Cucumbers can be found at almost any vegetable grower's summer cottage. It's quite difficult to find a person who doesn't like fresh cucumbers. While growing this vegetable, some people experience yellow spots appearing on the leaves of cucumbers. Therefore, before growing, it is recommended to find out how to cure yellow spots on cucumbers.
Why do cucumber leaves change color?
Before treating yellowing, you should understand why yellow spots appear on cucumber leaves. There are several most common reasons for this problem.
Nutrient deficiency
The main reason for leaf discoloration is a lack of magnesium or potassium. Because of this, red and dry spots begin to appear on the plant. In this case, at first only the edge of the leaves is affected, and the rest of them begins to turn yellow only after a few days.
With a serious lack of magnesium, the leaf blades between the veins are first affected. The lower leaves are the first to change color and only after that the lower leaves of the cucumbers become covered with spots.
If the problem arose due to a deficiency of nutrients, then you should use a medicinal onion infusion. To prepare it, 100 g of husk is added to 10 liters of water. Then all this is thoroughly mixed and boiled for about 20 minutes. When the prepared mixture has cooled completely, you can begin treating the cucumbers. Each bush is treated with a liter of prepared infusion.
Downy mildew
Spots on the leaves of cucumbers in the greenhouse and outdoors may appear due to powdery mildew. To find out that the plant has turned yellow precisely from peronosporosis, you should study its main symptoms. When this disease occurs, only the lower part of the bushes is the first to suffer. A faint gray coating with a slight purple tint appears on it. A few days after the onset of the disease, the spotting begins to spread throughout the entire bush.
The leaves gradually dry out and over time, because of this, the plant may die completely.
Most often, spots on cucumber leaves due to powdery mildew appear when grown in conditions of high humidity. Therefore, before treating yellow spots on cucumber leaves, you should lower the humidity level.
To protect cucumbers from the appearance of peronosporosis, you need to:
- water the bushes with heated and settled water;
- harvest the ripe crop in a timely manner;
- monitor crop rotation.
When the first signs of disease appear, you should immediately stop watering the plants and treat them with Bordeaux mixture. You can also use polycarbacin during treatment.
Cladosporiosis
Sometimes, the leaves turn yellow due to the fact that the plant suffers from cladosporiosis. This fungal disease of cucumbers has pronounced symptoms and therefore it is quite easy to distinguish it from other diseases.
At the initial stage, small round dots appear on the leaves. At first their size is only 1-2 mm, but after two days they begin to enlarge and dry. At the slightest touch with your hand, the inclusions that appear are destroyed.
To prevent cladosporiosis it is necessary:
- plant cucumbers in a new place every year;
- regularly ventilate cucumbers in the greenhouse;
- When watering, use only heated water;
- Before planting cucumbers, completely clear the area of the remains of plants that were previously grown on it.
If yellow spots have already appeared on the plants due to cladosporiosis, you should immediately stop watering for a week. For treatment, it is recommended to use foundationazole or Bordeaux mixture.
Anthracnose
Yellow spots on cucumbers in the greenhouse and in the garden often appear due to anthracnose. Most often, anthracnose appears due to the fact that undisinfected seeds were planted. The plant can also become infected due to a fungus in the soil.
When this disease appears on cucumbers, several inclusions of red color can be seen near the veins. Literally 2-3 days after infection, the leaves begin to dry quickly, and dark ulcers appear on the fruits.
Getting rid of the disease is quite simple.To do this, treat the plants with Bordeaux mixture and a weak solution of copper sulfate once a week. Some vegetable growers then sprinkle the cucumber bushes with lime or charcoal.
Field mosaic
There are cases when cucumber seedlings begin to gradually turn yellow due to infection with field mosaic. This disease appears equally often both in greenhouses and in vegetable gardens. On each leaf of bushes infected with this disease, at least one yellow spot appears near the vein.
If you do nothing, then over time the entire bush will become covered with such spots. This reduces the number of flowers, causing the yield to deteriorate. To cure field mosaic, it is enough to treat the bushes with whey several times a week. The procedure is carried out until the leaves begin to recover.
How to treat yellow leaves
The fight against yellow spots on cucumber seedlings is carried out using special drugs that help treat certain cucumber diseases. Therefore, before treating cucumber seedling disease, you should familiarize yourself with the most effective drugs.
Topaz
Using this fungicide, you can quickly get rid of fungal diseases that cause the cucumber leaves to become covered with spots. This remedy is also often used to prevent these diseases. The main advantage of Topaz is that it is non-toxic and therefore cannot harm human health in any way.
This product is available in various forms. Most often it is sold in the form of a blue powder or liquid solution. When using powder, you will have to prepare a working solution.To do this, 10 g of the drug must be mixed with 10 liters of water. At least two liters of the mixture should be consumed per ten square meters of area.
Hom
Some vegetable growers use Hom after the cucumbers begin to become covered with yellowish spots. Most often it is used as a replacement for Bordeaux mixture. This remedy is very effective in combating many different fungal diseases. The drug contains copper oxychloride, which has a contact effect. When this substance gets on the surface of the leaves, it prevents infectious agents from penetrating the plant tissue.
Khom is sold in the form of a green powder, which must be dissolved in water before use. To do this, 30 g of fungicide is mixed with 5-7 liters of water and left for half an hour. It is recommended to use Hom once a week in calm weather. If spots appear on almost every leaf, then you need to use the mixture more often.
Zircon
You can get rid of appearing spots with a yellowish color using Zircon. This drug not only protects young bushes from diseases, but also activates their growth. Zircon can be used at any stage of cucumber development. Many vegetable growers even use it during pre-sowing soil preparation, before planting in greenhouses.
The product is absolutely safe for people, since it contains no chemical components and the drug consists only of elements of plant origin.
Before curing the yellowing of the leaves, you should prepare a working mixture. To do this, the container is filled with 2-5 liters of water, after which 25 g of the drug is added to it. Then the mixture is mixed and poured into a ten-liter bucket of water.The finished substance is used once a week until the bushes are completely restored.
Oksikhom
If cucumbers have small brown spots on the leaves, then you should use Oksikhom. With its help you can protect plants from various diseases or cure them. The main advantages of the drug include its long therapeutic effect. After using this remedy for yellow spots several times, you can forget about fighting them for a long time. After penetrating the leaves, Oxychom acts on almost all the most important components of the fungal cells that lead to the yellowing of the leaves.
The drug is sold in powder form, and therefore before use it is worth preparing a working solution. 20-40 g of the drug is added to a filled ten-liter container. All this is thoroughly mixed and poured into smaller containers. The product is used once every two and a half weeks.
Conclusion
Many vegetable growers do not know what to do with yellow spots on cucumber leaves. To prevent yellowing from appearing, you should familiarize yourself with the main reasons for their occurrence and the means that will help get rid of them.
