Emerald Ash Borer in Green Bay: What Homeowners Need to Know

The emerald ash borer (EAB) has been devastating ash trees across Wisconsin for over a decade, and Green Bay has been hit hard. If you have ash trees on your property, understanding the threat and knowing your options is critical.

What Is the Emerald Ash Borer?

The emerald ash borer is an invasive beetle native to Asia. It was first detected in the United States in 2002 and in Wisconsin in 2008. The larvae feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients. An infested tree typically dies within 2–4 years.

Signs of Infestation

Look for these signs on your ash trees: D-shaped exit holes (about 1/8 inch wide) in the bark, serpentine (S-shaped) tunnels under the bark, canopy dieback starting at the top, bark splitting, increased woodpecker activity, and epicormic shoots (suckers) growing from the trunk.

Treatment Options

If your ash tree is less than 30% damaged, treatment with systemic insecticides can be effective. Treatments need to be repeated every 1–2 years and work best on healthy trees caught early. For trees with more than 50% canopy decline, treatment is usually not cost-effective and removal is recommended.

When Removal Is Necessary

Once an ash tree is heavily infested, it becomes a safety hazard. Dead branches can fall, and the tree itself may become structurally unsound. In Green Bay, many neighborhoods have lost dozens of ash trees to EAB. If your tree is beyond saving, prompt removal prevents the beetle from spreading to neighboring ash trees.

If you suspect your ash tree is infested, contact Green Bay's Best Tree Service for a free assessment from licensed arborists.