Why do cucumber leaves turn white: what to do, prevention

The main reasons why cucumber leaves turn white

If the cucumber leaves are covered with a white coating, then the first step is to understand the reasons for its occurrence.

Lack of light

Sometimes the cause of whitening of leaves can be insufficient lighting. Most often the problem occurs when grown in a greenhouse, but it can also occur in an open area. It should be borne in mind that whitening of the lower leaves on cucumber bushes is the absolute norm, since due to their density, they do not receive enough sunlight. You need to worry when the entire plant is covered with white spots.

Improper watering

The cause of the white coating on cucumber leaves may also be improper watering. Moreover, both excess and lack of moisture can be detrimental to the plant. The leaves are always the first to suffer, especially in open ground plantings, where it is more difficult to control the level of humidity. If the summer is rainy, the cucumber leaves will most likely turn white, and the roots will soon be damaged.

Insufficient moisture causes the leaves to turn white and begin to dry out quickly. However, getting rid of this problem is not difficult; you just need to water the bushes more often.

Lack of nutrients

The cause of white spots may be a lack of essential nutrients. This problem is typical for cucumbers grown both in greenhouse conditions and in open ground.

If the bushes begin to turn white from the bottom up - from the root, then the reason for this is most likely a lack of magnesium and potassium. In this case, it is urgent to add fertilizer rich in these microelements to the soil.

If dark veins on the stems and leaves are added to the main symptom, then the problem is an insufficient amount of iron and manganese. The main “symptom” of copper deficiency is the whitening of leaves from top to bottom.

Disembarkation time

Unlike tomatoes, cucumbers are extremely sensitive to planting. Any mistake at this stage may result in the plant not taking root. Incorrect disembarkation times are especially detrimental. Dates vary depending on regions, so their choice must be approached with special responsibility. Early planting is a common cause of leaves turning white.

In greenhouses, the soil warms up faster, so you can plant cucumbers several weeks earlier than the recommended time.

Soil acidity

Each vegetable crop has certain growing conditions. What is good for some plants can be detrimental to others. The optimal soil acidity level for cucumbers is 7 pH; any value below this level is potentially harmful to the cucumber crop. Increased acidity inhibits the development and growth of plants and complicates the absorption of nutrients. This leads to whitening of the leaves.

Aging

All living organisms on the planet age sooner or later; for plants this means a slowdown in photosynthesis and gradual whitening and wilting. Aging is an inevitable process. But it is worth considering that natural senescence for plants occurs only after harvesting; if the process began earlier, then the reason for this is some kind of disease.

Reasons for yellowing of cucumber seedlings

Despite the careful care of cucumber seedlings, the gardener often faces an unpleasant problem - the leaves of the plants begin to turn yellow.

Lack of light

Since cucumbers are early-ripening vegetable crops, they are characterized by a high intensity of photosynthetic processes. Plants respond positively to increased light levels. A high fruit yield can be obtained by growing the crop in open, well-lit areas.

Yellowing lower leaves on seedlings are a characteristic sign of light deficiency. Due to the large size of the upper leaves, the lower tier may not receive enough light.

Lack of moisture

Cucumber seedlings have a fast growth rate, so the plants need a lot of moisture. When there is a lack of moisture, there is a shortage of nutrients, because they are absorbed by the roots in dissolved form. Seedlings need to be watered with settled water heated to +25...+28 degrees 3 times a week.

Fungal diseases

Infection of plants by pathogens of fungal diseases can cause yellowing of leaves. When growing seedlings in a greenhouse, sometimes there is a violation of the irrigation and temperature regime.

Excessively moistened soil substrate and high air humidity provoke the development of fungal diseases.

Optimal air humidity is 70-75%, soil humidity is 70-80%. It is necessary to treat the affected plants with fungicide solutions.

Nutritional deficiencies

This vegetable crop removes relatively few nutrients from the soil, but due to the high rate of their absorption, early ripening and placement of roots in the upper ball of soil, the cucumber has high requirements for soil fertility. In the first two weeks after emergence, the plant needs to be provided with increased nitrogen nutrition.

