WSU Extension


Bacterial blight 
Leaf and shoot blight 
Leaf blister 
Leaf rust 
Marssonina leaf spot 
Oystershell scale 
Poplar petiole gall aphids 
Poplar-and-willow borer 
Satin moth 
Tent caterpillars 

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Caption: Poplar leaf blister
Photo by: R.S. Byther
Poplar : Leaf blister
(revision date: 1/22/2016)

Leaf blister is a fungal disease which infects the leaves of poplars. Leaves develop small to large yellow-green blisters or mounds on the upper surface. Severely infected leaves may be distorted. The undersides of the blisters develop a golden-yellow powdery or velvety coating or "bloom" which later turns brown. In early stages, the yellow bloom may be confused with rust. Rust, however, lacks the distinct, thickened, blistered areas common to leaf blister. Infection occurs following cool, wet weather in the spring. Infected leaves seldom drop. Although unsightly, leaf blister causes little real damage to trees.
Management Options

Non-Chemical Management
  • Pick out and destroy severely infected leaves, if desired, to improve appearance of small trees.
Select non-chemical management options as your first choice!

Chemical Management

Research data on controlling leaf blister is lacking. The disease is similar to peach leaf curl. Three sequential fungicide applications beginning January 1st and given at 3- to 4-week intervals may provide some control. 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 Fung-onil Multi-Purpose Fungicide Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 60063-9-4
  • Bonide Liquid Copper Fungicide Conc/Organic Gardening
    Active ingredient: copper octanoate  |  EPA reg no: 67702-2-4
  • GardenTech Daconil Fungicide Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 67572-82-71004
  • Ortho Max Garden Disease Control Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 239-2522
  • This list may not include all products registered for this use.

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Caption: Poplar leaf blister
Photo by: R.S. Byther