Many gardeners are trying to grow cucumbers on their plot in order to be able to consume fresh vitamin products during the summer, as well as provide families with preparations for the winter. But often with an inept or careless approach, plants are affected by various diseases, which, rapidly developing, can destroy the entire garden. Therefore, in order to achieve a guaranteed positive result, you should familiarize yourself with the signs of the main diseases of cucumbers, their prevention and treatment.
Cucumbers do not have too many pests, but the spectrum of possible diseases is quite wide. Therefore, growing them without observing preventive measures is an almost impossible task. In all cases, you should choose disease-resistant varieties for planting, avoid thickening of the plantings, correctly form the bushes, and remove old leaves from the lower tiers of the bush in a timely manner.
Here, everything around can become a source of disease - seeds, soil, frame structures, film. And all this must be disinfected, cleaned, processed before planting.
Preparations begin in the fall - immediately after the end of the harvest. The first thing to do is to remove from the greenhouse the fruit-bearing lashes, weeds (if any), and other debris. It is better to burn all this so as not to leave potential pathogens, which in the next season will find a way to return to the greenhouse.
The next thing to do in the greenhouse is to treat structures, glass and perennial film with a disinfectant solution. The drug Pharmayod has proven itself well for these purposes, which is produced in the form of a concentrated mother liquor in a glass or plastic container and can be stored in it for up to three years. It is successfully used for seed dressing, soil cultivation, and greenhouse structures.
Pharmayod is successfully used for seed treatment, disinfection of soil and greenhouse structures
So, 200 ml of the drug is dissolved in a bucket of water and all structures are thoroughly sprayed with a garden sprayer, which gives the smallest, foggy stream. After processing, close the greenhouse as tightly as possible and leave for 1-2 weeks.
You should know that the largest number of pathogens accumulates in the soil. Therefore, its disinfection should be given increased attention, as this will reduce the use of pesticides in the process of growing and harvesting, and helps to increase yields. For these purposes, before planting, the soil is watered with the already known Pharmayod in a concentration of 100 ml / 10 l of water, while consuming 1-2 liters of working solution per 1 m2. Since this drug does not have a selective effect and destroys both harmful and beneficial bacteria, then a week after treatment it is necessary to populate the soil and free space of the greenhouse with beneficial bacteria. For this, the preparations Baikal EM-1, Vostok EM-1, Radiance, etc. are used.
Baikal EM-1 preparation helps to restore beneficial soil microflora after chemical treatments
And also for the prevention of root rot and spotting, the biofungicide Trichocin is effective. After adding the drug to the soil, the Trichoderma soil fungus contained in it begins to grow actively and quickly fills all the free space, suppressing the development of harmful fungi.
After adding Trichocin to the soil, the soil fungus Trichoderma contained in it begins to grow actively and quickly fills all the free space, suppressing the development of harmful fungi
Trichocin is introduced by spraying or watering the soil, having previously diluted 6 grams of the drug in 10 liters of water. This amount is enough to process 100 m2 soil. After watering or spraying, the soil should be cultivated to a depth of 20 cm using a manual or mechanical cultivator.
In addition to the antifungal effect, Trichocin also improves the taste of fruits, increases their sugar content and vitamin content.
Just like in the greenhouse, sanitary and preventive work in the open field begins in the fall.
The soil for future planting is cleared of weeds, plant debris and other debris. Before the onset of frost, it is plowed deeply or dug up in order to raise wintering pests and pathogens to the surface. After that, treatment is carried out with a 3-5% solution of copper sulfate, Pharmayod (2% solution) or a pink solution of potassium permanganate.
It is known that all garden crops grow better after certain plants, and after others - worse. In the case of cucumbers, good predecessors are:
But after strawberries, pumpkin and melons, cucumbers should not be planted.
If the soil is prepared correctly, and the seedlings are healthy, then after planting and until autumn, regular treatments with biofungicides will be quite enough for preventive purposes (fungicides are antifungal drugs). Fitosporin-M Cucumbers are ideal for these purposes. It contains specially selected bacteria to protect against root rot, black leg, powdery mildew, late blight and other fungal diseases. And besides, the preparation contains microelements and humic acids necessary for cucumbers.
Fitosporin-M Cucumbers contains special selected bacteria to protect cucumbers from root rot, black leg, powdery mildew, late blight and other fungal diseases
Fitosporin is easy to use. The mother liquor (and it can be stored for 6 months) is made by dissolving 200 grams of paste in 400 ml of warm water and used to prepare a working solution. For processing cucumbers dissolve 2-3 teaspoons of the stock solution in 1 liter of water. The drug does not cause resistance (addiction) and can be used repeatedly. The interval of treatments is 2-3 weeks for prophylactic purposes and 1 week for the treatment of diseases.
