How to deal with powdery mildew on cucumbers. Diseases of cucumbers in the open field and methods for their treatment

Powdery and downy mildew appears on cucumbers in the form of spots and plaque. If you do not start taking action, then soon the cucumber lashes will begin to dry out and die. Therefore, it is necessary to know effective ways prevention and control of these dangerous diseases.

powdery mildew

signs

If spots appeared on the leaves of cucumbers about round shape white or cream color- this is the beginning of a disease called "powdery mildew". Outwardly, the disease looks like the leaves and stems are sprinkled with flour. The causative agent is a fungus that develops on plant tissues. It can hit them from the moment the green mass grows.

White spots on the leaves of cucumbers are first found on the upper surface. They grow rapidly both in size and quantity. Merging, they move to the lower parts of the sheet, covering everything with powdery coating white color. The leaves affected by the disease turn pale, acquire a light yellow color, then turn brown, curl and dry. If treatment is not carried out, then the stems and even fruits become infected in the future. Cucumber lashes do not develop, are chlorotic in appearance, begin to die off gradually. The disease spreads rapidly and soon manifests itself like a white patch on cucumbers. Infected fruits are underdeveloped and tasteless, have no sugar content, and are often deformed. Later, the plant dies.

Causes

Mealy spots are an overgrown mycelium on which conidia are formed. They will serve as a source of infection in the future. The fungus overwinters on the remains and rhizomes of infected horticultural crops and weeds (sow thistle, chicory, plantain, etc.), and in the spring the infection with drops of moisture enters the young leaves of the cucumber. The latent period of infection is very short - only 4-6 days.

A pathogenic fungus can give many generations in a season, so powdery mildew on cucumbers spreads rapidly and is quite difficult to remove.

If a cucumber beds many years are located on the same plot of land, the pathogen in large quantities accumulates in the soil. The infection can also get on cucumbers from plants planted nearby, carriers of the mycelium.

Distribution factors

Powdery mildew on cucumbers in a greenhouse is more common than outdoors. The vital activity of the fungus is highly suitable for excessively wet greenhouse conditions and insufficient ambient temperature, which is especially typical for greenhouses and unheated greenhouses in early spring. Contributes to the disease and the presence of condensation on the walls and film.

An outbreak of the disease occurs when improper watering cold water. If in the beds the decrease in yield reaches 50-85%, then in greenhouses the damage can reach up to 100%.

How to fight

To date, there are different ways fight the disease. Along with modern preparations for powdery mildew, gardeners do not forget about folk methods, rightly considering them more harmless and affordable. Let us consider in detail how to effectively process cucumbers if they are still sick. From powdery mildew, the following measures can help:

signs

This dangerous fungal infection, otherwise called peronosporosis, has recently spread widely and can affect cucumbers at any stage of growth.

Watch out for signs of downy mildew! If urgent measures are not taken, the landings will quickly die.

The causes and conditions for the spread of peronosporosis are similar to ordinary powdery mildew.

The fungus appears on the leaves as green-yellowish multifaceted spots that appear oily in appearance. Rapidly increasing in size, they capture the entire upper surface, and in the lower part appear as bluish purple bloom. What this type of fungal infection looks like can be seen in the photo.

The leaves begin to turn brown, as if the plant was burned with something. It will wither and dry out if not carried out in time. necessary processing cucumbers.

How to fight

It should be noted that it is more difficult to cope with peronosporosis than with ordinary powdery mildew. The main thing here is timely preventive maintenance and also prevent the disease from spreading. Good results are obtained in the following ways:

To save cucumbers from fungal infections, you must:

1. Timely remove old tops, plant remains and weeds around plantings.
2. Dig deep in the fall soil.
3. Plant seeds in the old place only after 3 years.
4. Alternate crops when growing, the best predecessors are onions, cabbage and legumes.
5. Plant varieties and hybrids that are resistant to the disease. The cultivation of early varieties and hybrids will also serve as protection. This way you can get away from a dangerous outbreak of the disease, which begins during the period of cool nights towards the end of summer.
6. Constantly maintain in greenhouses normal temperature and humidity level.
7. Watering, especially in cloudy weather, should be carried out only warm water, and it is important to ensure that it falls strictly on the soil, and not on the leaves.
8. Follow the schedule of feeding with potassium and phosphorus, which increase the resistance of plants to infection and are a good prevention of powdery mildew in cucumber beds.
9. If Rizoplan is used as a prophylactic, then downy mildew on cucumbers may not spread further. When working with it, follow the instructions, but usually it will take only 2 tbsp for a bucket of water.
10. Greenhouses after the final harvest are treated with a solution blue vitriol, based on a bucket of 3 tbsp. means, well shedding the soil. All infected plants are removed and burned outside the site.

