When specific white spots appear on the leaves of the cucumber, it means that the plant is spoiled, and the fruits can no longer be used for food. This phenomenon signals the damage to a healthy plant, and forces summer residents to take measures to solve the problem.
Wrong agricultural technology
The first thing that can cause an ailment is improper care. Plants may lack the sun, heat, and beneficial components. Sometimes the reason is the weak acidity of the soil or the wrong time for planting seedlings in open ground.
Lack of light
After transplanting seedlings into the soil, white spots may appear due to the small amount of light. In almost all cases, this reason occurs in greenhouses or greenhouses, but sometimes in open ground, especially if the area allocated for growing cucumbers is shady.
Due to lack of lighting, the lower sheets begin to whiten. If the rest do not deteriorate in this way, then do not worry, just put on additional lighting. Cucumbers are dense plants, so the upper leaves have time to be saturated with lighting, and the light reaches the lower leaves weakly.
The cause of the appearance of white spots on the leaves may be the absence or partial lack of all necessary components. This is very rare.
When the bush becomes lighter and the lower sheets dry, this means a lack of magnesium and potassium, so make these components as soon as possible. If, in addition to these signs, the sheets are covered with dark veins, then the bush needs manganese with iron. In the absence of copper, the upper foliage brightens and dries.
In this case, it all depends on the climate in the region where the cucumbers grow. If to summarize all the possible options, then planting this culture is better in mid-April. If you do this earlier, then the seeds may simply not sprout, and the sprouts will freeze and will not grow.
Pay attention to weather forecasts, if there are still frosts, then you do not need to rush to plant the plants in the soil.
Watering is very important in caring for cucumbers. Sometimes a large amount of moisture, or, conversely, a small amount, causes the appearance of white spots on the leaves. Often, plants growing in open soil are affected, since it is there that it is difficult to fully control watering.
In the summertime in some regions of the country too much rain falls, so the cucumbers turn white. Increased humidity negatively affects the state of the root system of the bushes, as a result, the root rots, and the plants themselves gradually die.
The absence or partial lack of water also leads to this problem. Foliage dries and turns white. To get rid of this problem, you should regularly monitor watering: reduce the amount of water, and sometimes increase it. More information about the rules and methods of watering cucumbers, we talked about earlier .
The leaves of cucumbers also turn white due to the increased acidity of the soil. In such a land, culture may completely stop developing. It is necessary to exclude this option or confirm it; for this, independently check the acidity of the earth.
Take a little soil and place it in a container, fill it with distilled water until a sour cream is obtained, add 1 tsp. soda. If bubbles begin to appear and hiss appears, the soil is too acidic.
Use ash to lower acidity. Take 5 g of ash in 5 liters of water and mix the ingredients. With this solution, fill the planting recesses in the process of planting seedlings of cucumbers.
Even perennials grow old, and cucumbers are no exception. During this process, photosynthesis slows down, the sheets begin to dry, white spots appear on them.
However, the natural aging of the culture occurs after harvest. If the plant began to dry earlier, then the reason is not aging.
Diseases and Pests
When the care is carried out correctly, but characteristic damage still occurs on the foliage, it means that the reason is the development of an infection.
Powdery mildew is a disease of fungal origin, it occurs on almost all vegetable plants. The disease progresses in the form of white plaque. This phenomenon not only changes the shape of the leaf, but also leads to its drying, as a result of which the plant dies.
The disease destroys more than one bush, the fungus spreads over all plantings. You can get rid of the disease, but it is difficult to do.
Causes of occurrence: high humidity, especially in June, air temperature + 18 ... + 22 degrees Celsius, too much fertilizing with nitrogen.
Powdery Mildew Prevention:
- Stick to crop rotation; it will help prevent the fungus from retaining in the soil.
- Clean the area regularly from weeds and debris.
- Treat the plot after harvesting.
- Maintain a temperature of +20 degrees Celsius, protect plants from temperature extremes.
- Water the plants only with warm water.
- Treat the bushes with special tools, Quadrice has proven its worth.
- Do not overdo it with nitrogen top dressing.
If you see obvious symptoms of this disease on a plant, then you should turn to radical measures.