During the growing season, weeds must be regularly removed, since they not only take away some of the food from the cucumbers, but also are a source of infection with diseases. And also the soil should be loosened, ensuring its permeability to air, which is necessary for the roots, which is the prevention of chlorosis.
The best prevention of disease is the use of immune varieties. As a rule, these are first-generation F1 hybrids of medium and late maturity. Almost all early cucumbers are susceptible to disease. Many immune varieties have been bred, we will give only a few. For greenhouses:
For open ground:
A large number of fungi can settle on cucumbers and it is not always possible to recognize them.
Cucumbers affect several types of mosaics. All its viruses are highly resistant. It will not be possible to destroy them by heating the seeds, since this requires too high a temperature. To destroy the seed infection, treatment is carried out in a 15% solution of trisodium phosphate for an hour, followed by rinsing in water for at least 50 minutes.
This disease is more commonly found in greenhouses. Its early signs appear even on seedlings:
Ordinary mosaic of cucumbers is more common in greenhouses.
The preventive measures described above usually prevent the onset of the disease. And you also need to deal with aphids, which are a carrier of infection.
This mosaic also mainly affects greenhouse plants. This is usually preceded by a sharp rise in temperature up to +30 ° C. The leaves wrinkle, their veins become lighter, sometimes the plants wither, which resembles root rot. The number of fruits decreases, their growth slows down, they acquire a mosaic color, deform, and their quality deteriorates sharply. The degree of development of the disease is influenced by stress factors. So, with a sharp increase or decrease in air and (or) soil temperature, the number of affected plants increases.
Green speckled mosaic on cucumbers appears against the background of stressful situations
This mosaic can often be seen on the leaves of open field cucumbers. Its first symptoms are the formation of enlightenments, yellow spots and star-shaped rings along the veins of the leaves, which eventually turn white and merge.. A similar pattern may also form on the fruit.
White mosaics can often be seen on open field cucumbers and zucchini.
This disease primarily affects seedlings in greenhouses, but it may well develop on adult plants. The fungus that infected the cucumber is localized in the stems at the soil level. It clogs the vessels through which food flows from the roots to the leaves, as a result of which the stem becomes thinner, loses its strength and elasticity, the bush falls to one side and dies. In the place of the fold, the stem turns black, which gave the name of the disease. The infection spreads very quickly and in a short time can destroy all the plants in the garden. Sources of infection are contaminated soil and seeds, and favorable factors for the development of the fungus are dampness, low temperature and poor lighting. Disease prevention - thorough preparation and disinfection of the soil. In addition to treatment with drugs, the seedling soil can also be calcined in an oven at a temperature of 100-140 ° C or in a water bath for 30-60 minutes. Information about seed treatment will be presented below in the corresponding section.
Black leg primarily affects seedlings in greenhouses
When the first diseased plants are found, they should be immediately removed and destroyed. After that, you need to sprinkle the soil with sifted wood ash, crushed charcoal or sprinkle with a pink solution of potassium permanganate. And also the biological drugs described above help well.
This is a common fungal disease, the first characteristic symptom of which is a white powdery coating on the leaves of cucumbers. As it develops, the density of plaque increases, the leaves turn yellow, wither and die off. The lesion begins with the lower leaves, gradually moving upward and covering the entire bush. In this case, not only leaves are affected, but also stems, flowers, ovaries, fruits.
Powdery mildew is a common fungal disease, the first characteristic of which is a white powdery coating on cucumber leaves.
The disease, if not stopped in time, can completely destroy plants and crops. It arises and develops rapidly under favorable conditions for it:
Prevention and compliance with the rules of agricultural technology prevent the onset of the disease. Treatment, if the cucumbers are already sick, consists in removing the affected leaves and other parts of the plant, followed by treatment with biofungicides.
The disease can be diagnosed by yellowish spots appearing on the upper side of the leaves. On the underside, sporulation is formed in the form of a grayish-purple bloom. At the next stage, the spots merge, their edges bend upward, then they dry up and crumble, leaving only petioles on the stem. Typically, the fungus is active in late summer if rainy weather sets in. And the provoking factors are the thickening of plantings, watering with cold water, sudden changes in day and night temperatures.
The provoking factors of the occurrence of peronosporosis are the thickening of the plantings, watering with cold water and sudden changes in day and night temperatures.
In addition to the main preventive measures, in the phase of three to four true leaves, seedlings are sprayed with the fungicides Quadris, Strobi, Ridomil Gold MC, Efal, Acrobat MC (this drug is used only for open ground). Repeated treatments are carried out no more than two times with an interval of 5-7 days. During the harvesting period, only biological products and folk remedies are used.
