Overview
A common fungal disease of spruce and other conifers that causes branch dieback, typically starting from the lowest branches and progressing upward. Colorado blue spruce and Norway spruce are especially susceptible. The fungus enters through wounds or stressed tissue. White resin bleeding on bark is a hallmark sign. Stressed trees are most vulnerable.
- Type
- Fungus
- Severity
- HIGH
- Source
- Colorado State University Extension
Symptoms
Branch dieback starting at the bottom of the tree and progressing upward, white to bluish-white resin patches on bark of affected branches, brown discolored needles on dead branches that remain attached, sunken cankers on branches with resin oozing, dead branches scattered throughout lower crown
Affected Species
Geographic Spread
Treatments
Pruning and Sanitation
Prune dead and infected branches during dry weather, making cuts well below the cankered area. Disinfect tools between cuts. Remove and destroy pruned material.
Stress Reduction
Water trees deeply during drought, avoid wounding bark, mulch around the base. Maintain tree vigor to resist infection since there is no effective fungicide treatment for cytospora.
Recommended Products & Tools
Helpful supplies for managing Cytospora Canker. Always read and follow label directions, and confirm a diagnosis before treating.
Broad-spectrum protectant for many fungal leaf and bark diseases.
Preventive spray for needle cast, leaf spots, and blights.
Sharp, clean cuts to remove affected wood — a tree-care essential.
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Frequently Asked Questions
What is Cytospora Canker?
A common fungal disease of spruce and other conifers that causes branch dieback, typically starting from the lowest branches and progressing upward. Colorado blue spruce and Norway spruce are especially susceptible. The fungus enters through wounds or stressed tissue. White resin bleeding on bark is a hallmark sign. Stressed trees are most vulnerable.
What are the symptoms of Cytospora Canker?
Branch dieback starting at the bottom of the tree and progressing upward, white to bluish-white resin patches on bark of affected branches, brown discolored needles on dead branches that remain attached, sunken cankers on branches with resin oozing, dead branches scattered throughout lower crown
Where is Cytospora Canker currently found?
Cytospora Canker is currently active in Colorado, Connecticut, Iowa, Illinois, Indiana, Kansas, Kentucky, Massachusetts, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, South Dakota, Virginia, Vermont, Wisconsin, West Virginia, Wyoming. It has been reported in 25 total states across the United States.
What plants are affected by Cytospora Canker?
Cytospora Canker affects Eastern White Pine, Colorado Blue Spruce, Norway Spruce, Douglas Fir. Susceptibility varies by species.
How do I treat Cytospora Canker?
Treatment options for Cytospora Canker include: Pruning and Sanitation, Stress Reduction. Treatment approaches may include chemical, biological, cultural, and mechanical methods depending on the severity and context.