Box Tree Moth
Exotic Insect Pest Fact Sheet
The Box Tree Moth (BTM) poses a threat to boxwood plantings.
Fact Sheet Authors
Jacob Leeser and Brian Eshenaur
New York State Integrated Pest Management, Cornell University
The Box Tree Moth (BTM) is an exotic insect pest native to North China and Korea which poses a threat to boxwood plantings. Box Tree Moth’s presence in Europe was initially detected in 2006, spreading throughout the continent over the subsequent 15 years primarily from nursery stock shipments. BTM first appeared in New York State in 2021, likely carried on a storm from a recent infestation just across the border in Ontario, Canada. Currently a federal quarantine prevents export of boxwood nursery stock from counties with known infestations.
Adult Box Tree Moth
Feeding damage to boxwood leaves
Box Tree Moth caterpillars
Don’t Spread Box Tree Moths
If removing clippings or entire shrubs from an infested site take precautions so the insect is not spread to new locations. At this point the recommendations is to bag the infested plant material, safeguard it on site and Contact New York State Department of Agriculture and Markets through their box tree moth reporting portal for additional advice.
Boxwoods (Buxus species) are the preferred food source for BTM. There are no native Buxus species in North America, and the lack of host plants in wild habitats limits the spread of the moth. Boxwood is a traditional plant used for topiary and hedges and is the highest-selling evergreen shrub. BTM damage threatens heritage sites, landscaping, and a boxwood nursery trade of over $140 million annually.
Box Tree Moth is most easily recognized by the webbing the caterpillars create as they mature, which is visible by spreading the branches and looking into the interior of the shrub. Caterpillars can be detected by heavy, characteristic feeding patterns, with leaves appearing “peeled” or only the midrib remaining. Green-black balls of frass (droppings) are also indicative of an infestation.
Severely-infested shrubs take on a brown or scorched look.
Box Tree Moth Appearance
The Box Tree Moth caterpillar is black and green, with green, yellow, black and white longitudinal stripes. Adult moths are typically white with a brown margin around their wings, and a less common variant is fully brown with small white spots on the forewing. They have a wingspan of approximately 1.5 inches.
Box Tree Moth caterpillars. Photo by Matteo Maspero and Andrea Tantardini
Adult Box Tree Moth. Photo by Matteo Maspero and Andrea Tantardini, Centro MiRT - FondazioneMinoprio [IT]
The ‘melanated’ brown variant of adult Box Tree Moth. Photo by Ilya Mityushev, Dept of Plant Protection, Russian State Agrarian University—Moscow Timiryazev Agricultural Academy.
Eggs are deposited on the underside of boxwood leaves and take about 3 days to hatch. Newly hatched caterpillars feed on the underside of the leaf, then continue to defoliate the plant as they grow larger, and eventually strip the bark under heavy feeding conditions. Depending on the weather, caterpillars mature into adult moths in about 14 days. In BTM can have several overlapping generations between May and October. They overwinter as caterpillars and can survive at temps as low as -22F (-30C).
Eggs are deposited on the underside of boxwood leaves and take about 3 days to hatch.
Photo by .
Look inside boxwood shrub canopies for the green and yellow caterpillars, cut or missing leaves, and white webbing.
Box tree moth is now a Federally regulated species and its distribution is very limited in NYS so it is important to report it. If you become aware of something that looks like box tree moth please submit a report to NYS Department of Agriculture and Markets through their Box Tree Moth Public Report portal.
- With small infestations hand picking the caterpillars can be effective.
- With larger outbreaks it may be most effective to treat with an approved insecticide for your area. Contact your local Cornell cooperative extension office for specific products.
- When treating, thorough coverage into the interior of the boxwood shrubs is necessary. You may want to hire a professional applicator to make insecticide treatments.
- If replanting is necessary, consider choosing an alternative shrub to boxwoods.
Removing clippings or shrubs from an infested site
If removing clippings or entire shrubs from an infested site take precautions so the insect is not spread to new locations. At this point the recommendation is to bag the infested plant material, safeguard it on site and contact NYS Department of Agriculture and Markets through their Box Tree Moth Public Report portal for additional advice.
Insecticides Labeled for Box Tree Moth Registered in New York State for Home Garden Use
Updated April 2023
Senior Extension Associate
NYS Integrated Pest Management
- (585) 753-2561
- bce1 [at] cornell.edu
NYS Integrated Pest Management