The disease is manifested by the formation of brown spots on the leaves and stems, and the fruits are also affected. Later, the spots increase, their color darkens, becoming almost black, after which the pulp inside the spots dries up and falls through, forming holes. Fruits develop brown, depressed spots, wet ulcers, making them unusable.
Anthracnose is manifested by the appearance of brown spots on the leaves of cucumbers.
The main prerequisite for the development of copperhead is high humidity. Fungal spores cannot germinate at less than 60%. Infected plants should be cleaned of affected leaves and fruits and treated with colloidal sulfur. At the same time, you should know that this drug is effective only at high temperatures - + 28-40 ° C, and the higher the temperature, the more effective its action and vice versa. During cool weather (when the fungus itself causes maximum harm), it is better to use a 0.5% solution of copper sulfate, followed by dusting with sifted wood ash or ground slaked lime, and the drug Tsineb is also effective (it is used only in open ground). It is poorly soluble in water, but forms a good fine-grained suspension. Therefore, for treatment, first thoroughly stir 40 grams of the drug powder in 500 ml of water, pour the mixture into a sprayer, add water to 10 liters and mix again, after which the plants are immediately sprayed. Consumption rate - 20-40 grams per hundred square meters.
This fungal disease is easy to diagnose by its characteristic features:
The fruits and leaves of cucumbers affected by white rot are covered with a white flocculent coating
If untreated, the disease progresses, spreads to neighboring plants, the affected bushes die. Like many fungi, sclerotinia develops in cool, humid weather. A rainy summer with an air temperature of + 10-15 ° C is the optimal conditions for the development of the fungus. Contributing factors are the thickening of the plantings and the lack of formation of bushes, which also leads to thickening. And you can also introduce an infection when trimming the leaves with non-sterile scissors or pruning shears.
To combat white rot, copper-containing preparations are used (after removing the affected parts of the plant):
They have a contact effect, do not penetrate into tissues and do not accumulate in fruits. And also in the fight against sclerotinia, various folk remedies are often used.
Cladosporia often occurs in the southern regions, and it also affects open ground cucumber beds in areas with a temperate and humid climate and in closed ground, especially in film greenhouses. Its characteristic features:
On the fruits of a cucumber affected by cladospoiosis, several depressed spots are formed, on which spores of the fungus collect in the form of an olive-gray bloom
If immediately after the appearance of signs of the disease, cucumbers are treated with biofungicides, then you can significantly reduce its harmful effects in the first 2 months of fruiting.
This is a common disease of all plants, which manifests itself in disturbances in the process of photosynthesis and the formation of chlorophyll, associated with various unfavorable factors:
Since the causes of the onset of the disease are different, then its symptoms are somewhat different depending on them. Common signs of chlorosis are:
But these signs can appear with other diseases, for example, with peronosporosis. Only with a close examination and observation of the course of the disease can an accurate diagnosis be established.
With a deficiency of manganese, cucumber leaves turn yellow, and their edges become rusty
|Magnesium||Blanching of the underside of the leaves starting from the edges, which, after complete discoloration, turn purple||Leaves curl and darken, roots die off|
|Nitrogen||Yellow spots appear on the leaves of the cucumber, starting from the lower ones, which soon turn brown||The leaves turn dark green and curl. At first, almost transparent spots appear on them, which subsequently turn yellow or brown.|
|Iron||Symptoms are the same as for nitrogen deficiency, but manifestation begins in the upper leaves.||Leaf discoloration between veins|
|Manganese||Yellow leaves with rusted edges||Brown spots on the leaves|
|Potassium||Abrupt color change from green to brown without yellowing||Mosaic pattern|
If there is a lack of any element, the situation can be easily corrected by introducing appropriate dressings. But with their excess, it is difficult to change anything. You can try to apply increased watering in order to flush out excess elements, but this, in turn, can lead to the formation of root rot and other fungal diseases. Therefore, nutrition should be balanced and carried out according to the principle - it is better to underfeed than overfeed.
The gardener cannot always immediately determine the cause of the disturbance in the development of the plant - at first he only detects certain changes in the color of the leaves, their shape, etc.
This phenomenon may indicate a deficiency or excess of moisture, the use of cold water for irrigation, a large difference between day and night temperatures. If everything is in order with this, then the yellowing may be caused by chlorosis. When affected by powdery mildew, the leaves also turn yellow, but this occurs already in the final stage and by this time the disease has most likely already been diagnosed.
The reasons for this phenomenon can be identical to the reasons for the yellowing of the leaves. Moreover, both phenomena can occur simultaneously. But there are other possible reasons:
The appearance of white spots, depending on their shape and type, can be caused by fungal diseases:
Such spots can appear with powdery mildew or chlorosis caused by a deficiency of nitrogen or iron.