Visual diagnosis of battery shortage:

The deficiency of macro- and microelements must be eliminated by fertilizing with special microfertilizers.

Damage to seedling roots

This vegetable crop has a very fragile and delicate root system, so cucumbers are often grown without picking. Some gardeners prefer to plant seeds immediately in separate containers so as not to injure the roots of the plant during replanting. The root system can also be damaged by pests, or the roots can be damaged by weeding and weed removal. When this unpleasant situation occurs, the plant cannot absorb nutrients. The leaf blades are the first to react - they turn yellow.

Sunburn

Pale yellow spots on the leaves appear due to sunburn. You need to water the seedlings at the roots, making sure that condensation does not accumulate on the leaves.

Diseases and pests

Of course, whitening of leaves can be a symptom of a plant disease. Quite a few diseases to which cucumbers are susceptible are characterized by the appearance of a white coating, but the nature of the spread will vary.

White mosaic

The virus takes effect when sudden changes in temperature occur. The first signs of the disease appear a month after planting. If the cucumber leaves curl at the edges, wrinkle characteristically, cracks appear on the stem, and spots appear on the fruits, then the white mosaic has completely affected the plant.

Causes of the disease:

• shaping, picking cucumbers with an infected tool;
• infection through insects.

The only thing that can be done in this case is to disinfect the tools in advance; if the disease has already penetrated the plant, then it cannot be saved.

Powdery mildew

This is a fungal disease. Characteristic of this virus is the damage to leaves by a white coating that appears along the edges of the plate. Over time, it moves first to the center of the leaf, then to the stems, ovaries and roots. The first sign of infection with this disease is the appearance of a white rash on the leaf. The spots soon turn black, the edges of the leaves dry out, as a result of which the plant begins to die.

The causes of infection may be:

• excessive amounts of nitrogen fertilizers;
• error in the irrigation system.

The fungal pathogen can survive the winter on the remains of a dead plant. The disease takes effect in gloomy, damp weather.

Spider mite

Small white spots appear first on the leaves, then on the stems and ovaries. The edges of the sheets curl and dry out over time. These signs are a sure sign that the plant is infected with a parasite. The mite that provokes this disease settles at the bottom of the leaf, where it gradually entwines the plate with a web and sucks out the nutritious juices. It is impossible to notice this mite with the naked eye.

Greenhouse whitefly

A fungus that makes holes in the leaves through which it sucks out the juices. The main symptom is a sugar-like discharge on the leaves containing fungal spores. After defeat, cucumbers quickly dry out and die.

Ascochyta blight

A fungal disease that affects many vegetable and cereal crops. The main symptoms: spots of different shapes, shades and sizes, which have a dark border. Soon, brown dots appear on top of the initial light marks, which contain the fruiting bodies of the fungal disease. The plant cannot be saved, but the future harvest can be saved if you carefully destroy the remains of last year’s harvest, organize correct crop rotation and take only healthy seeds for planting.

Anthracnose

A common fungal disease affecting almost all leaf crops. The most common cause of infection is infection by mycelium, which can survive the winter in seeds or organic remains of dead plants. The disease is characterized by the formation of deep light and dark spots and ulcers. Over time, the affected areas provoke breaking of stems, destruction of leaf plates and rotting of the root system.

Means for treating cucumbers against yellowness

If yellowness has already developed on cucumbers, use products that help restore the natural shade of the foliage. These can be folk recipes, chemical or biological products. When using them, it is necessary to take into account the cause of the damage and the general condition of the plant.

Folk remedies

To eliminate the yellowness of leaves, a whey solution is often used. It is diluted with water in a ratio of 1:5. Then add 1 cup of granulated sugar for every 6 liters of solution. This treatment, in addition to returning the normal shade of foliage, promotes better formation of ovaries.

To eliminate pests, spraying with a decoction of onion peels helps. Add 1 kg of onion scales to a bucket of water and bring to a boil. Then the broth is left to cool for 12 hours and filtered. The finished product is diluted with water in a ratio of 1:4. Then the diseased plants are sprayed and the soil is watered.

