Cucumber is a very useful vegetable that favorably affects the human body. This vegetable crop fell in love with the majority of vegetable growers in many countries around the world. But cucumber is subject to the negative impact of a huge number of various infections and diseases, and therefore requires proper care, as well as timely identification and elimination of the causes of the harmful effects of the external environment. The most common symptom of spoilage of a cucumber plant is the appearance of specific white spots on the leaves. This factor signals a violation of the health of the bush and requires special measures and decisive action depending on the type of disease.
Mealy dew
Mealy dew is a fungal disease of vegetables that stimulates the appearance of mycelium on sheets. Due to the progression of the disease, the mycelium covers almost the entire surface of the leaf and forms a kind of white bloom. 
This process not only changes the shape of the leaves, but also leads to their drying, which makes it impossible for the photosynthesis process, so the plant gradually weakens. Such a disease can lead to the loss of a significant part of the crop, as well as adversely affect the further cultivation of cucumbers in the designated part of the garden.
Important! The most favorable conditions for this disease are present in early summer with a high level of humidity, a temperature of + 17 ... +21 ° C, as well as excessive use of nitrogen fertilizers.
To prevent this disease, there are a number of specialized measures:
- periodic crop rotation, which will prevent the critical accumulation of the pathogen in the soil;
- cleaning of dead components from the place of cultivation, since it is on them that the fungus reliably live through the winter;
- special disinfection after harvesting;
- maintaining a stable temperature regime above +20 ° C, as well as protection against drops by means of special means (for example, plastic film);
- ensuring the process of irrigation with exceptionally warm water;
- processing of vegetable crops with a special preparation like "Kvadris";
- compliance with the rules in the application of nitrogen fertilizers (if possible replace with potash or phosphate).
In case of manifestation of the first signs of disease on the leaves, it is necessary to resort to more drastic and immediate measures.
Read also about the fight against powdery mildew and downy mildew on cucumbers.
There are many methods to combat powdery mildew:
- spraying the plants with a mixture of skim milk or whey with water. This will help isolate the disease and prevent its further spread. Sodium silicate can also be used as a substitute;
- A good killer of the fungus is lactic acid bacteria, which, for vegetable crops, remove the fungal disease. Therefore, you can treat the leaves with kefir (can be expired), sour milk or yogurt;
- You can pour one-third of a manure bucket with cold water and set aside for three days. Next, you need to separate the liquid and dilute it with water (1:10 ratio). Spray the plant with the resulting solution. Also nettle infusion with spray application to the leaves will be no less effective;
- A great method of treating plants immediately after the disease is the use of "EDC", "Tiovit Jet". For a later stage, “CE”, “Hom” or “Topaz” are considered the most effective;
- beds on open ground can be treated with a 20% solution of colloidal sulfur, and on closed ones with a 40% solution;
- a mixture of soap and baking soda in an equal ratio by weight will help get rid of powdery mildew with periodic processing every 5-6 days;
- an active remedy against this disease is also an infusion of weeds. They need to be finely chopped, add water, provide a place to settle for several days, after which the resulting liquid to process cucumbers.
Gardeners who do not want to use chemicals on their property can try to treat the plants with folk remedies and pharmaceutical preparations.
Video: folk remedies for powdery mildew
Spider mite
The spider mite does not harm humans, but it is a very dangerous phenomenon for cucumbers, as it not only interferes with normal photosynthesis, but also greatly reduces the plant's immunity against other infections. Tick-borne vegetable quickly begins to dry out and perishes. Also, this malicious element can cause spores of gray mold, which negatively affects the lower part of cucumbers (shoots, fruits and leaves).
Learn more about spider mites: types of spider mites, the best means of dealing with pests, how to get rid of spider mites on cucumbers.
The pest multiplies most intensively with significant temperature indicators and a dry climate. It is almost impossible to completely protect a plant from this disease, since spores are easily carried by the wind. The right decision would be to conduct all the preventive agrotechnical preventive measures. 
