Commonly seen as raised orange or brown/black spots or pustules on the underside of leaves and stems. Common on roses, hollyhocks, fuchsias, pelargoniums and many other plants.
Cultural measure: Avoid using plant foods which contain hight proportions of nitrogen. Pick off and burn diseased leaves.
Product solution: Consider using Systhane Fungus Fighter, Fungus Fighter Disease Control, ,Multirose concentrate 2, Multirose 2 Ready To Use where possible.