Safety

In the fight against powdery and downy mildew on cucumbers, it is often necessary to resort to toxic drugs. There are a number of rules that must be observed when using them so as not to harm your own well-being:

1. Wear protective clothing, gloves and a mask when working.
2. Treatment with toxic substances is not carried out during the flowering of fruit and berry crops so as not to kill pollinating insects.
3. Spraying is best done in cloudy weather so that the plants do not get burned.
4. Rinse all processed vegetables thoroughly with warm water before eating to wash off the remnants of the preparations.

As you can see, powdery and downy mildew are not so terrible if you know how to destroy them.

Powdery mildew on cucumbers is one of the most common diseases that causes a lot of trouble. If no action is taken against it, then the affected cucumber plantings will die, and there will be no harvest. In addition, in areas where plants were sick with powdery mildew, infection of new plantings is likely next year.

Powdery mildew is a fungal disease, the causative agents of which are located in the upper layer of the earth, on last year's plant residues, on dried weeds. They are not afraid of frost. They wake up in the spring when the air becomes warm.

A mandatory factor contributing to the activation of spores of this fungus is high humidity. In dry weather, powdery mildew rarely infects plants.

Spores are carried with the wind, with raindrops. They are attached to the leaves of cucumbers, most often to the lower ones. The leaf is covered with white rough spots, which at first have a small size. Then they grow, the sheet becomes completely white, and eventually turns gray, its edges fold to the top.

Fungus at favorable conditions quickly spreads throughout the plant, damaging stems, flowers, cucumbers. The plant looks like it's covered in mold. The cucumbers are starting to rot. Cucumber plantings, the disease of which has developed to such a stage, die.

Causes of powdery mildew in cucumbers and the conditions when the fungus spreads most often:

• a sharp change in air temperature;
• frequent rains;
• watering with cold water;
• thickening of plantings, in which cucumbers are not ventilated and do not dry out for a long time after rain;
• dried parts of last year's plants are not removed from the garden in the fall;
• unkempt area overgrown with weeds;
• insufficient illumination of the beds by the sun;
• an excess of nitrogen in the soil, and a lack of phosphorus or potassium.

Methods for dealing with powdery mildew on cucumbers

Biological

"Albit" - the drug effectively acts on the fungus, regardless of weather conditions and temperature fluctuations. In addition to medical and protective property has an immunostimulating effect, helps the plant recover from the action of chemical pesticides, promotes the formation of additional stems and the development of the root system.

"Alirin-B" - treats powdery mildew and other fungal diseases, restores the microflora in the soil, reduces the content of nitrates in fruits. When processing, soap should be added to the solution for better adhesion to the leaves.

"Gamair" - suppresses the action of pathogens of fungal diseases, restores the soil, reduces its toxicity, stimulates plant growth and improves immunity.

Biological preparations are used repeatedly, starting at the first signs of powdery mildew disease, and until the disease completely stops.

Chemical fungicides

If the spores have covered most of the plant, chemical fungicides should be applied.

• Bayleton - the protective effect lasts up to 4 weeks, depending on weather conditions;
• "Rayok" - the action begins 2 hours after treatment, the protection lasts about 7 days. Doesn't wash off with rain.
• "Thiovit - Jet" - the protective effect lasts up to 7 days, it can also be used to kill ticks;
• "Topaz" - the action lasts for 1-2 weeks, is used for prevention and treatment. It also has eradicating properties.

For the treatment of powdery mildew on cucumbers, the use of biological and chemical preparations can be combined. Chemicals are considered more effective, and biological ones reduce their toxicity and restore plants from stress after an illness.

Folk remedies for the fight against powdery mildew on cucumbers

Folk remedies are used for prevention or at the first sign of the appearance of a fungus. AT difficult situation when the disease covers large plantations of cucumbers, and in addition to the leaves, the stems and ovaries are infected, they are powerless.

