When customers are asked, what plant is designed the most in your landscape jobs the answer rings the same… Boxwoods. Whether you use them in a formal hedge, accent or as a specimen there seems to be no alternate that can accomplish the affect the homeowner is looking for. For this reason, the increase in production by all growers has them on high alert for the boxwood blight.
So, what is Boxwood Blight and where did it come from?
Boxwood blight (also known as box blight), caused by the fungus, Calonectria pseudonaviculata, is a serious fungal disease of boxwood that results in defoliation and decline of susceptible boxwood. Boxwood blight was first identified in a nursery location in Carroll County Virginia in 2011. By the fall of 2013 it was found in other commercial nursery/retail operations and landscapes in several counties in Virginia.
The fungal disease is spread by movement of contaminated plant material, container or field-grown boxwood and by boxwood greenery used for holiday decoration. Boxwood blight spores can also be spread on pruning tools, clothing, equipment and anything that might have contacted infected plants.
Most diseases have “host” plants that can make controlling problems more difficult. For Boxwood Blight host plants are found within the Boxwood family. Pachysandra terminalis (Japanese spurge), Pachysandra procumbens (Allegheny spurge) and Sarcococca species (sweetbox), which are in the same family (Buxaceae) as boxwood, are also susceptible to boxwood blight and infected plants of these species could introduce the disease to a landscape. Symptoms of the disease on P. terminalis are brown leaf spots.
What to do if boxwood blight is suspected in a landscape (1)
You and a professional should submit suspect plant samples for diagnosis to the local Cooperative Extension Office They can send samples for confirmatory diagnosis to a lab.
• Collect symptomatic boxwood samples (stems with black streaks, leaf spots, or defoliation) and double-bag
in sealed plastic bags before to your Extension office. – Plant samples should be accompanied by a completed
plant diagnostic form available at the county Extension office.
• Confirmatory diagnosis of this disease by a plant diagnostic lab is important because other problems on boxwood could be mistaken for boxwood blight. Additionally, to reduce spread of this serious disease, it is important for VCE to know where outbreaks of the disease occur and identify the source of any boxwood blight-diseased plant material.
Boxwood Blight is being found in throughout the US. Here are a few tips from Decker’s Nursery to assure you are not spreading the disease.