To repel whiteflies, planting strong-smelling plants between rows of cucumbers helps. It can be marigolds, tobacco, mint. A solution of wood ash and laundry soap is suitable for killing aphids. Mix 200 g of ash and 100 g of laundry soap shavings in 10 liters of warm water. If the number of insects is small, you can collect them manually by wiping the leaves with a sponge soaked in soapy water.

Fitosporin

When yellowish spots appear on the foliage, spray the plants with a solution of the drug “Fitosporin-M”. It is effective against many plant diseases. It works especially well during the period of active growth and flowering. To prepare the solution, dilute 15 g of the drug in 5 liters of water. The liquid is left to steep for 40 minutes. The bushes are treated 4 times with a week break. It is better to spray in clear weather when there is no rain.

Oksikhom

Some vegetable growers use Oxychom to combat yellowness. This is an effective remedy against a number of diseases at different stages of development. “Oxychom” can be used in open beds, greenhouses or greenhouses. A working solution for spraying plants is prepared from 10 liters of water and 30 g of the drug. The bushes are sprayed with the liquid twice a month with an interval of 15 days.

Topaz

When a light edging appears on the edges of the leaves, the fungicidal drug “Topaz” works well. It rids plants of powdery mildew and other fungal infections. The product is recommended for use for treatment or to prevent the development of diseases.

“Topaz” goes on sale in different forms, but for home use it is more convenient to use powder. Add 20 g of active ingredient to a bucket of water. This amount of liquid is enough to process 5 square meters. m. cucumber plantings. Treatment is carried out every 15 days for a month. If necessary, treatment can be extended for another month.

Quadris

This drug is suitable for treating plants when yellowness is detected along the edges of the leaves. The fungicide is also suitable for protecting plants from various diseases. It is effective for treating plants against powdery mildew or late blight. Active substances penetrate plant tissues and prevent further spread of pathogens.

To prepare a working solution, dilute 200 ml of the drug in 2.5 liters of water. Then add another 4 liters of clean liquid. The plants are treated with the solution immediately after mixing. It loses its effectiveness within 24 hours of preparation. Spraying is carried out in calm weather so that the solution does not fall on neighboring plants.

Feeding

To return the normal shade of the leaves, it is necessary to fertilize the plants with nitrogen. The solution is made in low concentration to prevent chemical burns of the leaves. Dissolve 20 g of ammonium nitrate in 5 liters of water and water the plants. Then the bushes are irrigated with warm water. Additionally, the solution is used for foliar feeding, spraying cucumbers on the leaf from a spray bottle.

Why do the leaves of cucumber seedlings turn white?

The main reasons for this phenomenon are:

• sunburn if the seedlings were taken out of the room into the scorching sun without preparation;
• various diseases;
• lack or excess of moisture;
• damage to the root system during planting.

As a rule, the causes differ little from other cases, but the first signs occur much earlier.

Viral diseases of cucumbers

Viral diseases are most often represented by mosaics, which are characterized by unusual leaf colors. They are mainly carried by fleas, aphids and other pests. They also enter the garden bed through infected seeds.

Mosaic pattern on cucumber leaves

The leaves become covered with colored spots and then curl. The fruits lose their natural color and become speckled. The flowers dry out, the ovaries fall off.

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Diagnosis : common cucumber mosaic (cucumber mosaic virus).

The virus can live in the soil for years, and becomes more active after a temperature change. Its first manifestations can be confused with chlorosis. But then the bush noticeably stops growing, the leaves become smaller. Sometimes cracking of the stems is observed. In a word, mosaic on cucumbers is not at all harmless, and it is better to remove severely affected plants immediately.

The mosaic virus affects not only cucumbers, but also many other garden crops, such as tomatoes, peppers, dill and beans.

