Diseases of grape leaves: descriptions with photos, treatment
Own vineyard is a very attractive prospect, but it certainly requires competent care. Even the most beautiful vine is not immune to diseases and problems. First of all, the leaves suffer - and this is a sure sign that urgent action is needed. We tell you what diseases of grape leaves you may encounter and what to do with them!
Pimples and tubercles on the leaves
Yellowness is by no means the only way for a plant to respond to illness or improper conditions. The spots on the leaves can be of different colors, and sometimes they become textured. This simplifies the search for the cause a little, because most often the matter is pests.
- The growths and swellings on the leaves are galls that cause aphid larvae. Phylloxera aphid is the main enemy of American and European grape varieties;
- Another parasite that creates textured traces on the leaves is itching. It leaves tubercles on the front surface of the plate, and on the reverse side there are hollows covered with hairs;
- In the worst case, growths appear on the leaves of grapes due to bacterial cancer. It is accompanied by the formation of tumors and ulcers along all shoots. The disease cannot be cured, so you need to get rid of the damaged vine as soon as possible.
Leaves turn yellow and dry
If the old vine turns yellow from the bottom to the end of the season, this is a natural process. But if young shoots turn yellow at the height of summer - it is worth worrying.
- Chlorosis - the reaction of grapes to a lack of trace elements, and in particular - magnesium. Less often there is a deficiency of iron, zinc and other beneficial components. In this case, an urgent need for a comprehensive dressing;
- The grapes turn yellow and dry due to lack of moisture, so adjust the watering regime;
- And if the leaves turn yellow, but become softer - this is a sure sign of decay, but already because of an excess of water;
- When the yellow leaves slowly dry from the ends, the grapes may be too hot. On hot days, the scorching sun is detrimental to most plants;
- The leaves turn yellow and fade if there is not enough sunlight, because the process of photosynthesis directly depends on it;
- Randomly scattered irregularly shaped spots that form like a mosaic pattern - a symptom of a mosaic. This is an incurable virus that has not yet been studied much, but most of its strains appear the same;
- Verticillosis is another reason why grape leaves gradually turn yellow and fall. In parallel, shoots quickly wither, and the nodes begin to unevenly lignify.
Brown spots on grape leaves
Sometimes spots on the leaves acquire a more saturated dark shade - orange, brown, brown. And there are reasons for that too!
- Most often, small dark spots randomly located on the leaves are a symptom of anthracnose. In the future, these spots will become more and more until the leaf dies;
- Bright and as if rusty spots indicate the disease of the same name - rust. This is another fungus that affects most garden crops;
- If the leaves of the grapes first turned yellow, and then began to turn red and soften - this may be a symptom of putrefactive processes and even root rot. It is necessary to carefully examine the root zone, reduce the irrigation regime and treat the plant with fungicides;
- Brown spots on the leaves, combined with black spots on the shoots - a symptom of black rot. The same spots on the berries are deformed and seem to sink;
- Light brown spots, covered with a velvety coating with a pronounced shine - a sign of alternariosis. In the future, they turn into necrotic foci.
Grape leaves turn black
If the leaves openly blacken, these are manifestations of necrosis, and emergency measures must be taken!
- On wet, cool days, phomopsis infection flourishes, due to which leaves turn black, shoots turn white and berries rot;
- The blackened oval dots on the leaves and all other parts of the grapes are the first symptoms of black spotting. A dangerous disease affects the vine completely and causes necrosis;
- Dark dots or light spots with black centers appear due to cercosporosis. The fungus hibernates safely in the ground and actively develops during the flowering of grapes. Black dots are visible even under the skin of ripening berries;
- If the leaves turn yellow at first, and then begin to turn black, and the grapes wither and fall, try to feed him potassium;
- Less often, the cause of blackening is too clay soil, because the grape roots do not take root well and suffocate in so dense soil.
White plaque on grape leaves
White plaque is a sure sign of fungal diseases, because in fact these are future mushrooms and spores.
- The first reason for the appearance is powdery mildew, which spreads on hot, dry days. The plaque gradually acquires a grayish tint, and the berries crack;
- Mildew is the most common grape disease in mid-latitudes. This is downy mildew, the spread of which is facilitated by moist, cool days;
- If the coating is initially gray in color - it may be gray rot. Grapes that have already formed, wrinkle, become covered with the same coating and rot;
- A white plaque resembling a cobweb leaves a spider mite. Each gardener has encountered him at least once. Damaged leaves turn yellow at first, and then turn red from veins.
Pale and light leaves
Sometimes the leaves of the grapes do not turn yellow, but seem to fade and fade. We have already figured out the possible reasons!
- If young shoots grow too faded, then immunity is weakened in grapes. Use special immunomodulatory drugs, because otherwise it is the right way to serious diseases;
- If the soil is too depleted, the young shoots also turn pale and weaken. Therefore, it is important to adhere to the feeding schedule;
- Healthy adult leaves are first deformed, and then covered with bright spots due to white rot. Always treat any cuts and wounds, because this fungus most often penetrates precisely through mechanical damage.
Grape leaves twist
If the leaves began to deform, this is also an alarming symptom, so do not be mistaken. This is not a question of aesthetics, because as a result, the whole crop may die!
- The most dangerous option is the virus of the same name, which rapidly covers the entire vineyard. The amount of the crop is halved, and the remaining clusters are much worse in taste and quality;
- In the best case, the leaves may curl due to a lack of oxygen. Therefore, you do not need to thicken the grapes too much to save space and do not forget to periodically thin out plantings;
- If the leaves are simultaneously curled, wilted and dried - most likely, the grapes are simply not enough water;
- Due to a lack of potassium, the plates are rolled down, and due to a deficiency of phosphorus, the young leaves also darken. If the sheet is bent like a boat in shape, there is not enough molybdenum. And when the edges are bent up and the leaves become smaller - the problem is zinc.