All information about late blight of potatoes from "A" to "Z". Disease-resistant varieties

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What kind of disease is this - Potato late blight? It turns out that this is an extremely dangerous phenomenon that affects both the tubers and the green mass of the plant.

According to statistics, 15% of the total root crop is annually exposed to this disease. Sometimes the rates increase up to 50%.

However, experienced summer residents know what measures must be taken to save the harvest. The main method of exposure is prevention.

From the article you can find out what late blight is, how it is dangerous for potatoes and how to detect it. As well as information about potato varieties that are not afraid of this disease.

Description of phytophthora

The causes of late blight disease manifestation are lower fungi, oomycetes, which are mainly found in the ground. Late blight infection occurs when the infection enters the plant. In the case of potatoes, the infection comes from the tubers.

Infected soil, seeds are sources of disease development.

The maturation period of the pathogen is from 3 days to two weeks, due to such a rapid spread of the disease. Spores are carried by the wind, and scatter tens of kilometers. Also, to create pathogenic microorganisms, appropriate weather conditions are required: high humidity and sudden temperature changes. It is in the spring, with its warm days and cold nights, that favorable conditions are created for the activation of phytophthora.

A photo

The images below show what the disease looks like on potatoes.

Where and when is it formed?

Fungal infection affects the stems, leaves and roots of agricultural plants. The Solanaceae family makes up a large percentage.

First of all, late blight attacks potato tubers, because infection occurs through the soil containing pathogenic microorganisms.

Therefore, they are the first targets of defeat, and then further spread. After 10-15 days, the disease spreads to peppers, tomatoes, eggplants. The infection is formed under favorable conditions:

  • high humidity;
  • when dew appears;
  • during fogs;
  • with fluctuations in night and daytime air temperature;
  • in swampy or flooded areas of the area.

The aggressiveness of late blight directly depends on meteorological factors.... In the rainy period, in the early morning during dew, an outbreak of the disease is peeping. Optimum temperature regime: during the day + 15-20 ° С, at night not lower than + 10 ° С. Dry and hot are considered unfavorable weather conditions for late blight, development is suspended.

Why is it dangerous?

Late blight is considered a serious headache for farmers around the world. The main danger of the disease is the incredible speed of development. From 1 diseased plant, a whole breast or planting can become infected within 7 days. The infection is transmitted to the tubers on which it gets, even during storage.

If 10% of the green mass of the bush is damaged, then it is no longer possible to prevent the disease... The plant should be removed and burned. Phytophthora causes loss of crop quality, infects crops, affects the resistance of plants to other diseases. It is important that the fungal pathogen is distinguished by its vitality, it does not die even from the winter cold.

How to find?

The appearance of this disease is noted on the tubers, trunk, leaves. Development begins during the flowering period. The first signs appear a week after infection. You can see brown-brown spots on the leaves at the bottom of the bush, then the spores are thrown over and damage the upper parts of the young shoots. In rainy weather, white mold is noticeable on these leaves - traces of sporulation of mycelium.

On the diseased parts of the plant, a secondary infection often appears, which leads to the death of the crop, turning the root crop into a rotten mass. The foliage turns black, withers and dries up. If the disease is not stopped, but subsequently the plant will die completely.

Treatment of the disease

How to deal with late blight? This disease is incurable. When eliminating it, one should resort to agrotechnical measures and chemical treatment. To stop the projection of the disease, there is a vegetable processing scheme:

  1. For the first time, we carry out the treatment when the potato bush reaches 25-30 cm in height. As drugs, it is better to choose 1% Bordeaux liquid, copper sulfate or copper sulfate.
  2. Without fail, before the flowering period, sprinkling should be performed with Epin, Exiol, but if the weather is hot and there is no rain, then limit yourself to Silk or Krezacin.
  3. After 2-3 weeks, contact action fungicides - copper oxychloride, Efal or Ditan M-45 - come into effect. Use them strictly according to the instructions on the package.
  4. If you use chemicals for preventive purposes, then the dosage should be halved.
  5. In case of severe damage, Oxyhom, Ridomil MC or Ridomil Gold MC should be used, the treatment must be repeated after two weeks.
  6. At the end of flowering, the tops are treated with the chemical Bravo, this procedure will also need to be repeated after 7-10 days.
  7. During the period of ripening of the root crop, spray the plants with the Alufit preparation.
  8. If it rains after the procedure, it should be repeated.

