Box Tree Moth Larvae Damaging Boxwoods in Royal Oak, MI

Residents of Royal Oak, Michigan, should be on high alert as Box Tree Moth (Cydalima perspectalis) larvae have been spotted infesting boxwood shrubs as early as April 2025. This invasive pest poses a significant threat to ornamental Boxwood shrubs, with potential for rapid defoliation and plant death if not promptly addressed.

What Is the Box Tree Moth?

Native to East Asia, the Box Tree Moth has become a destructive force in Europe and parts of North America, including Michigan. Its larvae are voracious feeders, consuming Boxwood leaves and eventually the bark, leading to plant death. Adult moths are white with a brown border and a distinctive white dot on each fore wing. Larvae are lime green with black stripes and white spots, growing up to 1.5 inches in length.  

Box Tree Moth adults vary in color. | Szabolcs, Univ. of West Hungary, Bugwood.org

Signs of Box Tree Moth Infestation

Early detection is crucial.  Look for:
• Skeletonized or chewed leaves
• Yellowing or browning foliage
• White webbing among leaves and stems
• Green-black frass (caterpillar droppings)
• Presence of caterpillars or adult moths
These signs indicate active feeding and potential damage to your boxwoods. Check out some of the pictures that I have included in this article so you will know what to look for. The damage happens very quickly, so be vigilant throughout the growing season.

Quarantine Zone and Reporting

In December 2023, the Michigan Department of Agriculture and Rural Development (MDARD) expanded the Box Tree Moth quarantine to include Oakland County, encompassing Royal Oak. In January 2025 the quarantine was expanded further to include the entire counties of Clinton, Eaton, Ingham, Jackson, Lapeer, Lenawee, Livingston, Macomb, Monroe, Oakland, St. Clair, Washtenaw, and Wayne.  

This means that Boxwood plants, parts, and nursery stock cannot be moved outside of the quarantined area. Residents are encouraged to report suspected infestations to MDARD's Eyes in the Field program. Prompt reporting helps track the spread and implement control measures.  

Treatment Options for Box Tree Moth

If you suspect your Boxwood shrubs are infested, consider the following treatments:
• Insecticidal Sprays throughout the growing season by a professional plant healthcare company, and under the guidance of an ISA Certified Arborist.
• Manual Removal: For small infestations, manually removing caterpillars and webbing can help reduce numbers.

In 2024, infestations were reported throughout Farmington, prompting immediate treatment measures. These actions helped mitigate damage and prevent further spread. The proximity of Royal Oak to Farmington underscores the importance of vigilance and early intervention.

During my time in Farmington last summer, it was surreal driving through neighborhoods seeing all the bare Boxwood stems at each house that were recently full, healthy Boxwood hedges. The only Boxwoods that seemed to survive were the ones that were being maintained by pest control and plant healthcare professionals. 

Boxwood hedge damaged by Box Tree Moth

Protecting Your Landscape

To safeguard your boxwood shrubs:
• Have your local plant healthcare company do preventative insecticide foliar sprays throughout the growing season.
• Regularly inspect plants for signs of infestation.
• Maintain healthy, well-pruned shrubs to reduce stress.
• Avoid moving boxwood plants or plant parts outside the quarantined area.
• Report any suspected cases to MDARD promptly.

By taking proactive steps, you can help protect your Boxwood shrubs and contribute to statewide efforts to control the spread of this invasive pest. Call Owen Tree & Lawn Care today to have your Boxwood shrubs inspected by an ISA Certified Arborist for Box Tree Moth.

For more information and resources, call Owen Tree & Lawn Care, visit the Michigan Department of Agriculture and Rural Development's website or contact your local extension office.