Why are there white spots on cucumber seedlings. Yellow spots on cucumber leaves. Causes of occurrence and effective methods of treatment. Why cucumber seedlings fall, wither and die

It's nice to see when your plantings turn green and bear fruit, but not everything always goes smoothly. Often some diseases appear, and in order to heal your plantings, you need to know what kind of disease has befallen and how to properly treat plants.

Cucumbers are a fairly common and beloved plant. They can be pickled, salted, added to a salad ... Therefore, they are popular in the beds of numerous summer residents. But in order to grow them, you need to know how to care for them, especially if the cucumbers get sick and white spots appear on the leaves of the cucumbers.

When growing this plant, vegetable growers face a lot of problems, among which is the appearance of white spots on the leaves of cucumbers. To grow a good crop, you need to know the diseases of the plant and the symptoms, causes, features of vegetable care, the rules for processing cucumbers, and much more. You will learn about all this in this article.

white mosaic

White spots may indicate the appearance of a fungal or viral disease. For example, a disease such as white mosaic is dangerous only for plants growing in a greenhouse.

A symptom of the disease are star-shaped spots. If no action is taken in time, the entire sheet will turn white. Only occasionally will veins of natural green color be visible. Affected cucumber usually does not bear fruit.

And if the fruits do appear, they look painful: small in size with numerous tubercles. Also, the vegetable is painted in a white-yellow stripe. We have listed the main symptoms of white mosaic. We hope this will help you in identifying this disease.

The disease has been identified. What to do next?

As soon as you notice white spots, you need to immediately destroy the plant, and not wait until it begins to bear fruit. White mosaic is a viral disease. Therefore, it is quite difficult to deal with it.

Immediately you need to disinfect all garden tools, buckets, containers and other equipment with a five percent solution of potassium permanganate.

It should also be remembered that only two-year (maximum three-year) seeds are suitable for planting. They are pre-soaked in solutions of strengthening action.

It is important to remember about crop rotation: the planting site must be changed every three years. Before planting the plant, it is recommended to treat the soil with special mixtures.

spider mite

Also, the appearance of white spots on cucumber leaves can be caused by a spider mite. The first symptom of this disease are white spots in the form of dots. The disease leads to the drying of the cucumber leaf.

Another symptom is the presence of cobwebs on the underside of the leaf. How to get rid of the pest and save the crop?

First of all, collect the affected leaves and burn them. It is also recommended to treat the vegetable with special solutions: Fitoverm emulsion or Bitoxibacillin suspension or Karbofos or Fufanon suspension. Any weeds near cucumbers should be removed.

Ascochitosis

White spots on cucumber leaves appear due to infection of the plant with ascochitosis. This disease manifests itself in the form of cracked white or brown spots on cucumber leaves. The fruit gives the impression of only being cooked. After a while, the cucumber may turn black and dry out. Ascochitosis is an infection that affects weak vegetables. A favorable condition for the development of the disease is the humidity of the air.

The causative agent of infection can be in the soil, seeds and plant debris for a long time. If you notice the first signs of ascochitosis, immediately spray the cucumbers with a 1% Bordeaux mixture. In case of a serious disease of the plant, burn the cucumbers along with the roots in the territory that is not adjacent to the summer cottage.

powdery mildew

Another threat to your cucumbers is powdery mildew. It can be recognized by the white spots on the cucumber leaves. The disease is able to cover the entire surface of the leaf with a white bloom in a short time. In turn, shoots and young stems suffer from this, which leads to crop loss.

This disease is curable. The main thing is to identify the disease in time and take measures to eliminate it.

The first step is to get rid of plant debris. A special solution is prepared directly for cucumber leaves: an ampoule of topaz is diluted in a ten-liter bucket of water.

With frequent use, resistance of the pathogen to Topaz may occur. Then the network if the effect of the use of the drug weakens, then use the drug Farmayod. Its solution at the rate of 2 ml per 1 liter of water usually suppresses powdery mildew well. If you cannot find Farmayod, then in order to prevent the emergence of resistance, it is advisable to alternate Topaz with such biological products as Alirin-B, Baktofit. In this case, it is better to dilute the drug Alirin-B in an increased concentration - at the rate of 5 tab / 1 liter of water

Anthracnose

It is a very dangerous fungal disease for cucumber. Anthracnose can affect not only the leaves, but also the fruits of the plant. Infection begins with the appearance of white spots on cucumber leaves. Then they turn brown.

The leaf dries up and falls off, as if scorched. Then anthracnose moves to the fruit, where it leaves brown spots with a depth of three to five millimeters. The infection can live in plant debris and soil for a long time.

Since the most common cause of infection of a vegetable with anthracnose is affected seeds, we recommend pickling them before planting.

Remember also about crop rotation. At the initial stage of the disease, colloidal sulfur solution (may be sold under the name Thiovit-Jet) and 1% Bordeaux mixture are very good remedies. In addition, Alirin-B mixed with Gamair and green soap or Liposam for stickiness is suitable for curbing diseases.

