Yellow spots have appeared on the leaves of cucumbers: what to do to save the harvest

Growing cucumbers poses a number of problems. One of them is yellowing of leaves during different periods of the growing season. This phenomenon may have several causes that need to be identified and eliminated in a timely manner.

The article will give a detailed answer to the question of what to do if cucumber leaves yellow spots appeared.

Causes of yellow spots on cucumber leaves

A change in leaf color is the main sign of a plant’s dysfunction. This fact serves as a signal to the vegetable grower: actions to save the crop must be taken as quickly as possible. The nature of yellowing of leaves and its causes are different, which means they require a different approach to treatment.

Lack of micro- and macroelements

The most common cause of yellowing leaves is chlorosis. This disease occurs due to metabolic disorders in the plant and failure of chlorophyll production. The source of the disease is a lack of micro- and macroelements in the soil.

Reference. Nutrient deficiency in cucumbers is of two types: temporary (due to disruption of root nutrition when transplanting seedlings into the ground or cold weather) and chronic.

To understand what the plant needs, study the location and nature of the leaf spots:

1. Yellowness between the veins indicates the need for iron and copper. This type of disease most often affects cucumbers, starting with the upper leaves on the shoots. Plants planted in calcareous soil suffer from it.
2. If the lower leaves are affected, especially at the edges, we are talking about a deficiency of potassium and magnesium. This happens in beds located on sandy soil.
3. Due to a lack of sulfur or manganese withAt first, young leaves turn yellow in the veins, and then the entire leaf blade changes color.
4. Plants planted in acidic or alkaline soil will suffer from nitrogen demands. The nature of the yellowing in this case is that the lower leaves near the center are affected; they gradually dry out.

Diseases

Viral and fungal diseases can affect greenhouse and soil crops. Most often, vegetable growers encounter powdery mildew, fusarium, downy mildew and anthracnose.

Powdery mildew

Pathogens are spores that have the ability to overwinter on plant remains. If small yellow specks appear on the leaves, which gradually grow and cover the entire leaf area, you are faced with this particular disease. Pigmentation grows in the direction from the bottom of the plant to the top. Over time, the seedling may die.

Fusarium

A fungal disease dangerous to the crop. It usually attacks cucumbers that are grown in greenhouses or greenhouses. The signs are easy to detect: first the tops of the leaves turn yellow and wither, then the roots turn brown and the stem begins to rot.

Downy mildew

The disease is indicated by yellow spots on the upper parts of the leaves and a greenish coating. A distinctive feature of peronosporosis is the ability not only to spread over the entire surface of cucumbers, but also to infect all plantings nearby.

Anthracnose

The result of the lesion is yellow-brown areas on the foliage, which are accompanied by a pink coating on the rest of the plant.Mucus appears on cucumbers, causing small ulcers to form. This leads to the death of the plant.

Important! Pathogenic microorganisms are spread by seed material and are well preserved in the soil.

Pests

It is possible that the cause of yellowing of the leaves is an “attack” of pests. Inspect the back of the damaged sheet. There you can find aphids, spider mites or whiteflies. Since the parasites feed on the sap of the plant, the tops gradually become depleted and begin to turn yellow and dry.

The whitefly is a small butterfly that settles in the garden along with seedlings. If it is she who is to blame for the damage to the plant, we advise you to tear off and destroy the damaged leaves.

Spider mite destroys cucumbers planted in open ground and in greenhouses. A sign of its appearance is that the leaf is shrouded in a thin, barely noticeable web. Despite its small size, spider mites can lead to the death of a plant.

Burn or hypothermia

The plant reacts to uncomfortable conditions. Failure to comply with the temperature regime causes the appearance of a yellow tint to the leaf plate. Cold interferes with full photosynthesis, as a result the plant does not fully absorb nutrients.

Cases of burns of cucumbers are common. This happens when seedlings come into contact with a hot or cold greenhouse coating (wall or glass window).

Reference. Temperatures considered comfortable for cucumbers are: before fruits appear during the day – +20…+24°C, at night – +17…+18°C; during fruit ripening during the day – +21…+26°C, at night – +18…+20°C.

Errors in care

We propose to consider the most common mistakes in caring for cucumbers, which are made not only by beginners, but also by experienced vegetable growers.

Improper watering

Excess moisture displaces air from the soil. This leads to disruption of the oxidation process of organic substances and slower absorption of nutrients. Culture loves moderate and constant watering. The soil should not be over-moistened or over-dried: it is recommended to pour a couple of buckets of water per 1 m² of soil.

Lack of light

A very common reason. Often the problem is due to the planting being too dense. If the interval between plants is maintained at 40-60 cm, the root system develops correctly, the above-ground part is comfortably located, and the necessary compounds are absorbed in sufficient quantities.

Excessive lighting

The polar problem is excessive exposure to sunlight. The most favorable place for full growth of cucumbers will be in light partial shade. This minimizes the risk of leaf burns and changes in soil moisture.

Hypothermia

If the plant had to be planted in unheated soil, it will almost certainly be affected by diseases. Sometimes cucumbers not only freeze in growth, but also react by changing their overall appearance.

Frequent ventilation

Cucumbers do not like wind and drafts; they prefer still, moist air. It is not difficult to create such conditions in a greenhouse or greenhouse, but problems may arise in open ground. Try to plant cucumbers in a place protected from the wind.

