High temperature and drought, beware of grape shrinkage

In Chongqing, high temperature often occurs in summer, and it is easy to cause the transpiration of the leaves to increase rapidly. The leaves not only get water from the roots through the stems, but also compete for water from the fruits for transpiration. In the case of loss of water and elevated fruit temperature, local burns may occur, causing grape shrinkage,

    The disease begins to occur about 30 days after the growth of the fruit, and the brown pockmark of the needle tip size occurs on the pulp under the epidermis of the fruit. If the pockmark develops rapidly, it forms a lesion. The shape of the lesion is near the garden, ellipse or long circular, and the size of the lesion can reach 1/3 of the surface of the fruit . The lesion is initially light brown, rapidly darkening, sag, like a finger indentation. The diseased spot of the disease has a hard feeling. The corrugated vascular bundle under the diseased part has a corked contraction and loses water. The subcutaneous skin seems to have a hollow feeling, but the fruit pieces generally do not fall off. In severe cases, several lesions will occur in one fruit, nearly half of the fruit will be damaged, and growth will stop.

    The lesion often occurs in the middle or upper part of the fruit or near the fruit surface of the fruit stalk. The occurrence is not related to direct sunlight. It occurs in the shady area under the leaf curtain, on the genital area of ​​the ear and on the bagged ear.

    The disease is scattered on the ears, and the lesions on the fruit surface are usually not concentrated. When the condition is mild, only a small number of fruit spikes usually occur, and the proportion of diseased ears does not exceed 10% . However, in some years, in some varieties, especially the mega-species varieties will be seriously ill, causing huge losses to production.

    Starting from the cause, improving the management of the orchard and enhancing the robustness of the branches and leaves is the fundamental basis for preventing the disease. It should be started from the following aspects.

    1 . Reduce the groundwater level, improve the drainage conditions, deepen the soil conditions, and improve the activity of the root system.

    2 . Balance the water management of the soil, especially to avoid the soil being over-wet throughout the growing season. After the rainy season, water should be flooded or covered with grass straw.

    3 . Strictly control the nitrogen fertilizer, timely pruning in summer, not allowed to grow, reducing the ineffective leaf area.

    4 . Foliar application of calcium fertilizer, commonly used calcium nitrate, amino acid calcium and so on. Calcium nitrate is used in a concentration of 0.4 to 0.5% . Amino acid calcium contains less calcium than calcium nitrate, but it has the highest utilization rate and is the safest and most effective. Used in the early and middle stages of the hard core period to promote healthy growth and prevent disease.

    5 . Before the hard core period, 2 to 3 times of O.1 to 0.15 % borax is applied to the roots , which is also beneficial to reduce the occurrence of this disease.