We fight powdery mildew in cucumber beds. Downy mildew on cucumbers: signs, prevention and treatment

One of the most frequent illnesses cucumbers - powdery mildew. This disease is dangerous because it can deprive a gardener of half his harvest. Especially if you do not start treatment on time.

Appearance powdery mildew You can immediately notice it on cucumbers. These are small round white or reddish spots on the underside of the leaves, which are located close to the ground. At the same time, the bases of the shoots are covered with the same coating.

The area of ​​the spots increases rapidly. And soon the fluffy grayish or white coating covers the entire leaf, gradually affecting the entire plant. The whole whip seems to be sprinkled with flour.

If you look closely, you can find fungal spores - these are small balls Brown. As they ripen, moisture appears on the white coating, which looks like dew.

Cucumbers growing in a greenhouse are more susceptible to powdery mildew than those growing outside. This happens because in closed ground a humid microclimate is created, which promotes the spread of fungal infection.

Powdery mildew development cycle

The fungus lives in plant debris left in the garden since autumn. In the spring it awakens and first takes over the leaves of the weeds.

Powdery mildew spores may develop if:

1. Summer is rainy and cold with sudden temperature changes.
2. The cucumber plantings are so dense that there is no air circulation between them. In this case, the mycelium can easily move to other plants due to their proximity.
3. The soil is alkaline or has excess nitrogen.
4. Watering is done too often when the soil is not yet dry. The situation gets worse if you use cold water.
5. Weeds have not been removed from the garden bed. Powdery mildew spores from the grass spread to more and more vines of cucumbers.

The fungus develops almost instantly:

1. The time from the moment the fungus hits the cucumber leaves until the plant becomes sick is from 3 to 7 days.
2. The period depends on air humidity: the higher it is, the faster the spores germinate.
3. Initially, the lower leaves suffer, especially those that touch the soil. Then the disease spreads to leaf petioles, stems, and fruits.
4. Over time, the spots increase in size, merging with each other. The plaque thickens and turns brown.
5. The leaves become loose, curl and dry out. Photosynthesis is disrupted, which is why the cucumber cannot eat properly.
6. The fungus spreads to the fruits, which rot and crack.
7. The tips of the shoots are bent. The lashes dry out, darken and die.

Favorable conditions for the life of fungi are light warmth (+16 – +20°C) and dampness. In such an atmosphere, they multiply quickly, managing to give birth to several generations within a season.

How to deal with powdery mildew on cucumbers

The main thing is to constantly monitor the condition of the cucumber leaves. If you take measures to combat powdery mildew on cucumbers when the first spots appear, the crop can still be saved.

The fight consists of destroying the mycelium (mushroom body) and its spores. Therefore, the first infected lash must be removed and burned along with the roots.

The plantings must be immediately weeded and, if necessary, thinned out.

If a white coating appears on several shoots only on lower leaves, they need to be carefully cut down to the stem and burned. It is better to remove the foliage that looks weakened. After this, the cut is treated with Trichodermin paste.

Then all cucumbers are sprayed with fungicides ( chemical method) or fermentation products (bacterial method).

Ready-made drugs

Industry produces effective drugs to fight fungal infection. But when using them, you need to take into account the fact that cucumbers after treatment with them long time will not be eaten. Therefore, it is better to use such substances before the flowering period or, in extreme cases, during it.

At the very beginning of powdery mildew disease and for prevention, cucumbers are treated with:

• Bordeaux mixture (a teaspoon per bucket of water);
• colloidal sulfur (sulfaride);
• "Ridomilom Gold";
• "Oxychom";
• "Tiovitom Jet".

The following agents block the spread of fungus and are harmless to the plant:

• "Fundazol" or its analogue "Fundazim";
• "Topsin-M";
• "Title CE";
• "Alirin-B";
• "Gamair";
• "Fitosporin".

Modern fungicides with a protective effect:

• "Privant";
• "Cumulus";
• "Kuproksat";
• "Bayleton";
• "Karatan EC".

Sulfur preparations are good for destroying powdery mildew pathogens. But they can burn cucumber leaves if the concentration of the solution is exceeded.