Signs of plant damage by this disease are:
- white spots on the back of the leaves;
- specific web on vegetable culture;
- slow vegetative maturation;
- yellowish leaves.
When planting cucumbers in an open area exists special set of measures to prevent the spread of spider mites to the maximum:
- after harvesting, it is necessary to destroy all parts of the plant;
- it is necessary to dig up the land area intended for planting cucumbers, since pests are waiting for the winter precisely in the upper layers of the soil;
- necessary food in the winter period the pest receives from the weeds, so they should be removed from the soil as much as possible;
- during the ripening of the vegetable culture, it is important to periodically carefully examine the elements of the plant and, when identifying affected leaves, immediately remove and destroy them (burn or bury);
- the alternation of planting cucumbers with tomatoes or cabbage will be useful;
- It is also necessary to treat the foci of infection with specialized biopreparations.
If cucumber growing takes place under greenhouse conditions, the risk of spider mites increases many times over, since excellent conditions are created for their comfortable stay and breeding: high temperature and relatively low humidity.
Learn how to deal with the withering of cucumbers and cure cucumbers in the greenhouse.
The most effective measure to combat these pests in the greenhouse is to increase the moisture level to 75-85%.
It is also necessary to produce fumigated sealed greenhouse after harvesting and before sowing. The top layer of soil must be removed, and the tapestry must be burned with a special device (for example, a gas heater). An effective method of prevention is the use of phosphate fertilizers.
Important! The main method of pest control - treatment with insecticides - is not effective against spider mites.
There are many tools for removing pests from vegetables. The most effective are considered insectoacaricides, but there are no spray systems safe for human health in the open area, therefore, they actively use the means of enteric contact. The frequency of use of these drugs is directly dependent on the temperature regime (the higher the temperature readings, the shorter the interval between sprays). These chemicals include Karbofos, Bitoxibacillin and others. It is recommended to process the plants with these preparations in the evening, so that the chemical elements do not evaporate immediately and have time to act on the affected areas. 
Phytoseiulus mite is considered the safest method of fighting against spider mites, which is located near the affected plant centers. This predator destroys the eggs of the pest, which contributes to its extermination. Planting phytoseiulus is recommended at intervals of three weeks.
Tips for gardeners: how to deal with diseases of cucumbers; folk remedies for diseases and pests of cucumbers.
There are also a variety of folk methods of exterminating the pest:
- treatment with soapy water;
- spread on the site of the mushroom entomoftor;
- planting dill, attracting ladybirds, which will help to quickly overcome the spider mite.
Video: fight with spider mite on cucumbers
White mosaic
White mosaic is quite common viral diseasewhich progresses most often on diseased or damaged plants. The virus penetrates the vegetable culture through damaged tissues and is directed to the roots. This type of infectious disease is very dangerous for cucumbers, as it significantly reduces the amount of the crop, and also reduces its quality characteristics. 
The reasons for the defeat of the culture of this infectious disease can be high temperature indicators (over +25 ° C) and its significant differences in the night and day periods.
Did you know? Once the cucumber was an extraordinary delicacy, so the very cruel and greedy Turkish Sultan Mahomet the Second opened the stomachs of seven of his servants when he learned that one of them had eaten a vegetable sent to him.
The most simple signs of detection of this disease are specific changes in plant appearance:
- the development of lashes decreases rapidly;
- on the formed young leaves, small white spots with a yellowish tinge appear, which, as the disease progresses, merge into one white spot with green veins;
- The fruit of the plant has a non-standard deformed shape and an unnatural color depending on the stage of the disease.
