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 

print version| pdf version| email url    
Caption: Willow canker
Photo by: R.S. Byther
Poplar : Canker
(revision date: 4/28/2014)

Canker of poplar is a fungal disease infecting twigs and branches of all sizes. The fungi enter twigs through wound sites and cause development of sunken, circular, brown cankers in the bark. Branch cankers are often associated with dead twigs and may grow down the branch and infect larger limbs. Bark beneath the cankered area turns black, and the wood is reddish-brown and appears water-soaked. Black, gray, or white fungal fruiting bodies may be present. Twig and branch dieback (with or without apparent cankers) is also associated with this disease. Weakened trees are more susceptible to infection. Injuries caused by heat, drought, frost, or other diseases can provide infection sites.
Management Options

Non-Chemical Management
  • Some poplar hybrids such as 'Easter', 'Mighty Mo', 'Nor', and 'Platte' are somewhat resistant.
  • Provide proper culture. Healthy plants are more resistant to disease and more tolerant of minor damage.
  • Avoid wounding trees. Wounds provide sites of infection for the fungi.
  • Prune out and destroy (do not compost) infected and killed twigs and branches, both to reduce spread of disease and for safety reasons.
Select non-chemical management options as your first choice!

Chemical Management

None recommended


+ Show larger images

Caption: Willow canker
Photo by: R.S. Byther