Poplar: Leaf and shoot blight

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

Use Integrated Pest Management (IPM) for successful plant problem management.

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

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

• Bonide Infuse Systemic Disease Control
  Active ingredient: propiconazole [EPA registration number: 100-773-4]
• This list may not include all products registered for this use.

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