Cucumbers are dying in the garden. Cucumber seedling diseases - how to protect a young plant? What difficulties can we face
Why do cucumbers die in a greenhouse? This question worries many summer residents, not only beginners, but also experienced ones. Such a problem can arise even when the plant began to grow well and produce a large number of fruits. The thing is that growing cucumbers, like any other cultivated plants, requires a special approach, and this applies to each variety of this vegetable. In addition, there are various kinds of pests and diseases that affect the root system of a plant, from which its fruits and the plant as a whole die.
However, the most common reason for the death of cucumber seedlings is improper observance of the temperature regime in the greenhouse itself, as a result of which the plants wither and soon die. Therefore, before you start growing cucumbers, you need to properly equip the greenhouse itself in order to avoid further troubles caused by the inappropriate microclimate in it.
What needs to be done for the normal development of cucumber seedlings? First of all, you need to start with soil cultivation. Properly cultivated soil is the first and most important basis for the quality of the future crop. The soil in the greenhouse must be cleared of weeds and dug up, fertilizing it at the same time. Such a procedure is necessary in order to enrich the soil with microelements that will nourish the planted seedlings, as a result of which the cucumbers will bear fruit well. After that, fumigation of the soil can be carried out, which is a complete disinfection of the space in the greenhouse.
This action will help get rid of any harmful microorganisms that can adversely affect the development of cucumbers and their further fruitfulness. To disinfect, kerosene and lump sulfur must be poured into an iron container and set on fire. At the same time, in order to achieve the desired effect, all cracks and holes in the greenhouse must be well sealed. In addition, the good fruitfulness of cucumbers depends on the optimal temperature that must be maintained in the greenhouse, and on the lighting of the greenhouse itself. These parameters for each variety of this vegetable are selected individually.
Diseases of cucumbers in a greenhouse (video)
Pests and diseases that adversely affect the plant
The most common types of pests in cucumbers are melon aphid and greenhouse whitefly. They are able to eat away the root system of the plant and its leaves.
These pests can be dealt with using various chemicals and more budgetary folk methods.
For example, get rid of annoying whiteflies You can use a piece of thick cardboard or plywood, painted yellow, which is then smeared with a sticky substance. The thing is that this pest is attracted to yellow, as a result of which they fall into a trap. You can get rid of aphids using a special garlic solution, which is sprayed on the affected plant.
The diseases most commonly affecting cucumbers are peronosporosis (downy mildew), various root rots, powdery mildew and gray rot. Peronosporosis in most cases is observed in cucumbers already during fruit ripening. The disease manifests itself in the form of small green spots that appear on the leaves of the plant. Over time, the spots increase significantly and the leaves turn brown, as a result of which the plant ceases to bear fruit and dries. The occurrence of downy mildew is associated with the presence of fungal organisms in the soil, which multiply intensively during irrigation of cucumbers with cool water and too much humidity required in the greenhouse.
Rots of the root system of cucumbers are formed due to the fact that watering the plant is carried out with water at too low a temperature. Rot can also appear if cucumber seedlings are planted incorrectly, in particular, if they are too deep into the soil. This disease is characterized by yellowing and the formation of cracks on the stem of the plant, as well as premature drying of the leaves.
powdery mildew called a disease in which the leaves of cucumbers are affected. As a result, round white spots form on their surface. After some time, they merge and increase, after which the leaves acquire a yellow or light shade, which leads to the death of the plant.
gray rot is a disease that causes gray spots on the leaves of cucumbers and their stems. The disease is formed as a result of severe freezing of the soil at night and insufficient ventilation of the greenhouse.
Common varieties of greenhouse cucumbers
Among the variety of varieties of cucumbers for greenhouses, early varieties of this plant, which also include various hybrids of cucumbers, are considered to be among the most productive. These include:
- Suomi F1. It is well resistant to cold climates and various diseases. In addition, the ripened fruits of this variety cannot outgrow, as their growth is limited.
