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Tree Texture

What is an Emerald Ash Borer? (EAB)

Emerald ash borer has been labeled as the most invasive pest to ever hit the United States and Canada. Since its discovery in 2002, it has killed over 20 million trees in Michigan alone. It will continue to spread and is a permanent member of our insect population in the United States, though this pest has not been identified within the state of Utah by a registered authority as of yet. In most cases, emerald ash borer has been present for multiple years before it is ever officially documented. It currently surrounds the state and will eventually, if not already, invade and infest our beautiful state. When it does happen, we will see mass loss of trees throughout the state. 

Signs and symptoms

**It must first be known that without proper identification of the pest, these signs and symptoms are attributed to a number of different problems that can happen to your tree. Just because your tree has all of these signs and symptoms does not indicate the presence of emerald ash borer. Proper identification should be made by a licensed professional**

Most signs and symptoms won't show until the tree has nearly reached infestation. It starts in the crown in areas where you cannot see. Pests generally like to attack branch unions that are less than 2”. Early signs are shown through canopy thinning and epicormic growth (fast growing water sprouts). Most thinning will happen on the south to southwest tips. By this time, it’s already been in the tree for multiple years. 

As the pest levels increase, woodpeckers might start feeding. *It must be known that woodpeckers feed on many different insects.*

In later stages of infestation, you begin to see cracking in the bark and “D”-shaped exit holes. If you pulled back the damaged bark you would see “S''-shaped feeding galleries. At this stage of infestation, the tree is beyond treatment and should be removed. 

What can I do about Emerald Ash Borer?

Emerald ash borer can be challenging to manage once it has infested your ash tree. Despite the challenges, you can take steps to prevent and protect your trees from EAB. Current insecticide technologies make it rather easy to protect your tree from EAB and other insects. Trees that are already infested with EAB can be treated with emamectin benzoate directly injected into the tree. Success is ultimately determined by both tree condition and predispositional stress factors. 

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