Emerald Ash Borer

The Emerald Ash Borer (EAB) is a small beetle that is invasive in Minnesota and many other states. It was first identified in Chaska in 2021.

The larvae feed on ash tree inner bark, killing the tree within a few years depending on the tree's size.

EAB in Chaska

Evidence of EAB has been found throughout the community. The Public Works team has been removing infected ash trees from boulevards and parks. When trees are healthy enough, they have used a pesticide treatment to save the trees. Property owners are responsible for trees on their property.

Signs of EAB

  • Wood pecker activity leaving behind patchy bark (there may even be scattered wood flecks on the ground)
  • Sprouting along the base of the trunk or on main branches

Branches sprouting

Tree with sprouting along the base of the trunk

Bark flaking

Tree with wood flecks on the ground

Patchy bark

Emerald Ash Borer Infected Tree with patchy bark, wood flecks on ground, and sprouting