There are many methods to combat the disease, but only their precise implementation and attentiveness of the vegetable grower will help to avoid the deplorable consequences and cure the plants. It is worth noting that transplanting or processing fungicides is not an effective way of getting rid of white mosaic, but the most effective measures are considered:
- periodic removal of weeds as the most productive vector of infection;
- buying seeds exclusively from verified vendors, as the plant from which they are taken should not be contaminated (seeds should be stored for three years after harvest);
- all residues of vegetable crops after harvest must be destroyed;
- close planting is also contraindicated;
- if possible, avoid watering cucumbers with cold water to avoid sudden changes in temperature;
- infected plants must be removed immediately from the site;
- carry out a full range of measures to prevent the appearance of aphids;
- disinfect healthy cucumbers and all summer cottage equipment.
We recommend reading about weed control: biological groups and a list of common weeds; methods of struggle and folk remedies.
Video: fighting mosaic on cucumbers
Aphid
One of the main enemies of cucumbers is aphid, which you have to start fighting in greenhouses in spring, and on open ground from mid-summer. This pest feeds on the plant's specific cell sap. The very process of consumption of the product is accompanied by the piercing of tissues and the injection of poison, which provokes the twisting of the leaves. In the leaves of this form, the insect breeds, and also hides from birds and other enemy insects, preserving its population. Aphil spreads quickly enough on all elements of the plant (ovaries, flowers, shoots).
Important! If aphids are detected, preventive measures should be taken as soon as possible, since this pest can quickly destroy a significant part of the vegetable crop and leave the vegetable grower without a crop. Experts say that if it were not for the natural "enemies" of this insect, then there would not be a single plant on the planet, since this pest is omnivorous.
Ants that feed on the sweet syrup that these pests emit are brought to the new sites of the aphids. Therefore, the main preventive action should be the extermination of ant colonies in the vicinity of the site of cultivation of vegetable culture. 
There is also a full complex of preventive measures to minimize any negative effects of aphids on cucumbers:
- it is necessary to select the most resistant varieties of crops for cultivation;
- in greenhouses it is necessary to secure the ventilation holes as much as possible (tighten it with gauze or any other fine mesh material);
- on open soil, covering plants with a nonwoven web will be an effective measure.
To combat the already spread insects can be used as a means of national origin, as well as products of modern agrotechnical industry.
Read also about the fight against aphids folk remedies, protecting cucumbers from aphids.
Among the popular methods of opposing the body there is a specific method of treating plants with tincture of tobacco. This method is best suited for ornamental plants, but not for cucumbers, which are intended for human consumption. 
Of the most suitable folk methods worth noting cooking profile compounds from:
- potato tops;
- celandine;
- garlic;
- onion peel;
- wood ash;
- dandelion;
- sorrel.
Learn more about making tobacco dust, potato and tomato tops.
For multiple enhancement of the positive effect in the composition also need to add a solution of laundry soap. The lower surfaces of the leaves of plants should be processed most carefully once a week until the insects are completely exterminated.
Important! It is necessary to strictly observe the concentration of the infusion, since busting can not only exterminate insects, but also burn the plant itself, and also destroy the natural enemies of aphids, whose population recovers much more slowly than aphids.
Also good service in the fight against these pests can have modern consumer products:
- vodka showed excellent efficacy when sprayed on infected plants, but the method has a huge minus - the price;
- Coca-Cola includes a specific component - orthophosphoric acid. This element very quickly kills all parasitic animals in vegetable crops with proper spraying;
- essential oil and soda in a ratio of 70 g of baking soda to 15 drops of oil and 2 liters of water. It is necessary to spray the culture with such a mixture once a day for three days, which guarantees complete destruction of insects.
It is worth paying special attention to the rules for the use of solutions. To test the effectiveness, it is better to process a small part of the vegetable garden and see the results, and only after that splash the entire planting area. Processing can also be carried out at the stage of ripening of fruits, but no later than 40 days before harvesting.
Find out why the ovaries and leaves of cucumbers turn yellow.
From the list of insecticides, Kinmiks, Inta-vir and Arrivo are most suitable, and from the chemicals - Fitoverm, Aktofit and other analogues. These drugs are quite toxic, so it is recommended to apply them no later than three weeks before the appearance of the ovary.
