Figure 1.2 Brown-veined leaves are suspected of manganese poisoning. Physiological problems are generally caused by crops absorbing excess manganese. It is recommended to spray the leaves with humic acid and other organic foliar fertilizers, and it is also recommended to apply humic acid and other organic leaf fertilizers as top dressing. Pay attention to the dosage when spraying, especially if it contains mancozeb fungicides.

Other suspected downy mildew, resistance varies from place to place. It is recommended to choose one or two mixtures of dimethomorph, manganese carbide, propamocarb hydrochloride, manganese metalaxyl, manganese oxalaxyl, flumorphazine, cyanofenazole, and flufenamid. , used interchangeably. Pay attention to controlling the humidity in the greenhouse. On rainy days when the humidity is high, it is recommended to use chlorothalonil aerosol to control the disease. Focus on prevention and comprehensive prevention and control. Alternate pesticide ingredients and do not use the same pesticide ingredients continuously. This is the principle of plant protection.