Peronosporosis of cucumbers in the greenhouse and their treatment, photos and symptoms of affected leaves, preventive measures

Peronosporosis of cucumbers in the greenhouse and their treatment, photos and symptoms of affected leaves, preventive measures

We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

Downy mildew, or downy mildew, is a fairly common disease of cucumbers in a greenhouse. It is important for novice gardeners to study in advance what his symptoms look like in the photo, because this will help identify diseased bushes and promptly treat them.


  • Peronosporosis, a description of the disease, as it looks in the photo
  • What are the symptoms of downy mildew
  • How does the disease develop
  • Causes provoking the development of the disease
  • What does the defeat of downy mildew lead to?
  • Treatment
  • Folk remedies against downy mildew
  • Prophylaxis

Peronosporosis, a description of the disease, as it looks in the photo

Bel, or powdery mildew, is a disease caused by ectoparasitic microscopic fungi. They belong to powdery mildews. The development of mycelium occurs on the aboveground part of plants: leaves, shoots, fruits. The cause of mycotic disease in cucumbers with very similar manifestations (downy mildew) is the representatives of the Peronosporonaceae family, more precisely, mushroom-like oomycetes.

If we look at the diseased plant in the photo, then it is not difficult to note the main distinguishing features of the lesion by peronospirosis: spots on the leaves of an irregular shape and a change in the color of the leaves themselves, and the browning of the leaves sometimes begins only in the last stages of the disease.

The transmission of infection is carried out in most cases by air, the foliage becomes the object of the lesion first.

The development of pathogenic microorganisms disrupts the processes of photosynthesis, the growth and development of the plant is inhibited. Further, the pathogenic pseudo-fungi move to neighboring plants.

Peronosporosis of cucumbers in a greenhouse is dangerous because it spreads at lightning speed, only their timely treatment will help preserve the plants, and it is recommended to start it as soon as you can recognize the symptoms of the disease. That is why it is recommended to consider the photos of the affected bushes thoroughly.

What are the symptoms of downy mildew

Experienced gardeners are well aware of how cucumbers affected by peronospora look. Their leaves are speckled with irregular spots. On the underside, you can see a whitish-lilac or grayish bloom.

After a while, the leaf is deformed, and the skin on the stems cracks. The sheets on which the spots have reached the central veins fall off. Against the background of healthy parts of the plant, the affected ones look more faded and limp.

In the process of development of the disease, the shade of the foliage changes to brown, then it dries up and falls off. Affected ovaries and flowers darken and change shape. First of all, the young lashes of the bush die, then the plant completely stops developing.

Another disease of cucumbers, black spot, has similar symptoms, but it affects the foliage from the bottom up, the leaves fall off in a few days.

More detailed information about peronosporosis of cucumbers in the greenhouse and their treatment, photos of diseased leaves, watch the video:

How does the disease develop

Although peronosporosis has a rapid course, it can be divided into several stages, they occur in the following sequence:

  • light yellowish spots appear on the outer surface of the sheets;
  • the color of the lesion site changes to yellow-green, oiliness appears;
  • the outer part of the leaf acquires a brown tint, the inner part is covered with bloom;
  • the lesion sites grow and they merge;
  • sheets perish;
  • complete death of the plant occurs.

Cucumbers grown in greenhouses are more susceptible to damage by peronosporosis.

Symptoms of damage to greenhouse plants and those grown in the open field may differ, for example: in the open air, the defeat may look like small spots on the leaves.

Let's watch a useful video about that. how the disease develops and the methods of dealing with it:

Causes provoking the development of the disease

Peronosporosis can affect not only cucumbers, but squash and melons. The active development of mushroom-like parasites begins when they enter a humid, warm environment.

On the positive side, the dry and hot climate in some regions avoids serious crop losses, even if cucumbers are affected by downy mildew.

As the main provoking factors, we note:

  • high humidity resulting from excessive watering or frequent rains;
  • use of cold water for irrigation;
  • growing in greenhouse conditions with insufficient ventilation;
  • Condensation constantly settling on the walls of the greenhouse;
  • thickening of landings;
  • poor ventilation of the beds;
  • frequent dew, foggy weather;
  • a large number of weeds in the beds.

