Grapes are a real gift of nature, a storehouse of vitamins and minerals that are so important for the human body. Many amateur gardeners cultivate this health berry, although this is not so simple. It is necessary to take into account many factors and features conducive to the normal growth of grapes, and very carefully monitor the appearance of various diseases, which, unfortunately, it can be affected.
Experienced gardeners know that if grape leaves begin to become stained, this is the first sign of a plant's disease. A disease that is not stopped in time can lead to the fact that not only the diseased bush, but also neighboring plants will suffer.
Causes of Grape Disease
Understanding why the leaves of the grapes dry or other changes in its appearance appeared, one has to incline to the fact that the plant is sick.
The reasons for this may be various:
- growing grapes in fairly cold northern regions already poses a risk that it will be susceptible to disease;
- grapes under winter shelter are also at risk, since air stagnation occurs there, increased humidity occurs, which is a favorable environment for the multiplication of various pathogens;
- improper soil composition, lack of moisture, heat and light contributes to the emergence of non-infectious diseases, when not only the vine leaves dry or brown, but also the comb dries out and the berries fall off (in addition, the plant becomes very weak and becomes more susceptible to infectious diseases);
- various bacteria, fungi and viruses are transmitted by the wind from diseased plants, and sometimes it is so difficult to deal with them that only replacing the affected bushes with more resistant grape varieties can get rid of this problem.
But, nevertheless, there are many ways to combat grape diseases, you just need to correctly determine the type of disease and know how to get rid of each of them.
Downy mildew
This dangerous disease, also called mildew, is usually caused by a fungus that can affect not only grape leaves, but also the ovary and young shoots. The fact that the plant hit the fungus is easily determined by the type of leaves. They are covered on top with bright spots of a yellowish tint, and a powdery white coating forms below. The fungus forms new spores so quickly that they, carried by the wind, immediately infect neighboring bushes.
The leaves on the grape cuttings turn yellow and crumble, then the spots creep along the shoots, as a result of which the inflorescences die off, and the berries begin to blacken, wrinkle and fall off.
A good way to prevent this disease is to plant dill around grape bushes. Also, an excellent effect is given by spraying with a Bordeaux mixture (1% solution) during the period when the buds open and before flowering begins. If the plant is still ill with mildew, then, again, when the first signs appear, it is sprayed with a Bordeaux mixture or with the Ridomil Gold preparation. You should be aware that spraying is stopped a month before the harvest.
If in your area this disease is quite common, then when planting grapes, you should initially choose varieties resistant to mildew, and there are many of them.
Powdery mildew
This disease is an oidium, by the name of the fungus that causes it, usually affects the aerial part of the grapes in an arid hot period. The first sign is that spots appear on the leaves of grapes of a characteristic ash color or the same coating forms on the entire surface of the leaf. Then the leaves dry and crumble, and the berries begin to crack.
If you do not get rid of this fungus, then it can safely winter on fallen leaves and buds, and in the spring again annoy the plant.
Such preventive measures, which consist in providing enough air for the grape bushes, namely: pruning thick shoots, planting bushes at a sufficient distance, regular weeding of weeds, helps well.
As for the methods of eliminating the disease, the use of chemicals, especially colloidal sulfur, is effective here.
Gray rot
This damage to grapes also applies to fungal diseases. Favorable conditions for its occurrence are a warm, humid environment. It usually covers the aerial part of the vine. First, vine leaves are affected, on which a fluffy gray coating appears. At the slightest movement of the leaves, it crumbles, and the disease spreads rapidly throughout the plant. Ripening or already ripe berries are especially affected. They turn brown and quickly begin to rot, which makes them completely unusable.
Effective ways to combat gray rot are very simple. It is enough to remove from the bush all the affected parts, and then burn them. After that, the grape bush is sprayed with a solution of baking soda, which is diluted at the rate of half a teaspoon per 1 liter of water, or a solution of green soap is used.
Cercosporosis
If you notice that the grapes dry leaves that are covered with an olive-colored coating on the bottom and then fall off, you can rest assured that it is affected by a fungal disease such as cercosporosis. Then this plaque in a velvet layer covers the stalks, after which the berries become firm, with a characteristic lilac tint. With a light touch, they fall to the ground.
Such measures help to rid the plant of this fungus:
- removal of infected parts of grapes with their subsequent burning;
- processing Bordeaux mixture at least 2-3 times;
- thorough care, creating optimal growing conditions for the vine.
Rubella
This disease has been known since time immemorial, when they began to cultivate the vine. It can be non-infectious and occur most often in extreme heat, which is characterized by mid-summer. Red leaves of grapes are a characteristic sign that the plant lacks potassium. If measures are not taken in time, grapes can die, and the timely use of fertilizers, which include 1% potassium nitrate, will help to cope with this problem.
General preventive measures
Virtually no grape varieties exist that would not be susceptible to a particular disease. But if you remove the dying leaves in time, mulch the soil, water it in a timely manner, tie up the vine, remove the stepsons and feed it with nutritious mixtures, then many diseases can be avoided by getting an excellent grape harvest.
By adopting the recommendations proposed in the article, you can grow beautiful grapes that will delight their fruits for many years.