One of the most common fruit plants is grapes. On the territory of Russia, it can be found in regions with both warm and cold climates. Its fruits are used not only for making wine.
It is a flavorful ingredient for popular dishes and treats. Berries are rich in essential oils, fiber, amino acids and beneficial trace elements. Gardeners often face the problem of yellowing grape leaves. As a result, not only the condition of the green mass worsens, but also the yield decreases.
If the vine leaves turn yellow and dry, the cause may be due to several problems. Inexperienced summer residents often violate the care procedure. A decrease in the viability of a plant occurs not only due to diseases or attacks from pests. Plants can suffer from lack or excess of nutrients. If the grapes are deficient in nitrogen, the foliage begins to die off at the base, and fruiting deteriorates. If the leaves lose their attractive shape and begin to arch outward, then the plant lacks potassium. The presence of dark veins indicates a deficiency of phosphorus.
Also, the vineyard must be periodically fed with the following components:
Correcting the situation is easy – just feed the plant with the necessary fertilizers. Both organic and complex compounds are used. Superphosphate is widely used, which is administered with a lack of phosphorus, and if you need to help the grapes grow green mass, then use ammonium nitrate, bird droppings or a mullein solution. These substances are rich in nitrogen.
A mandatory component of care is regular watering. Water performs a whole range of functions. It takes an important part in the process of photosynthesis, cools plants in the heat and delivers useful substances to plant cells. Some summer residents mistakenly believe that frequent watering is necessary for fruit crops, but excessive moisture will only cause root rot. Water the grapes about once every 1-2 weeks. With the onset of hot summer, irrigation is carried out more often. Also, the regularity will depend on the characteristics of each variety and soil structure. In arid regions, to maintain a comfortable level of moisture, the earth is regularly loosened and covered with a layer of mulch.
To obtain a rich and high-quality crop, you need to choose the right site for growing. It is advisable to plant young seedlings in black soil with a rich content of humus. If there is only a choice between sandy and rocky soil, additional substances are introduced into the soil. A portion of humus is sent to the planting hole. When grown in depleted soil, the leaves may begin to turn yellow. The earth around the plants must be constantly loosened so that they do not experience a lack of oxygen, and the water quickly reaches the roots. They dig the ground carefully, the main thing is not to harm the roots, especially when they are located close to the surface. If the work is done carelessly, the growth of young plants slows down, and the leaves dry out and fall off. Also, the root system may suffer from rodents or bears. This is a dangerous and large insect that attacks the underground part of the plant.
If symptoms of root damage were noticed, the vineyard should be treated with antiseptics or watered with a solution of manganese. During the healing period, reduce irrigation to avoid decay.
You can also dig up a shrub, remove damaged roots, and treat the healthy part with an anti-fungal compound.
Fruit crops often suffer from pests. They not only take the juice from the plant, but also cause damage. The waste products that remain from the slugs on the surface of the leaves interfere with biological processes. Grapes are often attacked by spider mites. You can identify the pest by the presence of a fine mesh. Aphids can be found on the back of the foliage. The larvae penetrate the leaves, deforming them. Sometimes aphids can be found on the roots, causing them to rot and crack. The marble beetle attacks plants gradually. At first, after the appearance, it is not so dangerous, but over time it is able to destroy young seedlings and damage the roots.
Fruits, leaves and buds are damaged by a leafworm. To cope with this pest, you will need insecticides, such as Akarin. You can also use special protective preparations designed to combat a specific pest. If it is not possible to visit the vineyard frequently and monitor the activity of insects, the plants should be treated according to the following scheme in the process of fruit crop development:
- green cone processing;
- the use of drugs after the formation of 5-7 full-fledged leaves;
- the last time the formulations are used about 10 days before and after flowering.
Note: Do not use chemicals about a month before picking berries. For example, if the harvest is received in mid-August, around the middle of June, the use of drugs with aggressive components should be stopped.
Treatment of diseases
This disease often causes yellowing of grape foliage. The disease can be of different nature. With iron deficiency or growing a crop in hard carbonate soil with insufficient oxygen permeability, non-infectious chlorosis begins to develop. The foliage gradually loses its color brightness (first the edges turn yellow, and then the entire leaf).
To keep the plant mass intact, you need to perform the following manipulations:
- regular spraying of branches with a solution containing iron sulfate;
- fertilizer ferrous sulfate;
- treatment of sections with iron preparations;
- ensuring proper soil ventilation.
The appearance of yellow veins indicates infectious chlorosis, which occurs as a result of infection on plants. It is almost impossible to get rid of the disease, so diseased shrubs are dug up and burned to save the vineyard. If you do not notice the problem in time, you can lose the entire plantation. Due to extreme weather conditions, as well as sudden changes in temperature, edaphic chlorosis develops.
Due to the stress experienced by the plant, the immune system weakens. You can determine the disease due to brown spots.
Fungal infections can also cause yellow leaves. Symptoms of downy mildew (aka mildew) are white spots that eventually change color to black and make the leaf thinner. The infection affects not only leaves, but also flowers and fruits. To get rid of the fungus, folk remedies are used:
- shrubs are treated with a solution with the addition of iodine, manganese and soda;
- After the rain, the leaves are sprinkled with ashes.
While the berries are not yet fully formed, you can use ready-made chemical compounds that can be bought at any gardening store. Wilt strikes at the root system. As a result, the plant does not receive sufficient nutrition, and deformation begins. If this disease is detected, diseased shoots must be removed and disposed of. If you do not notice the fungus in time, the plant will die in 2 seasons. Powdery mildew (oidium) affects the aerial part of the plant. First, a white coating appears on the leaves, and then the color of the foliage changes from green to yellow. As a result, the leaves dry up. Sick shrubs process the season. This procedure should be performed in warm weather so that the air temperature is at least 20 degrees. Processing is carried out in the morning.
You can cope with alternariosis with the help of ready-made chemical compounds (Skor, Bordeaux mixture, Rapid Gold, Quadris) or folk recipes (milk, manganese-based solution, soda and other options). This infection is often referred to as the hot climate disease. The fungus is identified by brown spots.
Other causes of yellowing
The distance between shrubs and rows should be from 3 to 3,5 meters. So the plants will receive a sufficient amount of light, and the roots will not interfere with each other. If you make the planting more dense, the grapes will not be properly ventilated and will begin to feel uncomfortable. Closely planted shrubs are often infected with cercosporosis, which is fought with fungicides. Severe frosts also harm the grapes, so many varieties are grown indoors.
Heat-loving plants need to provide special conditions:
- for the winter, the grapes are removed from the branches and covered with a layer of leaves or agrofibre;
- before frosts, shrubs are watered and fertilized;
- bonfires or smoke bombs are set up near the vineyards.
Also, before choosing a variety, one should take into account its compliance with certain climatic conditions. For example, varieties for the southern regions will not do well in the north or in other regions with cold winters.
To prevent the deterioration of plants, you must perform the following actions:
- soil mulching;
- regular feeding;
- adding peat and sand to the soil;
- clearing the area of weeds and debris;
- digging the soil in autumn;
- treatment with prophylactic compounds;
- regular pruning, during which they get rid of diseased and deformed shoots.
Some grape varieties are demanding on growing conditions and require special care. There are also fruit crops with a strong or weak immune system.