Elite is a metabolite of microorganisms, the latest biological pesticide. The product is mainly composed of proteins (enzymes), and after decomposition, it becomes an amino acid that has a nutritional effect on plants. It can also promote plant growth without any residual pollution. It is an excellent pollution-free pesticide for controlling cucumber downy mildew. Ailiite agent began to use the cucumber when it first saw the diseased plant after colonization. The recommended dose is 800-1000 times for the general ward, and 600 times for the severe ward. The method is: 600 times solution 150 times sugar (2 two) + 150 times vinegar, spray on cloudy days, sunny days in the afternoon spray, spray once every 3 days. If the seedling growth potential is weak, the melon growth is slower, with other diseases when used: Astra 600 times solution + Sterling 500 times solution + gene activator 1000 times solution, spray once every 5-7 days. When a large amount of melon comes on the market, appropriate amount of potassium dihydrogen phosphate can be added; if the melon is bright and sweet, 300 times solution of Scherfon and 300 times of plant photosynthetic accelerator can be added.