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The defeat of the vineyard by diseases and pests often causes serious damage to the vine. If the leaves dry on the grapes, the shoots wither and die, for the husband grower this becomes a serious loss. Twice a great misfortune, when the brush suffers, the berries dry out and a significant part of the crop is lost. Moreover, the drying process can begin as soon as the berries are planted, and already during their ripening, accompanied by symptoms inherent in the disease of culture, and proceed for no apparent reason.
Why do berries dry on grapes? There are many reasons for the loss of grapes. Most often, grape growers identify diseases caused by pathogenic fungi.
In the first place for harmfulness there is a false powdery mildew that affects not only the crests and brushes of grapes, but also the green mass, new and perennial shoots. The fungus, penetrating into the plant tissue, prevents the intake of food and moisture. Infected parts of the vine, including brushes and ripening berries, dry up and perish.
Mildew is not the only problem that threatens the loss of the harvest. There are other diseases of grapes, photos with the action of which on the vine clearly demonstrate the degree of danger and the need to combat them. Serious damage to crops can be caused by insect pests, there is a risk of loss of berries and insufficient care for the vineyard.
Dryness of the grape
Caused by fungusEutypa latavine disease is widespread in all wine regions, where winters can not be called soft, and causes particularly great damage in seasons with high levels of precipitation.
Since the pathogenic fungus is able to penetrate into tissues not only grapes, but also many other garden and fruit crops, this complicates the fight against manifestations of the disease and its spread. The ailment affects not only shoots and berries, a photo of grape disease clearly shows the changes in wood caused by the fungus. Particularly severe disease affects adult grape bushes, age of 8 years, and the symptoms of dryness are evident when the plant in early summer gives a growth length of 20-25 cm.
Shoots and leaves lag behind in growth, oh sizes and coloring differ from healthy ones. On the grapes, leaves dry, and then necrosis affects affected shoots. Bound berries wither or stop growing, and remain small until the end of the growing season.
Spotted anthracnose of grapes
One of the reasons why grape berries dry, can be anthracnose. The peak of infection with this serious disease falls on wet periods, and the pest is active not only in warm weather, but in the range of 2-30 ° C.
Manifestations of anthracnose are often mistaken for mechanical damage to berries and shoots caused by hail. But weather phenomena are nothing to do with.
Rounded necrotic spots with a brown-black border are the zones of penetration of harmful mushrooms. Such spots can merge, the dried up infected tissues inside them are destroyed, and the young leaves that dry on the grapes seem to be burned.
The disease infects all overground green organs of plants, including brushes. The grape disease, in the photo, is the greatest danger for the berries, before flowering, when the whole brush is affected, and also before the ripening of the crop. As the disease develops on the ovary and combs, spots that are characteristic of the disease form after the growth of which the brush fades in whole or in part.
Verticillium wilt of the vine
Verticillium, namely the causative agent of this disease, the pathogenic fungus Verticillium dahliae, penetrates the roots through the soil and, by multiplying, disrupts the supply of shoots and grapevines with moisture. The disease of grape berries, as in the photo, more often and more affects young plants, and its external manifestations can become visually perceptible only a year or two after infection.
The strongest damage vineyard carries with a high load on the bushes. More often it is noted with a lack of moisture, increased air temperature and early ripening of berries. First, the leaves withered on the grapes, having the appearance of burned, then comes the turn of shoots and bunches. Brushes located in the lower tiers of affected shoots dry, individual berries on grapes dry, mummified and remain in clusters in this form.
No less harm than pathogenic fungi, planting is able to inflict a buffalo, which increasingly attacks vineyards.
An insect that feeds on plant juices, on shoots and crests, makes characteristic annular lesions, length up to a centimeter, as a result of which the undernourished berries of the grapes dry, shoots wither and die.
For a season the wrecker gives one generation. In the stage of the larva, the squiggles live and feed on grassy plants under the grape bushes, and then adult insects climb the vine and begin their harmful activity.
The spread of the pest contributes to the abundance of vegetation near the bushes of grapes. A measure of fighting a dangerous insect is two-fold treatment of plants with benzophosphate. Such spraying should be carried out in June, and, in addition, good prevention will be the removal of weeds and disembarkation at the vineyard with beds and onions and garlic, which scares away the scotch.
Inflection of ridges during ripening of berries
The explanation why the berries on the grapes dry can become the ripening grapes themselves, under whose weight the bunches are bent, the supply of moisture and nutritious elements is broken and the fruits fade.
The danger of loss of crop for this reason is greatest for varieties and hybrids forming heavy large clusters.
Avoid the break of the crests and bearing brush of shoots, if you grow a bush with support on the arch or pergola. The hands hanging down are not constrained and develop well, and the branches experience a uniform load and do not bend.
Drying of the crests of grapes
If there are no visible causes, for example, of the symptoms of grape-berries, as in the photo, it is not revealed, and the brushes are not poured, and the berries are mummified, it may be necessary to talk about shrinkage of the crests.
This phenomenon, first noticed a little more than a century ago, has not been sufficiently studied, it is only found out that the peculiar paralysis, leading to a slowing or halting of the development of grapes, is associated with a metabolic disorder and carries a local character. The disease has no infectious nature, is not transmitted to other plants and can be associated with a violation of moisture penetration through the vessels of the crest to the ripening berries. Indeed, it is in the dry periods of paralysis, which leads to the drying of grape berries, is manifested most often.
The symptoms that precede desiccation, in the form of brown dark spots on the crest of the ridge, become noticeable during the ripening period, when berries accumulate from 7 to 12% of sugar.
Fabrics under the stains are affected by the depth of several layers of cells, and a moisture deficit aggravates the picture and necrosis covers all new areas. If the stain on the ridge is looped, the flow of moisture to the brush below stops, and the isolated berries of the grapes dry, wrinkle and lose flavor and commercial qualities.
Drying of the crests of the grapes is dangerous not only because of the loss of the crop, but also because mold and pathogenic fungi are often settled on the affected areas, causing secondary contamination of the crop.
There was no direct relationship between the frequency of desiccation of the ridges, the region of growth and the variety of grapes. But it was possible to determine by experience that the root-hive bushes are less likely to be affected by this grape-berries disease, as in the photo, than the grafted plants, especially on high-growth stocks.
The treatment of paralyzed bushes with fungicides or other plant protection products is ineffective. In some cases, when grape berries dry, spraying plantings, a 5% solution of magnesium chloride or 3% magnesium sulfate assists. Prevention begins about a month before the eventual onset of paralysis, and then two more sprayings are carried out at intervals of 10 days.
As an effective prevention, when the berries begin to acquire color and gain juice, the bunches and the nearby zone are treated with a 5% solution of magnesium sulphate.
However, the main means of combating the drying up of the crests of the grapes is for gardeners to observe the rules of agricultural technology. Only with competent formation and pruning of vines, use of balanced feeding, including magnesium and a moderate amount of nitrogen, and Also, with sufficient watering of the vineyard in combination with the treatment with chemicals, one can speak of the elimination of paralysis of the ridges and the saving harvest.