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Emerald Ash Borer

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What is an Emerald Ash Borer? 

Emerald ash borer, Agrilus planipennis, is a beetle that was first discovered in the U.S. in 2002 in southeastern Michigan. It has since been detected in more than 30 states, including Oregon. 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 invasive beetles have largely been spread through the movement of infested firewood.

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. 

  • Buy or obtain your firewood as locally as possible (within 10 miles or less is best. 50 miles is too far).  
  • Even moving firewood from one town to the next town could provide EAB with a free ride.

3) Assist with EAB Detection

  • 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 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. 

Emerald Ash Borers in Oregon

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

Oregon ash (Fraxinus latifolia), a member of the olive family (Oleaceae), is one of 16 species of ash in the United States. It is the only ash species that is native to the Pacific Northwest; however, ornamental ash species from other parts of the country and world are commonly used in landscaping in Salem, including: white ash (F. americana), flowering ash (F. ornus), Raywood ash (F. oxycarpa), green ash (F. pennsylvanica), European ash (F. execelsior), black ash (F. nigra), and velvet ash (F. velutina). 

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 taking hold within our community, and loss of shade and habitat along streams, to name just a few of the anticipated impacts.

Emerald Ash Borer is a small metallic-green buprestid, or jewel beetle, that bores into ash trees, feeding on tissues beneath the bark, ultimately killing the tree. 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. To identify the adult beetles, look for the following characteristics: 

  • Color: Bright, metallic, emerald green color overall. May have variable amounts of brassy, coppery or reddish reflections. When in flight (wings raised), the abdomen is bright coppery-red. 
  • Usually a little less than 1/2 inch long (10-13 mm)
  • Slender, bullet shaped body

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. 

Emerald Ash Borers are particularly attracted to stressed trees, meaning trees already in a weakened state from damage, such as broken limbs, lack of water, disease or fungal infection. Signs of infestation include thinning and yellowing leaves, D-shaped holes in the bark, woodpecker holes and thinning foliage, vertical bark cracks, and epicormic shoots (leafy sprouts) along the lower trunk. Scientists are working to find ways to stop the beetle. It's been proven that efforts to reduce the spread of the beetles can be improved by identifying infested trees in their first year.

Emerald Ash Borer(EAB) Temporary Quarantine