What does it mean if grapes are dry, sunken and shrunken?

It should be sunburn disease, which is a physiological disease and not contagious.

The occurrence of sunburn is directly related to strong sunlight. Reasons:

① Abnormally high temperatures cause the death of some pulp cells.

② High temperature causes abnormal respiration of pulp cells, and harmful substances such as ethanol and acetaldehyde are produced and accumulated in the fruit, causing damage.

③ There is a local lack of water in the tree, and the water absorbed by the roots cannot meet the transpiration needs of the leaves. The leaves compete for water from the fruits, causing physiological water shortage in the fruits.

④ If the tree body is deficient in boron, the degree of sunburn will be aggravated.

The occurrence of sunburn often occurs in long-term droughts or plots that are wet first and then dry; weather that suddenly clears up after a thunderstorm; fruit ears lack shade and are exposed; trees grow too vigorously or Too weak trees and plots with severe boron deficiency. And in terms of rack type, there are more fences than scaffolds, more fences on the west side than on the east, more upper parts than lower parts, and more fences near buildings than in fields.

Grape hard core is in the early stage and is prone to occur at high temperatures after rainy season. Bagging as early as possible, keeping more side shoots or stems near the ears, reducing direct light, controlling nitrogen and increasing phosphorus and potassium can reduce sunburn. After the hard-core period, sunburn generally no longer occurs.