Fungicides in the cucumber bed are used in doses, because they accumulate in all parts of the vegetable. Excessive amounts of the substance will lead to the fact that the concentration of pesticides in the fruits will be exceeded.

After using most drugs, a break of at least 20 days is required from the moment of treatment before eating the fruit.

In addition, such substances suppress the growth of not only harmful fungi, but also the development of the plants themselves. As a result, fewer ovaries are formed and the yield is reduced.

Folk remedies

Traditional methods for combating powdery mildew are good because they can be used all season long. They do not harm plants and are safe for the person doing the treatment. After spraying natural means The fruits can be consumed immediately.

You can make a remedy against powdery mildew using chemicals:

1. Potassium permanganate - 1 gram per bucket of water.
2. Silicate glue (sodium silicate) - 30 ml per bucket. A protective film forms on the surface of the sheet. It can be mixed with fungicides or used alone. But together with growth regulators it can cause the death of cucumber plantings.
3. Colloidal sulfur - 40 grams per 10 liters of liquid. This solution is used when infesting cucumbers in a greenhouse with powdery mildew spores. On open ground the concentration of the mixture is made 2 times less. The solution is not stored, it is used immediately. Air temperature - from +25 to +35°C.
4. Ground sulfur - 30 g sprinkled on 10 m2 of soil.
5. Copper sulfate - 80 g per bucket of liquid. Add 50 g of soda ash.

Other formulations with soda:

1. Soda ash - 1 part, laundry soap - 1 part.
2. Drinking soda - 5 g, water - 1 l. Add grated soap. You need to spray at least four times.
3. Baking soda and soap taken in equal parts. Spray daily for a week.
4. Destroys powdery mildew and iodine: milk - 1 liter, iodine - 10 drops, warm water - a bucket.

Infusions with laundry soap:

1. Liquid soap - 5 g, soda ash - 25 g, boiling water - 5 l. Stir well and cool. Spray 3 times: on the first day, on the second, then on the seventh day after repeated treatment.
2. Ash - 1 kg, water - bucket. Leave for 7 days. Not a large number of grated soap is added just before spraying.
3. Soap - 5 g, ash - 150 g, boiling water - 1 l. Leave for 2 days.

Sour dairy products work very effectively against fungi on cucumbers. They form a protective film on the surface of the leaves. The acidic environment that is created on cucumbers prevents the growth of bacteria.

Spraying solutions with fermented milk products:

1. Whey - 1 part, cold water - 10 parts.
2. Whey - 3 l, copper sulfate - 1 tsp, water - a bucket.
3. Kefir and liquid in arbitrary proportions.

The development of powdery mildew also stops under the influence of herbal infusions, especially fermented ones:

1. Chopped garlic - 50 g, cold water - 2 l. Leave for a day, strain.
2. Fill the nettles without seeds (fill the container halfway) with liquid, leaving about 10 cm to the edges for fermentation. Leave for 2 weeks. Dilute with water 1:20.
3. Horsetail - 1 kg, water - a bucket. Leave for a day. Then boil for about two hours. Can be used within seven days. Before use, dilute 1:5.
4. Marigolds - 1/2 bucket. Warm water - a bucket. Infuse, strain. Add laundry soap - 50 g.
5. Any weeds - half a bucket, hot water- to the brim. Leave for a week, strain.
6. Chop plantain, celandine, dandelion, coltsfoot, chickweed, grind, pour into a bucket hot water. Leave for 2 days. Strain, add 1 tbsp. l. liquid soap and 1 tbsp. l. urea. Spray twice at weekly intervals.

Treatments with manure and mullein are very effective against powdery mildew:

1. Rotted manure - a bucket, water 5 buckets. Leave for 5 days, strain, dilute 1:3. You need to spray cucumbers three times, taking a week break.
2. Manure - 1 part, water - 3 parts. Leave for 4 days, strain, dilute with water 1:10.
3. Rotted mullein - 1 part, water - 3 parts. Leave for 3 days. Dilute with water 1:2.
4. Liquid mullein - 1 l, water - bucket, urea - 1 tbsp. l. Leave for 2 days.

Spraying with manure not only rids cucumbers of powdery mildew, but also nourishes them.

