Willow Diseases

Disease	Symptoms	Pathogen/Cause	Management
Crown Gall	Rough galls form on stems at the soil line or on roots. If the galls engulf the stem or root, that tissue will be killed.	Agrobacterium tumefaciens	Remove severely affected trees. Do not replace them with herbaceous or woody plants susceptible to crown gall.
Black Canker	Black areas form on leaves and spread to engulf and kill larger woody twigs in the summer. If the weather is wet, pink spore masses form on blackened twig cankers. This disease often occurs on trees with blight (see below).	Phyalospora miyabeana	Do not plant highly susceptible cultivars in the landscape.
Blight or Scab	Newly formed leaves and twigs are quickly browned in the spring during wet weather. Infected leaves fall. Olive-brown spores form on the surface of infected tissue.	Venturia saliciperda	Apply a fungicide to protect the foliage of highly valued trees.