In the past two years, the consumption of sweet potatoes has grown rapidly and the prices have also increased. Many farmers’ friends have joined the ranks of sweet potato cultivation. However, due to improper introduction, black spot and stem nematode diseases of sweet potatoes have become increasingly serious. According to the author's investigation, the rate of diseased plants in many sweet potato plots was as high as 40% or more, which was caused by improper selection of seedlings. Therefore, how to choose sweet potato seedlings is an important issue that must be solved in the production of sweet potatoes. When selecting seedlings, we must grasp the following aspects: The high-quality and high-product varieties of China's sweet potato production areas are selected, and most of them are planted on thin and thin hills. Therefore, the spring potato should be selected to be drought-tolerant, thin-tolerant and long-lasting high-yield and high-quality varieties. Such as Jinshu 21, Xushu 43-14, Jishu 15, Yushu 13th, Yushu 12, Haoshu 6-8, Yantai 22 and other varieties. The purple sweet potato has higher nutritional and health functions than ordinary sweet potato, but the yield is slightly lower than that of common sweet potato. At present, purple sweet potatoes are mainly used for fresh food. They can be selected from fresh purple potato varieties such as Jishu No. 18, Caizi, Jingshu No. 6, Violet, and American black potatoes, etc. according to local conditions. The correct selection of seedlings and spring potatoes is best to use virus-free high-cut seedlings, one hundred seedlings weighing more than 500 grams, seedling height 20 to 25 centimeters, and between 5-7 shoots per plant, stout stalks, top three leaves flush, leaves green, Large and fat, no pests and diseases. High-cutting seedlings can not only prevent seedling damage and damage seed potatoes, affect the growth of other seedlings, but also reduce the spread of virus diseases, black spot disease, nematode diseases and other diseases. Planting high-cutting seedlings, generally more than planting rooted seedlings, disease reduction 36% to 85.7%, increase production by more than 10%. In the summer, the seedlings were planted and the mandibles of the secondary seedlings in Daejeon were used to produce the highest yield in the top section, followed by the middle section and the worst in the base section. According to tests, the top section increased production by 17.2% over the middle section and increased by 20.3% over the base section. This is because the top segment of the cell tissue activity is high, strong growth potential, is conducive to the formation of potato blocks, and the more the degree of lignification of cell tissue to the base, the greater the vitality of life is not conducive to the formation of potato block. Disinfection of seedlings on the basis of high-cut seedlings, 50% carbendazim 2000 times liquid seedlings before transplanting for 3 to 4 minutes, can kill black spot; with 50% phoxim 1000 liquid seedlings for 20 minutes, It can kill stem nematode diseases and prevent the spread of pests and diseases in the field. According to experiments, seedlings treated with phoxim solution can reduce the incidence of stem nematode disease by 85%. Do a good job in crop rotation. On the basis of selecting seedlings, choose land plots that have not been planted with sweet potatoes for more than three years. Changing manure, such as fertilization, is not only an effective measure to prevent and control diseases, but it is also very conducive to increase production of sweet potatoes. Tetanus Shot,varicella vaccine, Live,Hepatitis B Injection,Hep B Vaccine FOSHAN PHARMA CO., LTD. , https://www.foshanmedicine.com