Emerald Ash Borer Quarantine

Emerald Ash Borer Quarantine in Effect in Marion County

The US Department of Agriculture confirmed detection of the Emerald ash borer in Marion, Yamhill and Clackamas Counties on August 28, 2024. Marion County and the others have been placed in a permanent quarantine status. 




Emerald Ash Borers in the Willamette Valley

The Oregon Department of Forestry warns that the establishment of Emerald Ash Borers are expected to devastate ash woodlands and riparian zones where native Oregon Ash (Fraxinus latifolia) is a dominant species. These trees provide important shade, food and habitat resources in riparian areas where soils can drain poorly and where seasonally high-water tables can exclude other tree species. 

The loss of ash trees caused by Emerald Ash Borer infestations could lead to a reduction in urban tree canopy, an increase in invasive plants filling in Ash Tree niches, potential streambank soil loss, and loss of shade and habitat along streams.

The quarantine does not allow the movement of tree materials from ash, olive, and white-fringe tree outside of the county unless it meets certain conditions. Live plant material is eligible for compliance agreements with ODA if one of the following conditions is met:


  • Diameter at the base of the plants is less than 0.75 of an inch
  • Plants were grown in a screenhouse approved by the ODA
  • Plants have been properly treated with an approved insecticide
  • Debark wood and remove at least 1 inch of underlying wood
  • Grind or chip to 1 inch or less
  • Heat wood to a minimum of 140°F for at least 60 minutes
  • Bury under at least 12 inches of topsoil
  • Incinerate wood materials
  • Secondary processing to produce wood by-products (i.e., paper)
  • Other methods specified within a compliance agreement with the Oregon Department of Agriculture.

For more information visit www.OregonEAB.com 

For questions, please email EAB@oda.oregon.gov or call 503-986-4636


What can you do?

1) Take Care of your Ash Trees

If you have ash trees on your property, take care of them. Emerald Ash Borer is most attracted to trees that are stressed.

  • Water your trees in the dry months and maintain a layer of woodchips or mulch around the base of your trees. One of the main stresses for a tree can be summertime drought, and these measures will help maintain adequate water in the soil near the tree. 
  • Avoid pruning, especially during high EAB activity (April through October). Pruning can send signals to insects that a tree is in stress. If you do need to prune your ash tree, hire a professional arborist to ensure pruning is done properly. A professional arborist can also provide guidance on other things you can do to improve the health of your trees. 
  • If planting new trees on your property, carefully inspect plant materials before purchasing. 
  • Avoid planting new ash trees. 


2) Do Not Move Firewood!

To slow the spread of Emerald Ash Borer, it is important to not transport firewood or wood products. Insects and diseases, which can be microscopic and undetectable to the eye, can move much faster and farther by people transporting firewood and wood products than they can on their own. 


3) Assist with EAB Detection & Tree Inventory

  • Use the resources provided below and local training opportunities to learn how to identify ash trees and the emerald ash borer. 
  • Report observations of EAB or trees with symptoms by calling 1-866-INVADER or reporting online to the Oregon Invasive Species Online Hotline. 
  • Enroll in OSU Extension's Oregon Forest Pest Detector Program to learn more about recognizing and reporting signs and symptoms of high-priority, invasive forest pests like EAB. 
  • Join our Keizer Urban Tree Inventory to help establish our baseline data: https://www.keizer.org/TreeInventory


4) Talk with your Tree Care Providers

  • Before hiring a tree care company, ask them about their knowledge and experience with EAB and other tree pests. If they are not already familiar with EAB, share information with them and encourage them to become familiar with signs and symptoms of Emerald Ash Borer.

 

How to Identify Emerald Ash Borer and Ash Trees

Emerald ash borer, Agrilus planipennis, is a small metallic-green buprestid, or jewel beetle, that bores into ash trees, feeding on tissues beneath the bark, ultimately killing the tree. It is an exotic beetle that is native to Asia. It was first discovered in the U.S. in 2002 in southeastern Michigan near Detroit and has since been detected in more than 30 states, including Oregon. Since arriving in the U.S., the invasive beetles have largely been spread through the movement of infested firewood. The adult beetles nibble on the foliage of ash trees but cause little damage. The larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients.

The Emerald Ash Borer is capable of infesting all ash trees in the genus Fraxinus. It is more likely you'll notice tree stress before you notice the beetles. 

Signs that an Ash tree may be infested with Emerald Ash Borer:

  • Crown dieback due to larvae disrupting the flow of water and nutrients
  • Bark splits from larval tunneling
  • D-shaped exit holes 3-4 mm wide
  • Woodpecker activity seeking larvae for food
  • Epicormic sprouting


Note that there are a lot of bright green insects that are native to Oregon, and many may be found on or around trees. Use this chart to help distinguish Emerald Ash Borer from other shiny green bugs. 


OSU Extension Ash Tree identification and recognition site: https://extension.oregonstate.edu/gallery/recognizing-ash-trees-oregon-washington-northern-california