How to Tell If Emerald Ash Borers Are Killing Your Trees Before It’s Too Late

Like many trees, ash trees undergo leaf shedding each fall and winter. Unlike other trees, ash trees are specifically targeted by a pest: the emerald ash borer. These creatures are emerald ash borers, shiny green beetles that only target ash trees. How can you tell if you have emerald ash borers? The signs may be more visible than you think.

Signs You Have Emerald Ash Borers

The key to preventing emerald ash borers from infesting ash trees is to monitor them regularly. Most experts recommend monthly monitoring. However, even with regular monitoring, signs of beetle infestation can be easy to miss.

Some of the physical signs that an emerald ash borer infestation has begun include:

• D-shaped holes in ash trees in June and July as adult beetles emerge
• S-shaped tunnels under the bark
• Cream-colored larvae seen under the bark of the tree
• Adult emerald ash borers are seen regularly in the area

As the tree begins to die, key symptoms appear. Those symptoms, according to the University of Wisconsin, include:

• The crown of the tree thins out
• New shoots appear at the base of the trunk
• Vertical cracking in the tree trunk

All of these are signs that emerald ash borers are destroying the tree, and immediate action is needed to stop them.

How Emerald Ash Borers Destroy Trees

For many invasive species, the adult insects cause the most damage. However, with emerald ash borers, it is the larvae that are most harmful to trees.

Female emerald ash borers lay their eggs in the bark of ash trees. Each female can lay between 40 and 200 eggs at one time. The eggs take approximately two weeks to hatch. When this happens, the larvae burrow through the outer layer of bark until they reach the phloem and cambium layers of the tree to feed.

As the larvae feed on these layers of the ash tree, the tree’s ability to transport water and nutrients is disrupted. If left untreated, the tree will begin to die from the top down. It typically takes about three to four years for an infested tree to die after the initial infestation.

Where Are Emerald Ash Borers?

Emerald ash borers are not native to the United States. They are an invasive species that originated in Asia. It is believed that the beetles made their way to the States via shipping containers, with their first documented appearance in Michigan in 2002.

Since that time, emerald ash borers have had the largest populations in the Midwest. However, their territory and infestations increase each year, leaving very few states free of the beetles.

The states well-known for having emerald ash borer infestations include:

• Michigan
• Ohio
• Indiana
• Illinois
• Missouri
• Wisconsin
• Minnesota
• Iowa

States in the Northeast and Southeast have also reported infestations. However, to date, these infestations have been contained to regions much smaller than those seen in the Midwest.

What to Do If You Have Emerald Ash Borers

In states with known infestations of emerald ash borers, there are specific requirements that homeowners must follow to report activity on their property. This helps keep not only the community but also the surrounding areas informed of the presence of these destructive beetles.

Once beetles have been reported, time is of the essence to save trees from damage or death caused by emerald ash borers. Some popular methods for treating trees for emerald ash borers include:

• Insecticide treatment
• Removing overly infested trees
• Replace removed trees with species that are resistant to emerald ash borers
• Biological control programs may introduce predators that feed on the beetles into the environment
• Trunk injection
• Soil drenching

For trees showing signs of a small infestation, it may be possible to treat them without expert help. But it is always recommended to speak with an arborist before taking matters into your own hands. The infestation could be more severe than it appears, and if the invasive beetles are not eradicated, the damage to the trees may be irreversible.