The first thing a grower should do if they suspect blight is limit access to the area to avoid spreading it. The spores of the blight can move on people, animals, or tools, so it is important to do your best to reduce movement through the area. Second, take some samples (while still being careful not to spread the disease) and send them to a local Extension agent or plant disease diagnostic lab.
If the disease is confirmed, it is then important to try to remove the infected plants from the area and sanitize. The spores are sticky and heavy. They move from plant to plant contact and water splashing, so we recommend removing any plants showing symptoms and those boxwood immediately around them, as well as any very susceptible boxwood cultivars in the area. If the infected plant is in the landscape, remove the above ground portion first, then leaves and debris, then the roots.
Once the plants have been removed, sanitize the area with 70% rubbing alcohol, 10% bleach solution, or Lysol disinfectant. When able, applying a preventative fungicide is also recommended. The most important thing to do after you have cleaned up the area is to continue to monitor the remaining boxwood, scouting the area for any new infections. If the infection took place in a landscape and you are looking to replant, replant with more tolerant varieties and immediately mulch the area.
It is important for growers to understand that the threat of boxwood blight to our industry, though serious, is survivable. Recently on a trip around Europe, it was heartbreaking to see growers giving up on boxwood. They desperately wanted a solution, but weren’t terribly keen on exploring other varieties besides the species Buxus sempervirens (one of the most susceptible varieties).
We feel confident that with smart, simple phytosanitary practices and an increase of tolerant varieties in the market, one day boxwood blight will be just another bullet on the list of plant diseases managed in the U.S. Boxwood have been an essential part of gardens for centuries, and there isn’t a real boxwood alternative that will do the job a real boxwood can. We strongly encourage growers to not feel powerless in this situation. With the research efforts being made, and more tolerant varieties identified, boxwood will continue to prosper for years to come.