Methods of controlling powdery mildew:
- Spray the bushes with a solution of back. Such a tool will remove the disease and prevent its spread. Treat bushes with sodium silicate.
- Use lactic acid bacteria, they carefully treat cucumbers, but are merciless to the fungus. You can use kefir (preferably even one whose expiration date has expired) or yogurt.
- Pour the manure with cold water, leave for 3 days. Separate the solution and dilute with water (1:10). With this mixture, spray the bushes. Use herbs, for example, defend nettles.
- Special tools: Tiovit, Jet, VDG, Topaz, CE, Hom. Treat plants in open soil with a solution of colloidal sulfur 20%, in greenhouses 40%. Regular treatment with a mixture of soap and soda (1: 1) will help.
- Try to treat the bushes with infusion of weed grass. Grind, fill with water, leave for fermentation for 2 days, and can be used for spraying.
Do not immediately take on chemicals, try first folk remedies, in most cases they bring a positive result.
This viral disease begins to manifest itself already on sick and weakened plants. The disease penetrates the plant and reaches the root system. White mosaic is very dangerous, because it significantly reduces the yield of cucumbers, and then leads to the death of plants.
The causes of the disease: too high a temperature (above +25 degrees Celsius), its sharp drops both day and night.
Symptoms: obvious changes in plants, wattle stops developing, white spots with a yellow tint appear on young leaves, damage merges into a large spot as the disease progresses, cucumbers become deformed and lose their color.
Gardeners have come up with many ways to treat this disease, but they all need consistent actions and the care of the farmer.
Prevention and control methods:
- Regularly remove weed from the area.
- Purchase planting material only from experienced sellers.
- After harvesting, destroy all plant residues.
- Do not plant bushes too close together.
- Do not water plants with cold water and do not allow sudden changes in temperature. Tear infected bushes along with the root and burn.
- Carry out all the necessary steps to kill the aphids, as it is considered the carrier of the disease. Treat all healthy plants.
The spider mite is not afraid of people, but it does harm to cucumbers, as it significantly reduces immunity and prevents photosynthesis from plants. Affected bushes dry quickly and die.
Reasons: too high air temperature and dry weather. To prevent the appearance of a spider mite, it is necessary to carry out all preventive and treatment measures in advance (if a spider web was observed on plants last year, then it is necessary to spray this spring with the following preparations: Ditox, Antikleshch, Akarin, Fitoverm, etc.).
Symptoms of the disease: the appearance of white spots on the back of the foliage, the appearance of cobwebs on the plant, a slowed growing season, a yellow shade of leaves.
- After harvesting, burn or recycle all parts of the bushes.
- Before planting, dig a plot intended for growing cucumbers because pests hibernate in the ground. Pull out all the weedy grass, do not leave anything superfluous in the territory.
- At all stages of growth and development of this vegetable crop, inspect all parts of the bushes, if infected areas are found, immediately remove them and burn them.
- Alternate planting cucumbers with tomatoes. Treat infected plants with special tools.
If the spider mite appeared in the greenhouse, then the risk of infection of all plants increases at times, because all the best conditions for its distribution and development are created here: high air temperature and low humidity.
Ways to combat the spider mite:
- Remove the top layer of the earth and make firing of a trellis.
- Use insectoacaricides. In fact, the main insecticide treatment method does not work in practice. Insecto-acaricides are considered to be the most effective, but there are no safe spraying options for the person himself, so gardeners often use substances of intestinal contact. They are used depending on the temperature (the higher it is, the less intervals between procedures are made).
- Place the phytoseyulyus tick near the infected areas, it will quickly destroy the eggs of the pests. It should be planted 1 time in 3 weeks.
- Use folk methods: processing with soap, planting herbs that attract ladybugs, which can easily destroy this pest.
Best chemicals: Karbofos and Bitoxibacillin. Spend processing in the evening, so that the funds do not evaporate, but have time to earn.
This disease is extremely dangerous, it causes harm not only to adults, but to young bushes of cucumbers. In addition to this culture, the disease affects pumpkin, watermelon and melon. It does not matter where the cucumbers grow, the harm from azcositosis is the same. Plants with weak immunity quickly die, therefore it is better to prevent azcositosis than to try to get rid of it later.
