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

Non-Chemical Management

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.

Select non-chemical management options as your first choice!

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.

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 reg no: 100-773-4
This list may not include all products registered for this use.

Images

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Caption: Poplar leaf and shoot blight Photo by: R.S. Byther
Caption: Poplar leaf and shoot blight Photo by: G.A. Chastagner
Caption: Poplar leaf and shoot blight Photo by: R.S. Byther

WSU Extension

Hortsense