Frost of fruit trees, different kinds of fruit trees and the same kind of fruit trees have different minimum critical temperatures for their ability to resist cold and freeze, so the severity of frost damage is also different. However, if you encounter extremely bad cold air and cold current that continuously drops below 10℃, it will bring incalculable losses to any fruit tree, resulting in the death of some main branches or crowns. For example, in spring, when fruit trees sprout to bloom, they will encounter strong cooling frost, which will often cause a large area of fruit trees to reduce production. Seriously, it will stop harvesting, just like the severe cold and late frost freezing injury in 2018, which is fierce, causing severe freezing injury to large areas of fruit trees in the country, reducing production in a large area, and fruit trees that sprout and bloom early will stop harvesting. Frost mainly includes: autumn frost early frost, spring frost late frost in winter and spring alternate seasons (that is, late spring cold). Autumn frost is generally caused by intense cooling or continuous low temperature during the overwintering period of fruit trees. The main frozen parts are branches and roots, and relatively shallow root fruit trees are severely frozen. Spring frost is the frost caused by severe cooling when winter and spring alternate, and the freezing damage is relatively serious, including the freezing damage of branches, roots and flower buds. From the degree of freezing damage, the cold in late spring is more serious than the cold in autumn. Different kinds of fruit trees with shallow roots are prone to frost. In the same kind of fruit trees, young trees have weak cold resistance and are more prone to frost damage than older trees. Geographically, the frost damage on shady slopes is heavier than that on sunny slopes, the frost damage on hilltops is heavier than that on Sichuan roads, and the frost damage on weak trees is heavier than that on healthy trees. However, the internal management is extensive, and the consciousness of preventing freezing injury is not strong, which is also an important factor to increase freezing injury, such as unreasonable supply of fertilizer and water, inadequate pruning and thinning, excessive nutrient growth, low lignification degree of branches, or lack of fertilizer and water, insufficient nutrient storage of trees, which reduces the cold resistance of fruit trees and increases the degree of freezing injury, and the consciousness of preventing freezing injury is not strong. Obviously, there is a big cooling cold snap in the weather forecast, but we are still lucky. As a result, The frost damage in autumn mainly occurs in the tree body, branches and roots. When the frost damage is serious, the main branch or the whole crown will all die. When the frost damage is serious in the Spring Festival Evening, the flower bud inflorescence will freeze to death, and the branches will freeze to death. Even the flower buds left behind are not easy to set fruit, and the fruit that sits is easy to drop after setting fruit, and the fruit that sits is also of small fruit quality. (1), suitable for planting: when planting fruit trees, try to choose plots with fertile soil, flat terrain, good lighting conditions, leeward and deep soil layers, and avoid building orchards at the top of the mountain pass and the tuyere. ② Applying base fertilizer and increasing phosphorus and potassium fertilizer in autumn: after fruit picking, timely apply fertilizer to improve the nutrition of fruit trees before overwintering, so as to enhance the cold resistance of fruit trees. While applying sufficient decomposed organic fertilizer, stabilize nitrogen fertilizer, increase phosphorus fertilizer, supplement potassium fertilizer, control prosperity and promote growth, and improve the cold resistance and freezing resistance of fruit trees. ③ Reasonable pruning: In summer and autumn when fruit trees grow, combining pruning and thinning, control the overgrown branches to get too dense branches, reduce nutrient consumption, renew and rejuvenate, improve lignification and enhance cold and freezing resistance. (4) timely prevention and control of pests and diseases: sulfur mixture can be sprayed to prevent pests and diseases before germination of fruit trees, imidacloprid and mirex can be sprayed to prevent aphids and red spiders during the growth period of fruit trees.It is necessary to spray chemicals in advance to ensure the robust growth of fruit trees and improve their ability to resist cold and freezing. ⑤ White-coated trunk: Before entering the early winter, the trunk of fruit trees should be coated with stone sulfur mixture in time, and then wrapped with straw, and then wrapped with plastic strips, which can further keep warm and improve the cold and freezing resistance of fruit trees. ⑥. Chemical anti-freezing: In late winter and early spring, the whole tree crown can be sprayed with high-fat film to suppress evaporation and heat preservation agent to protect branches, and high-ion anti-freezing agent can also be sprayed to prevent freezing injury of fruit trees. Remedial measures after frost: ① Cut off the damaged branches in time. After cutting off the branches that are frozen and dead, it should be smeared with wound healing agent and wrapped with plastic strips to prevent evaporation and infection, which is beneficial to wound healing and prevention of pests and diseases. (2) Strengthen fertilizer and water, water ahead of time and topdressing chemical fertilizer, supplement nutrients, and promote the recovery of tree potential. ③ Spraying brassinolide and potassium dihydrogen phosphate, after freezing injury of fruit trees, spraying brassinolide solution can alleviate freezing injury and promote cells, and spraying it mixed with potassium dihydrogen phosphate can protect the trees and promote the recovery of tree vigor as soon as possible. The above is my personal opinion on this issue for your reference! thank you