Peronosporosis is extremely rare in dry weather. But when favorable conditions appear, infection and death of plants can occur in a very short time.

Often, the defeat of cucumbers with downy mildew is supplemented by bacteriosis: pathogenic oomycetes create favorable conditions for the development of another disease.

With a double defeat, the plants have a sick appearance, their leaves are covered with yellow-brown spots, powdered with white, flour-like pollen.

What does the defeat of downy mildew lead to?

The development of pathogenic false fungi leads to the following negative results:

  • disruption of the process of photosynthesis, due to which plants suffer from a lack of nutrients;
  • change in the shape of the fruit to the wrong one;
  • crushing of fruits and deterioration of their taste;
  • the complete absence of ovaries is possible;
  • yellowing and death of leaves, which, falling on the ground, infect the entire area.

To date, there is no reliable information about whether seeds taken from cucumbers grown on diseased plants are the source of infection.


Peronosporosis of cucumbers in a greenhouse and their treatment require an attentive approach, therefore we will provide a description and photo of effective means to combat the disease.

It is possible to stop the spread of the disease by using modern means for pollination and spraying of bushes.

You can provide an ambulance to a plant as follows:

  • stop watering and feeding;
  • spray the bushes with copper chloroxide, Bordeaux liquid, polycarbacin, the recommended solution temperature is +25 C;

A good effect is given by treatment with 0.5% solutions of drugs: Ridomil Gold, Cabrio Duo, Kurzat, Ordan. It is very important that during the treatment period in the greenhouse the temperature of the order of +25 C is observed.

When growing cucumbers in the open air, it is recommended to cover them with foil overnight.

Folk remedies against downy mildew

Those. those who do not want to treat the beds with chemicals can use folk recipes, we will indicate them in the table.

The composition of the productHow to prepare a solutionMultiplicity of treatments
Soda 25g, liquid soap 15g, hot water 5lMix everything thoroughly, after cooling, spray on the plant and on the top layer of soil under itMinimum 2 treatments, with a break of 7 days
Onion peel, 250-350g, water 10lOnion peels are added to a bucket of hot water, brought to a boil, infused for 2-3 days, filtered.2-3 treatments will be required, with a break of a week
Iodine 5% 10 drops, skimmed cow milk 1l, water 9lSpraying of bushesIt is applied 2-3 times with an interval of 7-10 days
Wood ash 2 cups, 2-3 liters of boiling waterAshes are brewed like tea, filtered, diluted with 10 liters of waterThe processing is repeated several times a season.

Recall that the leaves affected by the infection are recommended to be cut off and burned, such actions will help stop the spread of the disease to neighboring bushes.

Preventive measures

Any disease is easier to prevent than to cure; peronosporosis of cucumbers in a greenhouse is no exception. The correct application of preventive measures gives a chance to assume that the problem may not arise at all.

The most effective measures for the prevention of downy mildew:

  • periodic spraying of plants with a solution of whey;
  • disinfection of seeds with antifungal drugs;
  • pruning and burning affected leaves, fruits, shoots (fungal spores can winter in plant debris and resume their development with the onset of a new season);
  • at stages III and IV of the lesion, the fight becomes useless, it is more rational to cut off the damaged parts of the plant and burn it.

Naturally, the question arises of how to water the land in the beds in the greenhouse in order to exclude the peronosporosis of cucumbers. Experienced vegetable growers use watering the ground with hot water, followed by covering the beds with a film.

An important point is the replacement in the greenhouse or greenhouse of the upper 7-centimeter layer of soil, it should be done every 3-4 years.

For disinfection of the soil and all structural elements, a 1% solution of copper sulfate can be used.

Knowledge about the nature of a common disease will help to prevent peronosporosis of cucumbers in a greenhouse and to simplify their treatment, studying photos of affected leaves will help to learn how to identify symptoms of the disease at its earliest stages, when it is still possible to save the crop.



  1. Grohn

    Really even when I didn't think about it before

Write a message