PK-L05 · Yard, turf, and garden pests

How to get rid of Emerald ash borers

Agrilus planipennis

Also called: EAB

Emerald ash borer killed hundreds of millions of North American ash trees. Adults are small metallic green beetles; larvae snake under bark and girdle the tree. Homeowner “spray the trunk with a yard can” does not save a mature ash. Options are professional systemic treatments on still-viable trees, removal of dead hazard trees, and do not move firewood. If your ash is already 50% dead, treatment money is often wasted. This is an arborist conversation, not a hardware-aisle conversation.

Emerald ash borer (Agrilus planipennis) — identification photo
Identification photo of Emerald ash borer (Agrilus planipennis). Use this with the notes below — size, color, and markings matter more than a single photo, and look-alikes are listed in the sidebar.

How to identify Emerald ash borer

  • D-shaped exit holes in ash, serpentine galleries under bark, canopy dieback from the top, woodpecker flecking.
  • Adults metallic green, about 1/2 inch, in early summer. Not a carpenter bee (round holes in fascia).

Signs of an infestation

  • A dying ash in a neighborhood of dead ashes.
  • Sprouts on the trunk. Increased woodpecker activity.

Biology and why they show up

Invasive from Asia. Larvae in the cambium. Spread by flying adults and by people moving firewood and nursery stock.

Health and property risk

Dead hazard trees on houses and wires. Ecological loss of ash. Not a home indoor pest.

Proven control sequence

Work in this order. Skipping inspection or exclusion is why most “treatments” bounce back in a week.

  1. Call a certified arborist if the tree still has a living canopy. Systemic treatments are professional, timed, and not a miracle on a skeleton.
  2. Remove hazard trees. Dead ash drops limbs. This is safety, not spite.
  3. Do not move firewood. The slogan exists because it is how EAB and other borers hitchhiked.

Prevention that actually sticks

  • Plant diversity. Do not replant a monoculture of the next fad tree.
  • Buy local firewood.

When to hire a licensed professional

Always for treatment or removal of large trees. Utilities too.

Legal and safety notes. Quarantines have applied to ash material. Follow current USDA and state rules. Unregistered trunk injections are illegal.

United States and Tier 1 notes

Eastern and Midwestern US heavily. Expanding. Canada similar. Native to East Asia. Europe has its own EAB concern.

Common questions

Can I save a tree that is half dead?

Often no. Arborists use canopy thresholds. Spend on a living tree or a safe removal, not a gesture.

Sources

Written by the Pest Kill Editorial Team. Published August 25, 2026. Last reviewed September 13, 2026.