- Sarovskiy F1. This variety does well in greenhouses with low light and low temperatures.
- Hybrid Valaam. It is distinguished by its cold resistance and can be grown in greenhouses in the northern regions. The variety has limited fruit growth and a fairly significant period of fruiting, which ends with the onset of severe frosts.
In addition to cucumbers for greenhouses, which are of the usual size, there are varieties such as gherkins. These hybrid varieties differ from others in the small size of their fruits. The most common of these are Conrad, Alex, Moth and Enchanter.
Cucumbers: signs of disease (video)
Cucumbers, like any other plant, require proper care and compliance with the mass of nuances necessary for the proper development of its fruits, from the processing itself and planting seedlings, ending with the climate in the greenhouse and the presence of various pests.
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Perhaps there is not a single gardener who would not grow cucumbers on his plot. In order to crunch cucumbers in June - July, you must first grow strong healthy seedlings, and in central Russia also deal with adverse weather conditions. Nothing complicated, but seedlings need careful care and are prone to diseases, insect pest attacks and other problems. If you do not know the rules for growing seedlings, the crop will die.
How to sow cucumbers
Before sowing, cucumber seeds are soaked in a solution of potassium permanganate, which will protect against viral diseases. If the seeds are treated with protective substances (coated with a colored shell), soaking is not necessary. After 20 minutes, the seeds are washed and kept in a damp cloth for a day. Then put for a day in the refrigerator for hardening.
Now the seeds are sown in separate pots with earth and with a sufficient amount of organic matter, covered with cling film or cellophane and put in a warm place for germination. As soon as the first cotyledons appear, the cups are opened and placed in the brightest place in the house.
In the first three days, the temperature is maintained at +28+23°C, then lowered to +20°C. At this temperature, seedlings are less stretched. Water as the soil dries out. Monitor the condition of the sprouts to prevent the fall and death of plants.
How to prepare the ground
If the seedlings will grow in a greenhouse, you need to prepare it in advance. Since autumn, the earth has been cleaned of debris, but it is better to remove the top layer and pour new soil. If this is not possible, the beds are treated with Hyocladin solution. The soil is immediately fertilized and dug up.
On a note! Green manure works well on the composition of the soil. They can be sown in advance to enrich the soil.
Be sure to treat the frames with a solution of bleach at the rate of 400 g per 1 liter of water. Iron parts are painted with water-based paint, and wooden parts with vitriol.
For complete disinfection, fumigation is carried out. You can simply build a fire and carefully close the windows and doors, or set fire to lumps of sulfur mixed with kerosene in special containers. Do this at a temperature not exceeding 18 ° C.
To protect plants from harmful microorganisms and fungi, the soil is treated with Fitosporin before planting seedlings.
Before planting cucumbers, they check whether the earth has warmed up, whether there is enough organic matter in the soil, then the seedlings will take root well and will not disappear.
Note! Cucumbers do not grow in acidic soils. The optimal PH level for this crop is 7.
But even on alkaline soils, cucumbers will get sick. If it is not possible to take measurements, pay attention to weeds. Woodlice, horse sorrel, mint, bearberry, and moss grow on acidic soils. Such soil needs deoxidation or liming. Neutral soil is suitable for cucumbers, on which yarrow, wormwood, quinoa, nettle, clover, and bonfire grow.
Cucumbers are regularly fed and treated with special means for the prevention of diseases.
With further cultivation of cucumbers in the greenhouse, the temperature is maintained at 19 - 26 ° C.
For bee-pollinated varieties, insect attractants are used.
Seedlings are regularly ventilated, and shaded if necessary.
The fruits are harvested regularly, otherwise the leaves will wither.
Why do cucumber seedlings die?
To understand this, one must distinguish signs of the most famous diseases.
- Mealy dew. This common disease is caused by a fungus. The leaves on cucumbers are covered with a white powdery coating, and then wither and dry.
- Peronosporosis. The more well-known name for this disease is Downy mildew. The leaves turn yellow, the spots increase, and the sprouts wither. Without intervention, seedlings may disappear.
