The Buxus microphylla koreana – or more commonly known as the boxwood tree – is a popular plant often used in gardens, as hedges, or along driveways and walkways worldwide.
But its dark green foliage and pleasing uniform shape cannot ward off pests and diseases, which plague this majestic plant and can in fact be fatal.
Boxwood blight is the most common disease to impact the boxwood tree (which is not a tree at all but is considered a shrub). A fungal infection caused by Calonectria pseudonaviculata), boxwood blight is a disease which includes leaf spots or blotches, rapid defoliation, and stem lesions. If left untreated, the plant’s untimely demise will undoubtedly spread to other similar plants nearby.
While fungicides effectively protect plants from boxwood blight infection, they will not cure a plant that has already been stricken by the disease. This is the primary reason why SavATree encourages homeowners and commercial property managers to consider regular fungicide treatments to help ensure their boxwoods flourish for many years to come.
The Box Tree Moth Arrives
If boxwood blight wasn’t concerning enough, the USDA recently confirmed the presence of the box tree moth on U.S. soil.
“The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) has confirmed the presence of box tree moth, Cydalima perspectalis, in the continental United States and is taking action alongside state partners and the industry to contain and eradicate the invasive pest that was imported on nursery plants shipped from Ontario, Canada.”
In late May, the box tree moth infested plants in Connecticut, Massachusetts, Michigan, New York, Ohio, Tennessee, and South Carolina. As a result, APHIS took swift action and, as of May 26, 2021, halted the importation of plants from Canada which is where the infestation is believed to have started.
This included finding and destroying the imported plants, tracing additional locations where plants may have been sold, providing traps for the box tree moths to contain the spread, and educating agricultural and customs agents on the severity of the situation.
APHIS believes, “These immediate measures are focused on protecting the economic viability of the thriving U.S. boxwood industry as well as nurseries and other establishments that sell these plants wholesale and direct to consumers.”
Destruction and Treatment
The destruction, however, doesn’t come from the moth itself but the larvae. Measuring only 2 cm long, yellow to lime green in color with dark stripes, the larvae feed upon the bark and leaves of the boxwood and can quickly defoliate and even kill a large plant. To protect themselves, they create an unsightly webbing or protective cover which protects them from any predators and could limit the efficacy of insecticides once applied.
Garden personnel, nurseries, landscape professionals, horticulturalists, and the public are urged to be aware of this new pest’s existence by regularly inspecting their boxwood plants for signs of infestation throughout the growing season – especially if they were purchased and planted over the last year.
Commercial traps are an effective method for containing the spread of the box tree moth but are not guaranteed to stop the infestation. Your best alternative is to contact your SavATree professional arborist for a detailed inspection and identification of the boxwood plants on your property. They will also recommend effective options for both treatment and prevention going forward.
While little is still known about the long-term impacts box tree moths will have across the U.S., their history in Canada and Europe solidifies their presence as yet another invasive pest homeowners and commercial property managers will continually battle for many years to come.