If the small white patches of mildew are just starting, you should be able to catch it early and stop further spreading by using a diluted milk solution of equal parts water and milk.
If the situation is out of control, either remove the affected leaves or the whole plant and destroy it.
Chamomile tea is a fungicide. Prepare a cup of chamomile tea and allow it to steep for 10 minutes. Once cool it can be sprayed on the affected leaves, top and bottom.
Cinnamon powder sprinkled around plants and soil also controls fungus.
If you can make or buy good quality Compost tea, this is extremely beneficial. Compost tea balances the microbes and bacteria in the soil, thus fighting the disease organisms and providing active healthy organisms and fertiliser to strengthen plants and make them resistant to problems.
Clean pots: Between seasons with clay pots, give them a good clean if any sign of disease or pests was in the previous plants.
Fusarium wilt in potted herbs plants are an example. A soak in bleach works, but then you must re-soak in plain water to remove the bleach. One part vinegar to 5 parts water is a better soak solution, and give the pot a good scrub down also.
Natural Pest Control Remedies Exactly what solutions have proven to work!
The A-Z of Garden Pests Have you got one or more of these garden pests? Check these out.