Be on the lookout for a new plant disease, boxwood blight

A new disease of boxwood named boxwood blight (Claonectria pseudonaviculata or Cylindrocladium buxicola) has been detected in parts of the eastern United States. A new MSU Extension factsheet helps identify the symptoms of this serious plant problem.

In October 2011, boxwood blight (Claonectria pseudonaviculata or Cylindrocladium buxicola) was first detected in the United States by plant pathologists in Connecticut and North Carolina. Currently, Connecticut, Maryland, Maine, North Carolina, New York, Ohio, Oregon, Pennsylvania, Rhode Island and Virginia have all reported boxwood blight. It has also been found in British Columbia, Canada. The prediction is that boxwood blight will continue to be detected in many other states.

Boxwood blight occurs on all Buxus species and cultivars. English boxwood, Buxus sempervirens ‘suffruticosa,’ and American or common boxwood, B.sempervirens, appear to be highly susceptible. Pachysandra terminalis (common names pachysandra, Japanese spurge) is also susceptible to boxwood blight with similar symptoms of leaf lesions, visual sporulation on the leaves and quick leaf drop.

A new MSU Extension factsheet titled “Boxwood blight disease identified in North America” will help you identify the visual symptoms.

Leaf spot symptoms
Leaf spot symptoms. Photo credit: Sharon M. Douglas, Univ. of Connecticut