Boxwood blight, a serious fungal disease that attacks boxwood – a popular landscape shrub – has been detected for the first time in Michigan at three different locations in Southeast Michigan’s Oakland County at a landscape firm, a homeowner’s yard and in holiday wreaths being sold at a retail store, according to Michigan Farm Bureau Horticultural Specialist Kevin Robson.
“It’s imperative that consumers who may have purchased a holiday wreath take a quick look to make certain their products aren’t infected,” Robson said. “If you see any changing of the leaves on your wreath decor, we’re encouraging you to put the wreath in a sealed bag and dispose in the landfill to prevent further spreading.”
In a statement, the Michigan Department of Agriculture and Rural Development (MDARD) said it was notified by the Wisconsin Department of Agriculture, Trade and Consumer Protection that infected boxwood may have been sold at other retail locations in Michigan.
“Boxwood blight is a devastating disease that has caused significant losses to homeowners and the nursery industry in states that already have the disease,” said Gina Alessandri, director of MDARD’s Pesticide and Plant Pest Management Division. “In Connecticut alone, the first year after detection, boxwood losses in field-grown and container nurseries exceeded $3 million and we could see a similar effect in Michigan should it become widespread.”
Disease containment is absolutely essential for Michigan’s nursery/greenhouse industry, Robson said, which in addition to providing extensive wreath production throughout the Christmas holiday season, would suffer even more significant economic losses in the landscape business on a year-around basis.
Wreaths displayed outdoors are a potential concern if they are exposed to the elements. MDARD recommends that anyone who has a wreath containing boxwood plant parts should consider it infected and dispose of it by burning or by double-bagging it and including it with his or her trash for deposit in a landfill.
Boxwood blight produces dark brown leaf spots and causes rapid defoliation that sometimes kills young boxwoods. Boxwood blight first appeared in the 1990s in the United Kingdom and has now spread throughout Europe.
The disease was first found in the U.S. in Connecticut, North Carolina and Virginia in 2011, and has since spread to more than 24 states. Boxwood blight affects all species of boxwood; however, some species and cultivars are more susceptible than others.
American boxwood and English boxwood are highly susceptible. This disease also affects the related shrub, sweetbox, and Pachysandra, a common ground cover. Boxwood and Pachysandra are commonly used in commercial and residential plantings throughout Michigan.
To prevent introducing or spreading boxwood blight, MDARD recommends that nurseries, landscapers and property owners implement the following preventative actions:
Alessandri advises that anyone who suspects they have plants infected with boxwood blight should contact their local MSU Extension office.