Downy mildew of millet, commonly known as white disease of millet, is a systemic fungal disease. Oospores are attached to the surface of seeds or exist in fertilizers and soil. Oospores germinate at the seedling stage of millet and invade the seedlings. With the growth of millet, germs grow and multiply in plants, and finally symptoms appear. To prevent and control the disease, resistant varieties should be selected and the seeds should be disinfected (that is, chemical dressing), and metalaxyl dressing accounts for 0.2-0.3% of the seed weight. Third, it is necessary to pull out the diseased plants in time, take them out of the field and bury them or burn them. Don't treat the symptoms later, not the root cause.