Emerald Ash Borer

Agrilus planipennis

Invader Images

  • Adult EAB, wings open
  • Emerald ash borer adult
  • 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



  • Adult emerald ash borers are 1/4 to 1/2 inches long, narrow and bullet shaped with a flat back.
  • Adults are metallic in color with purple/red metallic abdominal segments beneath their wing covers.
  • Larvae can get up to 3 cm in length and are a creamy white color with no legs.
  • Larvae body is made up of flattened, bell-shaped segments. 
  • Attacks all species of ash trees.

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

Native Look-alikes

Emerald ash borer can be confused with many native insects. Check out these native look-alikes

how to identify an ash tree

In Vermont, we have three species of ash trees: green ash (Fraxinus pennsylvanica), black ash (Fraxinus nigra), and white ash (Fraxinus americana). Here are some helpful links for ash tree identification: Black ash leaf




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, USDA Forest Service.

The EAB generally has a one-year life cycle 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 do their damage to the tree by tunneling in the inner bark and outer wood. This kills the tree by interrupting the flow of food and water. 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. Adult emergence begins in late May or June.

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

Adult EAB feed along the margins of leaves, leaving small, irregular shaped edges.

Ecological threat

5% of Vermont's trees are ash. The majority of ash trees infested with emerald ash borer will die. The emerald ash borer poses a threat to Vermont's economy and ecology. It spreads very quickly, is difficult to detect, and eradication is not expected.

Management Options

  • Recommendations to Slow the Spread, and Resources for Forest Landowners and Managers, Homeowners, Municipalities, Volunteers, Educators, and others can be found here.

Vermont Distribution

A map of the Emerald ash borer infested area in Vermont can be found here.


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