- Anthracnose. In the people, this disease is called "Medianka". Copper-colored orange spots appear on mature plants and seedlings, and even on fruits.
- Fusarium. In other words - "root rot". It is caused by a fungus that lives in the soil for a long time and infects the roots of plants, causing the sprouts to rot and soon die.
- Sclerotinia. At first, the disease is manifested by the appearance of light fluffy mold on the seedlings. Then the plants become covered with dark spots and dry out.
- Black leg. So gardeners call a dangerous fungal infection. The spores of the fungus spread rapidly. All seedlings can fall in one day.
Important! In addition to infectious and fungal diseases, seedlings suffer from the invasion of insect pests.
Diagnosis of the causes of wilting seedlings of cucumbers
Cucumber seedlings require constant attention. Young shoots should be inspected regularly to understand why cucumber seedlings suddenly wither:
- if suddenly the lower leaves turn yellow, the plant lacks potassium, phosphorus, magnesium;
- if the upper leaves turn yellow, zinc, boron, iron, manganese are needed.
- if you overfeed the plants with nitrogen, yellow burns appear on the leaves. In such cases, they make up for the lack of the necessary trace elements or remove the extra ones, that is, they transplant the plant into a larger pot, wash the roots with water;
- if the seedlings are stretched, provide sufficient lighting to prevent burns, and check if there is enough space for the sprouts;
- if the cucumber leg dries, a constriction appears, the seedlings are mulched and watered with a solution of potassium permanganate and biological products.
Sometimes shoots in cups begin to wither and fall one by one. It is necessary to carefully examine them: whether the pest has entered the soil, whether there are signs of root rot. Immediately take appropriate measures and immediately remove infected plants.
What to do if cucumbers wilted after transplantation
It is recommended to plant seedlings so as not to damage the roots, place four plants per square meter. It is advisable to treat with Kornevin or Epin for better survival. Shade the seedlings for 2-3 days, water them in time, feed them according to the instructions for the preparation.
Seedlings will not die due to the fungus:
- milk serum;
- infusion of garlic;
- soda solution;
- preparations Topaz, Quadris, Thiovit Jet.
Spots and mold appeared on the cucumbers, the plants look lethargic - inspect the sprouts and take action.
seedling lethargy
At the first sign of infection, healthy bushes are selected, transplanted to a new place and treated with the necessary preparation. Sick, withered plants are taken out of the site and burned.
With the invasion of pests, you need to use the appropriate drug or folk remedies:
- aphids and whiteflies will be destroyed by KRA DEO SUPER aerosol, as well as infusions of garlic, yarrow, dandelion, tansy;
- slugs will be defeated by cleanliness on the site and the Thunderstorm preparation;
- the bear will have to be collected by hand, add oil or soapy water to the moves, plant marigolds nearby;
- ticks are afraid of water and humidity.
How to revive sluggish plants
When adverse weather conditions occur, the cucumbers will have to be additionally covered, and if there is a threat of frost, they will smoke on the site.
Advice. If the plants are weakened and sick with powdery or downy mildew, they stop watering for a week, and then they spray it with a solution of whey, add one teaspoon of copper sulphate per 10 liters of solution, treat it with Fitosporin, Ecosil or Epin.
If the leaves turn pale and droop, feed the cucumbers with infusion of onion peel, infusion of bread, ash, compost mash.
Thus, if you follow the requirements for growing seedlings of cucumbers: water and feed them on time, plant them correctly, maintain the temperature regime, respond to the appearance of diseases and pests, then fresh cucumbers will delight until late autumn.
Cucumbers, like all plants of the gourd family, are very demanding on growing conditions. A slight weakening of attention leads to illness and, possibly, death. But difficulties are there to be overcome. It is quite possible to grow a full-fledged seedling of cucumbers.
The most acceptable conditions for cucumber seedlings
Ideal conditions for the growth of cucumber seedlings will be conditions with an optimally balanced combination of lighting, temperature, humidity and nutrition.