• fermented milk products - yogurt, whey, kefir. Proportion: 1 part to 10 parts of water room temperature. Thoroughly stir and process the entire plant completely;
• soda ash - 1/3 teaspoon is diluted in 1 liter of water and a little soapy solution is added;
• wood ash - 1 liter jar ash per 5 liters of boiling water. Insist for about a day, filter, add liquid soap.

All these means are best to start using when it starts rainy weather, or in the morning the dew stays for a long time, and in the evening fogs rise. Processed once a week, wetting all cucumber plantings and the ground near them with a solution. The disease can and will arise, but will not progress.

Prevention

If preventive measures are taken every year, fungal disease can be avoided completely.

Stages of preventive work:

1. In autumn, after harvesting, all plants are removed from the garden, leaving no roots.
2. If in current year cucumbers hurt, then upper layer soil about 5 cm thick is removed.
3. The earth is being dug up.
4. Treat the soil with biological preparations.
5. In the spring, the area allotted for planting is spilled with boiling water or strong mortar potassium permanganate. This will help get rid of not only powdery mildew pathogens, but also other diseases and pest larvae.
6. When fertilizing, it must be taken into account that an excess of nitrogen, or a lack of potassium and phosphorus - favorable environment to develop disputes.
7. For planting, seeds of varieties resistant to powdery mildew are used.
8. When planting cucumbers, you should observe the distance between them recommended for the selected variety. It is better to plant them rarely than to thicken them.
9. After the cucumbers grow up to 20 cm in height, you should start preventive treatments folk remedies or biological preparations, and carry them out regularly, at least 1 time in 2 weeks. In rainy weather, the interval between treatments should be reduced.

Powdery mildew resistant cucumber varieties

"Goosebump" - parthenocarpic (not requiring pollination) variety, the ripening period of the first fruits is 45 days. Up to 5 ovaries are formed in the sinus, fruit length is up to 12 cm. Without bitterness. Grown in open ground, in greenhouses and greenhouses.

"Golubchik" is a bee-pollinated variety, the fruits ripen on the 50th day, the length of greens is up to 12 cm. Suitable for canning and pickles.

"Boy-with-finger" - small greens up to 10 cm, ripen on day 38, ideal for canning.

"Masha" - parthenocarpic, very early variety. The first fruits are ready for use on the 35th day, bear fruit for a long time. The length of cucumbers is up to 13 cm, without bitterness. Eat fresh, prepare for the winter. Grown in open ground.

"Benefis" is a self-pollinating variety. Fruit without bitterness. Ripens in 40-50 days. Suitable for summer food and preparations for the winter.

"Ibn-Sina" - parthenocarpic, for open ground. Ripens at 45 days. Cucumbers are long, up to 17 cm. There are 2-3 greens in one ovary. Consumed in fresh.

"Alekseich" - parthenocarpic variety, gherkin fruits, up to 8 cm. Ripen in 40-45 days.

Is not full list varieties of cucumbers resistant to powdery mildew. When choosing a variety, you should also pay attention to:

• suitable for growing in your area;
• grows best in a greenhouse, or only in open ground;
• suitable for salting or consumed only fresh;
• greens length;
• fruit ripening period.

When growing F1 hybrids, you need to know that it is pointless to collect seeds from your cucumbers. Quality and taste mother plants through seeds collected from hybrids are not transmitted.

Video

Powdery mildew is a disease that is dangerous for many garden plants and cucumbers are no exception. Unfortunately, a cucumber of any variety, both ground and greenhouse, can pick up this ailment. This happens to both amateur gardeners and professionals. Fortunately, the disease is curable, but treatment should be started as soon as possible.

Causes and symptoms of the problem

Powdery mildew is a fungal disease. Plantings that are excessively fertilized with nitrogen are especially often affected. High humidity and moderate heat favor infection. The first signs appear about a week after that. Powdery mildew looks like fluffy white spots scattered on the leaves, sometimes they can have a reddish or grayish tint.

At first, spots appear on the upper side of the leaf, but soon they pass to the lower side, merging with each other. Leaves close to the ground are affected first. Then the leaves dry out, become loose and eventually die. Little by little, the disease moves to the stems, and the whole whip becomes like sprinkled with flour. Perhaps the resettlement of the fungus and on the fruit. Since the plant loses its leaf apparatus, it weakens, which first leads to a slowdown in growth and fruiting, and then may end in death.

