Yellow spots on cucumber leaves: how to treat, how to prevent

How dangerous is yellowing of leaves on cucumbers?

The degree of danger of yellow spots on plants depends on the reason for their appearance. Usually this is an invasion of pests, diseases or the consequences of improper care. In order to start treating the plant in time, you need to analyze its condition and identify why the yellow spots began to appear. Lack of care for cucumbers will lead to:

• deterioration or complete absence of the harvest;
• rotting and drying of lashes;
• mass crop disease.

On a note!

If the leaves begin to turn yellow at the bottom at the end of the season, then you need to remove the old and damaged ones so as not to harm the fruiting.

Prevention measures

The presence of many reasons for the appearance of yellow spots on cucumber leaves and fruits suggests an integrated approach to their prevention.

To prevent the problem from occurring you must:

With all the variety of reasons leading to the appearance of yellow spots on the leaves of cucumbers, they can all be reduced to the strict implementation of agrotechnical rules for growing this crop. This is also a prevention of diseases and pests, since a healthy and strong plant is better able to resist their attacks.

Source

Causes of yellow spots on cucumber leaves

The appearance of yellow spots may indicate that the plant needs help. But in order to provide it correctly, the reasons should be identified:

1. Insufficient light. Due to very dense plantings, there is not enough light for the lower leaves, which is why they begin to turn yellow. To avoid problems, you need to get rid of weeds in time. If this happens to young seedlings, transplant them to a new location. The harvest will not be lost if you get rid of yellowed leaves, dry vines and rotten fragments.
2. Improper care and watering regime. A large amount of water causes rotting of the root system, and then the entire plant. Lack of moisture will cause yellowing and drying. You can check the watering conditions using a hole in the bed 10 cm deep. The soil must be deepened with a stick or the end of a shovel, but not dug. The soil at this depth will show the state of irrigation. If it can be compressed, but it crumbles, then there is a lack of water. If liquid is released, there is excess. In a greenhouse, it is recommended to water cucumbers with 1 bucket per square meter once every 2 days. In a temperate climate on open ground, the same regime is acceptable. During rains, you should refrain from watering. In hot weather, increase the amount of water; in cold weather, reduce it. To get rid of excess moisture, loosen the soil. The soil at the roots is sprinkled with sawdust or river sand, which helps absorb excess liquid.

3. Sunburn. The leaves are dry and faded in color on plants in open ground. However, a lack of light will lead to a poor harvest. Therefore, cucumbers need to be provided with sunbathing.
4. Unstable temperature and its sudden changes. When overheated, the sheet becomes thin and the color dull. The temperature should be between +18°C and +30°C.
5. Diseases. In this case, it is necessary to identify the specific disease based on its symptoms and only then begin treatment.
6. Lack of nutrients.
7. Pests. They, like diseases, are determined by their symptoms.

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.

Lack of macro- and microelements

Insufficient nutrients will affect the color and health of the leaves. The spots appear due to chlorosis. This is a violation of the exchange of useful elements in the plant and a deterioration in the production of chlorophyll. The disease develops due to a lack of trace and microelements in the soil. Characteristic spots appear in the following cases:

1. Due to lack of copper and iron. Spots may appear between the veins. Damage to cucumber plantings begins with the upper leaves. The disease affects crops planted in calcareous soil.
2. Lack of potassium and magnesium. Lesions are observed on the lower leaf blades. Seedlings planted in sandy areas suffer.
3. Lack of manganese and sulfur. The first leaves turn yellow between the veins, and then the whole color changes.
4. Cucumbers planted in acidic and alkaline soils suffer from a lack of nitrogen. The yellowed areas dry out and fall off.

To avoid a lack of macro- and microelements, you need to choose the right fertilizer. It is also necessary to observe the regime and frequency of fertilizing.