Video: growing seedlings of cucumbers
To get a decent harvest, it is necessary to provide seedlings with the following conditions:
- daylight hours - at least 10 hours, daylight and illumination with lamps (do not illuminate at night);
- daytime temperature within 22–24 0 С, nighttime - 15–17 0 С;
- abundant watering - once a week with settled water with a temperature of 24–26 0 С;
- carrying out two dressings - 2 weeks after germination (1 teaspoon of urea per 3 liters of water) and a week after the first (1 teaspoon of nitrophoska per 3 liters of water).
Causes of death of seedlings of cucumbers
In the process of growth, seedlings can be affected by a large number of various diseases and pests. Troubles can await young cucumbers both when grown on a windowsill and in a greenhouse. The most common misfortunes are the following.
Table: diseases and pests of seedlings
Diagnosis of seedling diseases
Having noticed the deterioration in the condition of the seedlings, the first step is to determine what exactly caused it and only after that proceed to eliminate the causes. After carefully studying the symptoms, decide on further actions: change the growing conditions, treat the disease, or start pest control.
Table: how to determine the cause of the poor condition of seedlings
| Symptoms of the disease | Possible causes of the disease | ||
| Mistakes in care | Disease | Pest | |
| Sticky spots appear on the leaves, on which sooty mushrooms grow, the greens turn black and dry. | - | - | greenhouse whitefly |
| Shoots, flowers, ovaries and leaves wrinkle and curl | - | - | melon aphid |
| Gradually increasing oily spots of green color appear on the leaves. They turn brown and dry out quickly. | - | - | |
| A spreading white coating appears on the leaves. The leaves dry up and the plant dies | - | - | |
| The color of the leaves and trunk changes | Deficiency or excess of minerals | - | - |
| The leaves have become stiff, the top has dried up | Excess fertilizer | - | - |
| In sunny weather, the leaves wither, the basal part of the stem turned yellow, has cracks. | - | - | |
| Decaying gray spots appear on the stems near the branches. | - | - | |
| Dry edges of leaves | High or low air temperature | - | - |
| Plants wither, translucent larvae are found on the roots | - | - | cucumber mosquito |
| There are gnawed leaves, stripes of dried mucus are visible on the soil | - | - | Slugs |
| The main stem is unnaturally distorted and dries out | - | - | wireworm |
| Small spots appear on the leaves, the lower surface is covered with a thin cobweb. | - | - | spider mite |
| Yellow edges of leaves | Insufficient lighting, excessive watering | - | - |
| Plants lie on the soil, the stalk near the root is bitten | - | - | Medvedka |
| Cucumber ovaries turn yellow or rot | - | - | |
| Yellow spots appear on leaves and stems, turning gray | - | - | |
| A white coating forms on the plant, in the places of its occurrence, the tissues rot | - | - | |
| Seedling not growing | Late transplant in open ground | - | - |
| An olive coating appears on the plant, these places dry out and break | - | - | |
| The stem at the root becomes thinner and rots, the plant dies | - | Blackleg | - |
| Angular yellow spots appear, then they turn brown and dry | - | - | thrips |
| The appearance of swellings and thickenings on the roots, the plant does not develop | - | - | gall nematode |
Do not confuse the cause of the disease with the disease itself. For example: the cause of the black leg may be increased soil moisture, but the plant does not die from moisture, but from the disease.
Cucumber disease control
Timely detection of the disease is 50% of success in their treatment, but some more effort is required to consolidate it.
