Box tree moth: what the agencies record

This page describes what the named sources say. It is not a diagnosis of any plant and does not say what should be done with one. Each section names its source, all read on October 9, 2026. Box tree moth feeds on boxwood shrubs, which are not a tree species. Rules by country are on the box tree moth regulated status page, and the moth has a row in insect pests of trees.

Names and origin

The Canadian Food Inspection Agency, called CFIA, gives the scientific name Cydalima perspectalis (Walker). APHIS says it is native to East Asia. The Morton Arboretum says it was introduced into Germany in 2006 and has since spread through much of Europe. The Royal Horticultural Society, called RHS, calls the larvae box tree caterpillars and says the species became established in Europe in 2007. It says the first adult moth reached Britain in 2007, moths came to light traps in 2008, caterpillars were found in private gardens in the home counties in 2011, and by the end of 2014 the moth was established in parts of London and surrounding areas.

Hosts

All four sources name boxwood, the genus Buxus. CFIA says that in Canada the pest is found exclusively on boxwood shrubs, and that it does not pose a risk to human health. The Arboretum says that in the moth's native range it has also been found on burning bush and Japanese spindletree growing near heavily infested boxwoods. It calls the moth a serious pest that can completely defoliate and kill boxwood shrubs.

What the sources list as signs

CFIA lists chewed leaves, larvae, webbing and sawdust-like frass. APHIS lists missing, skeletonized or brown leaves, young caterpillars hiding among twigs and leaves, lime-green caterpillars with black stripes, white spots and a shiny black head, frass, pupae sometimes wrapped in webbing, and white-winged adults with a thick brown border that are hard to spot because they are most active at night. RHS gives the main symptoms as foliage eaten and leaves webbed together, with patches of dieback that can be most apparent on trimmed plants. It says that dieback is not to be confused with the dieback of the disease box blight. The Arboretum says older caterpillars eat the whole leaf and leave only the midrib, and may then feed on the bark.

Life stages as described

RHS describes newly hatched caterpillars as greenish-yellow with black heads, and older ones up to 4 cm long with thick black and thin white stripes. Pupae sit in a cocoon of white webbing among leaves and twigs. The adult usually has white wings with a faintly iridescent brown border and a wingspan of around 4 cm, though a brown form exists. RHS says the pale yellow, flattish eggs are laid in overlapping sheets on box leaves and are very difficult to find. The Arboretum says the brown form is uncommon, and that adults live about two weeks. APHIS gives caterpillars up to 1.5 inches.

Timing and generations

The Arboretum says there may be two to five overlapping generations a year depending on climate, that the moth overwinters as partly grown caterpillars in cocoons on the leaves, and that larvae resume feeding in early to mid-spring, so adults emerge over a period in spring and early summer. RHS puts the most active period at April to October and says overwintering larvae web leaves together and shelter within. For growers in south-east England it says the problem is likely to recur repeatedly through the growing season and in successive years. CFIA recommends watching for signs from May to September. APHIS points to two forecasting tools but gives no dates on its page.

Where each source places it

APHIS, on a page modified October 7, 2026, says it detected the moth in New York in 2021 and lists Delaware, Kentucky, Maryland, Massachusetts, Michigan, Ohio, Pennsylvania, Virginia and West Virginia as other confirmed states. CFIA, on a page modified June 19, 2025, says residential properties in Quebec, Nova Scotia and New Brunswick had confirmed finds in summer 2023, and a residence in Prince Edward Island in August 2024. It names Ontario, Quebec, New Brunswick, Nova Scotia, Newfoundland and Labrador and Prince Edward Island as the regulated areas, and says it can fly an estimated 5 to 10 km a year and also spreads on infested boxwood shrubs. RHS reports it widely across England, most of all in London and the areas around it, and also in the rest of the United Kingdom and Ireland. The Arboretum says it is not found in Illinois.

Reporting

APHIS asks that sightings or damage be reported immediately and links the National Plant Board's list of state plant regulatory officials. CFIA asks for reports from Manitoba, Saskatchewan, Alberta and British Columbia, and links a British Columbia report form. For the offices see report a pest in the United States and Canada. This page gives no treatment steps, product names or rates.