Let's summarize

Growing cucumbers is not easy. The plant is susceptible to various diseases that you must recognize, distinguish and eliminate. The basic rules for the prevention of cucumber from pests are their mandatory weeding, meticulous inspection of each leaf, competent selection of the treatment solution and removal of infected leaves and fruits.

Verified by the scientist - agronomist Alexander Zharavin

Powdery mildew.

Perhaps the most common disease is not only cucumbers, but also many other crops. And as a result, infection can be transmitted not only from cucumbers. This fungal disease appears on the leaves in the form of white spots, which are formed due to the surface mycelium of the fungus.

For the germination of mycelium, a low temperature of up to 15-16g is required. and high humidity for 3-4 days. It can be noticed that the disease appears within 2-3 days after or during cold prolonged rains. In sunny weather, abundant sporulation and spread of the disease occur.

From individual spots, the leaves are covered with an almost continuous white bloom, later moving to shoots, the leaves are deformed and dry out. Without taking preventive measures at the first stage of the development of the disease, the plant may die completely. Cucumbers are susceptible to disease during sudden temperature changes and low light. A lack of calcium and an excess of nitrogen also makes plants not resistant to powdery mildew.

Prevention and treatment of powdery mildew of cucumber. As a preventive measure against the disease, it is necessary to create favorable conditions for plants, avoiding high humidity or, on the contrary, drying out of the soil.

If possible, cover cucumbers at night and on rainy days. Watering is best done with warm water in moderation. But if the disease has already appeared, then you can try to stop it with old folk remedies, this is spraying plants with skim milk or whey left after cooking cottage cheese, diluted 1:10.

Infusions and decoctions of nettles with an admixture of silicate glue for sticking also have a depressing effect on the fungus. Of the chemicals, these are the preparations Quadris, Topaz, Jet. Spraying is carried out both on the upper and lower parts of the leaves and shoots.

Anthracnose or verdigris cucumber.

A very dangerous fungal disease of cucumbers, which affects not only the leaves, but also the fruits. It begins with the formation of different shades of brown uneven spots on the leaves of the plant, later the spots grow, become darker, up to black, dry out and fail, whether they are burnt . Later, the fungus infects the fruits, forming depressed brown spots on them, going deep into the cucumber up to 3-5 mm. The cause of the disease is mainly infected seeds collected from diseased fruits, the fungus also persists on plant debris and in the upper soil layer.

Prevention and treatment of cucumber anthracnose. Therefore, seed dressing and mandatory crop rotation or replacement of the upper fertile soil layer serve as a preventive measure against this disease. Spraying is used as a treatment at the initial stage, using sulfuric preparations, Bordeaux mixture or the Quadris preparation.

Cucumber mosaic or cucumber mosaic virus.

This is a viral disease that can infect many other crops, such as those important to us such as tomatoes, peppers, cabbage, as well as a wide variety of other garden plants. Infection of cucumbers with the virus can occur through transmission from other plants by aphids or infected weeds such as bindweed, sow thistle or wood lice, the virus can survive on the roots of these weeds during the winter. The first signs may appear even on seedlings of cucumbers, the leaves become covered with yellowish spots, both large leaves and young nascent ones begin to curl. With the further development of the disease, the stem of the plant cracks along its length.

It is better to remove such seedlings, there will be little sense from planting them. If the disease develops on an adult plant, then in addition to damaging the leaves and stems, it also affects the fruits, especially at low temperatures. They are bent, mosaic yellow spots appear on the green body of the fruit, sometimes the fruits dry out, become wrinkled, and the flowers do not develop.

Prevention and treatment of cucumber mosaic. As a preventive measure, try to observe crop rotation, prevent weeds from appearing on the bed, plant cucumbers in composted soil, and shelter from possible cold snaps. Prevent the appearance of aphids as carriers of the disease. You can slow down the disease or stop it with the help of drugs such as Aktara, Aktelikt.

Green speckled and white cucumber mosaic.

This viral disease, in comparison with the usual mosaic, can develop, and consequently infect only plants of the gourd family, and even then not all, this virus does not infect zucchini and pumpkins. But for cucumbers, it is no less dangerous than a regular mosaic, especially its more aggressive strain, which causes symptoms of a white mosaic. The signs of such a disease are the initial appearance of swollen tubercles on the leaves, and the appearance of white dry spots or entire areas already indicates the transition of the disease from green to white mosaic. The virus is very stable and easily transmitted from plant to plant, persists in seeds, plant debris, and can even live on garden tools. A frolicking virus also infects fruits, which are deformed and may become stained.

Prevention and treatment of green speckled and white cucumber mosaic. As preventive measures, planting seeds with a shelf life of more than two years, or their thermal disinfection at 70 degrees for three days, can be used. The spread of an already emerging disease can be slowed down by spraying, skimmed 10% milk.