Table: treatment and prevention
| Disease | Treatment | Prevention |
| Stop watering and fertilizing, spray with the drug Oksihom (according to instructions), ventilate the room or greenhouse Can be sprayed with a solution of three liters of whey, one teaspoon of copper sulfate diluted in seven liters of water | Observe crop rotation. Water only warm (+22–24 0 C), avoid sudden temperature changes, exclude the appearance of condensation on film shelters | |
| Spray with Topaz or Zaslon (according to instructions). Or pollinate with finely ground sulfur, cover with a film for 2 hours | Observe crop rotation. Pour with warm water, do not allow temperature drops | |
| Rake the earth from the trunk and sprinkle wood ash, chalk or crushed coal on the affected areas. | Do not hill seedlings, do not deepen the stem when transplanting, avoid sudden changes in temperature | |
| Spray with Topaz or Zaslon (according to instructions). Or mix 1 cup of wood ash with 1 teaspoon of blue vitriol and dust with the plant mixture. | Avoid thickening of plants, water with heated water, ensure ventilation of the premises | |
| Remove the infected parts of the plant, cover the sections with crushed charcoal. | Avoid overcrowding of plants, ensure ventilation, and prevent an increase in air humidity. | |
| Treat with 1% Bordeaux liquid (100 g per 10 liters of water) | Avoid increasing air and soil moisture. | |
| Spray with Saprol or Vincit (according to instructions). | Do not allow an increase in air humidity, do not allow plants to thicken | |
| Spray with Fundazol (30 g per 10 liters of water). | Do not increase the humidity of the air, do not allow the temperature to drop | |
| Blackleg | Pour 1% Bordeaux liquid (100 g per 10 liters of water), sprinkle wood ash under the plants | Do not allow plants to thicken, do not allow soil moisture to increase |
Photo gallery: diseases of cucumber seedlings
White rot is an unpleasant disease of cucumber seedlings, which is difficult to fight. 
Root rot can destroy the entire crop 
Downy mildew is the most common disease of cucumber seedlings and adult plants. 
Powdery mildew on cucumber leaves 
Gray rot in the greenhouse 
Ascochitosis often occurs when plants are thickened 
Plants suffering from excessive humidity of air and soil are susceptible to bacteriosis. 
Cladosporiosis affects seedlings and mainly adult plants. 
It is extremely difficult to fight the black leg
Pests of cucumber seedlings
In addition to diseases, various harmful insects can damage cucumber seedlings. They appear both when grown in a greenhouse and indoors.
Table: ways to deal with harmful insects
| Pest | Fighting methods | Prevention |
| greenhouse whitefly | Spray with Actelik or Rovikurt (according to instructions) | Prefers high temperature and humidity. Hang yellow and blue glue traps for prevention |
| melon aphid | Before planting, treat the soil with Karbofos (60 g per 10 liters of water), upon detection - treat seedlings (40 g per 10 liters of water) | Prevent weeds from appearing, move ant nests outside the greenhouse |
| cucumber mosquito | Spray with Aktara or BI-58 (according to instructions) | Carry out thermal disinfection of the soil, hang yellow glue traps |
| wireworm | Pour the soil with a solution of potassium permanganate (5 g per 10 liters of water) | Carry out winter digging of the earth and cleaning of plant residues in the greenhouse |
| spider mite | Spray with Actelik or Aktofit (according to instructions) | Before planting, disinfect the greenhouse with bleach or sulfur bombs. |
| gall nematode | Pour the soil with a solution of potassium permanganate (5 g per 10 liters of water), but it will be more efficient to replace the soil in the greenhouse | Carry out winter digging of the earth, in the spring before planting - thermal disinfection of the soil |
| Slugs | Dusting plants with tobacco dust, wood ash, scatter superphosphate or potassium salt over the garden (300 g per 10 m 2) | Carry out winter digging of the earth with the addition of fallen needles |
| Medvedka | Pour pesticides into minks (Rembek, Medvedoks) | Set traps - a jar of liquid is instilled flush with the ground |
| thrips | Treatment with drugs based on thiamethoxam (Aktara, Cruiser, etc.) | Carry out winter digging of the earth, disinfect the earth with a solution of potassium permanganate (5 g per 10 liters of water) |
Foreword
Unfortunately, not every gardener manages to avoid cucumber seedling disease, especially if he is new to this business. In such situations, it is important to analyze and find the right ways to solve the problem. We will analyze what mistakes gardeners often make, and what to do so that the future crop of cucumbers is healthy.
