Emerald Ash Borer (EAB)

Information about the Emerald Ash Borer
A photograph of an adult metallic green colored Emerald Ash Borer insect on a leaf.
The adult Emerald Ash Borer is striking in appearance and smaller than a dime. Photo Credit: Leah Bauer, USDA Forest Service Northern Research Station (bugwood.org).


The first observance of EAB on the west coast occurred on June 30, 2022, in Forest Grove, Oregon.

Emerald ash borer (Agrilus planipennis), referred to as EAB, is a highly destructive invasive beetle that has killed hundreds of millions of ash trees in the US midwest and east coast, since it was first detected in Michigan in 2002. All North American ash species (Fraxinus spp.) are at risk, including the native Oregon ash (Fraxinus latifolia) and non-native ash species widely planted as street and landscape trees. In addition to the loss of trees in Oregon cities and towns, EAB is of particular concern in Oregon because ash trees are a vital component of natural areas along rivers and streams. Once EAB spreads, this habitat will change very quickly. 

This insect gets its name because adults are a bright, metallic green. The beetles cause canopy thinning and dieback because they disrupt the tissues that conduct water and nutrients in the tree. The beetles leave characteristic “D”-shaped exit holes in the bark, approximately 1/8-inch in diameter, when they emerge in late May/June. Heavy infestations can kill susceptible trees in a couple of years. 

Susceptible species

All species of ash trees (Fraxinus spp.) are at risk.

White fringetree (Chionanthus virginicus) and olive trees (Olea europaea) may also be at risk.

Check out this interactive map to find ash trees planted in Portland Parks and rights of way.  

What can you do?

1) Assist with detection of EAB.

2) Don't Move Firewood! If possible, buy or obtain your firewood as locally as possible. Even moving firewood from one town to the next town could provide EAB with a free ride. 

3) If you have ash trees or any of the tree listed as susceptible, take care of them. EAB is most attracted to trees that are stressed.

  • In the summertime, one of the main stresses on a tree can be drought. Water and mulch trees young and even mature trees, too.  
  • Pruning cuts can send signals of stress to pests, too. If you have ash trees, avoid pruning them during the height of EAB activity (April through October).  

4) If you are a local tree care provider, become familiar with signs of EAB. Report sightings and dispose of wood waste properly.

5) Spread the word! Share this information with friends, family, and neighbors.

What else is being done? 

Oregon Department of Forestry (ODF), Oregon Department of Agriculture, and community partners, including Portland, have been preparing for this event for the past several years:

Additional information