The DNR Division of Entomology & Plant Pathology has discovered boxwood plants in the landscape of central Indiana infected with the boxwood blight fungus. The infected plants had been purchased several years earlier from a local retail chain stores.
Boxwood blight (Calonectria pseudonaviculata) is a fungal disease that infests members of the popular Buxaceae family, and is often transported through the nursery trade. Hosts include Buxus (boxwood), Pachysandra (Japanese spurge) and Sarcococca (sweetbox). Annual inspections of nursery stock by the DNR verify that this pathogen is not indigenous to Indiana, nor can it be found in nursery stock that is sourced locally.
When the fungus, which can lay dormant in drier conditions, is present, it can be found on all above-ground portions of the plant and presents itself as dark leaf spots. It causes rapid defoliation, which typically starts on the bottom of the plant and moves toward the top. This fungal pathogen can move through sporulation in water and from dropped leaves. As a result, infection can spread to surrounding plants from a single infected plant.
If you suspect one of your plants shows signs and symptoms of boxwood blight, please call (866) NO EXOTIC (866-663-9684) use the information at dnr.IN.gov/entomolo.
For more information on this pathogen, see the following link extension.purdue.edu/extmedia/BP/BP-203-W.pdf
The DNR is currently surveying for boxwood blight in Indiana. To date, the DNR has not found the pathogen, except for a few interceptions at retail chain stores that source materials from out of state.
If you see symptoms of this plant pathogen, call the DNR at (866) NO EXOTIC (866-663-9684) with the location. Members of the public may report boxwood blight or any other invasive species to the DNR through the Report IN website eddmaps.org/indiana/ or by downloading the Great Lakes Early Detection Network (GLEDN) app on a smartphone.
For more information on all invasive species that could affect Indiana and ways to help stop their spread, see dnr.IN.gov//3123.htm.