Dahlia 'Camano Ariel' problems — and how to fix them

Favoured by warm dry days and cool nights; apply sulphur-based fungicide early or use potassium bicarbonate spray at first signs.

Particularly fond of waterlily-form dahlias; set traps of damp straw or corrugated cardboard near stems overnight and dispose each morning.

Damage young shoots in spring; use biological controls or iron phosphate pellets around emerging plants.

Causes yellow streaking and mottling on leaves; spread by aphids — control aphid populations promptly and remove infected plants to prevent spread.

Bacterial swellings at the stem base; avoid wounding tubers during planting and do not replant in infected soil for several seasons.