Emerald Ash Borer

Agrilus planipennis

Invader Images

    • Emerald ash borer adult
    • Adult EAB, wings open
    • Adult EABs feed on foliage
    • S-shaped galleries from larval feeding
    • Larvae feed on the inner bark, cutting off the tree's flow of nutrients
    • EAB Larva
    • Ash tree crown thinning
    • Woodpecker flecking on ash tree
    • D-shaped exit holes
    • Epicormic branching on ash tree infested with EAB
    • Epicormic branching on ash tree infested with EAB

Common Look-alikes

    • Bronze Birch Borer
      Bronze Birch Borer
    • Six-Spotted Tiger Beetle
      Six-Spotted Tiger Beetle
    • Two-Lined Chestnut Borer
      Two-Lined Chestnut Borer


The emerald ash borer is a very small insect - adults are 1/4 to 1/2 inches long - that feeds on all species of ash trees. EAB adults are metallic green with purple/red metallic abdominal segments beneath their wing covers. Their bodies are narrow and bullet shaped with a flat back. EAB larvae can get up to 3 cm in length and are a creamy white color with no legs. The body is made up of flattened, bell-shaped segments. 

signs and symptoms

  • Adult beetles emerge in late May/early June
  • Bark splitting 
  • S-shaped tunnels behind outer bark
  • D-shaped exit holes 1/8" wide on bark surface
  • Woodpecker flecking
  • Dead top branches of ash trees
  • Leafy offshoots from the lower trunk of ash trees

See image slideshow above for signs and symptoms.



Emerald ash borer (EAB), Agrilus planipennis, is an exotic beetle that was discovered in southeastern Michigan near Detroit in the summer of 2002. The larvae feed in the cambium between the bark and wood, producing S-shaped galleries that girdle and kill branches and trees. Emerald ash borer probably arrived in the United States on solid wood packing material carried in cargo ships or airplanes originating in its native Asia.


Emerald ash borer feeds and lives in all species of ash and, in some cases, it has been found on white fringetree (Chionanthus virginicus). 

life cycle

EAB Life Cycle
The Life Cycle of the Emerald Ash Borer

The EAB has one generation per year and goes through complete metamorphosis.

Adults lay eggs on the bark of the trunk or branches in the summer.

Eggs hatch in 7-10 days.

Larvae burrow into the tree and feed on the phloem and cambium layer, creating extensive galleries under the bark that disrupt translocation of water and nutrients in the tree. Galleries widen as larvae mature.

Pre-pupae larvae overwinter in shallow chambers in the outer sapwood or in the bark of thick-barked trees. 

Pupation begins in late April or May.

Adults chew D-shaped exit holes are 3-4 mm wide.

Adults feed on the tree’s leaves between June and August.

Ecological threat

Emerald ash borer has spread rapidly in the United States, killing millions of ash trees, and it will be in Vermont soon if it isn't here already. White ash is one of the ten most common tree species in Vermont, so this insect will have a major impact when it becomes established in the state. There are infestations in all surrounding states and Canadian provinces.

Management Options

  • Plan now if you have ash trees in your woodlot. It could be many years before emerald ash borer shows up, so stay abreast of emerald ash borer detections to avoid cutting ash trees prematurely. If your land is enrolled in the Use Value Appraisal program, contact your consulting forester if you wish to change your planned activities.
  • Retain at least some healthy ash trees as long as possible so they can continue replenishing seeds in the soil. The survival of ash trees may rely on the next generation of ash which will be maturing after biological control agents should be established.
  • Municipalities will take a hit financially when EAB starts attacking urban and community trees. Learn more about how to prepare your community here.
  • Don’t move ash trees, ash wood products, or firewood into Vermont, unless they are treated to be free of pests and comply with state and federal quarantines.
  • More information is at:

Emerald Ash Borer: Ash Management Guidance for Land Managers

Emerald Ash Borer: Information for Vermont Landowners

Emerald Ash Borer: Policy on UVA Plans & Amendments

Vermont Distribution

Emerald ash borer has not been detected in Vermont. 


Photo Credit

Taylor Scarr, Ontario Ministry of Natural Resources, Bugwood.org

Art Wagner, USDA - APHIS, Bugwood.org

David Cappaert, Michigan State University, Bugwood.org

Pennsylvania Department of Conservation and Natural Resources - Forestry Archive, Bugwood.org

USDA Forest Service - Northeastern Area, USDA Forest Service. Bugwood.org

Pennsylvania Department of Conservation and Natural Resources- Forestry, Bugwood.org

information credit

Biosurveillance Surveys


Map BioControl

National EAB Information Website

New York Invasive Species Information

USDA-Forest Service