How is the litchi fruit cracked? What shall I do? How to prevent it?

Litchi tastes sweet and warm, has the effect of tonifying the brain and fitness, appetizer and spleen, and promoting appetite. However, fruit cracking often occurs in the planting process, which brings economic losses to fruit growers, so what is the matter of litchi fruit cracking? What shall I do? How to prevent it?

I. the causes of fruit cracking in litchi

Litchi fruit cracking mostly occurs in the young fruit stage and before fruit ripening, especially the mature fruit cracking is the most serious, which has the greatest effect on the yield. The causes of litchi fruit cracking are various, such as fruit structure, environmental conditions of fruit development, pests and diseases, cultivation and management conditions and so on. According to the research and observation over the past few years, the main reasons for fruit cracking are:

1. The differences among varieties, such as Nuomici, Tianyan and Guiwei, are easy to crack, while Huaizhi, Heye, Feizixiao and other varieties have less fruit cracking.

two。 During the pericarp development, the accumulated temperature was high, the pericarp development time was shortened, and the pericarp development was congenitally insufficient.

3. In the early stage of fruit development, the body nutrition supply was not balanced, and the contents of nitrogen and calcium in leaves and the proportion of nitrogen and potassium in fruit were significantly correlated with the degree of fruit cracking. The content of nitrogen and calcium in leaves is higher and the proportion of nitrogen and potassium in fruit is small, the phenomenon of fruit cracking is relatively reduced; in addition, the content of calcium and boron in pericarp is also related to fruit cracking, if insufficient will cause fruit cracking.

4. Due to the imbalance of soil water supply and low atmospheric humidity, when the fruit enters the period of rapid growth of aril (pulp), such as prolonged drought and showers or typhoon and rain, it often results in the decrease of atmospheric pressure and humidity, the decrease of leaf transpiration capacity and the decrease of pulp osmotic potential, which leads to the rapid growth of pulp, which exceeds the bearing capacity of pericarp.

5. The damage of diseases and pests, especially Phytophthora and anthracnose, is one of the important causes of fruit cracking.

6. Improper cultivation and management, including unreasonable measures such as fertilization, irrigation and drainage, make the soil environment worse and cause fruit cracking.

2. Symptoms of fruit cracking in litchi

The results of litchi generally showed that the peel was cracked and the pulp was exposed. This situation is not only manifested in a certain grain or a certain tree, at least a few trees, more than a whole mu. It is usually a large area of fruit cracking. Cracking will cause the fruit to fall. After falling, due to the loss of some fruits, litchi trees will transmit more water and nutrients to other fruits. In this way, it enters a cycle until all the fruit on the fruit tree falls. If it is due to diseases and insect pests, the fruit should be treated as soon as possible to prevent transmission to other fruit trees.

III. Main measures to prevent fruit cracking

1. Maintain a balanced supply of water during fruit development: when the weather is dry during fruit development, in addition to irrigation, it is also necessary to spray water on the crown so that the fruit can grow in a stable environment.

two。 Balanced supply of nutrients needed during fruit development: in addition to balanced supply of nitrogen, phosphorus and potassium (N ∶ P ∶ K about 1 ∶ 0.5 ∶ 1), calcium, boron and copper which are closely related to fruit development should be supplemented in time. Or increase the application of organic matter fertilizer in the flower and ear development and young fruit stage.

3. Taking measures such as root cutting and ring cutting in the middle and later stage of fruit development can weaken the root activity (fertilizer and water absorption capacity) and play a significant role in reducing fruit cracking.

4. Pest control: especially the fruits infected by Phytophthora and anthracnose are easy to cause peel cracking, so it is necessary to do a good job in pest control at the flowering stage and fruit development stage.

5. The application of chemical anti-cracking fruit: spraying "litchi special anti-cracking hormone" or "compound cytokinin" once at 10 days, 20 days and 30 days respectively, a total of 2-3 times. Spraying 2-3 times in the middle and late stage of fruit development had a significant effect on disease prevention and crack prevention. 、