It should be powdery mildew. For powdery mildew, it is recommended to choose one of pyraclostrobin, pyraclostrobin, pyrizofen sulfonate, dimezofen, and tetrafluoroacetate. Use alternately. These products are highly safe and effective, but cost a little more. The dosage can be reduced during prevention. You can also use triazole pesticides such as propiconazole, flusilazole, myclobutanil or hexaconazole, etc., which are low-cost, but be careful that excessive dosage may inhibit growth or cause burnt flowers or deformed fruits. The pesticide should be applied all over. If it is a greenhouse, the humidity must be controlled, and aerosols should be used on rainy days to control the development of the disease. Be careful when using triazole pesticides such as triadecamorpholine, epoconazole, and triadimefon. 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.