Poplar: Leaf and shoot blight

categories: Ornamental trees Ornamentals Poplar Poplar Diseases

last review date: 2025-06-28 09:06

Biology

Leaf and shoot blight is a fungal disease which affects poplars, aspens, and willows. The fungus infects succulent leaves and twigs. Mature plant tissues are resistant.

Initial symptoms include the development of rapidly expanding dark brown or black spots on the leaves and shoots. Affected leaves and shoots are killed quickly, with the tissues turning dry and brittle.

Killed shoots often tip over in a blackened “shepherd’s crook”.

The fungi infecting poplars and aspens overwinter in infected shoots, but probably not in leaves. The disease can be spread by splashing water from the previous year’s infected shoots to new growth.

Management Options

See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.

Non-chemical Management

Select non-chemical management options as your first choice!

• Space trees and prune to reduce humidity in the planting.
• Provide proper culture. Healthy, established trees are less severely affected by disease.
• Prune out and destroy infected plant parts when noticed (if practical).
• Rake and destroy infected leaves as a precautionary measure.
• Avoid overhead irrigation.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• Make applications during early shoot growth in spring.
• Homeowners should not make foliar applications to trees over 10 ft tall.
• Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Approved Pesticides

Examples of pesticides that are legal for home use in Washington State are listed below.
The list may not include all products registered for this use.

• Bonide Infuse Systemic Disease Control
  Active ingredient: propiconazole (EPA reg. 100-773-4)