection, and here prevention is first of all important.
Observe crop rotation. Make it a rule never to plant potatoes year after year in the same area – diseases will accumulate. This culture can be returned to its original place no earlier than after 4 years.
Don’t use organic. Refuse organic fertilizers, especially fresh manure – it is not recommended to apply it even before winter on a potato field. And after harvesting, sow the area with green manure, best of all with mustard – it heals the soil well.
Grow clubs around the world. 2 weeks before planting, transfer the seed potatoes to a bright room – they form the poisonous substance corned beef, which inhibits the development of pathogens.
Update seeds. From large producers of planting material, you can order super-elite tubers free from pathogens.
Choose resistant varieties. Unfortunately, there are no completely immune to scab, but there are with increased resistance: Lugovskoy, Zhukovsky early, Impala (3).
Rhizoctonia (black scab)
The disease is very easy to recognize – the tubers are covered with black growths, similar to lumps of adhered earth, or deep and wide cracks appear on them, covered with a cork layer, similar to human scars. The spores of the fungus-pathogen hibernate in the soil and remain there for up to 3-4 years. If the spring is cold and rainy, the disease progresses, causing rotting of the eyes, sprouts and roots – up to 30% of plants can die from this. In summer, affected potato bushes usually lag behind in growth, wither during the day, but recover by evening. The leaves curl up in a boat. If the summer turns out to be rainy, the lower parts of the shoots are covered with a whitish film. Black scab is most pronounced on heavy loamy soils, especially if potatoes are planted too early or too deep (1), (4).
Is it possible to eat. Black growths are on the surface of the tuber, they are peeled off along with the skin. At the same time, the pulp does not suffer, so you can safely eat such potatoes.
Is it possible to store. Black scab does not transfer to other tubers during storage, so the affected ones can be sent to the cellar.
Methods of treatment
The main measure to combat black scab is prevention.
Observe crop rotation. Potatoes can be returned to their original site only after 4 years.
Observe fertilizer doses. It is better to completely refuse organics, and mineral ones should be applied strictly according to the instructions.
Choose the right landing time. It is equally important to observe the planting dates – it is better not to rush, wait until the soil warms up to 10 ° C. But with cleaning it is better not to pull – the sooner you dig, the less growths will be.
Plant tubers at the optimum depth. A lot also depends on the depth of planting tubers: on heavy loamy they are planted no deeper than 6 – 8 cm, on light sandy loam – 8 – 11 cm, on peat – 12 – 14 cm. It is desirable to plant large tubers – they get sick less.
Pull out the weeds. Black scab also affects them, and they are already becoming its peddlers around the site. This disease is most susceptible to sow thistle and quinoa.
Etch clubs. To avoid the spread of the disease through seed tubers, before laying them in the cellar, they must be pickled with Maxim Dachnik (2), or bacterial – Planriz, Baktofit, Agat 25K.
Fusarium dry rot
This disease is quite common and everyone has seen it: a large dark spot forms on the surface of the tuber, and if the potato is cut, there will be a rotten but hard flesh underneath.
Fusarium tubers are still infected in the field (4), but at first the disease does not manifest itself in any way – the first signs are usually found in the cellar after 3-4 months of storage.
Is it possible to eat. If the lesion is small, you can cut off the rotten part of the tuber, and use the rest for food.
Is it possible to store. Since the infection manifests itself in the cellar, it will not work to reject the tubers before laying. But it is necessary to check them from time to time and as soon as the sick are caught, immediately remove them, because they can re-infect the rest of the potatoes.
Methods of treatment
Here are the standard recommendations:
- observe crop rotation;
- pull out the weeds;
- destroy the tops after harvesting;
- seed tubers before being sent to the cellar, pickle with Maxim Dachnik (2).
Ring rot
All housewives are also familiar with her, her main feature is a dark rim around the entire circumference of the tuber at a short distance from the peel. Unlike previous diseases that cause pathogenic fungi, this one is bacterial.
Is it possible to eat. With a small lesion, it is possible, ring rot does not affect the taste of tubers, it is not dangerous for humans. And you don’t even have to cut it completely.
Is it possible to store. From the outside, it is impossible to determine the infected tubers – they are no different from healthy ones. And generally well kept.
Methods of treatment
Ring rot will spread only through infected tubers – the pathogen does not hibernate in the soil. Therefore, in the spring, cut several seed tubers – if at least one has signs of illness, you need to throw away (or eat) the entire batch, because with a high degree of probability all potatoes will be affected, just sometimes the disease is in a latent form. Buy new, healthy tubers.
And, of course, observe crop rotation.
Cancer
The main symptom of the disease is growths on the tubers (5), which makes them look like truffle mushrooms. At first, these growths are light, but then they turn brown and decompose, turning into a slimy mass with an unpleasant odor.
The disease actively develops in cool (14-24 °C) rainy weather (1). It is also provoked by increased doses of nitrogen and organic fertilizers.
Is it possible to eat. You can not.
Is it possible to store. In no case – the tubers in the cellar rot very quickly and can spoil the healthy ones. Such potatoes must be destroyed immediately.
Methods of treatment
Potato cancer is a quarantine disease; when it is detected, the plantings are completely destroyed. Potatoes can be planted in their original place no earlier than after 4 years.
And it is better to choose varieties that are resistant to cancer: Luck, Blueberry, Nevsky, Nikulinsky.
Popular questions and answers
We addressed several typical questions of summer residents about potato diseases agronomist-breeder Svetlana Mikhailova.
Are potato diseases transmitted to other vegetables?
Are potato diseases dangerous for humans?
But potato cancer can cause serious health problems, even death. Therefore, such tubers should be thrown away. But in general, hardly anyone dares to eat them – they are often covered with mucus and smell bad.
Is it necessary to treat diseased tubers with something before laying them in the cellar?
Sources of
- Peresypkin V.F. Diseases of agricultural crops. Volume 2. // Diseases of industrial crops and potatoes, Kyiv: Harvest, 1990. – 248 p.
- State catalog of pesticides and agrochemicals permitted for use on the territory of the Federation as of July 6, 2021 // Ministry of Agriculture of the Federation
https://mcx.gov.ru/ministry/departments/departament-rastenievodstva-mekhanizatsii-khimizatsii-i-zashchity-rasteniy/industry-information/info-gosudarstvennaya-usluga-po-gosudarstvennoy-registratsii-pestitsidov-i-agrokhimikatov/
- State Register of Breeding Achievements
https://reestr.gossortrf.ru/
- Anisimov B.V., Belov G.L., Varitsev Yu.A., Elansky S.N., Zhuromsky G.K., Zavriev S.K., Zeiruk V.N., Ivanyuk V.G., Kuznetsova M. A., Plyakhnevich M.P., Pshechenkov K.A., Simakov E.A., Sklyarova N.P., Stashevsky Z., Uskov A.I., Yashina I.M. Protection of potatoes from diseases, pests and weeds. – M.: Kartofelevod, 2009. – 272 p.
- Peresypkin V.F. Agricultural Phytopathology, 4th ed., revised. and additional // Moscow: Agropromizdat, 1989. – 480 p.