Michigan gardeners face a growing threat to their boxwood shrubs as box tree moths, an Asian invasive species, continue to spread across the state.
The destructive pests, first detected in the United States in 2021, have prompted quarantines in 13 Michigan counties, including Wayne, Oakland, Macomb, and Washtenaw, as authorities work to contain their spread.
“They will totally decimate a whole boxwood in a few days,” warned Dean Darin, English Gardens Retail Operations President.
Arnold Budin, who serves on the board of his condo association, observed deteriorating conditions in the landscaping of his community.
“They didn’t look right. They weren’t as green as they’ve been, and driving through the community, we saw other boxwoods that are similar,” Budin said.
Budin came to English Gardens for help, where Darin informed him that the boxwoods in his neighborhood can be saved.
Michigan State University Extension Educator David Lowenstein emphasizes the importance of early detection.
“Be vigilant about the appearance of your boxwoods. If you start to see your boxwoods go into decline, take a closer look,” he said.
Box tree moth caterpillars exclusively target boxwood plants for feeding and reproduction.
These small, green caterpillars can quickly strip plants of their foliage, potentially killing entire shrubs if left unchecked.
Local 4 photographer Erik Yettaw recently discovered the problem firsthand.
“We saw what looked like green little caterpillars, and they were all over. We have five bushes,” said Yettaw.
Despite the serious nature of the threat, experts say boxwoods can be saved if the infestation is caught early.
Darin recommends Bacillus thuringiensis.
“Spray on the plants. It coats the plants with an organic insecticide, and as soon that the box tree moths ingest it, it kills them,” Darin said.
Homeowners, landscapers, and property managers are encouraged to inspect their boxwood plants regularly for signs of infestation. Early warning signs include:
Declining green color
Presence of small, green caterpillars
Defoliation of plants
Webbing on or between leaves
Click here to report box tree moths to the state.
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