Treatments can be prophylactic (including pre-sowing seed treatment), aimed at preventing diseases, and therapeutic, the purpose of which is to get rid of an already developing disease. For their implementation, there are many chemical and biological drugs, as well as folk remedies. When choosing, you should be guided by the following simple rules:
Now on sale there are often seeds of cucumbers that have already been trained in a production environment, including they are processed from diseases. There should be appropriate information about this on the packaging. If such information is not available or the seeds were collected independently, then they should be processed before planting. For this:
For the purpose of disinfection, cucumber seeds are soaked in a slightly pink solution of potassium permanganate for 15-20 minutes
For the convenience of the user, we will summarize the data on the drugs mentioned in a table.
|A drug||Active substance||What are they used for?||Dosage||Allowable number of treatments||The duration of the therapeutic action||Waiting period|
|Pharmayod||Iodine||Disinfection of soil and seeds, treatment of viral speckled mosaic of cucumbers||Soil disinfection - 3-5 liters of 2% solution per 1 m3. Treatment of seeds - 0.05% solution. Treatment - 0.03% solution.||5||2-3 weeks||4-5 weeks|
|Quadris||Azoxystrobin||Treatment and prevention of peronosporosis, powdery mildew||0,06%||2||20 days|
|Strobe||Kresoxim-methyl||2 g / 7L||2||7 days||10 days|
|Ridomil Gold MC||40 g / kg mefenoxam and 640 g / kg mancozeb||Prevention of peronosporosis||200-400 ml / 10m2||3—4||10-14 days||5 days|
|Efal-Aliett||Fosetyl aluminum 80%||20 ml / 10L||3||20 days||40 days|
|Acrobat MC||Dimethomorph (90 g / kg) and Mancozeb (600 g / kg) Source:||Treatment and prevention of many fungal diseases||20 g / 5L||2||14 days||20 days|
|Tsineb||Tsineb||50g / 10L|
|Abiga Peak, Hom||Copper oxychloride|
|Trichocin||Trichoderma soil mushroom||Prevention of root rot||Tillage - 6 g / 10L per 100 m2||1||20-30 days||No information|
|Fitosporin||Bacillus subtilis bacteria 26 D||Prevention and treatment of all fungal diseases||Stock solution - concentration 1: 2. Working solution - 2-3 tsp. per liter of water.||Unlimited at intervals of 1-3 weeks||1-2 weeks||It is allowed to eat the fruits immediately after processing|
In addition to industrial preparations, various folk remedies can also be used. They are mainly used for disease prevention.
|Iodine||Dissolve 30 drops of iodine and 40 grams of grated laundry soap in a liter of milk or whey||Cucumbers are sprayed throughout the season with an interval of 2 weeks. The remedy is effective against various rot, including root rot.|
|Zelenka||Application and action are similar to iodine|
|Wood ash||A glass of sifted ash is poured with two liters of boiling water and insisted for a day||For prophylaxis, they are treated once a week, and for treatment - 2-3 times a week.|
|Serum + copper sulfate||Dissolve 100 g of vitriol in a bucket of whey||Cucumbers are sprayed when signs of peronosporosis appear with an interval of 3-4 days|
|Soda||Dissolve 75 g of baking soda in a bucket of water||Treatment against gray rot once every 3-4 days|
When growing cucumbers, special attention must be paid to the prevention of diseases, otherwise, in the event of diseases, you will have to use unsafe drugs for treatment or accept the loss of the crop. The use of effective biological products even at the stage of seedling growing and soil preparation, as well as the cultivation of disease-resistant varieties, will ensure that tasty and healthy fruits are regularly picked throughout the season.
[Votes: 2 Average: 5]
Many gardeners are trying to grow cucumbers on their plot in order to be able to consume fresh vitamin products during the summer, as well as provide families with preparations for the winter.
But often with an inept or careless approach, plants are affected by various diseases, which, rapidly developing, can destroy the entire garden. Therefore, in order to achieve a guaranteed positive result, you should familiarize yourself with signs of the main diseases of cucumbers, their prevention and treatment.
Both cucumbers growing in a greenhouse and those growing in open ground are susceptible to the disease. Many other vegetables, as well as fruit trees and shrubs, also suffer from this disease. From them, fungi can get on the cucumber beds. Most often, powdery mildew appears on cucumbers due to sudden changes in temperature and humidity, with an excess of nitrogen in the soil or a lack of calcium.
