Can tiny wasps save Berkshire ash trees? Researchers hope to slow the emerald ash borer
By Jane Kaufman
DATE: July 13, 2026
GREAT BARRINGTON — Within the mixed hardwood forest, the three ash trees at Three Mile Hill were instantly recognizable by the thin band of safety orange tape girdling them at eye level.
On closer inspection, they had unusual trappings: a metal eye-ring and wire attached to a 6-inch section of a branch set atop a pint-sized plastic container with water and plant food.
These ash bolts were deliberately infested with emerald ash borer larvae by none other than the U.S. Department of Agriculture.
The government agency is studying what happens when tiny wasps from Central Asia are introduced to the area in an effort to control the emerald ash borer, the invasive that is decimating ash forests in 37 states, including Massachusetts, and six Canadian provinces.
Migrating by cargo ship, the emerald ash borer was first seen in Michigan in the late 1990s. Its first sighting in Massachusetts was in Dalton in 2012 and is now in 11 counties in the commonwealth, but the Berkshires has been hit particularly hard.
It continues to spread.