Boxwood: Canker
Photo by: R.S. Byther
Biology
Boxwood canker is caused by a fungus which often infects branches through pruning wounds or at branch crotches, where infected, dead leaves have accumulated.
Leaves of affected branches often change color to light green, yellow, then tan. The leaves of affected twigs turn upward and lie close to the branch. Twigs may die back above the infection site.
Fungal fruiting bodies may be present on the affected leaves. They are rose-colored and waxy in appearance.
English or common boxwood (Buxus sempervirens) is reported to be susceptible to canker.
Management Options
See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.
Non-chemical Management
Select non-chemical management options as your first choice!
- Provide proper culture for plants, including proper irrigation and fertilization. Healthy plants are more disease-resistant.
- Plant in well-drained soil.
- Avoid wounding plants.
- Prune and destroy affected branches.
- Collect and destroy fallen leaves in and under infected plants, particularly those accumulated in branch crotches.
Chemical Management
IMPORTANT: Always read and follow label directions when working with pesticides.
For more information on using pesticides visit :
- Apply in spring before growth starts.
- Additional applications in late spring, summer, and fall.
Approved Pesticides
If you choose to use a pesticide, some examples of products that are legal in Washington are listed below. Some products are labeled for just INDOOR or just OUTDOOR use, or may allow both uses. Be sure to choose a product appropriate for your situation. Always read and follow all label directions.
WSU Extension programs and employment are available to all without discrimination.
Evidence of noncompliance may be reported through your local Extension office.