Minnesota Department of Agriculture: emerald ash borer confirmed in 54 counties; new quarantines and guidance announced

Jonathan Ostes of the Minnesota Department of Agriculture told listeners that emerald ash borer (EAB) infestations are now confirmed in 54 Minnesota counties and described new detections this winter in Aitkin County, Pine County and in Virginia, Minnesota.

Ostes said the infestations discovered this winter include trees found near a timber sale in Malmo Township, Aitkin County; two locations east of Willow River in northern Pine County; and eight trees near the eastern entrance to Mesabi Community College in Virginia. He urged landowners and municipal staff to check the MDA status map, which the department updates nightly, and to begin planning for tree management where EAB is nearby.

The nut of Ostes’s message was practical: EAB can be cryptic for years but spreads rapidly once established, and human-assisted movement of infested wood—especially firewood—remains a major pathway for long-distance jumps. “It’s a good idea just to buy firewood where you’re going to burn it,” Ostes said during the webinar.

Why this matters: Minnesota has a large ash resource and high local reliance on ash in urban and forested settings. Ostes said the state has “over a billion” ash trees and that, on average, ash accounts for about one in five trees in many communities; in some places in western and northern Minnesota ash can be one in two or three trees. Once EAB populations explode locally, Ostes said communities often face large-scale tree mortality over a short period and limited capacity to remove hazardous trees.

What MDA described at the webinar

Distribution and recent finds: MDA’s map shows the state’s quarantine boundaries and a “generally infested area” polygon (a buffered area around confirmed trees). Ostes noted that EAB’s natural spread averages about 1–2…