Injury

Carelessness in weeding cucumbers, that is, mechanical damage to the root of the plant, also leads to a deterioration in its condition and yellowing of the leaves.

"Starvation" of the plant

For normal functioning, cucumbers need fertilizing. An imbalance in the application of fertilizers or their absence will cause a lack of useful micro- and macroelements.

Why do yellow spots appear on cucumber leaves?

The reasons for yellowing of cucumber leaves are common and affect different varieties. However, the location of the beds may influence the predisposition to a particular problem.

In the greenhouse

No matter how hard you try to provide vegetable crops with comfort in a greenhouse or greenhouse, there are a number of factors that affect their health:

• some varieties of cucumbers may suffer due to insufficient pollination - this is a consequence of poor ventilation when insects cannot reach the plants;
• overheating of cucumbers in a greenhouse is a very common phenomenon: constant exposure to sunlight causes an excessive increase in temperature, which has a negative effect on the plant;
• Planting cucumbers and tomatoes in the same greenhouse is dangerous by increasing the risk of infections.

In the ground

In open ground, vegetable crops turn out to be vulnerable if comfortable conditions are not created for them:

• the unchanged arrangement of cucumber beds from year to year is fraught with problems - the soil is depleted, and pathogens accumulate;
• the root system of cucumbers is sensitive - watering with cold water will harm the plant;
• sudden changes in temperature contribute to the appearance of fungus on cucumbers.

What to do about it

Agrotechnical techniques and fertilizing will help get rid of yellowness on the leaves. If the cause of yellowing leaves is not due to care, chemical and folk remedies will come to the rescue.

Chemicals

In specialized stores there is a huge selection of remedies for treating cucumbers:

1. Fitosporin, a biologically active drug, will help rid cucumbers of bacterial and fungal infections. The solution is sprayed on the plants every 10-14 days as needed.
2. Bordeaux mixture is a remedy for the most advanced forms of diseases. Process no more than twice per season.
3. "Aktara" is a complex preparation for exterminating pests.
4. "Glyokladin" is used for fungal infections to combat their pathogens. The prepared solution is added to each bush that needs treatment.
5. Fungicide "Maxim" is one of the most effective drugs in the fight against late blight.

Traditional methods

If you do not want to resort to chemicals when growing vegetables, folk tricks will come in handy:

1. At the first appearance of yellowness on the leaves, garlic infusion will help. To prepare it, chop a few cloves and pour them with a liter of warm water. Let it brew for about a day. Then strain the resulting infusion through cheesecloth, dilute it in a bucket of water and add a little laundry soap. The plant is sprayed with this solution several times.
2. An infusion of onion peels will effectively solve the pest problem. The solution is prepared simply: boil the onion skins, leave and cool to room temperature. Spray the leaves of the plant with the solution or pour a liter jar of infusion into each well.
3. Recipe for a milk-soap “cocktail”: add 1 liter of milk, 20 g of laundry soap and 30 drops of iodine to 10 liters of water. Treat cucumbers with it once every 10 days until the effect is achieved.
4. Bread with iodine is an effective means for harvest rehabilitation. Soak a loaf of bread (black or white) in a bucket of water and leave it overnight. In the morning, mash the bread and add a jar of iodine. To obtain a spray solution, dilute 1 liter of concentrate in 10 liters of water.
5. Spraying with potassium permanganate is the simplest and most cost-effective way to combat yellowing of foliage and preventative treatment of plants.

Agrotechnical techniques

The main reason for the occurrence of fungal diseases in seedlings is violation of agricultural practices. Constant fluctuations in temperature and humidity provoke the processes of mycelium growth. Cover the plantings with film when the temperature drops, making sure that the leaves are not located near the cold glass of the greenhouse or window.

Plant burns can result from the evaporation of water droplets that remain after watering. Make sure the foliage is completely dry.

Reference. When watering, the soil should be moistened to a depth of about 10 cm. The use of humus, peat chips and sawdust will protect the soil from excessive evaporation.

Unlike fungal infections, there is no protection against viruses. Only preventive measures can save: compliance with crop rotation, dressing the soil, seeds and clearing of plant residues.

Feeding

If the plant lacks nutrients, add fertilizer:

• For chemical fertilizers, NPK complexes or a mixture of superphosphate, potassium sulfate and ammonium nitrate, diluted with water in a 1:1 ratio, are suitable;
• urea solution can be used for root and foliar feeding;
• if there is a deficiency of potassium, add ash fertilizer or onion infusion;
• Slurry or special nitrogen fertilizers will help compensate for the lack of nitrogen;
• The best natural fertilizer for cucumbers is a herbal infusion based on comfrey.

How to prevent the problem

Preventing a problem is much easier than dealing with its consequences.

Measures to prevent yellowing of cucumber leaves are simple but effective:

• loosen the soil after each watering and precipitation;
• clear the beds of weeds that can “thicken” them;
• disinfect seeds before planting;
• water with warm water, directing it under the roots and not along the leaves;
• Fertilize cucumbers, apply fertilizing strictly in the doses indicated in the manufacturer's instructions.

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.

Conclusion

Improper care, lack of microelements, diseases and pests are the main reasons for yellowing of leaves on cucumbers. If all preventive measures are taken, the risk of yellow spots on cucumber leaves minimal. By applying simple rules of care, you will get healthy plants and a rich harvest.