(I) Symptoms of onset of disease Bacterial wilt is harmful to the roots, stems and leaves of potatoes. The most obvious symptom is wilt. The affected plants did not have obvious symptoms a few days before the onset of the disease. A few days later, the stems and leaves suddenly withered. Since these leaves were still green at the beginning of the disease, they were called bacterial wilt. After the plants became infected, the initial diseased plants were wilted during the day and returned to normal after the evening. The diseased plants in the later stages did not recover and the whole plant withered and died. Diseased stems are rough, often with adventitious roots growing, longitudinal stem disease stems, visible vascular bundles have dark brown to black lines. The stalks were cut transversely and the incisions were squeezed by hand. Milky white mucus flowed out from the cut surface, and the interior of the stalk rotted empty at the onset of the disease. (B) the incidence of disease Potato bacterial wilt disease is a disease caused by Pseudomonas, pathogenic bacteria mainly with the disease residue left in the soil in the winter, without the host, the bacteria can survive in the soil 14 months to 6 years. The bacteria invade the roots of potato plants, mainly through rainwater, irrigation water, fertilizers, diseased seedlings, diseased soil, insects, humans, and production tools. Moreover, the bacteria can be repeatedly transmitted and infested several times in the same year, causing disease epidemics. Perennial disease has a higher incidence than land that is often planted in rotation, and disease-resistant varieties have a higher incidence. (C) control measures 1, selection of disease-resistant varieties in accordance with the actual needs of production, use the comparison of early disease resistance and good quality varieties, early maturing cultivation, for the morning market, in order to obtain higher economic benefits. 2. A reasonable crop rotation should be carried out in the dryland of the plot, and 3 to 5 years of crop rotation should be carried out with melons, soybeans, glutinous rice, etc. Paddy fields should be used for 2 years or more for potatoes and rice. Use loose, well-drained plots and use 2 rows of high-riding cultivation. The initial disease strain was removed and the treatment was concentrated. 3, rational fertilization more farm fertilizer, organic fertilizer, compound fertilizer, reduce the amount of fertilizer urea, about 15 days after emergence, per acre applied maturity 2000 kg of organic fertilizer or plant ash (generation of potash) 2000 kg, has a better defense Increased disease effect. 4. Chemical control 1 Inject 2% formalin or 20% lime water in the diseased hole, and remove lime from the diseased hole to prevent the spread of soil bacteria. 2 At the beginning of the disease, 50% of the water-soluble powder can be sprayed with 900-1100 times or 53.8% of the water-soluble powder and 900-1100 times of the wettable powder or 20% of the wet powder can be 1000 times or 50% of the mancozeb 500. Double or antibacterial agent "402" 1000 times Irrigation root or 1:2:240 (copper sulfate: Lime: Water) Bordeaux Irrigation roots, each root Irrigation 0.25-0.5 kg, sprinkled once every 10 days, continuous sprinkler irrigation 2 ~3 times, so that the above-mentioned agents alternately rotate and use better control effect. At the same time pay attention to the prevention and control of underground pests and nematode diseases, in order to reduce root insect damage and reduce the incidence.