Boxwood blight

The West Virginia Department of Agriculture (WVDA) has detected boxwood blight at several residential and commercial landscapes throughout West Virginia. Boxwood blight, caused by the fungal pathogen Calonectria pseudonaviculata, is the most devastating pest of boxwoods. Boxwood blight was first diagnosed in West Virginia on plants shipped from out-of-state nurseries in July 2015. “The first symptom of boxwood blight is dark brown to black lesions on otherwise green leaves. The dark lesions will coalesce, turning entire leaves brown to straw-colored and defoliating rapidly. Black, angular to elliptical shaped cankers form on the twigs and branches,” WVDA Plant Industries Director Tim Brown said. “Symptoms commonly begin low on shrubs and spread upwards.”

CHARLESTON — The West Virginia Department of Agriculture (WVDA) has detected boxwood blight at several residential and commercial landscapes throughout West Virginia, according to a press release from the department. Boxwood blight, caused by the fungal pathogen Calonectria pseudonaviculata, is the most devastating pest of boxwoods. Boxwood blight was first diagnosed in West Virginia on plants shipped from out-of-state nurseries in July 2015.

“Gardeners and landscapers need to stay vigilant for the presence of this damaging disease. Enacting best management practices is your best option to keep your landscape disease-free,” said Commissioner of Agriculture Kent Leonhardt. “If you have questions, please reach out to the department.”

Boxwood blight was first reported in the United States in 2011. The exact origin of the disease is not known but has likely spread to North America from Europe where it has been widespread since the 1990s.

“As with any plant disease, sanitation is a crucial step in dealing with boxwood blight. Purchase shrubs from reputable nurseries that are legally licensed and inspected by the WVDA and only purchase plants that appear healthy. Never work or prune your boxwoods when the foliage is wet or when the weatherman is calling for rain later in the day,” said WVDA Plant Industries Director Tim Brown.

The WVDA suggests citizens sanitize gardening tools like pruners between different plantings of boxwoods. Tools can be sanitized either with flame, 70 percent alcohol/10 percent bleach solution, Lysol or other commercially available sanitizers. Dead boxwood plant material should never be composted. Once boxwood blight has been confirmed, the infected shrubs should be removed. Those plants be can destroyed by burning or by double bagging to be sent to a landfill.

“The first symptom of boxwood blight is dark brown to black lesions on otherwise green leaves. The dark lesions will coalesce, turning entire leaves brown to straw-colored and defoliating rapidly. Black, angular to elliptical shaped cankers form on the twigs and branches,” Brown said. “Symptoms commonly begin low on shrubs and spread upwards.”

Potentially infected boxwoods can be confirmed by sending a sample to the WVDA Pest Identification Lab. Pictures of symptomatic plants can also be emailed to bugbusters@wvda.us.

Instructions for submitting a sample to the WVDA can be found at https://agriculture.wv.gov/divisions/plantindustries/Documents/PID_specimen_bs.pdf

For more information about best management practices, visit https://portal.ct.gov/CAES/PDIO/Boxwood-Blight/Boxwood-Blight

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