Box Tree Moth (BTM), an exotic invasive insect that is under quarantine in Delaware, has now been found in multiple locations in Kent County. Scout your boxwood plants for damage like the photos below. If you find BTM damage, please follow the protocol below for reporting.

What to look for:

Defoliation of leaves, brown or skeletonized leaves, webbing, and, of course, box tree caterpillars/moths. For more information and images: https://www.udel.edu/academics/colleges/canr/cooperative-extension/fact-sheets/box-tree-moth/.

Where to Report:

If you believe you have a BTM infestation, contact your local Cooperative Extension office and submit images or a physical sample. Offices are open Monday through Friday from 8:30 a.m. to 4:30 p.m.

Digital Images

Digital images should be submitted to the local county Extension agent. Three to four well-focused, quality images that show the overall symptoms on the whole plant, and close-ups of the symptoms are recommended. In some cases, a digital image is enough for a diagnosis, but we may request a physical sample to ensure an accurate diagnosis.

New Castle County: Carrie Murphy (cjmurphy@udel.edu)

Kent County: Megan Pleasanton (mpleasanton@desu.edu)

Sussex County: Tracy Wootten (wootten@udel.edu)

Physical Sample Drop-off Locations

If you are submitting a physical sample:

Submit samples in tightly sealed double-bags.
Put in the freezer for at least 2 hours before submitting, to kill the insects.

New Castle County	Kent County	Sussex County
Cooperative Extension Office 461 Wyoming Rd. Newark, DE 302-831-2506	Paradee Center 69 Transportation Rd. Dover, DE 302-730-4000	Carvel Research & Education Center 16483 County Seat Hwy. Georgetown, DE 302-856-7303

Treatment Options

If the Box tree moth is confirmed, then treatments include:

Bacillus thuringiensis (Bt) if the caterpillars are small (<0.5 inches)

Spinosad if the caterpillars are medium-sized (0.5 - 1.0 inch)

Pyrethroids (active ingredient ends in "-thrin") if the caterpillars are > 1.25 inches

Please refer to the Delaware Homeowner Insecticide List for assistance in locating these products.

Contact our offices with any questions/concerns.

Additional Resources:

Insecticide Options for Box Tree Moth Management
https:/ir4.cals.ncsu.edu/ehc/InvasiveSpecies/BTM_FactSheet_PotentialMitigationOptions_20210527.pdf

USDA Box Tree Moth
https://www.aphis.usda.gov/plant-pests-diseases/box-tree-moth

Download/Print PDF Version

UD Cooperative Extension

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