Angular leaf spot.

Another bacterial disease of cucumber, the main focus of infection are seeds obtained from diseased plants. The disease mainly spreads in film greenhouses at high humidity with the formation of droplets covering the leaves of plants. The disease manifests itself as the formation of angular gray spots on the lower leaves of plants.

The spots have an oily patina, and on the underside of the leaf there is an accumulation of yellow drops in which bacteria accumulate. When these drops are washed away, the disease spreads to other leaves and conquers more and more space.

If you reduce the humidity, then the drops dry up, and the spots turn black and fail. The ingestion of bacteria on the fruit leads to the formation of small ulcers and curvature of cucumbers. Prevention and treatment of angular leaf spot.

The main method of prevention is the use of clean or pickled seeds, crop rotation or renewal of the top layer of soil in the greenhouse. The disease itself can be stopped by spraying Bordeaux mixture in a 1% solution.

Downy mildew, or downy mildew.

This is a fungal disease of cucumber, which can arise from seeds or plant residues infected with the mycelium of the fungus. Moreover, the disease may not appear immediately, but already during the period of a developed plant.

All the time from the beginning of sowing, the disease develops inside the plant and moves up, right up to fruiting, and already at this time it can show visible symptoms of infection. This is the appearance of yellow pancake spots on the leaves, limited by veins.

A little later, a grayish coating appears on the back of the sheet. Then the spots grow, darken and the leaf dries up. The fungus can destroy the entire plant in a fairly short time. Prevention and treatment of downy mildew or peronosporosis.

As a preventive measure, it is necessary to observe crop rotation, warm up or dress the seeds and use disease-resistant varieties of cucumbers. At the first signs of the disease, spraying with Ridomil Gold, MC, Kuprosat is possible.

Olive spot or cladosporiosis.

The fungal disease of cucumber, which occurs as a result of sudden changes in temperature with high humidity, often manifests itself from irrigation by sprinkling with cold water. Infection with the fungus occurs as a result of mycelium entering plants from affected plant residues. This disease manifests itself first on leaves and cuttings, and then affects the fruits, forming Shrovetide spots are on them, turning into sores that penetrate inside the cucumber and change its color to a pale color. Prevention and treatment of olive blotch or cladosporiosis.

As preventive measures, they try to create favorable conditions, cover cucumbers during cold snaps and vice versa to ventilate in good weather. Sow cucumbers or seedlings in clean compost beds. Apply disease-resistant varieties. When symptoms of the disease appear, spraying with a solution of Bordeaux mixture or copper oxychloride preparations is used up to 4 times during the season.

White rot of cucumber or sclerotinia.

A dangerous fungal disease that affects all parts of the plant. It occurs, like most diseases, due to non-compliance with climatic and agrotechnical conditions. The beginning of the disease is the appearance of white fluffy mold on different parts of the plant, subsequently black dots form on it, the stem or other affected areas soften, and it is easier to rot and the higher part of the plant dies.

Prevention and treatment of white rot of cucumber or sclerotinia. The main preventive actions are the observance of sanitary measures before planting and during the growing period. This is the use of crop rotation or soil replacement in a greenhouse, watering with warm water without spraying, timely removal of dried leaves and affected areas. A biological product is used to suppress the disease. Fitosporin-M.

Root rot of cucumber.

Root rot can be both fungal and bacterial in origin. The source of infection can be affected seeds and soil containing pathogens. External factors that can weaken the resistance of plants are extremely low or high soil temperatures, and in conditions of hot, dry land, the disease develops faster.

Soil salinity can also be a negative factor. Signs of the disease are wilting of leaves during hot hours. The root darkens to brown, it becomes rotten and unable to provide normal plant growth.

Later, the root dies off completely and the plant dies. Prevention and treatment of cucumber root rot. Preventive actions should be as follows. Using clean or treated seeds.

Planting or sowing on plots with well-prepared composted beds, the use of crop rotation. Biopreparation Fitosporin-M. It can serve as both a preventive and a disease-stopping remedy.

Planting early seedlings of cucumbers in a greenhouse

Irina Leonidovna Ermolaeva, a specialist in plant protection against diseases and pests, an experienced gardener, tells how she gets a whole bucket of delicious, crispy cucumbers from one bush. May 1-5 - the earliest time (in the middle lane) for planting seedlings in an unheated greenhouse.

If you planted 15-day-old seedlings on May 1, then on June 1 the seedlings reach the age of 45 days (plant height 1 m), and it is time to start forming the plant.1. Shoots on a cucumber usually grow for a long time, this weakens the plant (shoots take food), so that this does not happen, the shoots must grow to 2 leaves, and after the second leaf we immediately pinch the crown (we leave the shoots from 10-11 leaves) and leave 1 on the shoot - 2 cucumbers.2.

