Cucumbers are one of the most popular crops among our compatriots; you can find it in almost every garden plot. It happens that the leaves of cucumber bushes begin to lighten, spots appear on them. This means that the plant is sick, and if you do not take action, you can lose the entire crop.
Wrong agricultural practices
The most common reason for changing the shade of cucumber leaves is care errors. Bushes may lack useful trace elements, heat, light or moisture. Less often, the reason is the weak acidity of the soil or the wrong time for planting young seedlings in open ground. Let’s take a closer look at each of these reasons.
lack of light
After planting cucumber seedlings, whitish spots appear with a lack of light. Most often this happens in greenhouses or in open areas when a shady place has been allocated for a cucumber bed. First of all, the lower leaves turn white, if the rest do not deteriorate, you don’t have to worry. It is enough just to provide the landing area with additional lighting.
Lack of nutrients
The leaves may lighten if the plant lacks beneficial minerals. If the lower leaves turned white and began to dry, it means that the plant does not receive enough potassium and magnesium, it is necessary to do nutritious top dressing with these minerals. When, in addition to these symptoms, dark-colored veins appear on the leaves, the bush needs iron and magnesium.
With copper deficiency, lightening of the color is accompanied by drying of the edges of the leaves and tops of the plant.
Watering
Irrigation is an integral part of caring for any garden crop, and cucumbers are no exception. Excessive waterlogging or, on the contrary, lack of moisture becomes one of the common causes of light spots on the leaves. Most often, cucumber bushes cultivated in open areas suffer from a lack of moisture.
In some parts of our country, it rains heavily in summer. High humidity has the same negative effect on the plant as lack of water. Waterlogging of the root system causes it to rot, as a result, the bush does not receive enough nutrients, brightens and dries out. To cope with this problem, it is necessary to control the level of irrigation, taking into account weather factors – sometimes increase, and sometimes reduce the amount of water.
Soil acidity
Leaves of cucumbers begin to turn white in case of acidification of the soil. In soil where the pH exceeds 6-7 units, cucumber seedlings may stop developing altogether.. Therefore, before planting, it is necessary to set the parameters of the acidity of the substrate using litmus paper.
If there is no indicator at hand, you can try to determine the pH using folk methods. To do this, a little soil is placed in a container and filled with water until a slurry consistency is obtained. Then some salt is added and the reaction is observed.
If active formation of bubbles begins, then the soil is too acidic.
To reduce the level of acidity, you can use ash. To do this, you need to make a solution at the rate of 5 liters of water per 300 g of ash. The composition is thoroughly mixed and watered the future bed. Alternatively, you can add a little dolomite flour or lime.
Treatment of diseases
Various diseases are very dangerous for cucumber culture: fungal, viral and bacterial. They cause a change in the color of the leaf plate. If left untreated, they lead to the rapid withering of the entire bush and a decrease in fruiting.
White mosaic
This is a viral infection that attacks weakened and diseased plants. The causative agent makes its way into the tissues and in a matter of days gets to the roots. Such a disease is very dangerous: it repeatedly reduces the yield of cucumbers, and if left untreated, leads to the death of the plant. The development of the virus is facilitated by elevated temperature (over 25 degrees), as well as its sharp jumps during the day and night.
At the first stage of the defeat, the lashes stop growing. On young leaves, whitish spots with a light yellowish tint appear. In the course of the development of the disease, they are combined into a single large spot, the fruits lose their color and curl.
It is extremely difficult to cure pathology, it is much easier to prevent it. For this you need:
- periodically clean the area from any weeds;
- destroy the remains of plants after fruiting;
- avoid crowded landings;
- avoid sudden temperature fluctuations;
- do not irrigate the bed with cold water;
- any affected plants should be uprooted and burned as soon as possible.
Ants are carriers of the virus, so you should actively fight them.
Mučnistaâ rosa
A fungal infection that almost all vegetable crops face sooner or later. Pathology manifests itself in the form of a light plaque on the leaves, in the absence of treatment, it passes to the trunk. The disease leads to deformation of the sheet and its drying out. As a result, the entire culture quickly dies. The danger of the fungus is its rapid spread. In the absence of prompt response measures, the disease can destroy the entire cucumber garden. The pathogen is especially active at high humidity, most often it attacks the crop in June, when the air temperature is between 18 and 25 degrees.
In addition, powdery mildew often occurs with excessive application of nitrogen-containing fertilizers.
Sodium silicate is used to kill powdery mildew. Lactic acid bacteria give a good result – they are aggressive to the fungus, but at the same time they are sensitive to vegetable crops. It is best to use yogurt or kefir, it is advisable to take those that have expired.
Organic treatment also helps in the fight against powdery mildew. Experienced gardeners pour manure with cold water, leave for 3 days, then filter and dilute the resulting solution with water in a ratio of 1 to 10. This mixture is used for foliar spraying. Alternatively, you can use an infusion of herbs, such as nettle.
