Occurrence law, leukoplakia is a fungal disease, mainly harmful to the leaves, mostly from the first part of the leaf. The suitable temperature for onset is 11-23 °C, and the relative humidity is above 60%. It is a low-temperature and high-humidity disease, and continuous rainfall can promote disease prevalence. Continuous cropping is low and the water is too popular to be susceptible to disease. Field identification, in the early stage of the disease, the leaves of the leaves have brown round small spots, which gradually expand into round white lesions. The surface can be faintly visible with one or two lines, the periphery of the lesions has a halo, and the back is convex. Later lesions are translucent, thin as paper, and sometimes cracked and perforated. When the disease is serious, the lesions become irregular large spots, the leaves are yellow and dry, and the leaves are yellow and dry from the outside to the inner layer, which may cause the affected field to be yellow. Control method: 2% antimycotic 120 water 200 times solution, or 1% agricultural anti-wuyin liquid 150 times solution, spray once every 6 days, even spray 2-3 times. Or use 70% thiophanate-methyl WP 800 times solution 75% chlorothalonil WP 600 times solution, 50% carbendazim WP 800 times solution, 50% carbendazim WP 1000 times solution , 50% Vinyl nucleocapsid WP 1000 times solution 60% cream Mn-Zn wettable powder 600 times solution, 50% different bacteria Fumei double wettable powder 800 times liquid spray, interval 10 days, 2-3 consecutive times When using the medicine, it must be used together with the new high-fat film. The medicine can be used alternately to improve the control effect and avoid the resistance. Xi'an Healthway Biotech Co.,Ltd , https://www.xianhealthway.com