Why do cucumber leaves develop a coating or white spots, and what can be done to treat them?

White spots appearing on cucumber leaves indicate a plant infestation with viruses, fungi, or pests. This is a common thought for all gardeners who encounter this phenomenon. However, it's not always associated with diseases or pests. To understand what you're dealing with, it's important to learn to recognize the symptoms of a particular disease.

Why do white spots appear on cucumber leaves?

Every gardener dreams of a bountiful harvest at the end of the season. But all their plans can change when the plant's leaves and stems become covered in white spots.

If you notice a white coating on cucumber leaves, it means the crop has been attacked by parasites that cause various diseases:

• powdery mildew;
• mosaic;
• white rot;
• anthracnose;
• Ascochytosis;
• spider mite.

The sooner a disease is recognized, the sooner treatment can begin. This increases the chances of saving most of the harvest. Otherwise, the crops will have to be destroyed. Even indoors, vegetables are vulnerable to microorganisms that can cause disease.

Powdery mildew

The parasites that cause the disease survive only if they can survive within cucumber tissue. While parasitizing, the microorganisms create mycelium on the surface of the leaves. They penetrate deep into the cells and thus survive undisturbed throughout the plant's growing season. Microorganism particles are then carried throughout the area by insects and wind.

Powdery mildew is characterized by the formation of a white coating that quickly covers the entire plant. This damages shoots and young branches, resulting in crop losses.

Getting rid of powdery mildew is possible. The first step is identifying the disease. Then, take action to eliminate it.

Cucumber mosaic

The main symptom of the disease is the appearance of star-shaped spots. In advanced stages, the leaf turns white. The normally green veins are rarely visible. Plants affected by mosaic stop bearing fruit.

Fruit may form during the disease, but they appear diseased. They are small and covered with numerous bumps. The cucumbers become covered with white and yellow stripes. Mosaic disease affects cucumbers grown in greenhouses.

White rot

Gardeners encounter this pathology when conditions are favorable for the development of the disease. Fungi are the cause of its appearance. white rot on cucumbersThey overwinter in the soil and begin to actively reproduce when the air and soil humidity increases.

At the onset of the disease, individual parts of the plant become covered with white bodies. Over time, these bodies change color and turn black. After some time, the stems, fruits, and leaves become covered with a solid white coating. Under the influence of the fungus, parts of the plant soften and rot. White rot is also known as sclerotinia.

Ascochytosis

White spots on cucumbers are often caused by ascochyta blight. Cracks in the leaves are visible beneath the white coating. This characteristic distinguishes ascochyta blight from other diseases with similar symptoms.

The color of the lesions doesn't remain white but changes over time. They can become brown. Ascochyta blight develops due to increased air humidity. Cucumbers should not be eaten fresh or pickled, as the spores penetrate the flesh.

Anthracnose

With anthracnose, white spots appear not only on the leaves but also on the stems, and later spread to the green fruit. Initially, the spots are white, but then gradually turn brown. The fruit becomes covered with pits of the same color.

If anthracnose is detected on a crop, it means the person planted it using poor-quality seeds. However, this doesn't mean the seeds are off limits, and the only option is to let them go to waste. Planting material must undergo a disinfection procedure. Otherwise, you'll waste a lot of time and effort, but won't get a harvest.

Spider mite

Due to its small size, the insect is difficult to spot immediately; it resembles a dot. This, in turn, delays treatment. The mite lives on the underside of leaves, spinning a web. Gardeners notice the plant's appearance when the leaves become covered in light spots.

They are practically white, and a web is visible between the stem and petiole. The leaf dries up and falls off. Cucumbers are susceptible to mites in hot weather with low humidity. The air is typically dry at this time.

First steps when white spots are detected

There are the following methods that help fight diseases:

• chemicals;
• traditional medicine.

Typically, treatment begins with the use of available means. If the disease is in a severe stage, chemical treatment is chosen. In some cases, both methods are used simultaneously.

Chemicals

These are considered the most popular method for combating cucumber diseases. Their advantage is that each is designed for a specific disease. They act quickly and kill pests immediately. They can also be used in greenhouses.

Cucumber mosaic and spider mite

Spraying with Fitoverm and Akarin is effective against spider mites. Aktara or Actellic will help stop the rapid development of cucumber mosaic. These products are applied not only to the plants but also to all tools.

Anthracnose and ascochyta blight

The well-known Bordeaux mixture eliminates diseases in their early stages. The product won't help if the diseases persist on crops for a long time. In this case, the only solution is to destroy the crop on the land; these are extreme measures.

Powdery mildew

Affected plants are sprayed once a week with a solution of copper sulfate and soap. Alternatively, the plant can be treated with a prepared colloidal sulfur solution. Both options are effective.

White rot

Controlling this disease is more like fertilizing cucumbers. To prepare a mixture, you'll need copper sulfate, zinc sulfate, and urea. The ingredients are diluted with water and applied to the plants.

Folk remedies

When white spots appear on cucumbers, chemical treatments aren't always an option. Most people turn to traditional, safer methods. When white spots are discovered, removing the affected parts of the plant is the first step in combating the disease.

Weeds are removed along with leaves, shoots and fruits, as the pathogen likes to hide on them.

To prepare a spray solution, use milk, whey, and potassium permanganate. Spraying is done using individual components. A "cocktail" can also be prepared using these ingredients.

Prevention of diseases and pests of cucumbers

Medications and folk remedies are good, but the best solution is to prevent the disease from progressing. These are preventative measures that don't require as much effort and resources as other treatment methods.

Rules that gardeners follow:

1. The beds are regularly inspected for weeds.
2. When planting cucumbers, maintain the proper spacing to ensure air circulation. This is especially important in greenhouses.
3. The bushes are watered with warm water.
4. After carrying out excavation work, equipment is thoroughly treated with disinfectants.
5. Crop rotation is practiced. Cucumbers should not be planted in the same spot every season.
6. Mulching procedures are regularly carried out in open ground.
7. The top layer of soil is disinfected by pouring boiling water over it.

The development of diseases can be prevented by creating optimal conditions for the crop. By carefully monitoring the growth and development of cucumber seedlings, pathologies are stopped at early stages. And the last valuable piece of advice is to carefully carry out preventative measures and feed the crop.