Control measures . Every 7-9 days, spray the bushes with a 0.03-0.035% solution of Farmayod, a 10% solution of low-fat milk. Fight aphids, which carry the disease, and soak the seeds in a weak solution of potassium permanganate or any other fungicide before sowing.

udobreniya.net

With a lack of nutrition, damage by fungi and bacteria, chlorosis may appear on cucumbers - a common disease in which the production of chlorophyll is disrupted and the process of photosynthesis slows down. The leaves of the plants turn yellow, but the veins remain green. Then the leaf dies.

To solve the problem, remove weeds, destroy pests and spray the bushes with Antichlorosin, Mik-Reacom or iron sulfate (50 g per 10 liters of water). Continue processing until the leaves turn green.

How and with what to fight white leaves

After determining the cause of the appearance of white spots, you can proceed to treatment. It often happens that this is the result of agrotechnical mistakes by inexperienced agronomists. If the leaves turn white, then special preparations can help.

Quadris

The drug can not only help eliminate the disease, but also protect against repeated damage. It is better to treat the plant with this preparation in the evening or early morning, provided that there is no strong wind. One application is enough to destroy harmful substances.

It is recommended to use 100-200 ml of medicine per bush. It is best to treat the bush 3 times with an interval of 3-5 weeks.

Cuproxat

This medicine is good for treating white cucumber leaves. The drug was released specifically to protect plants from insects and various diseases. Kuproxat is sold in large containers, ready for use immediately after purchase. The optimal time for application is before planting cucumbers in the ground. It is much more effective to use the drug as a preventive measure.

Jet

If the cucumber leaves slowly begin to lighten immediately after planting, then the drug Jet can help. It is sold in powder form for preparing a solution. The drug in an amount of 100 grams should be mixed with 10 liters of water. Leave the solution for 20-40 minutes. The prepared drug cannot be stored for a long time; it is advisable to use the solution immediately after preparation.

How to prevent the problem

In order not to have to look for treatment methods, it is necessary to carry out prevention in time. The main thing in preventing diseases is proper care. Vegetable growers who grow cucumbers according to all the rules very rarely encounter whitening of the leaves.

Fungal diseases can be avoided if you carefully remove the remains of last year's harvest and change the planting location annually.

Proper watering is equally important: using only settled, warm water and following the recommended regime. From time to time, it is necessary to disinfect a greenhouse or greenhouse.

Cucumber diseases are not uncommon, but they can be avoided. Following care recommendations is the surest way to protect your crop from diseases. If the plant is already affected, then the best solution is to identify the cause and take the necessary measures.

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Folk remedies

Methods of combating white leaves of cucumbers were invented long before specialized drugs appeared. Traditional recipes may not be as effective in advanced stages of the disease, but they are less harmful.

Onion peel

Onions help prevent white spots on plant leaves. For the mixture, just mix 300 grams of onion peels with 5-7 liters of water. The finished solution is brought to a boil, then infused for 10 hours. You can not only spray the leaves with the medicinal infusion, but also water the plant.

Milk serum

If cucumber tops have been blanched, then whey with kefir will help best. A 10-liter container is filled with 7 liters of water and 3 liters of kefir whey. Sugar added in small quantities improves the effect of the remedy.

Baguette

This mixture is very easy to prepare. It is enough to soak a couple of loaves of bread in a large (at least 10 liters) container. Soaking time - 12 hours. At the last stage, add 10 liters of water and a spoonful of iodine to the resulting mixture. It is best to use the remedy twice a month, then a white coating on the cucumber leaves will never appear.

Prevention

It is better to prevent any illnesses and diseases in advance than to get rid of them. Therefore, adhere to the main preventive measures to protect cucumbers:

• If you have been buying cucumbers of the same variety for a long time, and constantly have problems with growing the crop, then replace the manufacturer or change the variety.
• Follow all the rules of crop rotation; cucumbers can only be planted in their original place after 3 years. If this is not possible, then add fertile soil annually.
• After collecting the fruits, completely clear the soil of plant residues; if there are infected bushes, burn them.
• Regularly spray the plants with herbal infusions or Fisporin M, or Amulet.
• Maintain a healthy microclimate in the greenhouse, avoid temperature changes, winds and high humidity.
• Ventilate the greenhouse regularly. Open it as early as possible so that the air under the film does not warm up too much, otherwise due to the temperature difference there will be a slight wind effect.
• Water the bushes early in the morning or evening. Inspect the bushes regularly for diseased, yellow leaves with white lesions on the surface.