At the beginning of the development of the disease, white spots appear on the leaves. Severely diseased plants look like they have been sprinkled with flour, this is the sporulation of the fungus. This fungus absorbs nutrients, disrupts the process of photosynthesis. Fruit bodies (cleistocarps) are formed on severely affected leaves, they infect the plant the next year. Hibernates on plant debris. Transferable when planting, watering or wind. Diseased plants lag behind in growth, its leaves and shoots droop, and subsequently die off.
Control measures... As a preventive measure, crop rotation must be observed; cucumbers cannot be planted in their original place earlier than after 4 years. In the greenhouse, it is necessary to maintain the temperature at + 23 + 25 degrees. Watering should be regular, overflow or drought should not be allowed, water only with warm water.
When the first signs of the disease appear, cucumbers in the greenhouse should be sprayed with mullein infusion: 1 kg. pour manure with 3 liters of water, leave for 3-4 days, strain and add water to 10 liters. Can be sprayed with marigold infusion, serum, horsetail decoction: 1 kg. pour fresh or 100 grams of dried horsetail with 10 liters of water, insist for a day, then boil for 2 hours, cool, strain, dilute with water in a ratio of 1: 5. You can spray both plants and soil with this solution. Or spray it with a decoction of tansy, the decoction is prepared in the same way as from horsetail, only dry tansy needs to be taken 30 grams, and fresh 300 grams per 10 liters of water.
In case of severe damage, sick lashes cut in and treat the plants with a solution of colloidal sulfur (for 10 liters of water, take 40 sulfur and 2 tablespoons of liquid soap) or treat the plants with powder of ground sulfur - pour finely ground sulfur into a gauze bag and pollinate diseased cucumbers, consumption 25- 30 grams per 10 sq. meters. Carry out the processing several times with an interval of 7-9 days. It is possible to use such means as: "Quadris", "Topaz", "Jet", "Oksikhom", "Karatan". It is necessary to spray all parts of the plant and leaves on both sides. At the end of the season, in autumn, be sure to remove and destroy plant residues and disinfect greenhouses and hotbeds.
The most dangerous for plants is the treatment with the wrong means and fertilization with the wrongly chosen preparations, therefore it is important to determine the disease by its external signs and to know preventive and therapeutic methods.
Most often, cucumbers are affected by leaf diseases, covering over time their shoots, antennae, peduncles and ovary. With white rot, the plants are completely covered with mucus and bloom. The infection develops especially quickly in greenhouses with thickened plantings, high humidity and stagnant air.
To get rid of white rot, you need constant temperature control, thinning of plantings and timely weeding. The affected parts of the bushes should be carefully cut off, and the wounds should be powdered with ash or slaked lime. With this disease of cucumbers in the greenhouse or in the beds, disinfection of the soil is necessary (1-2% manganese solution or nettle infusion), and in case of severe infection, its complete replacement by 10-15 cm in depth. You should also spray the crops with a special solution (10 liters of water, 2 g of copper sulfate and 10 g of urea).
The disease is dangerous for the measles system, because with it part of the rhizome dies off, and the stem itself becomes rotten, and the plant dies just before our eyes. Root rot is caused by cold weather, heavy and too wet soil and poor quality seeds. Almost all diseases of cucumbers of an infectious nature are dangerous because the pathogen can be for a long time in the beds, in greenhouses or uncleaned plant debris.
If you notice that the root rot of cucumbers has begun, treatment is carried out by mulching the bushes with clean sand, peat mixture, chalk (limestone) or sawdust. Already infected - should be mercilessly cut and disinfected with dry bleach in a volume of up to 200 g per sq.m. It is advisable to use warm irrigation water.
It is this disease of cucumbers that is considered the most common.Its signs are noticeable not only on the leaves (small white spots, gradually covering the entire surface), but also on the stems with petioles. The disease stains the whips completely brown, they dry out and fall off.
The reasons for the appearance of powdery mildew are almost the same as those that cause other diseases of cucumbers with photos - temperature fluctuations, excessive humidity, excess weeds and neglect of plantations. Cold irrigation water, drafts and strong winds can also lead to its development.
If powdery mildew appears on cucumbers, measures to combat it will consist in pruning the affected parts of the stem and disinfecting the soil. Recommended processing:
Deep digging of beds, scrupulous destruction of plant residues, systematic application of potassium fertilizers will also not be superfluous for prevention.
The enemy destroying entire fields is manifested by a greenish bloom and yellow spots on the upper part of the foliage. It tends to spread over the entire surface of cucumbers and infect plantings growing in the immediate vicinity.
Downy mildew, also called peronosporosis, can spread rapidly due to frequent fogs, a large amount of dew, too cool watering and temperature changes.
