The 101 on Emerald Ash Borer

The 101 on Emerald Ash Borer

Emerald ash borer (EAB) is one small pest that has caused a lot of damage.

Since the bug’s debut in the USA in 2002, our Davey Institute scientists have been researching the best way to control emerald ash borer.

Our goal has always been to save your ash trees! After all, with EAB, the stakes are high. There are a whopping 7 billion ash trees in the USA that are in danger. Frequently, ash trees compromise as much as 35 percent of suburban tree canopies.

EAB was once thought to be a death sentence for your ash trees. Now, we know it’s not.

Read on to learn the newest, latest information about this damaging pest and raise awareness about emerald ash borer.

What Is Emerald Ash Borer?

Emerald ash borer is an invasive, wood-boring beetle from Asia that has been eating our nation’s ash trees since 2002. The bug itself is emerald in color, and it’s tiny – 1/2 inch in length and 1/8 inch wide.

While the emerald ash borer is small, the devastation this pest has caused is enormous.

Emerald ash borer has destroyed more than 50 million ash trees in 25 states. Through treatment, removal and tree replacement, the emerald as borer has cost an estimated $10 billion.

Once in your region, emerald ash borer will “ultimately kill all unprotected native ash trees” over the next 5 to 10 years said Colorado State University’s Whitney Cranshaw.

What is The Life Cycle of the Emerald Ash Borer?

In mid-May, just as the black locust trees bloom, the adult emerald ash borer emerges and flies through September. The rest of the year, the larvae are developing beneath the bark.

And, that’s when emerald ash borer wreaks havoc.

The beetles lay eggs in the trunk of ash trees. The larvae then begin eating a portion of the tree beneath the bark. In turn, this destroys the tree vessels that carry water and nutrients through the tree.

Where Is Emerald Ash Borer?

Emerald ash borer has been detected in 25 states as of today: Arkansas, Colorado, Connecticut, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and Wisconsin.

See the most recent emerald ash borer map from the USDA above. The map is often updated, so check back for recent additions.

How Can I Control Emerald Ash Borer?

Once emerald ash borer is in your area, take action. Have your local, certified arborist inspect your trees for risk. Did we mention we offer a free emerald ash borer consultation?

Early treatment of EAB is more effective, less invasive and less costly. Plus, there’s a higher survival rate.

How to Protect Ash Trees from Emerald Ash Borer

At Davey, we recently discovered a new way to detect emerald ash borer during the first year. That’s an entire year earlier than previously possible. When you spot EAB earlier, you can seek early treatment, which is more effective.

Look for these early symptoms of emerald ash borer:

  • More breakage at the top of the tree, which can be difficult to see from the ground
  • Visible cracks on the tree’s lowest Southwest branches
  • Branches that break close to the trunk instead of mid-point

Later on, look for these more pronounced symptoms of emerald ash borer:

  • Bark damage by woodpeckers searching for larvae
  • Chewing damage on foliage edges
  • Thin, 2-5 inch vertical slits in the bark
  • D-shaped holes in the bark
  • S-shaped tunnels beneath the bark
  • Multiple trunk sprouts with heavy infestation
  • Leaf wilt and branch dieback with heavy infestation

Is There Any Prevention for Emerald Ash Borer? How Can I Treat Emerald Ash Borer?

Yes, there are four types of EAB treatment options. Before they’re applied, your local arborist first determines if your tree is a good candidate for preservation.

When applied correctly, EAB treatment is effective 85 to 95 percent of the time.

For example, when EAB was found in Naperville, Illinois, they chose to treat their trees. Three years later, more than 90 percent of the treated ash trees show no signs of infestation. In communities, such as Naperville, tree inventories can save time and money.

Is your community at risk? Contact your local arborist to schedule a complimentary EAB inspection for your ash trees.

  • The Tree Doctor June 8, 2016 >Hi, Robyn. Thanks for reaching out to Davey for help. As you suspected, emerald ash borer is in your area. If you're seeing trees dying, you want to act fast to see what's best for your remaining trees. Your next step? Schedule a free EAB consultation with your local arborist by calling 336.554.7865 or filling out this form here: Then, your arborist will recommend the best course of action for the remaining trees in your yard. Here if you have any more questions, Robyn.
  • Robyn Sedillos June 8, 2016 >All the trees in my development are dying & I think it's from the emerald ash borer. Please tell me what we can do. I lost two trees already!
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