In stores you can buy ready-made preparations against the fungus: “Thiovit”, “Jet”, “Topaz”, as well as EC or “Hom”. The culture in open ground is sprayed with a 20% solution of colloidal sulfur, in greenhouses the concentration of the drug is increased by 2 times. At the fruiting stage, periodic treatment with a soap and soda solution will help.
Ascochitosis
One of the most serious diseases It harms not only adult bushes, but also seedlings. In addition to cucumbers, the disease can affect melon, pumpkin and watermelon.
The harm from ascochitosis does not depend on the location of the beds and external weather factors. The survival of plants is affected exclusively by their immunity – weakened plants quickly wither. Therefore, it is always easier to use preventive measures than to try to get rid of this infection.
Antraknoz
This is one of the most common diseases, it manifests itself in the clarification of leaf plates. This disease affects plants grown both in open ground and in greenhouses. Fungus spores can develop in any temperature conditions from +2 to +35. The infection affects all terrestrial parts of the plant, the incubation period is 5–8 days, depending on external conditions.
If the leaves are covered with whitish spots with a yellowish tint – landings need to be processed immediately. In the absence of treatment, the lesions merge into one large spot, and bristles appear on top. Soon the damaged areas dry and fall off.
With a large amount of infection, pathogens move to ripening fruits and form brown spots.
A 1% solution of Bordeaux fluid helps against this ailment. During processing, the aerial parts of the plant are sprayed and the substrate is shed. Alternatively, copper oxychloride or colloidal sulfur can be used. Gives good effect the preparation “Humus”, the compositions “Strobi” and “Kvadris”.
Pest Control
If the plant is properly cared for, but the leaves are still brightening, it is possible that this is due to the activity of insect pests.
spider mite
This mite is not dangerous to humans, but can cause significant damage to cucumbers.. The microscopic parasite feeds on the vital juices of plants, prevents full-fledged photosynthesis and causes a deterioration in immunity. Such plants dry out and wither very quickly. Dry weather and excessively high air temperature contribute to the development of infection.
It is impossible to notice the tick itself, the parasite is so small. Whitish traces on the leaf plates, resembling a silvery web, speak of his presence. To prevent the risk of a pest, in the spring it is recommended to treat the soil with means Ditox, Antikleshch, Akarin, Fitoverm.
To combat spider mites, it is necessary to remove the top layer of soil, and then use insectoacaricides. In previous years, insecticides were used in the fight against ticks. But as the experience of summer residents testifies, in practice this method is ineffective. Insectoacaricides are enteric-contact preparations, the frequency of their use depends on the temperature background.
The higher the temperature, the shorter the intervals between treatments should be.
Among the chemicals, Karbofos and Bitoxibacillin proved to be the best. In the early stages of the lesion, folk methods of struggle give a good effect, among them soap treatment is distinguished. Spraying damaged bushes is best done in the evening – then before the onset of the warm time of the day, the funds will have time to earn. If you do the treatment in the morning, then with the onset of heat, the active substances simply evaporate.
If possible, try to place Phytoseiulus mite near the affected area. Alternatively, you can plant herbs that attract ladybugs. These are the biological enemies of the tick, which very quickly destroy the entire styling.
greenhouse whitefly
The whitefly attacks exclusively greenhouse beds. In this case, yellow or whitish dots appear on the sheets. The danger of the pest is in the high rate of reproduction, it can destroy the entire crop in a week.
The pest will have to be collected manually, you can use sticky traps. A good effect is the use of natural insect enemies. For example, the Encarsia parasite is grown specifically to kill the whitefly. As soon as he eats it, he immediately dies. Infusions and decoctions give a good effect, if the volume of infection is large, then it makes sense to turn to insecticidal preparations.
Preventive measures
Everyone knows that the disease is always easier to prevent than to fight it. Regardless of the reason why the leaves began to lighten and fade, it is important to resort to preventive measures. This will reduce the risk of illness.
The rules are simple.
- After fruiting, recycle into compost or burn all plant residues.
- Before planting a crop in open ground or in a greenhouse area, dig up the land intended for the bed. The causative agents of fungi and pest larvae often hibernate in the ground, once in the air, they die.
- Be sure to destroy all weeds – nothing superfluous should remain on the territory.
- Throughout the growing season, regularly inspect all parts of the cucumber bushes.. At the first sign of damage – immediately remove such areas and immediately burn.
- Observe crop rotation – it is best to alternate the planting of cucumbers and tomatoes.
- Do not irrigate the plant with cold water, especially in hot weather.. Temperature fluctuations can significantly weaken the bushes.
- Buy seed exclusively from trusted manufacturers.
- Every year, treat the soil with a solution of potassium permanganate or formalin. The land in the greenhouse should be steamed.
- In the early stages of development, spray young cucumber bushes with copper sulphate, taken in a ratio of 3 g per 5 liters of water, or urea in a ratio of 5 g per 5 liters of water.
- And of course Give preference to varieties that are resistant to diseases.
