Box Tree Moth Found in New Castle County

DOVER, Del. (Sept. 22, 2025) - The Delaware Department of Agriculture has confirmed a find of a box tree moth (Cydalima perspectalis) in New Castle County during inspections of traps set up on the New Castle County-Kent County border.

The box tree moth is a federally regulated pest that primarily feeds on boxwood species (Buxus spp.). If left unchecked, it causes significant damage and can potentially kill the plants. Boxwoods are a popular ornamental evergreen shrub common to many landscape environments.

This is the first discovery of a box tree moth in New Castle County. The first box tree moth in Delaware was confirmed in July 2024 in Kent County. The first box tree moth in the United States was confirmed in New York in 2021.

"We continue to work closely with our partners at the U.S. Department of Agriculture and University of Delaware extension to monitor this invasive pest," said Jeffrey Brothers, Delaware Department of Agriculture's Plant Industries Administrator. "A box tree moth caterpillar can quickly defoliate boxwoods and remain active until September or October. Homeowners and nurseries should be on the lookout for signs of damage to their plants."

The caterpillars, which can grow to 1.5 inches, will start out as lime-green, with black stripes, white spots, hair, and a shiny black head. They then create a large amount of webbing on the plant. The caterpillars are ravenous feeders and, in heavy infestations, can completely defoliate host plants. After the leaves are gone, they feed on the bark, eventually killing the plant.

The adult box tree moth generally has white wings with a thick brown border. It can be hard to find as it is most active at night. The box tree moth can sometimes be confused with the melonworm moth.

What You Can Do

Delawareans can help prevent this invasive pest from spreading throughout the state's landscape, by monitoring and controlling infestations.

• If you have boxwoods in your landscape, monitor your shrubs for brown or skeletonized leaves, defoliation, and webbing with caterpillars.
• Contact Delaware Cooperative Extension Master Gardeners at the Garden Helpline to learn what pest management tools are available:
  • New Castle County: 302-831-8862
  • Kent County: 302-730-4000
  • Sussex County: 302-831-3389
• Refer to the following link for Insecticide Options for Box Tree Moth Management. Remember the label is the law. Always read and follow the pesticide label.
  • https://ir4.cals.ncsu.edu/ehc/InvasiveSpecies/BTM_FactSheet_PotentialMitigationOptions_20210527.pdf
• Remove infested boxwood plant branches. For heavy infestations, cut the boxwood from its base. Your plant should grow back from its roots. All boxwood debris should be double-bagged in plastic and placed in the trash. Homeowners should follow the Delaware Cooperative Extension's pesticide recommendations.
• Nursery owners should monitor their boxwoods and implement safeguards to limit pest risk. All nursery businesses should report box tree moth detections to the Delaware Department of Agriculture at [email protected].

Learn more about the box tree moth at https://www.aphis.usda.gov/plant-pests-diseases/box-tree-moth. or https://www.udel.edu/academics/colleges/canr/cooperative-extension/fact-sheets/box-tree-moth/.