Aspen shoot and leaf blight

Venturia macularis

Aspen shoot and leaf blight occurs primarily on trembling aspen (Populus tremuloides). New infections happen in the spring during bud break and leaf expansion.

On this page

• Description
• Host tree species
• Damage symptoms
• Management
• Identification images

Description

Venturia macularis causes shoot blight which stops the growth and causes deformities in terminal shoots, resulting in a "shepherd’s crook". Black leaf spots also occur, and these spots expand and merge, covering the entire leaf, which wilts. Periods of mild wet spring weather are conducive to epidemics, but the disease diminishes with the arrival of hot and sunny summer days. 

Venturia macularis is widely distributed throughout the range of its hosts across the province but infection is particularly severe in northern B.C. . This disease is most severe in young stands, and has the greatest impact in intensively managed plantations.

Host tree species

Aspen shoot and leaf blight typically only affects trembling aspen (P. tremuloides)

Damage symptoms

V. macularis can kill most shoots in trembling aspen stands that regenerate by sprouting. Repeated infections cause a reduction in growth and may result in small and stunted deformed crowns. The damage is most commonly reported from the Northeast, Omineca and Skeena regions.

Management

In managed plantations it can be possible to reduce the magnitude and spread of the disease by removing and destroying the leaves that drop to the ground in the fall.

Identification images

Further Reading

Read more about a aspen leaf blight in the Field Guide to Forest Damage in B.C. (PDF, 6.6MB)