When infected with powdery mildew, the leaves are covered with abundant white bloom, slowly wither, then die off.

Usually in a greenhouse, the humid microclimate is quite stable, so greenhouse cucumbers get sick more often than ground. And since the fungus overwinters in plant debris, plants in poorly cleaned greenhouses become especially sick. The following factors contribute to the development of the disease:

• rainy weather with temperature fluctuations;
• thickened fit that prevents air circulation;
• excess nitrogen in the soil and its alkaline reaction;
• excessive watering, especially with cold water;
• insufficient general level of agricultural technology, in particular, the abundance of weeds.

The sooner the fight against the disease begins, the higher the chances of winning.

Video: powdery mildew on cucumbers

How to deal with powdery mildew: drugs, measures, folk remedies

Regular inspection of plantings allows you to notice the disease in the early stages, after which it is necessary to immediately take measures to destroy the fungus and its spores. If signs of powdery mildew are found only on 1-2 lashes, it is better to pull them out and burn them immediately, and then start spraying the plants. But before that, all weeds should be destroyed and, possibly, thinned out plantings, removing the weakest plants.

If the plaque was found only on the lower leaves of several plants, you can cut off only these leaves, and treat the cut points with Trichodermin. This does not cancel the treatment of landings with chemical, biological or folk remedies. The choice of such drugs is wide. However, fungicides can be used long before harvest, which must be taken into account when developing a control strategy.

Trichodermin is one of the safest and most effective fungicides

If the disease manifested itself early, even before flowering, it is quite possible to use purchased drugs which will fix the problem. You can select them, for example, from the following list:

• Bordeaux liquid;
• colloidal sulfur preparations;
• Ridomil Gold;
• Phytosporin;
• Oksikhom;
• Byleton.

Since it will not be possible to try earlier than three weeks after processing the cucumbers, it is better to try to use folk remedies; they can be used repeatedly. The list of such recipes is huge, all of them can be briefly summarized as follows:

• milk products ( spoiled milk, kefir, curdled milk, diluted in water approximately 1:4);
• milk-soap composition (1 liter of milk, 20 g of soap, 25 drops of iodine);
• mullein infusion (a third of a bucket of manure is infused in a bucket of water for 3 days, then diluted 10 times);
• infusion of herbs (they act similarly to manure, but can be diluted to a lesser extent);
• infusion wood ash(1 kg of ash is insisted in a bucket of water for a week, a little soap is added);
• garlic infusion (200 g per bucket of water, insist for a day).

how chemicals, and folk cucumbers sprayed in the evening, in calm weather, processing all the leaves, if possible on both sides. Folk remedies can be used every one and a half to two weeks.

Video: fight against powdery mildew

Infection prevention

It is perhaps impossible to completely protect cucumbers from powdery mildew, but preventive measures can drastically reduce the risk of the disease. One of them is the absence of other vegetables with powdery mildew on the site. In addition, the following must be observed:

• take into account crop rotation: cucumbers are returned to their original place no earlier than after 3 years;
• constantly destroy weeds;
• in the fall, after harvesting, carefully remove the remains and disinfect the garden bed with potassium permanganate or blue vitriol;
• treat seeds before sowing with potassium permanganate or Trichodermin;
• water only with warm water, if possible under the root;
• systematically ventilate the greenhouse;
• do not overfeed cucumbers with nitrogen fertilizers;
• periodically add mustard to irrigation water (2 tablespoons of powder per bucket of water);
• shortly before flowering, spray plantings with Quadris.

It should be borne in mind that in addition to powdery mildew, there is a disease called downy mildew. However, their prevention measures are identical.

Powdery mildew can completely deprive a gardener of a crop, but if it is detected in time, it is not difficult to save the plants. It is even better to prevent infection by applying on time and correctly. preventive measures. At proper management gardening, the disease is noted only in the most unfavorable years.

Under conditions of cool and rainy summer a whitish coating often appears on the foliage of cucumbers. This is how powdery mildew manifests itself - a disease caused by the activity of a microscopic fungus that lives in the soil. This dangerous disease appears both on plants planted in a greenhouse and on those that grow in open ground. It is capable of spoiling most of the crop if left untreated. Therefore, at the first signs of infection of plants with powdery mildew, it is necessary to take all measures to eliminate the fungus.