For information about the causes of white leaves in cucumbers and methods of treating the plant, watch the following video:

The appearance of white spots on the leaves of this crop is a clear sign of its deterioration. This factor signals the poor health of the plant; it requires treatment and further preventive measures, otherwise the consequences may destroy the plant.

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Preventive measures

If the leaves of the seedlings turn white even before they are planted on the ground, and the defect is not associated with a lack of light, it is better to purchase other seedlings or seed material from more reliable sellers. The seeds may have already been infected. The soil is prepared in advance - the future bed is dug up in the fall, watered twice with a weak solution of potassium permanganate - in the fall and in the spring, before the start of the gardening season. When setting up the greenhouse, frames are installed so that, if necessary, it is possible to provide through ventilation. If the sun's rays fall on the greenhouse all day, the glass or film is covered with agrofibre. Plantings should be protected from excess moisture - provide reliable protection from rain and precipitating dew.

Plants planted in open ground also require protection. Trim the branches of surrounding trees - with a lack of light, the leaves become pale. After rainfalls, the top layer of soil is loosened so that puddles do not appear due to the formed crust, and mulched with sand or sawdust, which absorbs moisture. Fertilizing should not be neglected; it is advisable to apply nitrogen and phosphorus fertilizers.

It is necessary to periodically disinfect gardening tools, carry out preventive treatment, and inspect the root zone of cucumber vines and leaves from the underside. It is recommended to regularly check the plant in order to detect insects or signs of infection in time, treat it with a soapy solution and apply fertilizer in a timely manner. The development of powdery mildew spores is suppressed by lactic acid bacteria. You should not wait for more pronounced signs of the disease. As soon as you notice that the cucumber leaves are turning white at the edges, the plant should be sprayed with sour kefir or whey.

If the leaves of cucumber seedlings turn white after planting in open ground, this indicates improper care. An important factor is the time of planting. The period from mid-April will be suitable. Early frosts can destroy the crop. In a greenhouse, the leaves of cucumbers turn white much less often, since the plant is protected from temperature changes.

Growing cucumbers is a labor-intensive process. The plant is sensitive to cold, improper watering, and lack of light. Errors in care affect the appearance of cucumber foliage. One of the signs that you need to respond to in a timely manner is the appearance of white spots. The leaves of cucumbers may turn white due to improper care or various diseases.

1. The leaves of cucumbers have turned white: improper care Lack of light and nutrition
2. Improper watering

Methods to combat stains

How to deal with stains depends on the causes of their occurrence. The appearance of pests - aphids, spider mites, whiteflies - requires treatment with insecticides. Pests, especially spider mites, are tenacious, so multiple treatments are usually required in compliance with the intervals specified in the instructions for the product. Fungicides help against powdery mildew, white rot and other fungal diseases. Solutions of copper oxychloride and colloidal sulfur can replace ready-made preparations. Or a universal folk remedy - a solution of laundry soap with soda, marigold infusion, or horsetail decoction. Seedlings can be treated with lime or crushed charcoal. Trisodium phosphate will help in the fight against mosaic.

If the problem is caused by a lack of nutrients, you should feed the plants with a complex fertilizer for vegetable crops. Cucumbers growing in open ground should be sprayed with the medicine in dry, windless weather so that the particles of the medicine linger for a long time on the surface of the leaves and stems. In the greenhouse, processing can be carried out on any day. If the leaves of cucumbers turn white, it is necessary to remove all affected ones, and bushes that are completely captured by the disease should be torn out and burned. Plants affected by pests or fungi should not be placed in compost or left lying next to healthy ones - diseases spread quickly.