Also, phosphate and potash fertilizers will help to overcome aphids, which should be added once a week. The solution is created by adding 18-20 g of superphosphate and 8-10 g of potassium chloride per 10 liters of water.
Video: ways to deal with aphids on cucumbers
White rot
White rot is a common fungal disease of greenhouse plants that affects all parts of the crop, including the stem, leaves and fruits. Favorable conditions for the development of the sclerotia fungus are high humidity and a sharp decrease in temperature indicators of the external environment. Also, the disease shows a greater intensity during dense planting and irregular ventilation of the greenhouse. The slightest spore of the fungus, caught in the wound of vegetables, leads to infection of the plant. 
Signs of white rot differ depending on the stage of infection:
- at the initial stage, wet spots are formed, which relatively quickly rise up from the roots;
- then on the spot of the spots a peculiar growth is formed - a mycelium (visually resembling cotton wool);
- then mucus is formed from this cotton, which drips from the leaves of the affected plant to other bushes;
- then the mycelium becomes more dense and creates specific sclerotia;
- after this, the complete destruction of the vegetable culture takes place.
Important! Sclerotinia can have a negative impact on different stages of ripening of a crop, starting from germination and ending with the fruiting stage.
White rot gets into the soil with bulk soil, water or through garden tools. Infection occurs through mycelium, which is spread by air and mechanical routes. 
To the death of cucumbers causes rotting of the roots and stems. Also drying shoots significantly reduces the yield of the plant. Therefore, it is necessary to eliminate the disease immediately after identifying the first signs (preferably on a windless day with normal humidity). Для начала необходимо прекратить полив и удобрение пораженных растений для снижения влажности. Саму инфекцию нужно лечить теплым раствором "Топаза" или "Оксихомом" при нормальной температуре.
There is also a popular method using whey diluted in water (3: 7 ratio). To improve the effect on 10 liters of solution, you must add a teaspoon copper sulphate.
Learn more about the use of blue vitriol: use in horticulture, harm and consequences of copper sulfate poisoning.
If the infection struck a small part of the plant, then it is necessary to carry out next set of measures:
- apply a solution of chalk, potassium permanganate and water to the affected parts;
- to separate and destroy the affected areas (it is important to seize some healthy tissue when separating to minimize the likelihood of re-infection);
- process the cut with lime or coal to accelerate the regeneration process;
- then it is necessary to produce foliar fertilizer with a solution of urea (10 g), zinc (1 g), copper sulphate (2 g) in 10 liters of water. This will help strengthen the protective functions of the plant;
- to ensure normal maturation conditions for the bush: + 17 ... +19 ° С, periodic airing and less frequent watering.
With a strong infection of the bush (when white rot has absorbed almost the entire plant), the treatment does not make any sense, so it is necessary to remove the plant and nearby soil in order to save neighboring cultures.
Preventive procedures include the standard components of the system: treatment of the soil before planting, ensuring normal distance between plants, removal of residues after harvest. The specific measures for this type of disease are considered to be regular airing, maintaining the normal level of air humidity, as well as a one-time treatment of the bushes with a 0.01% planriz solution.
Video: prevention and control of white rot
Greenhouse whitefly
The greenhouse whitefly is a fairly dangerous pest for cucumbers that lives in protected greenhouses. This parasite reproduces rapidly, especially if the appropriate plant protection measures are not followed, this insect occupies the entire greenhouse structure. An adult representative of the greenhouse whitefly is characterized by the presence of a yellowish body in sizes from 0.9 to 1.5 mm. 
The wings of the insect are white, rough, able to fold as one. Whiteflies have light brown antennae. The larvae of this insect grow up to 0.8 mm long, have a oblong-rounded shape, yellow-green shade and reddish eyes. Each of the females of the greenhouse whitefly is capable of producing more than a hundred eggs, the development of embryos in which varies from a week to two, which depends on the temperature regime in the environment.
