1. Causes of Rot: Rot is the most common failure phenomenon in cactus flower cultivation. Cutting is easy to rot, grafting is easy to rot, sowing seedlings are easy to rot, and the formed plants will suddenly rot when they are good. There are many reasons for decay, which can be summarized into two categories, one is pathological and the other is physiological. Pathological decay is caused by pathogenic bacteria infection. There are pathogenic bacteria and fungi in soil and surrounding environment, water and fertilizer, and tools for reproduction. If you don't pay attention to disinfection and sterilization, bacteria can easily multiply in soil and environment and harm plants. Wounds caused by human beings during reproduction, wounds caused by insect bites, epidermis of seedlings and the lower part of stems of molded plants are usually "shortcuts" for germs to invade plants. When environmental conditions are conducive to the propagation of pathogenic bacteria, plants, especially seedlings, often die quickly in batches, and physiological rot is mostly caused by poor management. Persistent excessive humidity and waterlogging of potted plants often lead to hypoxia and suffocation of roots, which quickly destroys roots. If the light is too strong, the ventilation is not smooth, and the ambient temperature is too high, plants may rot quickly. When pests are rampant in the soil, the roots may be completely destroyed, which will lead to plant rot over time. Excessive fertilization or fertilizer mixed with incompletely decomposed organic matter will cause "root burning" and plant rot after application. Inappropriate temperature adjustment in the cultivation site continuously exceeds the optimum temperature for plant growth, which accelerates the respiration rate of plants and consumes more energy than that formed by long-term photosynthesis. In this case, plants grow weakly, and even lead to decay in severe cases.

Second, the prevention and control of rot: the prevention and control of rot should be put in the first place. First of all, to improve the environmental conditions of cultivation sites, especially the molded plants cultivated at the roots, requires clean environment, good ventilation, sufficient light and moderate temperature, which can greatly reduce the occurrence and spread of pathogenic bacteria. Secondly, it is necessary to strengthen cultivation management, and the cultivated soil used should not be mixed with immature organic fertilizer, and the fertilizer should be light and not thick. If you find soil waterlogging, you should immediately buckle the basin, wash the roots and blow; If the root system does not change color, the root hair of the fibrous root is still intact, which can be observed in the semi-shade of the basin for a period of time; You can cut off part of the root system and plant it after the wound is dry; All the bad roots should be cut off, and then cut off the roots when the wound is dry.

It must be pointed out that some large plants grow well and have dense plant tissues. When the roots are damaged by pests or other reasons, sometimes the appearance changes little, and some can still bloom as usual, and gradually weaken after a long time, and finally rot. In this case, it is necessary to strengthen observation during cultivation. If it is found that there are many rodents and other pests in the basin or the soil in the basin is delayed after watering, it is necessary to suspect that there is something wrong with the root system of the plant, and the inspection of taking off the basin may be able to save it. Spraying fungicides on plants or the surrounding environment regularly has a certain effect on preventing the occurrence of rot. Commonly used fungicides are zineb (concentration 0. 15 ~ 0.35%), carbendazim or thiophanate-methyl (concentration 0. 1%). Once yellowish brown soft rot spots caused by local infection are found on plants, they should be dug out immediately, and a part of adjacent healthy tissues should be dug out, and then coated with sulfur powder or charcoal powder to dry the wounds. When the weather is bad, you can dry the wound with a hair dryer and then isolate it for a period of time. When the local rotten part is large, the healthy part can be cut off for cutting or grafting, and the diseased part will be destroyed. If the diseased part is in the upper part, the upper part can be removed first. The lower healthy part is regarded as the mother plant. Because the plants around the diseased plants are likely to be infected again, they should be sprayed immediately and the environment should be ventilated.