Why grape leaves turn yellow and dry, what to do and how to treat them

Grapes are perennial vines and belong to cultivated plants grown for the production of juices, drinks, raisins, extracts and homemade preparations. Growing a healthy bush is quite a difficult task, especially for novice gardeners. Often yellowed leaves are the first signal of the presence of a disease or pest. What to do if grape leaves turn yellow, what is the reason.

Why might grape leaves turn yellow?

To grow grapes, you need to follow agricultural cultivation techniques and carry out preventive measures.Grape leaves can turn yellow for several reasons:

1. The soil is oversaturated with fertilizers.
2. Lack of nitrogen or potassium in the soil.
3. No watering in dry weather.
4. Lack or excess of sunlight.
5. Pests.
6. Infectious, non-infectious chlorosis.
7. Fungal diseases.

Beginner gardeners should pay special attention to time and type feeding grapes. Incorrectly applied fertilizer or frequent fertilizing affects the formation of the vine and the harvest. Particularly dangerous is improperly applied manure or bird droppings, which release large amounts of carbon dioxide and increase chlorosis.

A lack of nitrogen may be accompanied by other symptoms: decreased yield, formation of spots - burns, stunting of growth, shredding of new leaves.

Potassium deficiency manifests itself as yellowing of leaves along the edges and spreading further. Thanks to nitrogen and potassium in the soil, the grapevine grows intensively, ripens quickly and safely tolerates winter frosts, and also saturates the berries with taste and aroma. And also a lack of magnesium and iron contributes to yellowing.

On hot summer days, an adult, and especially a young seedling, requires intensive watering; its absence weakens the plant’s immunity to many diseases. A lack of water contributes to the withering and drying of the root system of grapes, after which the leaves begin to turn yellow, dry out and fall off. And excessive watering during such a period can contribute to the development of fungal diseases.

It is especially important to choose the right planting site for grapes. Some varieties like a shaded place, others - sunny. An excess for some and a deficiency for others can affect the proper development of the plant and yellowing of the green mass, weakening the vines.

Pests large and small can damage the root system or suck the juice from the leaves. Rodents, such as moles, mice, and mole crickets, eat up the root system and can infect the plant with a disease, after which the leaves on the vines begin to turn yellow and fall off or wither. Onion fly larvae, grape mite or aphids also suck out beneficial juices from them, the lack of which leads to yellowing and curling.

Chlorosis on grapes may be infectious or non-infectious due to the development of certain factors:

1. With excess lime in the soil.
2. Unfavorable weather conditions - long periods of rain.
3. Soil depletion.
4. Nematode infection.

First of all, it is necessary to eliminate the factors causing chlorosis, prune damaged specimens and fertilize the grapes.

It is important to know! If the upper leaves of the bush begin to turn pale and then turn yellow, then chlorosis is due to a lack of iron. If they are lower, then there is a lack of nitrogen. Along the entire length of young and old vines, you need to loosen the soil and make drainage grooves to remove excess water.

Fungal diseases, as well as chlorosis, can occur due to improper care, weather changes, and pests that carry fungi from other plants. The most common diseases that lead to yellowing of green mass:

1. Mildew is a dangerous disease that reduces the plant’s defenses and reduces the amount of yield. The leaves begin to turn yellow in the form of spots, then dry out and fall off.
2. Oidium - spreads quickly throughout the vineyard, first a white coating appears on the plates, then on young vines, after which they turn yellow, brown and dry out. A plant treated at the wrong time risks not surviving the winter cold due to decreased frost resistance and weakening.
3. Verticillium (wilt) manifests itself in the form of quickly yellowing and drying leaves of the vine after the vine, and subsequently the complete drying of the bush.
4. Fusarium usually appears on the plant in early summer, often in June; dry yellow spots form on the leaves, which quickly spread throughout the plant.
5. Alternaria blight occurs in the middle - late spring, small yellow spots form on the leaves, after which they become gray, brown, black and dry out.
6. Gray rot looks like a white coating that gradually grows throughout the bush, the leaves change color to pale green, then yellow and dry out.
7. Root rot manifests itself as the first sign: yellowing of leaves and weakening of young shoots, especially after heavy rains or in the absence of drainage.
8. Black spotting - can appear due to high humidity or when pests carry a disease. The affected areas of the grapes begin to rot, the leaves turn yellow, and the color of the berries changes.

