An article in today’s Washington Post caught my eye about a new Asian species of moth spotted in this counrty, one I hadn’t heard of before. I quickly did a bit of research. According to Cornell College of Agriculture and Life Sciences, we indeed have another invasive species to worry about: the box tree moth. As if spotted lanternflies weren’t bad enough!
Originating from North China and Korea, the box tree moth first spread to Europe on nursery stock shipments in 2006. By way of Canada, it is inow in Michigan, Ohio and New York (detected there in 2021). Scientists say our climate is conducive for it to thrive in the temperate regions of North America. Its preferred food is– you guessed it– boxwood, also from Asia. Despite its many problems boxwood remains popular for hedging. Nurseries routinely distribute boxwood plants nationwide, adding to the likelihood of spread. (sigh.)
Next to box blight, this is just one more reason to plant an alternative to box like inkberry holly, plum yew, or bayberry instead.
Since New York and Ohio are right next door and this pest is expected to spread quickly, here’s what to look for if you have boxwoods on your property. It is only a matter of time until they arrive.
Identification
Foliar damage is done by the striped and spotted lime green caterpillars. They strip the leaves of all edible tissue leaving only skeletonized remains. They may also wrap themselves in webbing. Clusters of translucent yellowish eggs are laid on the undersides of the leaves, making them hard to notice. The caterpillars resemble other species but their presence on boxwood means they are likely box tree moth larvae.
Adult moths are dull white with wide brown margins and rarely seen during the day. They are most active at night, complicating detection.
As evidenced below if left unchecked, severe damage can result and even kill a mature boxwood.
What to Do
If you think you might have an infestation:
- Take extensive photographs to share with the experts.
- Don’t dispose of infected or damaged plants in a way that will spread the pests inadvertently. Bag it carefully and call your local Ag Extension office for further instruction.
- Since this is a relatively new pest here, extension personnel may wish to see the evidence directly to confirm identification, so be sure to preserve some infected material to show or send them.
- There are many pesticides and organic solutions that will likely kill the larvae effectively; however, it is always best to seek professional guidance on the least-toxic options that will do the job with minimal to no contamination or harm. Often there are very specific measures that need to be taken with newly invasive species.
- Lehigh County residents can contact their Penn State Extension office at lehighext@psu.edu, or call (610) 391-9840. (Other ag extension offices may be more appropriate for residents of other counties.)
- Spread the word — not the pest! Tell your neighbors and friends. The more people are prepared the better we can deal with the consequences. Forewarned is forearmed!
For more detailed information, check out Cornell’s posting on this exotic insect here.
Rethink your boxwoods
If nothing else, consider replacing any boxwoods you have now, before they get infested, with a hardy, beautiful alternative. There are various inkberry hollies and other similar evergreens to choose from. For some possibilities see my “favorite greens” in the article, Green and White, Always in Style.
