For powdery mildew treatment and control, you can do a number of things.
Firstly, powdery mildew treatment involves removing and destroying all infected plant parts immediately. Powdery mildew grows best in damp or high humidity, so avoid overcrowding plants by pruning and thinning, as this will create good air circulation and minimise humidity.
It is also a good idea to avoid sheltered spaces, such as walls or fences, as this is where the air is most likely to be still - increasing the likelihood of infection. Instead, we recommend planting seeds in sun-soaked areas of your garden or allotment and avoid overhead watering early in the morning or in the evening.
To remove the spores, wash the leaves thoroughly top and bottom every 1-2 weeks. You can use an appropriate fungicide to treat this disease, but make sure you follow the manufacturer’s instructions.