Ever wondered how to spot the sneaky emerald ash borer wreaking havoc on trees? Picture this: you’re strolling through a lush green park, admiring the towering ash trees, when suddenly, you notice something unsettling about one of them. Its once vibrant leaves are wilting, and strange patterns adorn its bark. What’s happening to this tree?

In this article, you’ll discover the telltale signs of a tree infested with the emerald ash borer. By learning to identify these visual cues early on, you can take proactive steps to protect your beloved ash trees from this destructive pest. Stay tuned to unveil the secrets hidden in the appearance of an ash tree under the attack of the emerald ash borer.

Key Takeaways

  • Look for D-shaped exit holes on the bark of ash trees as a distinctive sign of emerald ash borer activity.
  • Check for thinning or yellowing leaves, unusual bark patterns, and vertical splits on the trunk as visual cues of infestation.
  • Increased woodpecker activity on ash trees during spring and summer can signal emerald ash borer larvae presence.
  • Canopy dieback starting at the top of the tree is a significant visual clue of emerald ash borer infestation.
  • Act promptly by contacting certified professionals if you suspect an infestation and consider preventive treatments for ash trees in affected areas.
  • Monitor for signs like bark splits, woodpecker damage, canopy dieback, serpentine galleries, sucker growth, and peeling bark to detect emerald ash borer infestation early.

Overview of Emerald Ash Borer

When observing your ash trees for signs of emerald ash borer infestation, it’s crucial to recognize key indicators that can help you protect your trees effectively.

Main Characteristics to Look Out For:

Inspect your ash trees for D-shaped exit holes, which are a distinctive mark of emerald ash borer activity. These small, circular holes are about 1/8 inch in diameter located on the bark of the tree.

Visual Cues to Identify Infestation:

Look for thinning or yellowing leaves at the top of the tree, as this can indicate emerald ash borer damage. Additionally, watch for unusual and wavy patterns under the bark as well as vertical splits that can be present on the trunk.

Signs of Emergence:

During spring and summer, keep an eye out for increased woodpecker activity on the tree. Woodpeckers are known to feed on emerald ash borer larvae found just beneath the bark, so their presence could suggest an infestation.

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Infestation Impacts:

Be aware that once infested, the tree can exhibit canopy dieback, starting at the treetop and gradually moving down as the infestation progresses. This dieback is a significant visual clue of emerald ash borer presence.

Response Measures:

If you suspect an infestation, it’s essential to act promptly. Contact a certified arborist or your local forestry service to assess the situation and determine the best course of action to protect your ash trees from further damage.

Preventive Steps:

Consider preventive treatments for your ash trees, especially if emerald ash borer has been detected in your area. These treatments can help safeguard healthy trees and prevent infestations before they occur.


By familiarizing yourself with the characteristics and visual cues associated with emerald ash borer infestation, you can take proactive steps to protect your ash trees and preserve their health and vitality. Remember to remain vigilant and seek professional guidance when needed to ensure the long-term well-being of your trees.

Signs of Emerald Ash Borer Infestation in Trees

Spotting signs of emerald ash borer infestation in trees is crucial to protect your ash trees from devastating damage. Here are key indicators to help you identify if your trees are affected:

1. Foliage Changes

Look for early signs of infestation by checking for canopy thinning, premature yellowing, or browning of leaves. Infested ash trees display these symptoms as the emerald ash borer disrupts the tree’s nutrient flow.

2. Bark Splits and Patterns

Inspect the bark of your ash trees for vertical splits and serpentine patterns created by the larvae tunneling underneath. These patterns are distinct indicators of emerald ash borer activity.

3. D-Shaped Exit Holes

One of the most telling signs of emerald ash borer infestation is the presence of D-shaped exit holes on the bark. These small, distinct exit holes are left behind by adult beetles emerging from the tree.

4. Woodpecker Damage

Keep an eye out for increased woodpecker activity on your ash trees. Woodpeckers feed on emerald ash borer larvae, and their presence could signal an infestation. Look for missing bark or small patches where woodpeckers have been foraging.

5. Canopy Dieback

Notice any significant dieback in the upper branches of your ash trees. Canopy dieback occurs as the tree’s nutrient supply is compromised due to emerald ash borer infestation, leading to wilting or dead branches.

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6. Gallery Formation

Check for serpentine galleries beneath the bark of affected ash trees. These galleries are created by emerald ash borer larvae as they feed on the tree’s inner bark, disrupting nutrient transport.

