The DNR Division of Entomology & Plant Pathology has discovered that a shipment of boxwood plants infected with boxwood blight was shipped to Indiana in May.
Boxwood blight (Calonectriapseudonayiculata) is a fungal disease that ingest members of the popular Buxacceae family and is often transported through the nursery trade. Hosts include Buxus (boxwood), Pachysandra (Japanese spurge) and Sarcococca (sweetbox).
In total, 23 stores in Indiana received infected material in early spring (particularly “Graham Blandy” cultivar), and it’s possible that members of the public inadvertently purchased some plants.
The fungus, which can lay dormant in drier conditions, 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 Which will included pictures of infected leaves. Since diseases life on this perennial plant, the control option is to remove infected plants from the site. This fungal disease and stay viable in the soil for years, so early detection and plant removal are key to protect the planting.
A DNR inspector found the plants at a national chain home and garden store in early October. The shipment originated at a nursery in Oregon. It was also sent to stores in 11 other states. Potential counties impacted in our area include Marshall, Elkhart, Kosciusko, and Porter
Upon confirmation of boxwood blight on these plants by the Purdue Plant and Pest Diagnostic Lab, the DNR required that the chain remove all boxwood from their shelves for disposal and that the stores mitigate the area through disinfection to ensure that the pathogen is no longer present and able to infect further shipments of plants.
The DNR is currently surveying for boxwood blight in Indiana. To date, the DNR has not found the pathogen, except for a few interceptions like this one. If you have questions on this disease, please call the Marshall County Extension Office (574) 935-8545 or e-mail ryoder@purdue.edu.
