The pathogen of winter jujube seedlings: the pathogen of jujube stem rot is Alternaria spp. belonging to the subfamily of fungi. It is a common soil resident in the tropical and subtropical regions of the world. The conidia are nearly spherical or oblate, 89-275 micrometers x 98 - 225 micrometers in diameter, buried under the host epidermis. The posterior hole penetrates the epidermis and is exposed. The conidia are elliptical or ovate, colorless, 16 - 32 μm × 5 - 10 μm in size. It has a wide range of hosts, which not only harms jujube trees, but also many kinds of seedlings, such as seedlings of conifers and broad-leaved trees, such as ginkgo, camphor, cedar, fir, metasequoia, masson pine, slash pine, sylvestris, cypress, and side. Cypress, gum arabic, blackbird, jatropha, Eucommia, etc. Most of it happens on the trunk and the trunk. At the beginning of the disease, the surface of the affected area was reddish brown, slightly swollen and watery. The diseased tissue is soft, the diseased skin is easily peeled off, and the internal tissue is dark reddish brown with an alcoholic odor. Sometimes the yellow-brown liquid flows out of the affected area. In the later stage, the diseased parts of jujube seedlings were dehydrated, dried and shrunk, sunken, hardened, dark brown, and cracked at the edges. There are many small black spots on the surface. This is the subunit of the pathogen. There are conidia and capsules inside. After the rain or when it rains, a small yellow curly silky satiety horn is ejected from the top of the small black spot. If the lesions wrap around the branches, they can cause the branches to die. Prevention and treatment methods of winter jujube seedlings: 1. Add high-quality organic fertilizer to promote the growth of jujube seedlings and improve disease resistance. Applying manure as a base fertilizer, 3000-5000 kg per 667 square meters, can greatly reduce the disease rate. At the same time, it may affect the changes of the antagonistic microbial population in the soil and inhibit the growth and spread of the bacteria. 2. In the early stage of the disease, use 50% carbendazim or 65-generation Mn-Zn WP 500 times solution, or 70% chlorothalonil WP 800 times solution. In the middle stage of the disease, use 98% carbendazim 2000~3000 times liquid irrigation. root