Harrisburg, PA – On Friday, state officials hosted an educational update regarding boxwood blight, a fungal disease that causes sudden leaf loss and sometimes death of the popular broadleaf evergreen shrubs. In an effort to minimize the disease’s impacts to plants this summer, the state Department of Agriculture announced the enactment of a quarantine order as a part of the discussion.
The order, which appears in the June 25 edition of the Pennsylvania Bulletin, puts parameters in place to minimize the spread and impact of the Calonectria pseudonaviculatum fungus. This fungus causes blight in all types and ages of Buxus species, including boxwood, common groundcover pachysandra, and sarcococca (sweet box).
• Allows for the quarantine of any property, facility, premise, place or area where boxwood blight is confirmed.
• Restricts movement of any material or object that may carry or spread the fungus. This restriction applies to both inter- and intrastate movement.
• Requires proper inspection of any material that would enter the commonwealth from another state. That state must certify that the shipper meets commonwealth standards before its plants are allowed to enter Pennsylvania for resale distribution.
• Requires businesses within the commonwealth that can meet the requirements of the quarantine order to enter into compliance agreements with the department for clean stock production.
Boxwood blight, first found in Europe and then detected in the United States in 2011, was detected for the first time in Pennsylvania in 2012. In each case, the department has eradicated all known plants found positive for blight.
“In our increasingly global world, biosecurity is an increasing concern in order to safeguard our citizens, animals, and plants, and this quarantine implements important cautions,” said Agriculture Secretary Russell Redding. “This summer’s heat and humidity provides perfect conditions for the spread of boxwood blight, so we’re working in partnership with the green industry and homeowners to prevent the establishment of this dangerous fungus.”
Symptoms include leaf spots, rapid defoliation, distinctive black cankers on stems, and severe dieback. Plants can become weakened by the fungus and susceptible to other fatal diseases. Only a lab certified for plant disease identification can confirm a diagnosis for boxwood blight.
Fungus spores are sticky and cling to anything exposed to an infected plant, including gardening tools, gloves, shoes, pets and lawnmowers. Spores can last more than 10 years in soil and dropped leaves.
Some fungicides are available to prevent infection and spread, but none can cure a plant once it is infected. To reduce the risk of boxwood blight infecting your plants:
• Purchase plants from reputable sources;
• Water the plant’s roots (not leaves) in the morning rather than evening, due to fungus thriving on wet leaves; and
• Clean tools after pruning each bush in a 10-percent bleach solution (one part chlorine bleach to nine parts water).
If you think you have found any signs of boxwood blight on your property, contact your local Penn State Extension Office for free diagnosis. Staff will take samples for laboratory analysis to determine if blight exists. Do not destroy your shrubs until a diagnosis is made, as symptoms are similar to other leaf-dropping insects and diseases.
Discard diseased plants through burial, burning if allowed by the municipality, or by double bagging the entire plant and disposing at a landfill. Do not compost infected plants. Once cleared, do not replant areas affected by blight with at-risk species.
For more information about boxwood blight, visit http://extension.psu.edu.