Emerald Ash Borer Found in Carlton and Lake Counties

Emergency quarantine on wood movement put in place for portions of Carlton County and Lake County

The Minnesota Department of Agriculture (MDA) has confirmed the presence of emerald ash borer (EAB) in Carlton and Lake counties for the first time. EAB was first discovered in Minnesota in 2009, and there are now 34 counties in the state with EAB.

In Lake County, a staff member of the Superior Hiking Trail Association noticed insect and woodpecker damage to an ash tree along a trail in the city of Two Harbors and reported the find to the MDA. MDA staff were able to find live EAB larvae and collect samples.

While working in northeastern Minnesota, MDA staff also noticed a tree in the city of Cloquet with extensive woodpecker damage. Live EAB larvae were found and collected for official identification.

Emerald ash borer larvae kill ash trees by tunneling under the bark and feeding on the part of the tree that moves nutrients up and down the trunk. Often, the trees show several signs of infestation because of this. Woodpeckers like to feed on EAB larvae and woodpecker holes. This may indicate the presence of emerald ash borer. Also, EAB tunneling can cause the bark to split open, revealing characteristic S-shaped galleries underneath.

Because this is the first time EAB has been identified in Carlton and Lake counties, the MDA is enacting emergency quarantines which limit the movement of firewood and ash material out of the areas. The emergency quarantine will cover the northeast corner of Carlton County, from the Fond du Lac Reservation on the west to the county line on the east and the Carlton/St. Louis County line on the north to Highway 210 and the border of Jay Cooke State Park on the south (click for map). In Lake County, a partial quarantine will cover the southwest corner of the county and extend approximately from the northern edge of the St. Louis County quarantine east to Lake Superior, with the quarantine’s eastern edge southwest of Castle Danger (click for map).

The MDA issues quarantines for all counties known to have EAB to reduce the risk of further spreading the tree-killing insect.

A virtual informational meeting for residents and tree care professionals in Carlton and Lake counties will be held on Monday, May 9, 2022. Experts from the MDA will give a brief presentation followed by a question-and-answer session.