When the cucumber grows to the wire, we throw the crown over the wire and lower it down. The top of the head, which has reached 50 cm from the wire, is pinched (i.e., removed). This limits the growth of the plant, and the food goes faster for the filling (ripening) of cucumbers.3.

From about June 5 on the 15-day planted seedlings, it is already possible to collect the first cucumbers. Harvest during June should be in 1 day.4.

Watering with ordinary warm water (+25°C) with the addition of PhytoAcidity (10 teaspoons per 10 liters of water) every day in the evening (when the heat subsides). We water under the root. PhytoKislinka biopreparation will make irrigation water of optimal acidity for your plant (ordinary water with pH - 7.2 - 8.0, and the plant needs 6.2).5.

We continue feeding, as we started in May, once a week: the first week with liquid complex bio-fertilizer Rich, the second time with Gumi-Omi soft fertilizer (we insist in water for 1 day) and so we alternate each time. Top dressing should be carried out under the root.6.

Spray with Gumi and Fitosporin-M.7 biosolution once a week to prevent diseases and stress. It is necessary to monitor the temperature in the greenhouse, it should not exceed 25-27 ° C. A higher temperature inhibits the plants, and therefore it is necessary to ventilate the greenhouse.

Open windows, doors. If the temperature does not drop, then we whitewash the roof (roof). We dilute the chalk to a liquid creamy mass and whiten it with a brush (as we paint). Whitewash "Doctor Sad" is good for this purpose.

The rays of the sun are reflected from the whitewashed roof of the greenhouse, and the temperature drops.8. In June, pests - insects can attack cucumbers. These are spider mites, tobacco thrips and melon aphids.

Every time you enter the greenhouse, look at the cucumber leaves. If light dots appear on the sheet, this is a spider mite. The leaflet must be plucked (leaving the petiole), rub the pests in the hand and take them out of the greenhouse.

If this is not done immediately, then pests can multiply quickly. Interesting. Subject to the correct agricultural practices: watering, fertilizing, prevention - pests are not particularly disturbing. The same should be done if leaves are damaged by tobacco thrips and melon aphids. What to do with seedlings planted on May 15-20 in a greenhouse in June. May 15 planted 15-day-old seedlings. In this option, the difference with the above dates is only that all work on the formation of a cucumber plant is carried out 2 weeks later. In terms of time, this is from June 11 to the end of the month. At the end of June - early July, the first cucumbers begin to be harvested. And the rest of the work - watering, top dressing, disease prevention, maintaining the optimum temperature, pest control - is carried out, as with daytime seedlings planted on 1 May.

More related posts

Spots on cucumber leaves

Often you can see spots on the leaves of cucumbers. Potassium deficiency may be the cause of old cucumber leaves being covered with yellow spots. At first, the edges of the leaves acquire a yellow color, then a color change is observed with the tissue between the veins towards the center of the leaf.

If the plants lack magnesium, then this is expressed in the yellowing of the leaf blade between the veins - this happens earlier than others with older leaves. The cause of spotting may be the development of such a disease as anthracnose (the stems and petioles are covered with depressed spots, the fruits are sores, the leaves soon acquire a pink bloom).

If it's all about ascichitosis, then the spots are large, round in shape, light yellow in color, black dots can be distinguished on their surface, which are nothing more than a spore-bearing layer of the fungus. To combat the listed diseases, a 1% solution of Bordeaux mixture or phytosporin is used. A possible cause of cucumber leaves being stained may be a mosaic lesion.

Cultivated plants are susceptible to green and white mosaic disease, the characteristic features of which are the presence of dark and light shade zones on the leaves (often they are star-shaped), after some time wrinkling of the leaves can be observed. If it is clear that the cucumber is affected by the mosaic, then such plants should be removed. If spots become visible on the leaves of the cucumbers, then this may be caused by the development of a disease such as downy mildew (peronosporosis): the upper part of the leaf (along the veins) is covered with small yellow oily spots.

The lower part of the cucumber acquires a lilac-gray coating and is covered with a spore-bearing layer of the pathogen fungus. After some time, the spots become brown, brittle, there is a risk of tissue loss, where the disease develops.

If the disease has a large scale of infection, then the plant may lose all the leaves. The carrier of this disease is infected seeds. If there are spots on the leaves, it can be assumed that the plants are affected by melon aphids.

In most cases, aphid colonies choose the lower part of the leaves, as well as shoots and flowers, as the place where they live and breed. If the leaves are damaged by pests, then spots appear on them first, then they twist, after which they fall off. Aphids are capable of spreading cucumber mosaic, and along with this, a number of other viral diseases.