Peronosporosis of cucumbers, the treatment of which experts recommend using a milk-iodine solution (10 drops per 10 l) or urea (1 g per 1 l), will not interfere with obtaining beautiful ripe fruits. The main thing is not to forget about the disinfection of seeds, warming up the soil and mandatory feeding.
Yellow-brown spotting on foliage and pink bloom on the rest of the bushes is most often the result of anthracnose, which develops to a greater extent with excess moisture. At first, barely noticeable mucus appears on the culture, however, in places of its concentration, small ulcers are almost always formed, which lead to the death of the bush.
The virus is transmitted with the seed and the affected plants remaining in the ground, and rainy weather and humidity create favorable conditions for the spread of pathogenic bacteria.
To prevent the disease of cucumbers in the greenhouse and on the plots, it is necessary to sow only proven seeds in sufficiently heated and treated soil. It is better to purchase seed material from friends, from official agro-technical companies, or procure it yourself. With already proven anthracnose, the treatment of cucumbers from diseases with folk remedies helps:
Many of the diseases of cucumbers considered and their treatment concerned damage to the foliage and stem, from which the plant itself died. Cladosporium damage mainly affects the fruit itself. Small, but numerous spots of a watery type appear, which quickly grow and harden, which leads to cracking of the skin of the vegetable and its death.
This ailment is also called olive spot, which can spread directly through the air, infecting areas with cucumbers during irrigation or during rains.
Preventive treatment of cucumbers for diseases is carried out with a 15% suspension of Bordeaux mixture. However, the problem may not be completely resolved. If the remedies do not help, and contaminated cucumbers constantly appear, airborne diseases are prevented by reducing humidity and choosing the most resistant varieties.
This disease can be massive or spread by foci in vegetable gardens and greenhouses without proper heating. Fungal diseases of cucumbers affect plantings at different points in their growth. The problem with fusarium is that the infection may not manifest itself externally until the plants enter the fruiting phase, when they begin to droop and die.
Fusarium wilting of cucumber, the treatment of which does not bring the desired results, must be prevented even at the planting stage. You can avoid infection:
The main sign of downy mildew on cucumbers (see photo) are yellow-green specks that cover most of the leaf. They are also mistaken for traces of acid rain. A violet-gray bloom appears on the bottom of the leaf, as a result of which it dries completely and crumbles. Downy mildew of cucumbers affects plants regardless of age. It is typical in most cases when growing cucumbers in the open field.
The prerequisites for the emergence and development of peronosporosis are high humidity and air temperature up to 16-18 0 C. The disease develops from small droplets on a leaf.
Spores are capable of maintaining their dangerous life activity in the soil for a long time, therefore it is very difficult to fight them. If peronosporosis or downy mildew has manifested itself on cucumbers, then control measures should include the use of certain preparations containing copper (Bordeaux liquid, Ridomil Gold, Oxyhom). These funds are effective as a preventive measure.
If cucumbers are affected by downy mildew, then treatment is carried out with the drug "Rizoplan". It is based on living cells of some bacteria. They are absolutely harmless to humans, but destructive to downy mildew spores. The drug also does not accumulate in the soil, but immediately decomposes.
To protect cucumbers when grown in a greenhouse from diseases and pests, it is recommended to observe the following disease prevention rules:
To prevent ailments, before planting, cucumber seeds are pickled to kill microorganisms or fungal spores that live on the surface of the seed. To do this, they are soaked in Alirin or Gamair. An important stage in the prevention of cucumber diseases is the preparation and disinfection of the soil in the greenhouse. For this, hydrogen peroxide or potassium permanganate is suitable.
In order to get a good harvest of cucumbers, you need to know about the possible diseases to which this crop is susceptible, to prevent their appearance in time. Powdery mildew, root rot, downy mildew, white rot - these diseases often cause the death of not only individual plants, but even entire cucumber plantations. Insect pests such as melon aphids or spider mites also pose a threat to cucumbers.
This culture is susceptible to a number of diseases, which can be divided into two types: fungal and bacterial.
Diseases of cucumbers of fungal origin:
Among the diseases of cucumbers and other garden crops, powdery mildew is one of the most common. It provokes infection of plants with the fungi Sphaerotheca fuliginea and Erysiphe cichoracearum. These parasites mainly inhabit the leaves of the plant. They affect the epidermis of the leaf plates, resulting in the formation of a white bloom - mycelium.
If you do not take any measures to combat this ailment, then the vitality will slowly leave the plant. Leaves begin to wilt, dry and die off. The fruits rot and turn black. Powdery mildew fungi rapidly attack large areas of planting. Other names for the disease are "leucorrhoea" and "ashstone".
The main symptom confirming the fact that cucumbers are affected by powdery mildew is a characteristic sloppy bloom - white spots on the leaves. The rash can be either whitish or light reddish.
