Cotton brown wilt also known as "half yellow", wilt disease, verticillium wilt disease, also known as black heart disease, are vascular bundles, soil-borne diseases. At the same time, it can also spread through irrigation, farm implements, etc. The pathogens infect the cotton tissue and cause the whole plant to become infected. The diseased plants showed signs of wilting due to the impediment to the transport of water, and at the same time, the performance of the leaves and plants was abnormal. Often in the middle and late stages of cotton growth occurs. Dwarf wilt disease occurred in the cotton area, ranging from 10% to 30% to 50%, and the quality of cotton was significantly reduced. Therefore, prevention and control of yellow wilt is the key to increase cotton production and increase income. First, the symptoms of the two diseases are manifested as: vascular lesions after the victim, so that the stem appears brown stripes. Among them, wilt leaves showed yellow reticular markings. All or part of the diseased leaf veins faded and turned yellow. Finally, the whole leaf became yellowish and dry and coke came off. Verticillium wilt diseased leaves showed mosaic spots, leaf veins and nearby leaf were still green, and the edges of leaves were slightly Roll up but don't fall off easily. Severe dwarfing of plants, falling bells, falling bells, reduced fruit branches, or even fruit branches, the weight of single bolls is reduced, and the quality deteriorates. II. Comprehensive prevention and control measures 1. Breeding and cultivation of disease-resistant varieties: The selection of disease-resistant varieties is the fundamental way to prevent disease and produce high yields, and it can effectively control yellow wilt. The new varieties with both resistance to disease and high quality and high yield include Xinluhan No.13 and No.15. 2. Seed disinfection treatment: If concentrated sulphuric acid is used to remove fluff: Concentrated sulphuric acid is heated to 80-100 °C, cotton seeds are warmed to 20-30 °C, and then the hot sulphuric acid is slowly poured into the cotton seed, and it is stirred down to cotton. The cashmere is thoroughly de-absorbed, and the cotton is washed repeatedly with fresh water until it is not acidic. Then immersed in 55-60°C antibacterial agent "402" 2000 times hot liquid for 30 minutes, soaked and dried to sow. 3. Seedling transplanting and strengthening seedling management: Practices in various places have proven that transplanting cotton seedlings is not only an increase in production measures, but also a measure to reduce the damage caused by diseases. Using disease-free soil seedlings to transplant, you can avoid the infection of the seedling stage bacteria, delay the onset of disease, enhance the disease resistance of cotton seedlings to achieve control effect. 4. Rotation of crop rotation, reduce the source of disease: cotton field adhere to grass, green manure and other more than 3 years of rotation, the conditions of the implementation of flood and drought rotation, can effectively reduce the soil bacteria source, play a preventive effect. 5. Chemical control: (1) Foliar application of potassium dihydrogen phosphate. (2) Irrigation: In the early stage of disease, perforation is performed near the cotton root, or the head of the sprayer is unscrewed. Each cotton root is irrigated with cotton withered net, DD mixture, etc., so as to allow natural diffusion and adsorption to achieve curative effect.