Gardeners often ask the question - why do cucumber seedlings stretch? The reasons may be different, but the most common is the lack of sunlight or, conversely, its excess. Everything needs balance. In order for the plant to grow healthy, it must be kept in cool conditions at a temperature not exceeding 22 ° C. The plant needs increased heat only at the stage of spitting seeds and emergence of shoots. Many gardeners forget about this rule, continuing to "wrap" the seedlings.
Elongated seedlings of cucumbers
Do not throw out seedlings, they can be saved. Gently press the elongated stem to the ground with a loop and sprinkle it with earth to the very cotyledons. This will slow down the growth of cucumber seedlings, build up an additional root system, and make the central stem strong and thick. There is a high probability that cucumber seedlings will stretch out even if all the rules of care are followed. P Therefore, we recommend using tall cups for growing this crop, so that it is more convenient for you to add the right amount of soil.
It is impossible to answer unequivocally the question of why cucumber seedlings turn yellow. The main sources of yellowness can be fungal infections, or adverse external factors. However, in most cases, it is the violation of the rules for caring for seedlings that leads to the spread of this problem.
yellowed cucumber leaves
One of the first reasons is tight space. The active growth of seedlings leads to the fact that it becomes uncomfortable, because of which the root system receives less nutrients. There is only one way out - transplant the seedlings into a large container. Micronutrient deficiencies can also play an important role, especially when nitrogen is deficient. To fill the gaps will help the introduction of complex mineral fertilizers, as well as top dressing. For cucumber seedlings, we recommend Vermistim and Azogran.
Don't forget the pick. When 2-4 true leaves appear on the seedlings, and a developed root system is formed, the plant must be transplanted from a small container. Many people forget about this, and as a result, the plant begins to hurt. Think about lighting. Do not place young seedlings on a windowsill with direct access to sunlight. This can cause burns and yellowing of the leaf blades.
Seedlings started to wither suddenly? The cause may be a pathogenic soil fungus. It penetrates deep into the tissues of the root system of the plant and begins to gradually destroy it from the inside, the growth of seedlings slows down. The top begins to fade first, losing its elasticity. However, it happens that all seedlings immediately die. This is a very bad sign, it is worth checking the root system. If you notice brown rings when you cut the root, it is infected with a fungus.
wilting plants
Such indicators are typical for fusarium and verticillium wilt. Although they have similar symptoms, the reasons for their appearance are different. Favorable conditions for the development of verticillium wilt are low air humidity and temperatures in the range of 16-20 ° C. Fusarium wilt, on the contrary, develops in conditions of dry air and temperatures above 25-28 ° C.
Cleaning greenhouses from last year's plant residues and disinfecting the soil helps prevent cucumber seedlings from wilting. Crop rotation is also important. Picking is always extra stress for the plant and a high probability of infection. Therefore, before performing this procedure, treat the planting soil with a solution of a biological product Trichodermin or Planriz. We remove diseased sprouts with obvious signs of root rot, and spill the soil with any antifungal solution.
The most common disease not only of cucumbers, but also of other cultivated plants is the black leg. This is a fungus that settles in the soil mixture, and when conditions favorable for it are created, it begins its activity. The reasons provoking the harmful effects of the fungus are standard - increased soil moisture, thickened plantings, sudden changes in temperature and light.
Black leg of cucumber seedlings
How does this type of seedling disease manifest itself? At the base of the stem, closer to the ground, you will notice black formations. This is the same fungus that clogs the conducting vessels of the plant and prevents the penetration of nutrients to the root system. As a result, the seedlings begin to slowly die and tend to the ground. Fighting this disease is pointless. Damaged specimens must be immediately removed, the soil treated with a disinfectant solution and healthy seedlings transplanted into disinfected soil.
Major mistakes can be made at the beginning. The first thing to remember is to always steam the soil in the oven or microwave to kill pathogens.