Initially, plaque appears only on the upper sides of the leaf plates, later their lower parts are also affected. If nothing is done at this stage, then the fungal colonies will gradually populate all the green parts of the plant, right down to the shoots. The path of spread of infection begins with shoots and leaves located closer to the surface of the soil, and further upward.
Prolonged heavy rains increase the humidity of the air and soil, which stimulates the growth of colonies of harmful microorganisms. In addition to dampness, the following factors contribute to the appearance of ash:
An unfavorable factor is the annual planting of a cucumber crop in the same place. If the plants have been ill during the season, then next year it will be more expedient to prepare other beds for the cucumbers, since the causative agents of the ashtrays can remain in the soil and weeds.
There are many ways and means to treat this disease. It is important to use only strong cucumber varieties or their hybrids for planting. At the first signs of powdery mildew infection, all suspicious parts of the plant must be urgently cut off and burned.
Then the cucumber bushes can be treated with sulfur (30 g of ground sulfur per 10 m2 of planting). A solution of colloidal sulfur helps well: 30 g per bucket of water. Spraying cucumbers with a mullein is considered an effective measure. To strengthen the strength of the plant, fertilizing the soil with potassium in increased doses helps.
You can find effective chemicals in stores. Their disadvantage is toxicity and danger to human health. It is important to correctly observe the dosage indicated in the description of the drug. The following fungicides can help even in advanced cases:
Treatment is carried out by thoroughly spraying the plants according to the scheme indicated in the instructions.
In the early stages of the disease, environmentally friendly means - biofungicides - help well. These include Planriz and Fitosporin. They can be used not only during the growing season, but also to spray the fruits that have already appeared.
At home, you can independently make an inexpensive medicine for cucumbers, which is often not inferior in efficiency to the purchased one:
Without complying with comprehensive preventive measures, it is almost impossible to defeat powdery mildew forever. The following rules must be observed:
This cucumber disease is caused by the fungus Peronospora. It differs from the ash ash in the character and shade of the spots formed on the plant. With ordinary powdery mildew, the leaves look like they are sprinkled with flour. With a false rash on the foliage, they differ in color and shape. Both diseases bring enormous harm to the plant and cucumbers die without treatment.
First, light spots of a greenish-yellow hue and an oily consistency are poured on the front side of some leaves. Their shape ranges from round to triangular. If you look at the back of the leaf plates, you can see a gray-lilac bloom.
After a while, the colored plaques begin to grow and gradually transfer to all leaf plates. In this case, the color of the latter changes and acquires a brown-burgundy hue. The leaves become dry and brittle, crumble and the stems of the plant are gradually exposed.
Pathogenic organisms are able to live in the ground for up to 6 years, without showing themselves in any way. Then, for a number of reasons, they can begin to actively reproduce. Factors contributing to their spread:
This disease of cucumbers can develop with sharp and frequent jumps in ambient temperature, which can occur both during the day and at night, and contributes to the formation of dew drops on the plant. In order to protect cucumbers from this phenomenon, it is recommended to cover them overnight or provide heating.
You can treat diseased plants with a sulfuric solution. To do this, you need to dissolve 50-80 g of sulfur in water (10 l) and spray the cucumber bushes and the ground under them with the resulting drug.
Fungicides are a good help in the fight against peronosporosis:
With these means, the beds need to be processed once every 2 weeks.
The following preventive measures will help protect cucumber plantations from infection:
An important preventive measure to combat the fungus is the choice for sowing cucumber varieties that are most resistant to spore damage. These include hybrids:
After collecting cucumber seeds intended for subsequent sowing, it is recommended to soak them in a saturated solution of potassium permanganate for disinfection purposes.
The following recipes have stood the test of time and are good for their safety for humans:
Plants can be sprayed with such liquids at any time of the day and with any frequency. In the event that the cucumber bushes are already sick, then they must be processed as often as possible. At the same time, it is desirable to protect the culture from wind and drafts.
Already from the name itself it is clear which part of the plant is affected by this common ailment. Root rot can affect cucumbers at any stage of their development. It is important to react as quickly as possible to the characteristic signs of the beginning putrefactive processes.
The onset of the disease is signaled by a brown color, in which the root collar and the roots themselves are stained. In this case, the lowermost leaves turn yellow quickly, while the rest begin to wilt, especially in sunny weather. If the process occurs during the flowering period, then you can see how the flower baskets dry up and the further development of the plant stops.
As the disease progresses, the color of the root collar becomes more and more dark. The structure of the roots becomes loose, the stem is also gradually loosened at the bottom and separated from the root system. Such a plant is already doomed to perish.
