Invasive Species Profile: Emerald Ash Borer

Ash trees are highly utilized trees. They can be found across multiple cities in the United States and are often sources for firewood, creating baseball bats, bows, acoustic guitar bodies, and hand tools. Ash wood is dense, but very elastic, making it an ideal resource to have available. Unfortunately, the introduction of the emerald ash borer positioned ash trees in crisis mode.


Emerald ash borers (EAB) were introduced to North America and are thought to have come over in a wood shipment from East Asia.


EAB is a metallic green beetle that usually doesn’t grow much larger than 1/3” (8.5 mm). In terms of being detrimental to ash trees, the adults don’t damage the tree as much as the larvae. The larvae feed on the inner bark of the tree, disrupting the channels for water and other nutrients. Since the tree doesn’t get the sustenance it needs, the ash tree begins to decay from the inside out.


The EAB population is quickly spreading across the United States, primarily in the Midwest region. More than 20 states are labeled as “quarantined” and cannot transport ash tree firewood across state lines.


The first reported case of EAB in the United States was June 2002 in Michigan. According to the Minnesota Department of Agriculture, the first confirmed case of emerald ash borers was May 14, 2009, in St. Paul.

WHY (raise awareness)?

The bottom line is that emerald ash borers kill ash trees. Minnesota has the nation’s largest volume of ash trees. Not only is our environment at risk, but our local economy as well. On a residential level, an ash tree that has been compromised by EAB will lose its structural integrity, resulting in a potentially dangerous break in the tree under windy conditions.

HOW (can I tell if my ash tree has been infested)?

Signs to look for on your ash tree include:

  • Increased woodpecker activity at the tree (woodpeckers love EAB)
  • Bark cracks that expose s-shaped patterns and “galleries”
  • D-shaped holes appear in the tree’s bark during spring

To learn more about EAB in Minnesota, visit the Minnesota Department of Agriculture’s website.