Seedling diseases. Blackleg Blackleg is a fungal disease. The infection is located and stored in the soil. Together with the soil, the infection also enters our boxes and paper cups, where we grow seedlings. It is worth over-moistening the soil unnecessarily, it is worth the air temperature in the room where the seedlings are grown, as the black leg goes on the offensive. If the black leg starts up in greenhouses and greenhouses, then the soil in such greenhouses and greenhouses is disinfected with special compounds. We can reduce the risk of this disease if we add a sufficient amount of wood ash to the nutrient mixture in which we grow seedlings (see the story about seedlings - “The First Victory”). To avoid this terrible disease, we must carefully monitor that the soil in boxes and in paper cups where seedlings are grown, was not too wet and did not overheat. It is also extremely important to add a little dry sand to the plants every time after watering to combat dampness. The black leg affects not only cabbage seedlings. It can attack both tomato seedlings and cucumber seedlings - in a word, any seedlings grown at home, in a greenhouse or in a Dachnaya 2dum greenhouse should be protected from this disease. fomoz Phomosis is also a fungal disease, and cabbage also suffers from it, first of all. But if the black leg is transmitted through the soil, then phomosis is transmitted through the seeds, so it is much easier to deal with phomosis than with the black leg. It is enough to disinfect cabbage seeds before sowing, and a dangerous disease of cabbage can be avoided. (You will learn how the seeds are disinfected by reading the story "Seeds".) If you notice that blurry spots have appeared on the cotyledons, stem, leaves of seedlings, on which black dots are visible, know that phomosis has gone on the offensive and attacked your seedlings. Helping a sick plant is already difficult, just like a plant with a black leg. And you just have to wait and see what happens next. And then the following usually happens ... After planting in the garden, the plant begins to lag behind in growth, the lower leaves become bluish or purple, and then very often the stem breaks off the plant, as in black leg disease. If you happen to overlook the disease and plant a diseased plant in the garden, then it will not be possible to plant either cabbage or other cruciferous vegetables in this place for 4-5 years, because the fungus that has entered the soil is stored in it for about 4 years. White leaf spot This is a fungal disease of tomatoes. The disease affects leaves and stems. First, single off-white spots with a dark rim and black dots on a light background appear on the lower leaves of the seedlings. From the lower leaves, the disease passes to the upper ones, the spots on the plant become more and more, then they merge and cover the entire leaf. Affected leaves turn brown, dry up and fall off. The causative agent of this disease is preserved in the remains of diseased plants. A leaf that died from white spotting fell to the ground, it was not taken away from the garden by you, it was not destroyed, and the disease will remain until next spring in the soil, and from here it will fall on seedlings and infect it. In order to prevent the disease, to prevent it from taking root, it is necessary, at any suspicion, at the first guess that this disease has come to you, remove and destroy all diseased leaves, and then destroy the diseased plants. Potassium permanganate helps to contain almost all tomato diseases very well - we will tell you about this when the time comes to get to know tomatoes better. Brown leaf spot This disease most often affects the leaves of tomato seedlings. The disease, like white leaf spot, begins with the lower leaves. Yellowish blurry spots appear on the surface of the leaf. An olive coating appears on the underside of the leaf in this place. Soon the spots turn brown and spread throughout the leaf, and the plaque on the underside of the leaf becomes dark brown. Affected leaves dry up and fall off. This disease develops rapidly in high humidity and high temperatures. Diseased leaves, and then diseased plants, must be destroyed so that the disease cannot be stored along with plant debris. You can avoid this disease if you remember all the time that tomatoes arrived in Europe from the mountain plateaus of South America, where the air is always dry, and therefore humidity is the most dangerous for tomatoes - it is in conditions of high humidity that many diseases of this plant begin. Remember: you need to grow tomato seedlings only in conditions of low air humidity, and if, nevertheless, the humidity in the room where the seedlings are located is too high, the room must be constantly well ventilated. And at the first opportunity, tomato seedlings should be taken out to harden into fresh air. Root death in seedlings of cucumbers, zucchini, pumpkin Often, seedlings of cucumbers, zucchini, pumpkins suddenly start to hurt in an inexperienced gardener: they stop growing, wither, and even die. You are looking for various spots on the leaves, which, in your opinion, will reveal to you the secret of the disease; look for a black streak on the stem, suggesting that your seedlings have been attacked by a black leg. But you do not find any black stripe on the stem, or spots on the leaves of the seedlings. And the plant dies. And only you are to blame! You forgot that cucumbers, zucchini, pumpkins can begin to die off the roots if these plants are watered with cold water. But wait, you always watered the seedlings only with warm water, what is your fault? But there is still some fault ... You really watered the seedlings with room, sufficiently warmed water, but then the watered seedlings were moved close to the window, and it was cold outside that day, it was cold on the windowsill, and here, on the windowsill, quickly the paper cup in which the cucumber (pumpkin, zucchini) grew cooled down, the earth cooled down, damp, just watered, and the roots froze and began to die. So you accidentally ruined a healthy, strong seedling. You see what attention is required from everyone who undertakes to grow seedlings of vegetables in a room on the window. You may be interested in reading other articles:

Many families who have a small plot of land choose to grow vegetables such as cucumbers. This will allow you to enjoy environmentally friendly fruits during the summer period, to make pickles and seamings for the winter. However, growing these seemingly unpretentious plants is fraught with some difficulties. Many gardeners complain about the appearance of yellow leaves on cucumbers. The reason for this phenomenon is unknown to many - perhaps a disease or lack of something. Let's figure out why cucumber leaves turn yellow and how to deal with it.