Some overly caring gardeners try to water the cucumbers as often and abundantly as possible, hoping that thanks to this, the plants will develop well and bring a rich harvest. However, with a strong increase in the level of humidity, favorable conditions appear for the development of many diseases, including the formation of root rot. Other negative factors include:
Sharp temperature fluctuations during the night and daytime also contribute to the development of the disease.
The following actions help to stop rot:
If the leaves of the cucumber began to wither and there was a suspicion of the onset of root rot disease, then you need to gently free the lower part of the stems from the ground with a small spatula. It is important not to injure the roots.
Top dressing recipes:
If, despite all efforts, the cucumber bush could not be reanimated, then it must be dug up, burned, and the place where it grew should be treated with a solution of copper sulfate.
Another dangerous ailment of a fungal nature is white rot. Plants in greenhouses are most often infected. On the areas attacked by the infection, a white bloom appears, which over time begins to occupy larger areas. This is a mushroom mycelium.
Cucumber stem tissues infected with this disease become watery and soft. The process of delivering water and nutrients from the soil to the plant cells is disrupted. Over time, the mycelium darkens and thickens in some places, which indicates the beginning of the sclerocial stage. If the cucumber fruit comes into contact with the infected areas, then the rot quickly spreads to them.
The very first signs of the disease can appear with a sharp drop in air temperature, when this phenomenon is accompanied by high humidity. If the greenhouses are poorly ventilated, and the cucumber bushes are very densely planted, further progression of the process is possible.
As soon as the first signs of the development of white rot were noticed, it is necessary to stop watering the plantations and stop feeding for about 6-8 days. This will help lower the humidity.
After the specified period, cucumber bushes need to be sprayed with Topaz or Oxykh. The temperature of the solution for processing should be at least 22-24 degrees. After spraying, the greenhouse is ventilated, while it is necessary to ensure that the temperature in it is kept at around 20-25 degrees during the daytime and 18-22 at night. At night, it is recommended to additionally cover the plants with a film to prevent hypothermia of the bushes. Re-processing is done in a week.
To get rid of the disease, sprinkles made of chalk, crushed coal or ash are also used. You need to sprinkle both the earth and the fruits themselves, affected by rot. Many experienced gardeners use a composition of water, chalk and potassium permanganate to treat infected areas.
After harvesting the cucumbers, it is necessary to process the soil and the remaining bushes with a solution of copper sulfate, and after a day, carefully collect the remnants of the greenery along with the roots and burn.
Often in the country, a spider mite starts up - a small pest that causes great harm to plants. Cucumbers are attacked both outdoors and in greenhouses. Favorable conditions for the reproduction of these insects are dry air and high ambient temperatures. The appearance of an unwanted guest is signaled by the following signs:
Due to the spider mite, the photosynthesis of the plant is disrupted, as a result, the cucumber bush becomes vulnerable to various infections. Often the activity of the pest is accompanied by infection with spores of gray rot, which affects the entire ground part of the plant: the stem, leaves and fruits.
You can protect cucumbers from ticks by doing the following:
It is better to carry out the processing in the evening hours, when there is no longer a strong sun. This is necessary so that chemicals do not evaporate from the surface of the plants and destroy the pest.
Greenhouse cucumbers are more susceptible to spider mite infestations. It is important to maintain high humidity in the greenhouse within 80-85% - this will be the most reliable prevention. If the pest has already settled in the greenhouse, then you need to resort to the following measures:
One of the most effective ways to combat spider mites is the phytoseiulus mite. If this predator is placed next to the affected plants, then it begins to destroy the eggs of the spiderweb. For a more reliable result, it is recommended to add phytoseiulus every 3 weeks.
Many people reject the use of chemicals in their garden plots. In this case, you can get rid of the spider mite using the following folk recipes:
This parasite migrates to cucumbers from other plants, most often from weeds. Weed roots are a favorite wintering place for melons and gourds. Damaged plants begin to ache, their leaves curl, and flower baskets and fruit ovaries fall off. The pest literally sucks life out of the culture, simultaneously infecting it with various infections.
Aphids are activated in spring as soon as the air temperature rises above +12 degrees. This pest is very prolific. During the summer months, aphids are capable of producing up to 20 generations of offspring. If you do not fight with it, then most of the crop is doomed to perish.
It is very important not to let milkweed, plantain, shepherd's bag and other weeds grow in the garden.
Chemicals to protect plants from aphids:
These funds are used only before the formation of ovaries or after harvesting. In greenhouses, it is recommended to spray the soil and air with karbofos (2 tablespoons of the drug are diluted in a bucket of water).
Of the popular methods, the most famous is spraying and washing all parts of the plant with soapy water, sometimes ash is added to it.