7. Sucker Growth

Observe the base of your ash tree for sprouts or sucker growth. Trees may exhibit vigorous sprouting in response to stress caused by emerald ash borer feeding activities.

8. Peeling Bark

Monitor for peeling or cracked bark on ash trees, especially around branch unions. Disrupted nutrient flow from emerald ash borer infestation can lead to bark separation from the wood.

Physical Characteristics of a Tree with Emerald Ash Borer

When you’re inspecting trees for signs of emerald ash borer infestation, keep an eye out for specific physical characteristics that can indicate the presence of these destructive beetles. Here are the key features to look for:

Bark Patterns:

Check for distinct serpentine galleries created by the larvae beneath the bark. These winding tunnels disrupt the tree’s vascular system, leading to visible damage.

D-shaped Exit Holes:

Look for small, D-shaped exit holes in the bark. These are left behind by adult emerald ash borers as they emerge from the tree after completing their life cycle.

Canopy Dieback:

Observe any upper branches of the tree that show signs of dieback. Discolored or wilting foliage in the upper canopy can be a clear indicator of emerald ash borer infestation.

Woodpecker Damage:

Keep an eye out for increased woodpecker activity on the tree. Woodpeckers feed on emerald ash borers, so high levels of woodpecker damage may point to an underlying infestation.

Sucker Growth:

Watch for excessive growth of small branches or “suckers” sprouting from the tree’s trunk or main branches. This can be a stress response to borer infestation.

Peeling Bark:

Inspect the bark for areas where it is peeling or splitting. This can be a result of larval feeding activities beneath the bark, leading to structural weakness.

Gallery Formation:

Look for winding galleries created by larvae under the bark. These galleries disrupt the tree’s ability to transport water and nutrients, causing further damage.

By familiarizing yourself with these physical characteristics of a tree affected by emerald ash borers, you can promptly identify infestations and take necessary steps to mitigate the damage to your ash trees. Remember, early detection is key to preserving the health and longevity of your trees.

Treatment and Management Options

To effectively address an emerald ash borer infestation on your ash tree, you have several treatment and management options available. It’s crucial to act promptly upon detection to prevent further damage. Here are some strategies to consider:

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1. Insecticide Treatment

Consider using insecticides specifically designed to target emerald ash borers. These treatments can help protect your tree from further infestation. Consult with a professional arborist to determine the most suitable insecticide and application method for your specific situation.

2. Tree Removal

If the infestation is severe and poses a significant risk to your ash tree, tree removal may be necessary. Removing the affected tree can prevent the spread of emerald ash borers to nearby trees and help protect the overall health of your landscape.

3. Tree Replacement

In cases where the emerald ash borer infestation has caused irreparable damage to your ash tree, consider replanting a new tree species in place of the affected tree. Choose a species that is less susceptible to emerald ash borer infestations to avoid similar issues in the future.

4. Monitoring and Prevention

Regularly monitor your ash trees for signs of emerald ash borer infestations, especially if you live in an area where these pests are prevalent. Implement preventive measures, such as trunk injections or soil drench treatments, to protect healthy trees from potential infestations.

5. Professional Consultation

Seek advice from certified arborists or tree care specialists to assess the extent of the infestation and determine the most effective treatment plan for your ash tree. Professional guidance can help you make informed decisions and ensure the best possible outcome for your tree’s health.

By considering these treatment and management options, you can proactively address emerald ash borer infestations and safeguard the vitality of your ash trees. Remember, early intervention is key to minimizing damage and preserving the beauty of your landscape.


Identifying emerald ash borer infestations early is key to protecting ash trees. Look out for foliage changes, bark patterns, D-shaped exit holes, woodpecker damage, canopy dieback, gallery formation, sucker growth, and peeling bark. Treatment options include insecticide treatment, tree removal, replacement, monitoring, and prevention strategies. Acting promptly upon detection is vital to preserve the health and longevity of ash trees.

Frequently Asked Questions

How can I identify emerald ash borer infestations in trees?

Look out for foliage changes, D-shaped exit holes in bark, woodpecker damage, canopy dieback, gallery formation, sucker growth, and peeling bark.

What are the treatment options for emerald ash borer infestations?

Consider insecticide treatment, tree removal, tree replacement, monitoring, prevention strategies, and consulting professionals.

Why is early detection crucial when dealing with emerald ash borer infestations?

Early detection helps prevent further damage, preserve ash tree health, and extend their longevity.

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