Treat cucumbers on a warm, windless evening, trying to wash both sides of the leaves with the solution.

What to do for prevention

By following the rules of agricultural technology for growing cucumbers, you can protect them from infection with powdery mildew. So, you need to make sure that within a radius of 20 m there are no plants that suffer from this fungus.

Basic rules for preventing powdery mildew on cucumbers:

1. Cucumbers can be planted in their old place only after 3 years. You should not choose places for the beds in the lowlands and in the shade. The soil in the area where cucumbers are planted is periodically loosened. After harvesting, you need to completely clear the planting site of plant debris and weeds, and water the soil with a solution of potassium permanganate.
2. The seeds are pre-treated with hot water (+55°C) or by special means: “Trichodermin”, “Grandsilom”. Seeds or seedlings are placed in soil heated to +12 °C.
3. It is necessary to monitor the temperature in the greenhouse. During the day it should be about +20°C, but not higher than +30°C, at night - +17°C.
4. When watering, drops should not fall on the leaves and stems. Water with water no colder than +20°C.
5. In order for cucumbers to grow strong and be able to resist powdery mildew pathogens, they need to be fertilized. A bucket of liquid requires 6 g of ammonium nitrate, 10 g of urea, 8 g of potassium chloride, 10 g of superphosphate.

To prevent infection with powdery mildew, cucumber plantings are treated with the following compounds:

1. Copper sulfate - 5 g, soap - 50 g, water - 5 l. Spray cucumbers 2 times, taking a break of 7 days.
2. Mustard powder - 2 tbsp. l., warm water - a bucket. Used for irrigation.

Ready-made preparations “Topaz”, “Quadris”, “Planriz” and “Strobi” can be used to treat powdery mildew on cucumbers, but they are more effective in preventing the disease. They can be used to spray seedlings that have 5 leaves each. Before flowering begins, treatment is carried out every 2 weeks.

Varieties resistant to powdery mildew

Breeders have developed many varieties that successfully resist powdery mildew pathogens. These are mostly hybrids.

It should be noted that powdery mildew fungi are mutating and becoming increasingly resistant to the effects of industrial insecticides. Therefore, it becomes preferable to grow varieties and hybrids that do not suffer from this disease.

Cucumbers, like many others vegetable crops, are exposed to powdery mildew. This does not depend on the variety of cucumbers and growing conditions (open ground, greenhouse). The culprit of the disease is the mycelium on the leaves. Over time, the fungus grows, forming a white coating. The leaves dry out and the process of photosynthesis is disrupted. The plant weakens and dies. Powdery mildew on cucumbers is a disease that is treated by amateur gardeners and professionals who grow vegetables on an industrial scale.

In all cases, it is necessary to get rid of the disease. Let's consider what to do, how to save and cure cucumbers in the open ground or in a greenhouse.

Brief characteristics of the pest What is powdery mildew? Its causative agent is a fungus. It appears on plants that are over-fertilized with nitrogen compounds. Factors predisposing to the onset of the disease are air, and the temperature is about 20 degrees Celsius. The incubation period is about a week. The most vulnerable to the disease are cucumbers that grow in rainy and warm temperature. Often harmful dew appears on the leaves after heavy rain. Powdery mildew looks like White spot on the leaves.

The disease can be recognized by its first signs: white spots with a reddish tint appear on the top of the leaf blade.

Then spots appear on the bottom plate. The spots gradually merge with each other, forming a single plaque. The leaves dry out, acquire a loose surface, and die. The plant is weakening. A greenhouse does not protect against pests. Due to the presence of drip moisture in this structure, plants often deteriorate there too. The fungus is located on the leaves and cotyledons. Treatment of the plant consists of spraying the leaves with various preparations, including iodine-containing compounds, with the addition of soda in a greenhouse or garden bed.

What to do: preventive measures to combat the fungus

In order to prevent the occurrence of the disease or fight it, gardeners carry out a set of preventive measures, including folk remedies:

1. Maintain crop rotation (disease pathogens should not accumulate in the soil).
2. Regular removal of plant remains from the beds.
3. Carrying out disinfection measures after harvesting.
4. Maintaining the optimal temperature for plant life in the greenhouse. These are indicators above 20 degrees Celsius.
5. Watering of vegetables is carried out warm water.
6. Spraying plants with specialized compounds. For example, a composition called Quadris.

