Two invasive insects are spreading in the United States. Neither is known to be established in Maine, although both are closing in around our borders. Please be aware of these insects and report any suspicious sightings to help our efforts to manage them.
Box Tree Moth
If you have boxwood plantings, keep your eyes out for box tree moth. This invasive pest was first discovered in New York in 2021 and has subsequently spread to at least 10 other states despite state and federal quarantines. It has also been confirmed in New Brunswick, Canada near the Maine border.
Boxwoods infested with box tree moth are characterized by leaf defoliation, the presence of silken threads, and girdling of twigs. A heavy infestation will lead to plant mortality.
Although adult moths are strong fliers, box tree moth mostly moves to new areas as eggs and overwintering caterpillars on boxwood plants. These life stages are easy to miss, so it’s important to check your boxwoods carefully for signs of this new invasive insect. If you suspect you have box tree moth, immediately contact horticulture@maine.gov.
Clockwise from top left: adult box tree moth (Ian Redding), box tree moth caterpillar feeding and leaving tell-tale silk webbing (Ilya Mityushev), infested boxwood shrubs in Ohio (Joe Boggs), characteristic damage from feeding caterpillars (Ferenc Lakatos), a “hibernaculum” – 3 boxwood leaves stitched together by an early stage overwintering caterpillar (DACF).
The spotted lanternfly (SLF) is a large planthopper that has been spreading around the eastern half of the United States since 2016, where it is now in 18 states. It is still not known to be established in Maine, although we periodically receive reports of adult lanternflies, generally observed at rest areas and in warehouses.
Originally from Asia, the spotted lanternfly “hitchhiked” to Pennsylvania as egg masses on stone tile imports. When the eggs hatched in the spring, the little planthopper nymphs found their way to some preferred host plants, like tree-of-heaven, maple, and grape. Planthoppers have straw-like mouthparts (“stylets”) that they insert into plants to suck out the juices. This type of feeding can severely weaken the plant and sometimes spread diseases. The spotted lanternfly sticks its stylet into the stem and bark of plants, extracting the sap and exuding “honeydew,” a sticky liquid that rains down on surfaces, promoting the growth of sooty mold.
The spotted lanternfly has caused plant mortality in states where it’s firmly established. Please familiarize yourself with the different life stages of this bug and report any sightings. Please send photos or collect the specimen and email us: bugwatch@maine.gov.
Adult spotted lanternflies. Photos by MJ Raupp, Emelie Swackhamer (PSU), Heather Leach (PSU), Richard Garner (Bugwood.org)
