Box tree moth wreaking havoc in Southeast Michigan

Yahoo

22-05-2025

The Brief
Gardeners beware: a new invasive species is creating problems for Michigan plants in and around Metro Detroit.
The Box Tree Moth likes to feed on boxwood plants, stripping the vegetation of its nutrients.
The solution is a product called bacillus thuringiensis, according to a gardening manager at English Gardens.
WEST BLOOMFIELD, Mich. (FOX 2) - There's a new pest in town, and it's wreaking havoc on local gardeners and their boxwood plants.
The box tree moth is the latest invasive species to create problems for Southeast Michigan, which already wrestles with dozens of other non-native plants and animals.
Local perspective
About five years ago, the box tree moth traveled from Europe to Canada. How it made its way across the Atlantic Ocean, and then into the U.S., is a mystery.
Left to manage the growing fallout of a pest with no predators to keep it in check are the gardeners and landscapers of Southeast Michigan.
First appearing in Washtenaw County in 2023, they have become a growing concern around Metro Detroit, targeting boxwood plants, including the popular bush homeowners use as a natural border on their property.
According to one local garden manager, cases of box tree moths are climbing a lot - including nearly 30 people just this week.
"We're seeing a big concentration in the Farmington Hills, West Bloomfield area right now," said Dean Darin of English Gardens.
Big picture view
In 2023, the Michigan Department of Agriculture and Rural Development implemented a quarantine on boxwood shrubs due to the concern driven by the moth's emergence in Michigan.
It's since expanded to 13 counties, including Clinton, Eaton, Ingham, Lapeer, Livingston, Oakland, Jackson, Washtenaw, Wayne, Lenawee, Monroe, Macomb and St. Clair.
Michigan State University worked with the state to develop an early-detection program for the box tree moth that made use of special traps. The university's science communication arm, MSU Extension, says the traps were hung along the perimeter of the quarantine area.
What you can do
Once a box tree moth's eggs hatch, the offspring feed on the plant, turning it from a vibrant green shrub into a faded plant with falling vegetation.
According to Darin, the caterpillars hatch and feed on the leaves.
"Once they hatch they'll be on the plant for a week before they start eating. If you see them, that's when it's time to spray. You're going to spray a product called BT or bacillus thuringiensis," said Darin.
BT is a natural insecticide that stops the caterpillar but won't hurt the plant or the pets.
It may feel satisfying to squash the caterpillars, but it won't make a difference. Each moth lays around 120 eggs.
"Squishing them isn't going to help. You really want to kill them with the BT, that's the most effective way," said Darin.
The Source
Interviews with local experts and information from Michigan State University and MDARD was used while reporting this story.