Yellow spots on cucumber leaves: causes

1. Most often, leaf lesions of this beautiful vegetable are associated with adverse environmental conditions and diseases. For example, such a fungal infection as anthracnose manifested by the appearance of yellow and light brown spots on the stems and leaves of the cucumber. It usually occurs due to excessive air humidity, which is typical for greenhouse cultivation of a watery vegetable. Over time, these spots become sores filled with pink mucus.
2. The reason that the leaves of cucumbers turn yellow in spots may be another disease - ascochitosis. This is also a fungal infection, which can be suspected by the fact that the leaves of cucumbers turn yellow at the edges, and there are also light brown and light gray spots that are covered with black dots - spore-bearing particles of the fungus. Such manifestations appear first on the lower nodes of the plant stem. Then the lower leaves of the cucumbers turn yellow - the weakest and less illuminated. Ascochitosis quickly spreads throughout the vegetable, and the fruits also become affected: the stalk turns yellow, and then the fruit itself fades and blackens.
3. There is also a disease of cucumbers when the leaves turn yellow: spots appear on the upper part of the leaf along the veins, while the lower side is covered with a gray-purple bloom - spores of the pathogen fungus, or downy mildew. As the infection progresses, these oily spots turn brown, the affected leaf tissue falls out, and the plant dies.
4. The reason that the leaves of cucumber seedlings turn yellow may be mosaic- a viral disease. It usually develops on the leaves of young plants in the form of white-yellow spots in a star shape.
5. Blackleg- This is a fungal disease characteristic of seedlings. The root system first becomes affected, then the cotyledon leaves (the first two) turn yellow in the cucumber, the root neck turns brown. The disease is dangerous because it often leads to mass death of seedlings.
6. Sometimes leaves turn yellow lack of potassium. If, on the leaves, parts of the leaves between the veins become yellow, this is how lack of magnesium.

What to do if there are yellow spots on the leaves of cucumbers?

If anthracnose is detected, all affected plants should be removed to exclude infection of the entire planting. If the first symptoms of the disease appear, it is necessary to spray the cucumbers with the so-called 1% Bordeaux mixture - a solution of copper sulfate and lime (100 g of each substance per 10 liters of water).

In case of ascochitosis, it is recommended to wipe the affected areas of plants with a dry mixture of lime and ash, as well as spraying basal part of cucumbers.

At the first symptoms of downy mildew, cucumber plantings can be treated with a solution of potassium permanganate, taking 2 g of the substance per 10 liters of water. In severe lesions, special fungicides are needed to combat the disease.

If the plants are affected by the black leg, watering with a weak solution of potassium permanganate will be required.

When a mosaic appears, the main measures are reduced to the destruction of single-affected plants and tillage with a 5% formalin solution.

Growing cucumbers is a pleasant pastime for a summer resident. But often this process is accompanied by various problems associated with pests and diseases. Vegetable culture is prone to bacterial infections, fungal and viral diseases. Experts see the main cause of damage to plants in improper care. Why do white spots form on the leaves of cucumbers, how to recognize the problem in a timely manner and treat the cucumber? These questions have been of concern to farmers since ancient times.

Powdery mildew is the main cause of white spots on cucumber leaves.

Powdery mildew disease is a common culprit for leaves turning white on cucumber seedlings. Spots quickly spread over the entire surface of the leaf and cause damage to young stems and shoots. What to do to save the harvest? To begin with, they get rid of diseased vegetation and prepare a solution of topaz (1 ampoule per 10-liter bucket of water). The mixture is then used to spray the cucumbers through the device with a slight spray. Processing is carried out in calm weather.

The folk method is based on the use of mullein infusion. As soon as you notice that whitish lesions have appeared on the cucumber seedlings or the foliage seems to be covered with a coating, mix 1 kg of manure with 3 liters of water. Leave the dishes with food to infuse for 3 days. Then strain the infusion and dilute with 3 liters of pure water. Use the solution to treat infected specimens.

white mosaic

The second answer to the question of why the leaves of cucumbers are covered with white spots will be a fungal-viral disease. For example, a white mosaic is dangerous for greenhouse plants. Its main symptom is star-shaped spotting. In advanced cases, the cucumber leaf turns completely white. On a light background, several veins of green color are visible. A diseased plant either does not bear fruit at all, or produces a crop of small, bumpy fruits, colored with white-yellow stripes.

What to do, how to save the remnants of seedlings from infection with a white mosaic? Destroy the plant immediately, even if it has fruit hanging on it. Disinfect garden tools and all devices that facilitate fuss in the beds with a solution of potassium permanganate (5%). For the future, follow the rules of crop rotation - change the planting site every 3 years. But every time on the eve of planting a crop, treat the soil with protective mixtures.

