Answer:
The classic symptoms of chrysanthemum rust are brown pustules on the underside of leaves with yellow-green spots on the corresponding upper surface. Good hygiene is important, as this disease is thought to overwinter on decaying plant matter. So it is important to keep your site free of plant debris and well-ventilated. Also, when watering your plants, you should avoid wetting the leaves. Any infected parts should be removed and destroyed. Some gardeners use a diluted Bordeaux mixture or sulphur spray to control the spread of this disease. This should be applied as soon as symptoms are evident and can be re-applied every 10 days.