Description of the disease and signs of infection

Powdery mildew is a fungal disease of plants that causes the appearance on the leaves of white plaque. As a result of the activity of the fungus, the leaves fade prematurely and dry out. In addition to leaves, the disease can spread to stems. Fruits suffer from powdery mildew to a lesser extent.

The main condition for the development of powdery mildew is cool and cloudy weather with high humidity air. The fungus stops spreading at temperatures exceeding +18 degrees. In greenhouses, this problem most often affects plants located near doors or windows, where it is often cool and damp.

On plants planted in open ground, powdery mildew appears under the condition of significant fluctuations in day and night air temperatures, as well as in case of non-compliance with the irrigation regime. In this case, the disease can appear both from waterlogging and from a lack of moisture.

Powdery mildew on cucumber leaves

First of all, the disease manifests itself on weakened plants. When affected, the plant stops its growth, the leaves and shoots wither and lose their shape. Lack of treatment leads to the death of the plant.

Powdery mildew is a dangerous disease that destroys the crop of cucumbers, regardless of variety.

Downy mildew on cucumber leaves

In addition to true powdery mildew, cucumbers can also suffer from peronosporosis - downy mildew. This disease affects the leaves of cucumbers. Light yellow spots appear on them, limited by veins. Over time, the spots acquire angular outlines and become oily, their hue changes to brown. On the underside of the sheet at the site of the formation of spots appears dark patina. If left untreated, the plant dies from peronosporosis in 2-3 days.

Preventive measures

To prevent the occurrence and development of these diseases, you must adhere to the following rules:

• Observe crop rotation so that pathogens of powdery mildew and downy mildew do not accumulate in the soil. For this cucurbits grown in the same place 1 time in 4 years.
• Regularly collect plant debris from plantings.
• Disinfect after harvest.
• When growing cucumbers in a greenhouse, maintain optimal conditions for plant development. The air temperature in the greenhouse should be above +20 degrees.
• For watering vegetables, use only warm water.
• Periodically spray the vegetable crop with specialized compounds. For this purpose, the drug "Kvadris" is often used.

In addition to the above measures, it is important when growing cucumbers not to abuse the application of fertilizers of potash, nitrogen or phosphorus composition.

It is much more difficult to deal with peronosporosis than with powdery mildew, since this disease is very transient. To prevent it, the following measures must be taken:

• do not thicken the landing;
• observe the rules of crop rotation;
• water the culture only with warm water;
• harvest regularly.

Ways to fight

To combat these dangerous plant diseases, there are several methods. But the main thing is to recognize the disease in time, to identify it at an early stage, then the chances of curing the plant and saving the crop increase significantly. In order to detect infection in time, it is necessary to regularly inspect cultures.

The effectiveness of the fight against fungal diseases directly depends on the degree of development. The sooner you start fighting the disease, the more successful the result will be.

If an infection is detected, it is necessary to immediately remove all parts of the plants damaged by the disease and burn them. Then you can start treatment with chemicals or with the help of folk remedies.

Chemicals

If the initial signs of damage to cucumbers are found, it is necessary to immediately take measures for treatment. Immediately you need to abandon any kind of top dressing and spraying, improve the coverage of the vegetable crop, thin out the plantings by removing old leaves and diseased plants, cut off the flower stalks. These measures make it possible to achieve an effective result in the fight against both mycelium and fungal spores.

In addition to these drugs, to cure powdery mildew and peronosporosis, you can use drugs such as Bayleton, Previkur, Acrobat MC, Skor or Vitaros. At an early stage of the disease positive result gives the use of drugs with a sulfur content: "VDG" or "Thiovit Jet". All chemical substances must be diluted and used according to the instructions on the package.

You can use preparations containing copper as a spray. To do this, prepare a solution of chloroxide or Bordeaux liquid. The funds are diluted in 10 liters of water, adding 1 tsp each.

Folk remedies

Folk remedies for the treatment of powdery mildew are very diverse and have proven themselves for long years use. From folk methods The following treatments are recommended:

For the treatment of peronosporosis, a solution of whey with the addition of copper sulphate is used. In a ten-liter bucket of water, dilute 3 liters of whey and add 1 tsp. copper sulfate. The resulting solution is abundantly sprayed with plants.