Kilmarnock Willow Scab and Canker: Pruning and Cultural Control

Identifying the Disease

Orange powder on leaves that crinkle and die on a 2-year-old Kilmarnock (weeping) willow matches willow scab (Venturia saliciperda) and possibly black canker (Glomerella miyabeana). Scab hits early spring leaves; canker appears later on twigs.

Control Measures

• Prune out diseased twigs in dry weather; disinfect tools.
• Rake and destroy fallen leaves/twigs to remove overwintering spores.
• Avoid overhead irrigation—splash spreads spores.
• Maintain even soil moisture—drought stress worsens disease.

Chemical Options (Limited for Homeowners)

Mancozeb or captan sprays can protect new growth, but large willows make coverage difficult. Focus on cultural practices.

Protecting Nearby Trees

• Space plantings for air circulation.
• Monitor other willows/fruit trees for early symptoms.
• Clean tools between trees.

Memorial Tree Value

Given sentimental importance, prioritize sanitation and vigor. Consult a local arborist for on-site assessment if decline continues.