Before adding the soil to the container, make sure that it is sterile, or rather, pre-soak it in a disinfectant solution. In the soil where the seedlings will be grown, we add wood ash, and after watering, sprinkle the bushes around with a small amount of dry sand. Among the biological products that help prevent the development of the black leg, I would like to note Gamair, Trichocin, Alirin and Glyocladin, as well as chemical Previcour.
If wet spots appear on the leaves of your seedlings, which, after drying, leave black dots, this is ascochitosis. There is no cure for this disease. Its fungus penetrates deep into the root system, as a result of which the root hairs die first, and then the entire root, which begins to rot from the inside.
cucumber mosaic
Root dieback is another common disease among cucumber seedlings. Its main danger is the absence of external signs. The plant abruptly stops growing, dries up and dies. It provokes the development of the disease by watering seedlings with cold water. However, if you are sure that you are using warm water, look for other factors: a cold window sill, drafts, or high humidity. Under these growing conditions, the soil cools rapidly, causing rot and root cell death.
Waterlogging of the soil and cold air flow, as well as deep seeding, are the main factors in the development of root rot. External signs of the disease are the fragility of the stem and the blackening of its tissues, the gradual death of the top. At the initial stage of seedling formation, cucumber cotyledons turn yellow, and in the phase of formation of the first 2-4 true leaves, the root neck becomes thinner and deformed. If you start treatment on time, then you can fight for the life of the plant. To do this, do a double treatment with a chemical preparation. Previcour with an interval of 20 days.
The cucumber mosaic virus is considered the most dangerous of all the presented diseases.. Unfortunately, viral diseases are still little studied by biologists, and there is no effective treatment for it. The main sources of infection are pests such as aphids, whiteflies, and poor-quality planting material. External signs of the disease are a mosaic pattern of light spots that occupy the entire leaf plate. As a result, the leaves curl, fall off, and the plant itself dies. Infected specimens must be removed along with the ground and burned.
Powdery mildew is not uncommon in our gardens. In addition to open ground, it also develops in greenhouses and other indoor areas for growing seedlings. Its white mealy fungus infects the leaves, and with further development captures all other parts of the plant. Such seedlings are significantly behind in growth from healthy seedlings, its shoots are weakening. The development of the fungus can provoke a number of the following reasons - a sharp temperature drop, irregular watering, an excess of nitrogenous fertilizers or calcium deficiency.
Powdery mildew on seedlings
Among folk remedies, a decoction of horsetail or an infusion of marigolds has a detrimental effect on the fungus. From fungicides, choose copper-containing preparations using 1% Bordeaux liquid, 0.4% solution of copper or iron sulfate. We carry out the processing from the outer and inner sides of the leaves, repeating the procedure if necessary after a week.
Peronosporosis (downy mildew) has a different manifestation. When infected with a fungus, yellow spots with an oily structure can be seen on the outer side of the leaf along the central veins, and a gray coating with spores is visible on the inside. As the disease develops, the spots darken, the leaf tissue breaks down and becomes brittle. In advanced cases, seedlings die.
To keep your crops safe from this fungal infestation, always decontaminate the seeds. For these purposes, you can use a solution of zinc sulfate, heated to 50 ° C. Dry after soaking. Avoid dense plantings and high humidity, and use a biostimulator Radipharm using it according to the instructions.
Quite unexpectedly, brown spots formed in the lower part of the stems of several cucumber plants, right near the roots, literally four days later they joined, and the stem began to rot. I removed almost all of these plants from the site, leaving only a few to see what happens next. The following happened - the apical leaves withered, then turned yellow and withered, the plants died. What is this? Maybe a nematode? And is it possible to save such plants at all?
