Introduced Pests Outreach Project

Emerald Ash Borer

(Click on an image below to see the captioned full-size version)
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Scientific Name: Agrilus planipennis
Common Name: Emerald Ash Borer, "EAB"

Known Hosts:
White ash (Fraxinus americana), black ash (F.nigra), red ash (F. pennslyvanica), green ash (F. pennsylvanica var. subintegerrima) and several horticultural varieties of ash.

Key ID Features (Adults, Larvae):
  • The body is a golden green or brassy color overall with darker, metallic emerald green wing covers. (Figure 1)
  • Adults measure ½” 8.5-13mm) in length. Females are larger than males. (Figure 2)
  • Adults are present from mid May to late July and feed on leaves leaving irregularly- shaped patches with jagged edges.
  • Larvae are flattened in appearance, consisting of 10 cream-colored, bell-shaped segments with a pair of brown pinchers at one end. (Figure 3)
  • Larvae about 1-1 ¼” (26- 32mm) in length when fully developed.(Figure 3)
Description of damage:
  • Distinct S-shaped tunnels are formed beneath the bark from larval feeding. (Figure 4)
  • Vertical splits in the bark are caused by callus tissue forming in response to larval feeding. (Figure 5)
  • Adult emergence leaves D- shaped exit holes (3-4 mm in diameter) in bark. (Figure 6)
  • The upper third of the tree dies back.
  • Numerous shoots arise below the dead portion of the trunk (Figure 7)
Similar Species:

last reviewed August 1, 2014

Massachusetts Department of Agricultural Resources
Massachusetts Introduced Pests Outreach Project is a collaboration between the Massachusetts Dept. of Agricultural Resources and the UMass Extension Agriculture and Landscape Program. This website was made possible, in part, by a Cooperative Agreement from the United States Department of Agriculture's Animal and Plant Health Inspection Service (APHIS). It may not necessarily express APHIS' views.