Among gardeners, the method of combating late blight is popular in the form of folk remedies that can be safely used at any stage of the growing season. It is advised to use milk with the addition of iodine, garlic infusion, wood ash.

Informative video about potato late blight disease and its treatment:

Prevention to protect tubers

To reduce the risk of developing the disease, you should:

  1. Every spring, before planting the root crop, treat the breasts with chemicals to destroy the remaining pathogens.
  2. Do not use tubers damaged by late blight as a seed.
  3. Choose beds for potatoes on flat areas of land, in the lowlands the possibility of spreading infections is greater.
  4. The soil should be light, loose, well-drained.
  5. In areas after tomatoes, peppers, eggplants, potatoes are advised to grow no earlier than after 5 years.
  6. It is important to place beds with Solanaceae away from each other.
  7. It is recommended to plant potato varieties resistant to late blight.
  8. Before and during planting, potassium-phosphorus fertilizers can be used, and with an increase in young tubers in size, the potassium component can be increased by 1.5-2 times.
  9. Avoid overgrowing the beds, eliminate weeds.
  10. Use the hilling technique, which will also help against late blight infection.
  11. Immediately after the potatoes are ripe, it is better to remove them and let them dry in a warm, dry, ventilated place.

Disease Resistant Varieties

Planting material certainly affects the quality and quantity of the harvested crop.... The ideal option is elite potatoes. They are more resistant to various kinds of diseases, harmful insects bypass them, and also have excellent taste characteristics. However, the choice of root crop variety also depends on the growing area.

For northwest Russia

The climate in this area is quite cold. The winter period lasts from November to February, the spring is cool, and in summer there is only a couple of weeks of heat, and the rest of the time there is cloudiness and precipitation. Therefore, in such conditions, not every variety can grow and give a good harvest.


Medium early appearance, the color of the tubers is white, their weight is 180-220g... The pulp is also white. Has good performance in the cooking process, semi friability, excellent taste, starch content 18-22%. This variety is not afraid of sprout breaking, it is also not seen in "kidding".

Stores well. The variety is resistant to cancer, late blight, scab, viral diseases. The sorcerer has a powerful and strong root system that even drought is not a problem, remaining green and resilient. The flowering is profuse, there is a light aroma from the inflorescences.


Mid-early ripening period... Tubers are oval-rounded, white with pink spots around the eyes. The eyes themselves are small.

Good taste and keeping quality. Starch content 14-17%. This variety does not like excess moisture.

A fairy tale can produce from 30-50 tubers from one bush, however, this characteristic depends on the growing parameters. The yield of the variety is 40,000 kg / ha.

Peter's riddle

Mid-season variety.

Oval shape, color - red with small pink eyes.

Has a high yield... The presence of starch is 14-19%.

Decent storage characteristics.

The variety is resistant to cancer, scab, macrosporiosis, late blight, rhizoctonia.


A universal, early, high-yielding variety of domestic selection.

Good taste, starch 14-17%.

The pulp is creamy. Disease resistant.

Correct oval shape of tubers, color - white.

For the Urals


Mid-season variety... Forms tubers at the end of summer.

Has a high starch content up to 20%.

Good taste... Resistant to late blight.

Potato tubers are oblong, pink with small eyes.


Universal grade, ripens in 80-90 days.

Tubers are yellow, oval in shape, with a smooth skin.

It has excellent resistance to late blight, cancer, nematodes, viruses.

Productivity from 1 bush 800-1000g... The pulp is light yellow. The starch content is low 10-14%.


Early ripening variety of Finnish selection.

Has frost-resistant qualities, not susceptible to potato cancer, alterniosis, late blight.

Tubers are round-oval, white.

It is impossible to achieve a complete cure for late blight in potatoes. But it is worth adhering to the correct agrotechnical requirements and the timely implementation of preventive measures. This is the only way to save the potato crop.

Watch the video: Late blight of potato. Botany. Intro. Symptoms. Disease cycle. Control. Notes (May 2022).