Native Borers and Emerald Ash Borer Look-alikes (E2939)
DOWNLOADFebruary 11, 2016 - Mary Wilson
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Native ash borers are North American insects that tunnel under the bark of ash trees, sometimes causing enough damage to seriously weaken trees.
These two borers attack healthy ash trees:
Banded ash clearwing, Podosesia aureocinto; adult (Fig. A), larva (Fig. B)
Ash/lilac borer, Podoesia syringae; (Fig. C).
- Wasp-mimicking moths that feed on xylem of ash trees.
- Larvae are round with legs and expel frass from tree (Fig. D).
- Round exit hole (1/4 inch); pupal case exposed in exit hole upon emergence (Fig. E).
These three borers attack stressed or dying ash trees:
Redheaded ash borer, Neoclytus acuminatus; adult (Fig. F), larva (Fig. G).
Banded ash borer, Neoclytus caprea; adult (Fig. H).
- Longhorned beetles (roundheaded borers) that attack stressed ash trees, but also colonize elm, hickory, oak, linden, and others.
- Larvae tunnel deep into xylem (Fig. I) and adults emerge from round-oval exit holes measuring 1/4 inch (Fig. J).
Eastern ash bark beetle, Hylesinus aculeatus; adult (Fig. K).
- Cylindrical bark beetle that forms galleries beneath the bark of ash trees (Fig. L).
- Infested trees peppered with tiny, round exit holes measuring approximately 1/16 inch (Fig. M).
Emeral Ash Borer Look-alikes
The following insects are common to Michigan and could possibly be confused with emerald ash borer.
- Six-spotted tiger beetle, Cicindela sexguttata; adult measures 1/2 inch long (Fig. N).
- Caterpillar hunter, Calosoma scrutator; adult measures 1 inch long (Fig. O).
- Japanese beetle, Popillia japonica, adult measures slightly less than 1/2 inch long (Fig. P).
- Bronze birch borer, Agrilus anxius; adult measures approximately 1/2 inch long (Fig. Q).
- Two-lined chestnut borer, Agrilus bilineatus; adult measures approximately 1/2 inch long (Fig. R).
- Several other uncommon metallic wood-boring beetles.
