During the growth of the oil and melon, if it is malnutrition, improper management, or in the case of bad weather and certain diseases, it often causes the leaves to turn yellow, which affects the growth of the oil and melon and even the harvest. There are three main reasons for the yellowing of the melon and melon leaves. The first one is the lack of yellow leaves. The lack of yellow leaves is divided into middle and lower old leaves first yellow and middle and upper young leaves first yellow. The middle and lower old leaves are yellow, and the missing elements are mostly elements easily reusable in the plant body, such as nitrogen, potassium, and zinc. The growth of the whole plant was inhibited, and the older leaves were lack of green in the whole leaf. Prevention and control measures are foliar spray 0.2% urea solution 2-3 times. Plant growth was not significantly inhibited, leaf margin chlorosis and necrosis, sometimes there are chlorosis to necrotic spots on the leaf, potassium deficiency. Prevention and control measures are foliar spray of 0.3% potassium dihydrogen phosphate solution 2-3 times. The middle and upper young leaves are yellow, and most of the missing elements are difficult to move within the plant, such as calcium, zinc, and iron. The growing point was dead, the leaves lacked green and shrunk to necrosis; the roots were not well developed and there were few melons, which was caused by hypothermia. The prevention and control measures were foliar spraying of 500 times Green Fenway III. The growing point does not die, the leaves are yellow and white, and they are zinc deficiency and iron deficiency. The prevention and control measures are foliar spray of 0.3% iron sulfate plus 0.2% zinc sulfate solution. "Leaf by root length." In addition to foliar spraying, rooting agents or bio-fertilizers should also be applied to promote root growth and strengthen root system nutrient absorption. The second is the yellow leaves caused by the disease. Symptomatic use of drugs to prevent disease caused by yellow leaves. Such as yellow downy mildew, the prevention and control strategy is available 58% metalaxyl manganese zinc 500 times, 600 times of dimethomorph morphological spray, 5-7 days, continuous spraying 3-4 times. Another example is the wilt yellow leaf (when scions do not cut off roots or grow new roots, causing fusarium wilt caused by the inoculation of fusarium wilt). The prevention and control strategy is to use 50% carbendazim 300 times solution and 50% DT300 times solution to root control, 5 Irrigation once a day, even irrigation 2-3 times. The third is yellow leaves caused by phytotoxicity or gas damage. Most of the air damage occurred in the middle and lower leaves, mostly because the base fertilizer was not fully cooked or undercompetent or was flushed with excessive ammonium nitrogen fertilizer. Therefore, to avoid the occurrence of airborne yellow leaves, the first priority should be paid attention to the base fertilizer must be decomposed, and the amount of nitrogen fertilizer should be appropriate. , to release the wind in a timely manner and other aspects of management. The phytotoxicity is a common problem in the production of oil and melon. It is mainly caused by excessive medication and excessive spraying. In severe cases, it can cause the plants to stop growing and even die. Therefore, to remind vegetable farmers in the production of winter oil melon must pay attention to the rational drug use this pass, in order to facilitate the prevention and treatment of diseases, but will not affect the growth of melon. The prevention and treatment of such yellow leaves can be sprayed with 6,000 times the amount of cytokinin mixed with 600 times more cytokinin supplemented with 500 times the nucleic acid leaf lotion for treatment.