Monthly Archives: January 2024

Emerald ash borer quarantined in Minnesota

emerald ash borer
Photo by Babette Kis

On November 1, 2023, the Minnesota Department of Agriculture declared a quarantine to prevent the further spread of emerald ash borer. It prohibits the importation of firewood and other regulated articles into the state, and the movement of those articles from quarantined areas to uninfected areas.

Emerald ash borer, also known by the acronym EAB, is an exotic, invasive, small to medium-sized, metallic wood-boring beetle. It is native to northeastern Asia, including China, Mongolia, North and South Korea, Japan, Taiwan, and far eastern Russia.

Emerald ash borer was first detected in North America in 2002 in Detroit Michigan. It was probably imported in the wood of a shipping crate in the late 1990s. It has spread rapidly since its introduction. It now occurs from Maine to northern Georgia, west to Minnesota and northeastern Texas. It was discovered for the first time in Minnesota on May 14, 2009, in South Saint Anthony Park in St. Paul. It is now common in southeastern Minnesota, and it is continuing to spread in the state.

Emerald ash borer larvae feed exclusively on black ash, green ash, and white ash. They feed on the inner bark (cambium), creating serpentine tunnels (galleries) that interrupt the flow of food. They eventually girdle and kill the branch or tree. They have killed millions of trees in the eastern United States, including over five million trees in a 3,000 square mile area of Michigan.

Adults are active in Minnesota from May 1 through September 30. They are found in deciduous forests and woodlands, in parks, and in urban and residential areas, anywhere ash trees are found.

On October 8, 2003, the USDA Forest Service imposed a quarantine on emerald ash borer. It prohibited the interstate movement of all firewood and other regulated items out of infected areas. The USDA removed the quarantine effective January 14, 2021. An emerald ash borer female can fly up to 100 miles in her lifetime. The quarantine had not been effective in preventing the spread of the beetle into adjacent areas.

The Minnesota Department of Natural Resources estimates that there are nearly a billion ash trees in the state. Infected forests dominated by black ash will become grasslands, brushlands, or marshes. City budgets will be strained by the costs of removing dead trees from their streets.

The Minnesota quarantine will remain in effect until cancelled.