Urgent New Pest Alert: Box Tree Moth Found in the US

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Box tree moth, Cydalima perspectalis, is native to Asia. It was introduced into Europe in 2007 and quickly spread across the continent. Box tree moth was introduced to Ontario, Canada in 2018 which was the first introduction to North America.

Box tree moth larva, webbing, and leaf damage. .S.D. Frank, NCSU

Box tree moth larva, webbing, and leaf damage. .S.D. Frank, NC State University

In May 2021, plants were shipped to Connecticut, Massachusetts, Michigan, New York, Ohio, Tennessee, and South Carolina from an infested nursery in Ontario. Nurseries or retail outlets that received boxwoods (Buxus spp.), Euonymus, or hollies (Illex) from Canada should scout for eggs, larvae, pupae, and adults.

Box tree moth larva and webbing. Ferenc Lakatos, University of Sopron, Bugwood.org

Box tree moth larva and webbing. Ferenc Lakatos, University of Sopron, Bugwood

USDA APHIS is taking steps to trace the plants and determine if any were infested and begin eradication protocols or take other measures if necessary. Importation of boxwood, holly, euonymus, and other hosts from Canada have been halted by federal order.

White morph box tree moth adults. Szabolcs Sáfián, University of West Hungary, Bugwood.org

White morph box tree moth adults. Szabolcs Sáfián, University of West Hungary, Bugwood

Box tree moths are up to 4 cm and have two color morphs. The morph seen in Canada has white wings with brown borders. The brown morph also found in Europe is almost entirely dark brown with characteristic white specks on the forewings. Males can be monitored with pheromone traps. Caterpillars are up to 2 cm and yellow to lime green with dark stripes. They eat boxwood leaves and bark and can quickly defoliate and even kill large hedges. Caterpillars also create unsightly webbing and frass within plants which protects them from predators and could reduce insecticide efficacy.

Damage from box tree moth larvae. Ferenc Lakatos, University of Sopron, Bugwood.org

Damage from box tree moth larvae. Ferenc Lakatos, University of Sopron, Bugwood

Public garden personnel, landscape and nursery professionals, extension personnel, diagnosticians, and the public need to be aware of this new pest and look for it. A scouting guide is available to help identify box tree moth life stages. Box tree moth pheromone lures and traps are commercially available. It would be valuable to monitor with these for early detection.

There have not been experiments to document insecticide efficacy for this pest in the US. In Europe and Canada, many insecticides are not permitted for use on ornamental plants. A fact sheet is available listing insecticides labeled for caterpillars in nursery and landscape ornamentals.