Causes of the appearance of spots on the leaves of cucumbers and their treatment

Cucumbers - one of the most popular vegetable crops, which is cultivated by every summer resident. It happens that spots appear on the leaves. We will tell you about the causes of such an ailment and measures of struggle in our article.

If the leaf plates of cucumber seedlings are covered with brown spots, which are associated with deformation and drying of the leaves, this may indicate a deficiency of useful trace elements. For active growth and development in the early stages of the growing season, cucumbers need a lot of nitrogen, it speeds up metabolism in tissues and stimulates active growth of green mass. Then phosphorus, potassium, and magnesium come to the fore. They contribute to the correct formation and rapid ripening of fruits.

With a lack of potassium, the appearance of cucumber seedlings practically does not differ from the usual state... Only the tips of the leaf plates indicate the problem, they acquire a slightly noticeable brown tint and begin to curl. Magnesium deficiency manifests itself more obviously - red spots spread over the surface of the entire leaf in the direction from the center, moving along the veins. As soon as you notice that the plant lacks minerals, be sure to apply specialized feeding.

The formation of spots on the leaves can be a sign of fungal infections.

• Downy mildew - when affected by this fungus, the upper part of the leaves begins to turn yellow and becomes covered with reddish spots in the form of an irregular square. A whitish bloom is visible on the back of the leaf. In the absence of treatment, the shoots become thinner, lose their tone, the ovaries fall off, and the formation of fruits is suspended.
• Copperhead - better known as anthracnose, this parasite develops on all green parts of the plant. The first symptoms of the disease are yellow spots on the back of the leaf plates. The damaged areas are quite large, up to 3-4 cm in diameter. Soon they begin to exfoliate and crumble, so the leaf looks like it is perforated.
• Cladosporium - the causative agent of this disease usually affects greenhouse plants. In the early stages of infection, dotted blotches of a yellowish tint appear on the leaves. As the disease progresses, they increase in size and merge into large spots.
• Alternaria - with the appearance of this ailment, dry, slightly convex spots appear on the lower part of the leaves. Greenhouse plants are also more likely to encounter this disease.

Viruses, such as cucumber mosaic, are more dangerous - this disease leads to the destruction of chloroplasts. The first sign of infection is dots-specks over the entire area of ​​the leaf plate. They gradually increase in size and transform into stains.

Biological products are harmless, they do not accumulate in fruits and decompose very quickly. Effective remedies against fungal spores include:

• "Alirin";
• "Gamair";
• "Gaupsin";
• Trichodermin;
• Fitolavin;
• Fitosporin.

To achieve maximum results, it is necessary to start spraying and treating the soil immediately after the very first spots appear, even small ones. However, it should be borne in mind that biological agents work only in dry, warm weather. Therefore, the processing must be carried out at least 2-3 times.

With a massive defeat, biological products may not cope with the disease... In this case, it is better to give preference to chemicals:

• 1% bordeaux liquid;
• copper sulfate;
• "Ditan";
• Ridomil;
• Oxyhom;
• "HOM";
• Fundazol.

Lovers of folk remedies can independently prepare antifungal infusions.

• With soda... 40 g of soda is dissolved in 5 l of water and 15 ml of green soap or ordinary liquid soap is added. All components are thoroughly mixed to a homogeneous structure. This solution is used to spray the leaves 4 times with a frequency of 7-9 days. It is necessary to process not only the bushes themselves, but also the earth.
• With serum. Dissolve 30 g of soapy substance in 1 liter of milk whey and add 30 drops of iodine. Mix until final dissolution and do spraying every 10-14 days during the entire growing season - from planting seedlings in open ground to the end of fruiting.
• With ash... 1 kg of ash powder is poured with heated water and left to infuse for a week. After that, it is filtered, 30 ml of liquid soap is added and processing is carried out. Spraying with such a composition can be done with any regularity; experienced gardeners do this every 3-5 days.
• With mustard... 2 tbsp. l. mustard powder is stirred in hot water and cooled. After that, it is poured into a spray bottle, and the cucumber beds are processed.
• With garlic. 50 g of chopped garlic is poured into 2 liters of cold water, insisted for about a day, filtered and immediately sprayed with seedlings. It is not necessary to dilute the infusion with water.

Unfavorable external factors can also lead to the appearance of stains on cucumber bushes. Deformation of sheet plates is often caused by scorching sunlight. Dew drops on the leaf reflect them, resulting in burnt spots.

The appearance of spots on cucumber leaves is not yet a reason to be upset and grieve about the lost crop. This is just a signal to start the fight. If measures are taken in a timely manner, then most of the fruits can be saved. Nevertheless, any disease is easier to prevent than to cure. Therefore, it is very important to follow preventive measures.

• Avoid thickening plantings. Infections spread much faster in places where leaves lack space and light.
• Water with warm water only. Cold water, especially after long hot hours, is stressful for the plant. In addition, it can provoke the activity of the fungus.
• Stick to a crop rotation. The causative agents of most diseases and insect pests remain in the ground for several years. Therefore, it is possible to return cucumbers to the previous bed only after 3-4 years.
• Remove plant residues. The causative agents of infection are very fond of hibernating in fallen leaves and uncleared lashes. It is best to collect the tops and send them to compost, and cover the beds with mowed mulch.
• Regular spraying with "Fitosporin" or milk whey allows you to increase the immunity of plants. A similar effect can be achieved by pouring ash broth over a cucumber patch.
• Use high quality planting material.Be sure to soak the seeds in a pale potassium permanganate solution before sowing.
• When growing cucumbers in the greenhouse, ventilate regularly. The fungus is very fond of high humidity, warmth and stagnant air. Therefore, it is necessary to ensure air exchange in greenhouses.
• To avoid the appearance of light, yellow, gray or brown spots on the leaves, and not to worry about the lost crop, give preference to varieties that are resistant to temperature changes and diseases. Choose sunny, well-lit areas for growing cucumbers, and avoid drafts as much as possible.