Post category: Willow canker
Willow canker is a severe disease of some kinds of willow. It is a fungal disease that attacks the leaves and twigs soon after leaf-break in spring. It causes spotting, which sometimes join up and the subsequent drying of the leaves causes curling and distortion. Badly damaged leaves wither and are shed.
It can affect twigs too causing them to die at the tip and fall off. It can severely affect the appearance of a tree. Although spraying with copper sprays, potato blight sprays or Bordeaux mixture might reduce infection, this is not practical. It is worst in damp weather and less in a dry year. The weeping willow variety ‘Chrysocoma’ is very susceptible. Persistent attacks might require removal of the tree. An application of potash at 30g per square metre in spring for three years might help to toughen the bark and foliage.