Ascochitosis

In continuation of the topic “why white spots are drawn on the leaves on the seedlings of cucumbers,” consider the disease ascochitosis. The spots have a cracking effect. Their color can be not only white, but also brown. The development of the disease is favored by high humidity. Cucumbers dry and blacken from it.

At the first sign of ascochitosis, spray the plantings with Bordeaux liquid. In advanced cases, burn the affected greens along with the roots away from summer cottages.

spider mite

Why else can white spots appear on the leaves of cucumber seedlings? Experts warn of a possible damage to greenery by a spider mite. They recognize it by white dots, which gradually lead to the drying of the leaves.

To protect cucumbers, cut off and burn the affected parts. Treat the crop with special solutions and regularly pull out weeds growing near cucumbers.

Anthracnose

The danger of this disease for cucumbers is that leaves and fruits suffer. The first alarm signal will be the appearance of light spots, which turn brown after a while. The leaves appear scorched and fall dry. Next, vegetables are involved in the process. On their surface, anthracnose leaves brown dents 3–5 mm deep.

Why do cucumbers get anthracnose? The reason for this trouble is the resistance of the infection in the external environment and long-term preservation in the soil and the remains of the tops. Another reason for the infection of a vegetable lies in the affected seeds. Therefore, they should always be dressed before planting. As soon as you notice white dots on the greens of cucumber seedlings, try to treat the plants with Bordeaux or sulfuric solution as soon as possible.

How to prevent white spots on cucumber leaves

Knowing why white spots can appear on cucumber greens, you must learn how to deal with these misfortunes. If you want to reap rich harvests, regularly set aside time to prevent diseases that are dangerous for vegetables. Technical and chemical measures to protect cucumbers should be as follows:

Preparations for white spots on cucumber leaves

Chemical exposure to plants is necessary as a treatment and prevention. Depending on the problem that has arisen, you can buy specialized preparations in the appropriate stores. For seed processing, the seller will offer you Pentaphage. Topsin is suitable for the treatment and prevention of fusarium. Cucumbers are saved from powdery mildew by treatment with Trichodermin, Quadris, Topsin. Wilting and root rot are prevented by spraying with Trichodermin.

Many gardeners dream of getting a bountiful harvest of vegetables every year, but white spots on the leaves of cucumbers threaten the death of most plants. The presence of plaque indicates the appearance of diseases or pests on plants. The sooner the problem is identified and treated, the more likely it is to save the crop.

Experts identify a number of diseases that are characterized by a white coating on the leaves of plants. The most common disease in summer cottages is powdery mildew, mosaic. On the leaves of cucumbers, white spots indicate infection with a spider mite.

powdery mildew

A white coating on the leaves of cucumbers indicates infection of the plant with powdery mildew. It appears first at the edges of the leaf plate, gradually covering the entire area. Then the disease spreads to shoots and stems. A characteristic symptom is not only spots, but also a fluffy coating of light color.

Infection of plants begins from the top of the front plate. The disease can appear on bushes located closer to open windows. In the absence of a fight against the disease, the bush begins to fade, the crop completely disappears.

Reasons for the appearance

If we talk about what powdery mildew can appear from, then pay attention to the conditions for keeping cucumbers. The prerequisites for the appearance of a disease in a greenhouse are:

• coolness and high humidity;
• increased density of landings;
• increased nitrogen content in the soil;
• overdrying of the soil with subsequent overflow of plants;
• excessive watering of plants;

Fighting methods

Powdery mildew responds well to treatment. When the first signs of plant damage appear, it is necessary to start fighting it.

To cure powdery mildew you need:

• stop all types of spraying;
• exclude fertilization;
• improve lighting in the greenhouse;
• thin out plantings;
• remove affected, old or weakened leaves;
• cut flower stalks.

Directly with stains, the treatment of plants with antiseptic compounds allows you to fight. In garden plots, chemical antifungal drugs and folk remedies are used.

1. Topaz. Antiviral drug with the active substance - penconazole. To prepare the solution, 1 ampoule per 10 liters of water is used. Plants are treated every two weeks until the plaque stops appearing.
2. Emulsion Tilt CE. An effective drug based on propiconazole. It is dangerous for bees and fish. Suitable for fighting plaque and disease spores. Most effective at elevated temperatures.

In addition to Topaz and Emulsion, Sulfaride, Bayleton, Skor, Vitaros showed high efficiency. In the early stages, Bordeaux liquid and oxychloride are suitable for the fight. Soap-soda solution helps to remove powdery mildew with folk remedies. What to do and what methods of struggle to choose directly depends on the degree of damage and the spread of the disease.

white mosaic

White, or cucumber mosaic is a viral disease. Cucumbers, tomatoes, cabbage and other vegetable crops are susceptible to it. The main development of the disease occurs in the living cells of the plant. But the virus can be transmitted through a dry leaf. It remains in the soil and on inventory for a long time.

