Signs and Symptoms of the Emerald Ash Borer (E2938)

This bulletin covers the basics of what you need to know to identify the Emerald Ash Borer.

Adult

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  • Bright, metallic green (Figs. A, B).
  • 1/2 inch long, flattened back (Figs. A, B).
  • Purple abdominal segments beneath wing covers.

Larva

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  • Creamy white, legless (Fig. C).
  • Flattened, bell-shaped body segments (Fig. C).
  • Terminal segment bears a pair of small appendages.

Canopy Dieback

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  • Bigins in the top one-third of canopy (Fig. D).
  • Progresses until tree is bare (Fig. E)

Epicormic Shoots

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  • Sprouts grow from roots and trunk (Figs. F, G).
  • Leaves often larger than normal.

Bark Splitting

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  • Vertical fissures on bark (Fig. H) due to callous tissue formation (Fig. I).
  • Galleries exposed under bark split.

Serpentine Galleries and D-shaped Exit Holes

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  • Larval feeding galleries typically serpentine (Fig. J).
  • Galleries weave back and forth across the woodgrain.
  • Packed with frass (mix of sawdust and excrement).
  • Adults form D-shaped holes upon emergence (Fig. K).

Increased Woodpecker Activity/Damage

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  • Several woodpecker species (Fig. L) feed on EAB larvae/pupae.
  • Peck outer bark while foraging (Fig. M).
  • Create large holes when extracting insects (Fig. M).

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