After the rose, no flower is more popular than the chrysanthemum — Japan's national flower, grown in every colour and form. Its diseases are few, and each has a simple answer.

A white-to-grey powder on the leaves, which curl and die; a heavy attack kills the plant. Space plants for light and air; spray baking soda at 5 g per litre every 7–10 days, three to five times; in a severe attack use a sulphur fungicide (Thiovit) at 2 g/litre or propiconazole (Tilt 250 EC) at 0.5 ml/litre.

Yellow spots on the lower leaves turning brown to black. Mulch with straw so the lower leaves stay clean; water carefully and never wet the foliage; in a severe attack, carbendazim at 1 g/litre or a copper fungicide.

Brown water-soaked patches on petals, leaves and stems, then a grey-brown powder, in long damp cloudy weather. Space for air; spray Rovral (0.2 per cent) if needed.

Small, soft, black-green, worst in winter, sucking sap from leaves, shoots and flowers and deforming the buds. Pick off and destroy infested parts early; spray soap at 5 g per litre every 7–10 days, two or three times.

Clean tools, clean beds and healthy planting material prevent most of it before it starts.

Photo: Chrysanthemum × morifolium — Shuvaev / Wikimedia Commons (CC BY-SA 4.0)