Pests

Yellow leaves also appear due to pests. The main ones include:

1. Whitefly. Signs of the presence of these parasites are wilting and yellowing of the leaves. The whitefly is located on the inside of the plate and is distinguished by white wings. It reaches a size of up to 2 mm. Butterflies and larvae are dangerous.
2. Spider mite. Has a white sticky web. It is small in size. It is recommended to treat all bushes. The spider web feeds on plant sap.
3. Melon aphid. Size up to 2 mm. The color may be yellow or dark green. The pest overwinters in fallen leaves. The carriers are ants. The aphid spreads in August. The leaves begin to wither and lose color.
4. Muravyov. They carry aphids and spoil seedlings.
5. Root nematode. Small worms living in the ground. They are active at +24…+27°C heat and high humidity. When affected, the leaves curl and change color.
6. Tobacco thrips. Its length is 1 mm. The female lays larvae in the leaves. Their presence is indicated by yellow-brown spots.
7. Slugs. They feed on young shoots, causing them to wither and die.

On a note!

Cucumbers in the greenhouse and in the ground are characterized by the same diseases and pests. The methods of struggle are also similar.

Cucumber diseases

Damage to leaves with yellow spots depends on the presence of diseases in the seedlings. The main ones include:

1. Powdery mildew. A serious disease that can harm the entire crop. Its appearance leaves bright yellow spots on the leaves. The causative agents of the disease are spores. Small specks growing in size indicate the presence of infection. Pigment spots spread from bottom to top, killing the seedling. A grayish coating is an indicator of powdery mildew.
2. Fusarium. A fungal disease characteristic of cucumbers grown in greenhouses and greenhouses. The tops of the leaves turn yellow and die, and then the root and stem rot.
3. Downy mildew. It is worth remembering that this is a common disease that causes yellow leaves and a green coating. It affects cucumber plantings and crops growing nearby. If the disease is not treated, the fruits will stop growing and the foliage will fall off.
4. Anthracnose. Yellow areas on foliage with a pink coating. The mucus that appears causes the formation of ulcers.
5. Mosaic virus. The disease develops regardless of care. Its development begins due to temperature changes. The leaves curl and change color to yellow. The ovaries fall off.

Diseases can be cured with drugs and folk remedies. But it is better to prevent their occurrence with preventive actions.

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.

Errors in care

Errors in caring for and planting cucumbers can lead to loss or lack of harvest. The main ones include:

• seedlings not planted on time;
• failure to maintain distance when boarding;
• permanent landing area;
• the presence of unnecessary lashes;
• improper watering;
• excessively sunny place;
• draft in the greenhouse;
• unfavorable weather conditions.

Cucumbers need to be watered on time. It is important not to forget to feed them and protect them from possible diseases.

Advice from experienced summer residents

When growing cucumbers, advice from experienced summer residents will be useful:

1. Immediately after planting cucumbers, mulch the ground around the bushes and between the rows. This will retain moisture and prevent weeds from developing.
2. Feed every two weeks - nitrogen fertilizers for growth, potassium fertilizers for fruiting.
3. If you plant dill or borage next to cucumbers that have problems with pollination, they will attract insects and prevent the plants from dying.

Chemicals

There are remedies to help save cucumbers from serious diseases. These include:

1. Bordeaux liquid. Used in extreme cases, with advanced disease.
2. Fitosporin. Used for prevention.
3. Aktar. Helps fight pests.
4. Zircon. Helps in the initial stages of diseases.
5. Topaz. Destroys fungal infections and yellowness.
6. Glyocladin. Fights fungal spores.
7. Home. Used instead of Bordeaux mixture.
8. Maksim. Effective against late blight.

The dosage of drugs depends on the type of disease and its degree of development. Before use, read the instructions; sometimes there are photos of pests for comparison.

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.

Folk remedies

In order not to use chemical compounds to treat cucumbers, you can use traditional methods. Effective:

1. A solution of milk and soap. 1 liter of milk, 30 drops of iodine and 20 g of soap are diluted in a bucket of water. Treat every 10 days.
2. Spraying with a weak solution of potassium permanganate.
3. Treatment with garlic solution. Add 50 crushed cloves to 1 liter of water. Leave for a day, then filter and add a little soap.
4. A solution of bread and iodine. The loaf is crushed and left to swell in 1 liter of water. After 24 hours, add 5 g of iodine. Dilute the resulting solution in a ratio of 1:10.
5. Onion peel. 100 g is poured into 1 liter of water, boiled, left for 6-8 hours, and then the resulting product is sprayed on the plantings.

On a note!

The listed methods help only at the early stage of the disease. If traditional methods do not help, you must resort to chemical drugs.