Prevention of powdery mildew also lies in the absence of abuse in fertilizing plants for the purpose of treatment with preparations of nitrogen, potassium and phosphorus composition in the greenhouse, regardless of the variety.

Effective methods of combating the disease

Powdery mildew is a plant disease that destroys crops, regardless of the variety of cucumbers.

The danger of fungus appearing on cucumber leaves is that powdery mildew can destroy up to 70% of the crop.

• Creation of a whey solution for the variety. Spraying cucumber leaves with it. A film forms on the leaves, which protects the variety and prevents the proliferation of the fungus. Treatment with serum is effective.
• Purchasing a sodium silicate solution. This solution has a similar effect to serum. Is a variety protection.
• Spraying leaves with kefir. It is not necessary to take fresh kefir: a composition with an expired expiration date will do. Lactic acid bacteria, which are part of kefir, eliminate the disease by killing the fungus on the leaves. This does not harm the cucumber variety. This is a safe treatment without the use of chemicals.
• Spraying the variety with a solution of manure and water. Fill in cold water manure, leave the solution for 5 days. Next, you need to filter the solution and dilute it 1:10. Spray the resulting mixture onto the leaves.
• Using nettle infusion as a means of control.
• Use of chemicals. These are drugs: JET, TIOVIT, etc.

Folk remedies, including solutions of soda and iodine, are more effective when used on varieties after infection.

Iodine is mixed with warm water. Iodine is sprayed on the leaves.

In addition, use:

• Colloidal sulfur. In the garden bed you need to use a 20% solution, in the greenhouse - 40%.
• Laundry soap, soda. They are diluted in water in equal proportions. Spray the plant for 7 days.

In addition, sprayers with iodine are used. The usefulness of iodine is that it is an antiseptic. Iodine destroys the fungus. The dosage of iodine in the solution should be strictly observed.

Fighting powdery mildew and protecting plants from it with folk remedies carried out over different periods of time.

It all depends on the means used to fight. For example, plant treatment can be carried out before the flowering period and repeated several times. Please pay attention to the waiting times. This is the time when cucumbers are forbidden to eat. Taking into account the short growing season of the plant, you need to carefully select measures to combat the fungus.

Downy mildew- one of the varieties of cucumber leaf disease.

1. It also needs to be fought. The difference from the above disease is the color of the leaves. With downy mildew, it is not white, but yellow. The gardener must take measures to protect and combat this fungus, since in practice it is even more difficult to get rid of it than the first pathogen.
2. Firstly, it is necessary to take preventive measures.
3. Secondly, do not sow cucumber seeds close to each other.

Thirdly, observe crop rotation.

• do not water the cucumbers with ice water;
• Pick cucumbers regularly.

If downy mildew occurs among plants, it is necessary to immediately use preparations. Among them, Kuprosat, Oxychrome, Ridomil stand out.

Thus, the factors leading to the appearance of fungus on cucumber leaves are:

• humid and warm air;
• improper care of cucumbers.

The most disease-resistant varieties

No one is immune from the disease. But gardeners identify several varieties that exhibit increased resistance to the pests in question. Let's list them:

• ant F 1;
• bee-pollinated variety;
• Masha F 1;
• goosebumps F 1;
• boy with thumb F 1;
• benefit;
• Alexeyevich.

These are one of the most popular cucumbers. They can be easily recognized by appearance. IN middle lane They are common in Russia; a person who is not a gardener can easily distinguish varieties from each other on store shelves and markets. Gardeners grow the varieties in question with great pleasure: in addition to powdery mildew, they are resistant to other diseases: mosaic virus (cucumber), cladosporiosis.

These cucumbers are partially resistant to downy mildew.

Gardeners and professional growers of cucumbers need to make efforts to combat and protect the plant. The main action of the gardener to combat the disease is spraying. There are many compositions for spraying. Their components contain both natural and chemical substances. If you do not protect plants from pests, you may lose your harvest.