Did you know? From the fertilized eggs, both males and females appear in a 1: 1 ratio, but the higher the air temperature, the greater the number of males. Of unfertilized eggs, only males are produced.
The life cycle of an insect is characterized by the presence of six stages, starting with the egg, four stages of the larva and imago. From the egg stage to the next stage, it takes from 20 to 40 days, which directly depends on the temperature (optimal indicators - + 21 ... +27 degrees above zero) and air humidity (from 60 to 75%). In one season, the development of ten and more generations of whiteflies can take place.
We advise you to read about the methods of cucumber pest control.
Greenhouse whiteflies prefer placing in groups of several dozen individuals on the underside of the leaf, forming a figure similar to a ring. Adult whiteflies, like their larvae, feed on sap of selected plants, which do not allow it to develop normally. After that, the insects secrete a sugary liquid with a sweet taste, which is the cause of the appearance of fungal diseases (black fungus) on the foliage of the plants, which further aggravate the damage to the vegetable crop. 
In case of serious damage the leaves become almost black from plaque and twisted, gradually drying out, because this black plaque prevents photosynthesis. The culture begins the process of the disease, the number of fruits becomes less and less, and the resulting harvest is minimal. First, the leaves are damaged at the top, after which the whitefly is moved down along the entire stem of the crop, falling on the neighboring plants and adapting there. In the summer, however, it switches to vegetable crops and weeds in open areas.
Important! The greenhouse whitefly has been characterized by the greatest degree of activity since the second half of summer and autumn. In many ways, the life activity of the pest depends on the plant on which it was occupied: it is maximally on eggplants (35 days or more), and minimally (4 days) on pepper.
Hothouse whitefly can settle on more than 200 species of cultivated plants, but especially it is dangerous for cucumbers and tomatoes. To avoid the appearance of the greenhouse whitefly on crops, it is necessary to take precautions, carry out prophylactic treatment:
- the ventilation openings of greenhouses are recommended to close with mosquito nets;
- Before planting vegetables in a greenhouse, weeds should be completely removed and done with constant regularity and beyond;
- process cultures constantly with a solution of household soap;
- it is recommended to maintain a mode that is not high in temperature in the greenhouse (the pest likes heat and heat);
- You can mulch the soil by adding foil to scare the whitefly, but this method is suitable for low crops.
Such preventive measures are not always effective, and they begin to appear. signs of the presence of the greenhouse whitefly:
- yellowish spots appear on the leaves with outlined borders, which gradually increase in size;
- leaves and shoots are twisted, then completely dry;
- on the top of the leaves there is a raid with a pronounced brilliance;
- a fungal infection develops, later on blacks affect the fruits themselves.
Learn what to do with midges on cucumbers.
After identifying such signs will have to apply whitefly fighting methods:
- Mechanical control methods (picking visible pests by hand, discharging with a stream of water, treating crops with a solution of laundry soap) do not differ with an absolute guarantee, since pests can again get to the crops, however, it will become easier for plants for a while. The mechanical methods include the manufacture of sticky traps from yellow or blue paper treated with a solution of castor oil, petroleum jelly, rosin, honey.
- Biological methods of control: parasite enkarsia, which is specially grown to fight whitefly and dies as soon as it eats it all; natural decoctions, infusions (the first option - 1 head garlic pour half a liter of water, leave for a week, then dilute with water in a proportion of 5 g of infusion per liter of water and process all plants; the second option - 80 g of yarrow leaves pour a liter of water, insist two days, strain, spray on culture);
- Chemical control methods (the use of insecticidal agents in extreme cases with significant damage to crops greenhouse whitefly).
Video: fighting with the whitefly
Treatment of cucumber diseases: reviews
Cucumber cultivation is a fairly simple process if it is treated responsibly, carefully, and also if all preventive measures are carried out at strict intervals. With this approach, the plant will thank the magnificent harvest of delicious, beautiful and healthy cucumbers, and the soil will remain clean and fertile.