Answered by N. V. Khromov, Ph.D. biol. Science
Hello, no, this is not a nematode, this is cucumber root rot. It is noteworthy that cucumber plants are really affected by root rot unexpectedly and at the most important moment of their development. Usually visible to the naked eye, the symptoms of this disease become noticeable when it is already late, that is, at the beginning of fruiting. The whole danger of root rot lies precisely in the timing of their appearance. They develop very actively during periods of active growth of cucumber plants and their fruiting. Under the influence of rot, plants are greatly weakened and other fungal and bacterial diseases begin to overcome them, the rudiments of which may be in the soil. Root rot develops most actively if cucumbers have been growing in the same place for several years. Over the years, the risk of a sudden outbreak of this disease increases significantly.
Quite often, outbreaks of root rot can be observed on acidic and dense soils, on soils that, due to adverse weather conditions, cool down to 12-14 degrees or, on the contrary, overheat when the temperature rises above 28 degrees. Excessive watering can also cause root rot, especially if the water is cold.
When the very first signs of root rot appear, you must immediately take action and do not rush to destroy the plants. Sometimes young cucumber plants can be saved by just adding a small layer of fertile soil to the stems. Plants form a new root system and begin to live off it.
In the event that the cucumber plants are already quite mature, then all the lower leaves can be removed from the stem, allowed to dry at the cut points, and then the stem is laid on the ground, either straight or rolled into a ring, and poured with moist fertile soil. Ten days later, additional roots should form on the stem, after which you can add a little more soil, covering these roots, and the plant will continue to fully develop.
However, the methods described above are applicable only if the disease was detected at the very beginning of its development. If the disease is already in an advanced stage, then really the best option is to dig up diseased plants along with the soil, and pour fresh substrate into the hole. This will prevent the disease from spreading to healthy plants.
Of course, prevention is better than cure. And it should start with seeds. Try not to use untested seeds for sowing, choose disease-resistant varieties, especially if you plan to grow cucumbers in a greenhouse where diseases spread at lightning speed.
Be sure to follow, which provides for the return of the cucumber to its original place no earlier than three years later. In an open area, crop rotation, of course, is much easier to observe, but if we are talking about a greenhouse, then there are more difficulties. But there is a way out of this situation - you need to change the soil in the greenhouse approximately every two years. It makes no sense to change the entire soil, it is enough to remove the soil to a depth of about ten centimeters, because the disease persists in the soil only in a layer of this thickness. After replacing the soil, stimulate the development of beneficial microflora by introducing well-rotted manure into the soil, it is most convenient to do this for digging the soil, simply by scattering the humus over the surface of the substrate.
Do not forget about folk methods of prevention - it is very useful to spray nettle tincture. Preparing it is very simple, just cut nettles (necessarily before flowering), chop them well, put them in a plastic bucket, stuffing to the top, pour water, cover with a lid and put in a sunny place. To make the infusion steeper, you need to stir the nettle in a bucket every day for a week with a stick. Nettle usually releases bubbles, so as soon as their release stops, the infusion will be considered ready. Usually this liquid smells very unpleasant, so that this does not affect the quality of the cucumber fruits in any way, the infusion must be diluted ten times. Such an infusion is suitable for tillage not only in a greenhouse, but also in an open area.
In general, with regard to the greenhouse, there are somewhat different laws. You can often get rid of the appearance of root rot by simply airing it, but in no case should you allow drafts when a stream of cold air suddenly bursts into a heated greenhouse. It’s great if there is a constant flow of air in the greenhouse, which does not cool the plants, but also prevents the tropical “bath” climate from forming in it.
Do not forget to look at cucumber plants every morning, or at least once every two or three days, this is the optimal time period when you can detect the disease in the initial stage and have time to fight it, or remove the diseased plant before it infects healthy ones.
Maximum attention to cucumber plants will have to be paid in August, when rot most often appears on them. Try to constantly remove all the lower leaves and side shoots that the plant no longer needs, so it will be easier for fresh air to pass over the surface of the soil, refreshing the plants.
During this period, in no case do not flood the plants, on the contrary, try to water them less often, only in the morning and only if the day promises to be fine. Do not forget about mulching the topsoil, this is a simple event, but very important for plant health.