Signs: bright spots appear on the leaves, which then fill the entire foliage. Black spots appear on the affected areas - fungi and spores. Small white-brown spots appear on the root system and neck of the root, with repeated damage, gum is released. Cucumbers change color and mummify; they can also be covered with a dense grid of black blotches.
The disease is most active during the fruiting season. Appears due to the large amount of organic residues, is carried by the wind, and may also already be in the seeds of cucumber. After the defeat, the fruits are no longer suitable for food, plants are very difficult to cure, and sometimes completely impossible.
Prevention and control methods:
- Do not pour cold water, do not allow temperature fluctuations.
- Use grains only from trusted manufacturers.
- Steam and treat the soil with a solution of potassium permanganate or formalin annually.
- Spray the plants with Bordeaux liquid (1%), vitriol (3 g per 5 l of water) and urea (5 g per 5 l of water).
- Grow disease-resistant varieties.
It is considered one of the most common and dangerous ailments; anthracnose affects a crop in a greenhouse and in open ground. Fungal spores develop at any temperature (from +3 to +33 degrees). The disease affects all the terrestrial parts of the culture. Seedlings affected by the disease quickly die. The incubation period is approximately 7 days, it all depends on the conditions.
The main symptoms: white spots appear on the leaves, they may be yellow, during development they merge into one large spot, brown bristles appear on top, the affected areas often flow. With a large-scale damage to the plant, large brown spots are formed on the fruits.
Methods of struggle:
- Pour a solution of Bordeaux fluid (1%) or Abig-Peak solution (0.5%) under the root.
- Moisten the soil well before applying.
- If the first treatment does not help, then carry it out several more times.
- Treat infected leaves with copper oxychloride or polyram.
- Use such remedies: colloidal sulfur, Cumus, Strobi and Quadris.
Whitefly only affects greenhouse cucumbers. White or yellow spots of a dotted character appear on the leaves. The pest breeds very quickly, especially without following proper crop care measures. An adult insect is characterized by the presence of a yellow body with sizes from 1 to 1.5 mm. The wings of the insect are white, with a rough surface, can be folded into one.
The insect has light antennae 0.7 mm long. One female can bring more than 100 eggs, the embryo develops in about 2 weeks. Only in 1 season can more than 10 generations appear. Insects are grouped and placed on the underside of the leaf, feed on plant sap, which does not allow the culture to fully develop.
- Close ventilation openings in greenhouses with nets.
- Before planting sprouts of cucumbers, clean the soil in the greenhouse, remove all weed grass.
- Maintain a low temperature in the greenhouse.
- Mulch the soil, also add foil that repels the insect.
Methods of struggle:
- Collect pests manually, use sticky traps.
- Plant the parasite with enkarzia, it is specially grown to fight whiteflies, as soon as it is eaten it dies.
- Try using decoctions and infusions, if they do not help, turn to chemical preparations.
Any ailments and diseases are better to prevent in advance than to get rid of them. Therefore, follow the main preventive measures for the protection of cucumbers:
- If you have been buying cucumbers of one variety for a long time, and there are constantly problems with growing a crop, then replace the manufacturer or change the variety.
- Follow all crop rotation rules; they can be planted at the same place of planting of cucumbers only after 3 years. If this is not possible, then add fertile soil annually.
- After collecting the fruit, completely clear the soil of plant debris; if there are infected bushes, burn them.
- Regularly spray the plants with herbal infusions or with Fisporin M or Charm.
- Maintain a healthy microclimate in the greenhouse, avoid temperature extremes, winds and high humidity.
- Ventilate the greenhouse regularly. Open it as early as possible so that the air does not get warmer under the film, otherwise, due to the temperature difference, the effect of a little wind will occur.
- Water the bushes early in the morning or evening. Regularly inspect the bushes for sick, yellow leaves with white lesions on the surface.
On the causes of white leaves in cucumbers and methods of treating the plant, see the following video:
The appearance of white spots on the leaves of this culture is a clear sign of its damage. This factor signals the poor health of the plant, it requires treatment and further preventive measures, otherwise the consequences can destroy the plant.