Features of manifestation

Cucumber mosaic, falling on the leaf of a healthy plant, leads to the destruction of chlorophylls. As a result, the level of carbohydrates in the plant decreases. The characteristic symptoms of white mosaic are light spots, which at first have fuzzy contours. Their localization occurs in the region of the veinlet.

Gradually, the spots increase in size. Cucumber leaves turn completely white or yellow. Plant growth is suppressed, yield is reduced.

White mosaic is a greenhouse problem. The reasons for its appearance include:

• high density of landings;
• increased temperature in the room;
• sharp fluctuations in air temperature.

The disease often appears on cucumber seedlings that have just been transplanted into the ground. Young leaves and shoots of the plant are also affected.

Fighting methods

If many white spots and signs of mosaic damage appear on the leaves of cucumbers, then it is necessary to start the fight against the virus as soon as possible. It should be understood that the treatment of plants is ineffective.

To cure the disease and prevent its occurrence, a number of rules should be observed.

1. Temperature normalization. In the room where the cucumbers are located, the temperature should be reduced and its drops should be excluded. Optimal conditions are temperatures below 30 degrees.
2. Removal of affected leaves. It is necessary to remove all leaves on which white spots appear. In some cases, whole cucumbers are removed.
3. Inventory processing. All inventory with which cucumbers came into contact must be treated with boiling water, an antiseptic solution or alcohol.
4. Reducing the density of plantings. Cucumbers should be thinned out and given more air and space.

Prevention of the appearance of white spots on cucumbers is the use of mosaic-resistant varieties, regular weeding of the greenhouse and cleaning the premises, and the use of only high-quality seeds for sowing seedlings.

spider mite

Features of manifestation

The appearance of a spider mite on cucumbers is indicated by the presence of a number of signs:

• light dots on the sheet plate;
• thin cobweb on the back surface of the sheet;
• plant growth retardation;
• yellowing of the green mass.

Fighting methods

The emerging disease is easier to prevent than to deal with it when it has struck adult plants. As methods of prevention before planting cucumbers, they carry out:

• digging the soil;
• rotation of planted crops.

If the leaf on the cucumbers turns white and signs of a tick appear, then it is necessary to process the plants and carry out preventive work. To do this, all dry and infected leaves are removed and burned. Humidity in the greenhouse is increased to 70-80%. The tick does not tolerate humidity above 60%.

To cure the disease completely allows disinfection with chemicals. High efficiency in the fight against ticks was shown by:

• Actellik;
• Apollo;
• Neoron;
• Karbofos;
• Sunmite;
• Fitoverm.

Most drugs have a wide spectrum of action and belong to the budget category. If you are fighting diseases with folk methods, then the following are considered effective:

• soap solution;
• garlic;
• onion solution;
• decoction of Caucasian hogweed.

The fight against the tick should begin as soon as the first signs of damage are detected. If its spread is not prevented in the initial stages, all plants will be covered with white dots.

Ascochitosis

White spots on cucumbers in a greenhouse can result from ascochyta infection. The disease affects weakened bushes. The fungus is soil-borne or carried in organic debris.

Features of manifestation

The disease manifests itself in the form of white or brown spots along the edges of the plant. Gradually, the entire leaf becomes covered with spots. The affected area dries up. As a result of a fungal infection, the cucumber stops growing. Copper exudate appears on the stems.

Fruit mutation occurs. They are covered with black dots, resemble boiled vegetables, and are completely unfit for human consumption. The most active disease manifests itself during the fruiting period.

If you figure out why ascochitosis appears on the leaves of cucumbers, then gardeners identify a number of reasons:

• weak plants;
• high humidity in the room;
• the presence of fungus in the soil;
• non-observance of cultural circulation in the garden plot.

Fighting methods

White plaque on cucumbers can be prevented if you follow the rules for the fight and prevention of ascochitosis.

1. Cultural turnover. It is necessary to regularly change the places of planting crops on the ridges.
2. Mulching. So that the leaves do not become stained, the surface of the soil after planting is covered with mulch or plastic wrap.
3. Use of resistant varieties. To prevent the development of ascochitosis allows the use of varieties resistant to the fungus.
4. Sowing on the plot of sanitary crops. Seeding green manure (rye, oats) allows for a comprehensive sanitary treatment of the soil.
5. antiseptic treatment. If the leaves are stained, then it is necessary to remove the affected areas and treat the plants with antiseptic solutions. High efficiency was shown by spraying with Bordeaux liquid or smearing the stems with copper-chalk powder.

Most often, spots appear on the leaves of cucumbers in the greenhouse. This is due to the increased temperature and humidity in the room. When choosing how to treat, it is necessary to rely not only on the experience of gardeners, but also on the type of disease that affected the plants. Timely prevention and competent care of plantings also prevent infection.