Powdery mildew:

A simple method of dealing with mildew, is to spray when the weather is humid or after periods of heavy rain with "milk of lime" or a cupric hydroxide solution.

(Milk of lime can be made by mixing 1 tablespoon of builders lime in 9 liters of water).

trace element deficiency :

To avoid trace element deficiency, always use a good quality fertilizer or supplement your fertilizing with a complete trace element. We recommend that you consult your local nursery for advice on feeding your PatioApple™