Update on the Boxwood Blight Situation, VA ---- August, 30, 2016

Update on the Boxwood Blight Situation in Virginia (08/30/16): 

Recent outbreaks of boxwood blight, caused by the fungus Calonectria pseudonaviculata, are causing concern in Virginia. Boxwood blight can cause severe defoliation of susceptible boxwood, including English and American boxwood, and is of serious consequence to nursery growers, landscapers and homeowners. All diagnoses of boxwood blight in home landscapes made by the Virginia Tech Plant Disease Clinic since last fall are linked to new boxwood purchased from several Virginia locations of one national retailer, and new cases are likely to emerge. (See news article at: http://www.newsadvance.com/news/local/boxwood-blight-hits-lynchburg/article_a2860e97-438c-523a-9c63-202902eaf42b.html).  Agents will likely get inquiries, so we wanted to update you on the disease, the current situation in Virginia, and available educational resources.

Symptoms of boxwood blight include leaf spots, black streaking on stems and severe defoliation. Other diseases of boxwood, such as Volutella blight and root diseases, can be confused with boxwood blight; therefore, laboratory confirmation is necessary. Learn to recognize symptoms of boxwood blight by viewing the image gallery on the Virginia Boxwood Blight Task Force web site http://www.ext.vt.edu/topics/agriculture/commercial-horticulture/boxwood-blight/.

In all the cases diagnosed by the VT Plant Disease Clinic in home landscapes, the disease was introduced on infected boxwood plants. The fungus has sticky spores and is not adapted for movement on air currents; however, spores may stick to and be transported by spray hoses, tools, clothing, shoes, and vehicles. The fungus can also be transported in soil and likely by animals moving through infected plants, e.g. deer, dogs. Infected boxwood may also be present in holiday greenery.

What to tell clients concerned about boxwood blight:

• Although the disease has been found in 21 counties/independent cities in Virginia, to our knowledge it does not appear to be widespread in any county. 
• English and American boxwood are very susceptible to the disease. 
• Other plants in the boxwood family that are susceptible to the disease include pachysandra and sweetbox (Sarcococca), so avoid introducing those plants into landscapes with highly valued boxwood. 
• The primary way the disease gets around is on infected plant material, so avoid introducing diseased plant material, especially if susceptible boxwood are already present. 
• Because the disease can also be transported on equipment, it is important for landscapers to sanitize tools and equipment between properties. Home growers should only hire landscapers who demonstrate awareness of the disease and who are implementing measures to prevent transport of the disease from one property to another. 
• We strongly recommend that growers purchase boxwood from a nursery or retail outlet that has purchased boxwood exclusively from a boxwood producer in the Boxwood Blight Cleanliness Program (http://www.vdacs.virginia.gov/plant-industry-services-boxwood-blight.shtml). These growers follow stringent practices to avoid the introduction of this disease to their nurseries. 
• Purchase cultivars with resistance to boxwood blight (e.g. Green Beauty, Nana, Golden Dream, Northern Emerald, Wedding Ring). 
• Familiarize yourself with the symptoms of the disease and best management practices by visiting the Virginia Boxwood Blight Task Force web site (http://www.ext.vt.edu/topics/agriculture/commercial-horticulture/boxwood-blight/). 
• Monitor all boxwood plants in areas where new boxwood has been introduced within the past year for symptoms of the disease. 
• If you suspect boxwood blight, collect symptomatic branch samples with at least a few green leaves still attached. Double bag the samples and take them to your local Virginia Cooperative Extension office (http://www.ext.vt.edu/offices/index.html). Samples will be forwarded to the Virginia Tech Plant Clinic for diagnosis.