When EA Beetles Attack

Emerald Ash Borers can carve "tracks" into ash trees.

The adult emerald ash borer is a beautiful creature - half an inch long and a bright metallic green. But it can wreak havoc on your trees.

What Do Emerald Ash Borers do to my Trees?

Adult beetles lay eggs in the bark of your ash trees. When the larvae hatch, they feed just under the bark, making tunnels or galleries that damage the tissue that carries sugar, water, and nutrients. As a result, the tree begins to die. After the first year, adult beetles emerge and re-attack the same or other trees, producing more beetles and causing more damage. Most trees die within two to four years after first showing signs of decline.

Look for these signs of emerald ash borers on your ash trees.

  • Bark splitting. The bark on infested trees starts to split vertically as the larvae feed underneath.
  • Galleries. As the larvae eat, they wind back and forth, leaving snaking tunnels that may be visible through the fissures in the bark. The galleries are packed with sawdust.
  • Exit holes. When the new adults fly out of the tree, they leave D-shaped holes in the bark.
  • Canopy decline. The tree makes fewer, smaller leaves and the canopy thins over time. Sometimes, whole individual branches die. Also, infested trees send out so-called epicormic shoots--sprouts that grow from the roots and trunk.
  • Woodpecker activity. Many woodpeckers eat emerald ash borer larvae and can make big holes to get at the insects, especially in winter.

Take pictures of damage and of any adult beetles or larvae you see. An expert can help figure out if you're looking at emerald ash borers. They aren't the only shiny metallic beetles that might live in your woods. Here are some bugs they're often confused with.

I've got emerald ash borers. Now what?

If the signs point to an emerald ash borer infestation, you can still control the damage.

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