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Emerald Ash Borer

If you have ash trees, you need to be informed about an invasive tree pest that is spreading in Missouri and throughout the St. Louis area. Trees in at least 15 states have suffered through the spread of emerald ash borer, and taking a proactive approach will go a long way in stopping its spread.


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What Is Emerald Ash Borer (EAB)?

Emerald ash borer is an invasive pest first introduced from Asia to North American around 2002. This small, metallic green beetle is about half an inch long and spread from Michigan to other states such as Indiana and Illinois before making its way to Missouri in July 2008. Since its discovery in Michigan, EAB has spread to 30 other states and continues to devastate ash trees because it spreads from tree to tree.

Steps to Identify Emerald Ash Borer Damage

Step 1: Is your tree an ash tree?
Before you begin to worry about emerald ash borer, you must first determine if you have an ash tree because ash trees are the only ones affected by this pest.

To determine if your tree is an ash tree, check for all of the following:

  • Oppositely branched – Do the branches of your tree form a Y shape, or are do they alternate rather than line up in that shape? If so, your tree may be an ash tree.
  • Compound leaves – Do the leaves join together on a woody stem by a stalk, forming a grouping of leaflets? Trees that are not ash trees have single leaves joined by a stalk to a woody stem, so if you have groupings, your tree is more likely to be an ash tree.
  • Numerous leaflets – Do the leaflets group in sets of 5 to 9 rather than in 3 to 5 groupings?

If you are uncertain if your tree is an ash tree, a certified arborist can help you! At Omni Tree Service, we have the skills and experience to identify and care for trees of all kinds.

Step 2: Does the tree show signs of damage?

Has your tree been damaged by emerald ash borer? To know for certain, check for these problems:

  • Sparse leaves and/or dying branches in the upper crown
  • New sprouts on lower trunk and branches or on the roots
  • Short, vertical splits in the bark about three to five inches long
  • Increased woodpecker activity
  • Winding, S-shaped tunnels under the bark
  • White or cream-colored larvae under the bark

Step 3: Does the tree have multiple D-shaped holes?
EAB make D-shaped holes in the trunk of ash trees that are about ⅛ inches thick. If you are having trouble seeing the true shape of the hole and think it might be D-shaped but the bark is blocking your view, you might try using a knife to slightly shave the bark flat to get a better view of the hole.


Emerald Ash Borer Prevention

If your tree is infested with EAB, there are steps you can take to stop the spread of the pest. For one, don’t move firewood of trees that have been infested. If you are camping somewhere, buy your firewood locally and burn it all before you leave a campsite rather than bring it home. Also, if you are traveling to a campsite, leave your firewood at home.

Unfortunately, EAB infests ash trees and not other types of trees. To avoid the spread of EAB, plant other large shade trees instead of considering ash trees for your landscaping. Keeping informed about EAB and where it has spread will also help you stay ahead of the problem.

Emerald Ash Borer Treatment

Even the most prepared homeowner can experience an EAB infestation even after using proper prevention techniques with their ash trees. If you do find that the signs and symptoms described above have led to EAB among your ash trees, it’s time to discuss the problem with a certified arborist like those at Omni Tree Service. We treat tree problems throughout the St. Louis area and can properly diagnose and treat ash trees infested with EAB.

We recommend and treat EAB with Arborjet TREE-äge. It is an effective insecticide that kills both the EAB larvae that thrive under the bark and adult beetles that might be under the bark but also that you might visibly see on the trunks and branches of trees.

Arborjet TREE-äge can be applied at any time of the year when EAB is discovered amongst ash trees, but spring is the best time to use it to prevent EAB in the first place. Application of the Emerald Ash Borer insecticide is only done once per year both for the health of the tree and to ensure EAB does not spread to other trees.

If you suspect your tree has been infested or would like additional help with tree removal, contact the experienced tree care professionals at Omni Tree Service today!

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