Yellowing can also be caused by anthracnose or bacterial cancer. Any change in the color of the leaves or change in their shape should alert the owner and force them to take preventive measures to eliminate diseases.

The leaves of an adult plant turn yellow

An adult grape bush most often suffers from a lack of nutrients or diseases that are carried by rain, wind, pests, and gives signals in the form of yellowing of the leaf blade. Also, on vines, by the end of summer, in August, premature aging of the leaves may begin; they begin to turn yellow at one edge, gradually covering the rest. The reasons for this yellowing may be:

1. Sudden changes in temperature, heat during the day, decrease by 10 °C or more at night.
2. It also affects aging if there were frequent frosts in the spring, the summer was hot and humid, and the end of summer and autumn were cold.

Leaves that are located at the bottom of the bush or in the middle, where there is little access to sunlight, usually begin to turn yellow.

Edaphic chlorosis can also occur, caused by climate change, changes in soil composition, acid rain, replanting a bush or grafting a rootstock.

Yellowing of leaves on young grapes

Rooted cuttings or young seedlings are most susceptible to external influences and immediately react to improper handling. First of all, this is reflected in the leaves, which become pale green and begin to turn yellow: in spots throughout the entire plate, except for the veins. There is a high probability that improper care contributed to the occurrence of non-infectious chlorosis:

1. Watering with cold water.
2. Lack of soil aeration.
3. Incorrectly selected fertilizer, which can cause yellowing of the entire vine or the upper young leaves.

Therefore, in the first years of cultivation, any grapes require special attention and adherence to agricultural technology.

What to do if the leaves start to turn yellow?

Before you start treating with chemicals or pouring fertilizers, you need to find out the reason why the leaves began to turn yellow:

1. Inspect the plant completely for pests and fungal spores.
2. Inspect diseased leaves. Where it starts to turn yellow or after what. If the entire plate turns yellow, withers or curls, the bush does not have enough moisture or, conversely, the soil is dry. The presence of holes or bumps in the soil around the bush may indicate rodents that have damaged the roots.If at the same time the plant stops growing, the vines wither or dry out, it means that the plant has overcome root rot. Rodents must be controlled by placing baits or making repellent devices.
3. If yellow or brown spots appear in the middle, which then darken and dry out, or the disease begins to spread throughout the vines and berries - black rot, oidium, mildew. In this case, quick and effective treatment is necessary so as not to lose the bush.
4. If the entire leaf turns yellow, but the veins remain green, this is non-infectious chlorosis, which can be treated by applying fertilizer with iron, nitrogen, potassium, and manganese. Treat the leaves with iron chelate or pour in iron sulfate.
5. If there are small insects on the inside of the leaf, and a yellow spot forms there, then they need to be removed mechanically and sprayed with an insecticide.

After finding out the cause, you need to choose the right drug or fertilizer complex, which is used in accordance with the instructions.

Preventive measures

Disease prevention should begin with removing leaves and weeds around the plant, which often become the cause of infection. The second important point of preventive measures is treatment in the spring when new buds appear, then when the leaves bloom with the following preparations:

1. Bordeaux mixture;
2. "Aktofit";
3. "Fitosporin";
4. "Trichodermin";
5. iron sulfate;
6. "Maxim"
7. colloidal sulfur;
8. urea;
9. "Vitaros."

The second time in the spring they spray preventively against awakened insects:

1. drug 30B;
2. "Topsin-M";
3. "Oxychom";
4. "Envidor."

The next treatment with drugs is carried out after flowering and harvesting, as well as in the fall before preparing for winter.

It is also very important to loosen the soil around the bush, add sand, peat, and light mixtures so that the air permeability of the soil is better. When transplanting grapes, make a large layer of drainage to prevent the roots from rotting. If the bush cannot be replanted, then make grooves around it to remove excess water.

Complex fertilizers need to be applied in early spring, during flowering, and in autumn. It’s better to take the soil to a laboratory to find out what is missing in the soil, its acidity, and then add individual elements to improve the composition.

Most grape varieties require careful care and the right planting location; new varieties are less demanding and have better immunity against diseases. To grow a healthy bush with a bountiful harvest, it will take a lot of effort.