Potato late blight prevention methods: 1, agricultural control: 1 strengthen field management: more cultivator, deep cultivator, high soil between the plants, pay attention to ridging after irrigation; furrow irrigation, low pay attention to drainage fields, reduce soil moisture. Prevention of epidemics of late blight occurs. 2 Remove the central diseased plants in time: When the potato plants in the field are budded and ridged, the cultivars should be checked in dense, high-humidity, flowering susceptible varieties and fields, and when the central diseased plant is found, the deep-buried plant should be removed in time to prevent the central plants from growing around. The spread has expanded the area of ​​late blight. 2. Chemical control: After the potato enters the early flowering stage, a central disease strain appears in Daeje. Soon, the new drugs such as Rhizoctonia, Dioscorea, and Baidefu are used for spraying to prevent late blight. Watered 45 kg manual spray or watered 10 kg motorized spray. According to the forecast and the incidence of disease, every 7 - 10 days 1 time, continuous control of 2 --- 3 times.