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| Table: Diagnosis and Control of Cytospora Canker | ||
| Pest Identification | Host Plants | Damage Symptoms |
| Cytospora Canker Cytospora species |
In the Midwest: spruces, especially Colorado blue and Norway, and firs |
Scattered branch defoliation and dieback that typically occurs on lower branches
first and progresses from the branch tips inward.
Cankers (localized dead areas on branches or the main trunk) develop and are often covered by copious amounts of exuding sap. |
| Monitoring | Control Options | Pesticides |
| Inspect nursery stock carefully, and plant only healthy trees. Look for individual branch dieback that progresses from the branch tip inward. Branch dieback can be evident any time of year. Look for sap exuding from cankers on branches and the main trunk. |
Physical: Maintain good tree vigor. Mulching, watering during drought, periodic fertilization, and weed control may be helpful. Select planting sites carefully. Avoid stress-prone sites such as open, exposed sites where trees are more apt to experience drought and winter injury. Prune out and destroy severely infected branches. Prune only during dry weather.
Chemical: |
None available. |
| Description and Life History | ||
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Description: Trees under stress are most susceptible to attack. Common stressors
include drought, mechanical injuries caused by hail, ice or snow, freeze damage, poor
site conditions, and other disease or insect problems. Life History: The fungus invades branches through breaks in the outer bark. Once established, the fungus produces fruiting structures on dead tissue and releases gelatinous threads of spores during wet weather. These infective spores are spread by wind, rain, and on pruning tools. | ||
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