Emerald Ash Borer – Treatment

Below you will see two photos of the same Ash tree. The photo on the left was taken in 2014. (Notice the totally dead Ash trees in the background of this photo.) The photo on the right was taken a few days ago.

ash tree   ash tree treated for EAB








It is evident that the Emerald Ash Borer (EAB) population has begun to subside in this particular neighborhood and that our customer’s tree is making great strides at recovery now that there are fewer borers attacking it.

Ash trees under treatment may appear stressed and look like they are starting to decline even though you are having them treated. This is normal until the pressure from the insect completely subsides and the tree can begin to heal internally and recover. While this may be the case in ‘most’ instances, it will unfortunately not be the case in ‘all’.

Yes, we have lost some Ash trees – 4% to date.  In those cases the client either started treating them too late or there were additional stressors on the tree besides the constant ongoing attack from the Emerald Ash Borer.

What happens is this….

Even though you are treating your Ash, the female Emerald Ash Borers in the area continue to fly to Ash trees and deposit their eggs on the bark. After all, they do not know that the tree is undergoing treatment. The little ones hatch and immediately begin to burrow into the bark to begin feeding inside the tree, obstructing the sap flow. The products that we injected into your tree then work to kill them before they can reach maturity. Even though we kill the borers while they are small, a tree may have thousands of them burrowing inside. They still cause some damage, which is why the tree appears stressed during its treatment. Once the pressure from the insect subsides, the tree will do all it can to repair itself to make a comeback.

We mentioned that we have lost about 4% of all the trees that we are treating. Why?  Once people heard about the EAB situation and then realized they had an Ash tree on their property, they may have begun treating later than others. These trees with later starts are more at risk than those that had started treatment earlier. Unfortunately, even a few of the trees that we started treating earlier have gotten to the point where we have had to recommend ceasing treatment. In all of these cases, there have been additional stressors that have contributed to this unfortunate recommendation. Some have been in ‘wet zones’ where drainage is poor. Some have been in unbelievably poor, heavy clay soil. Some of our clients routinely use ‘Roundup’ herbicide to kill weeds which is not supposed to affect trees but we have discovered that as the weeds die and decompose, the tree roots pick up the herbicide and it can stress or even kill the trees. It is known that most parkway trees are in poor soil as they have notoriously heavy clay content to buffer the road. While we have managed to save most of the parkway trees that we treat, it is the parkway trees that make up the vast majority of the total 4% that we’ve lost to date. Not only is there clay in the parkway but the trees also have diminished root systems supporting them because the street itself limits the tree to a smaller root system than it would normally develop, since roots cannot live under asphalt or under your concrete driveway. If you combine those factors with the constant onslaught from the insect, sometimes the tree is just not able to overcome all of those negative influences.

In instances such as this, only time and the tree itself can let us know if it will make it through this devastating situation.

Parkway Planting Hazardous to your Ash Trees’ Health

We hope you are enjoying our mild Chicago summer.  Even though the weather has been cooler than usual, that doesn’t mean your landscape doesn’t need special care.  Here is a photo that illustrates this beautifully:

Here you can see two lines of “Green Ash” trees on opposite sides of a parking lot. So why do those on the left look so much worse than the ones on the right?

Any tree on a parkway, sandwiched between the street and the sidewalk, is at risk as it ages. Its roots are in a ‘soil coffin’ so to speak and unable to freely stretch and grow.  Notice the cement coffin the Ash trees on the left are in compared to the Ash on the right. Although those on the right still have a parking lot on one side, they are much farther away from the lot. They are also at least 30 feet away from the building so the roots have a more expansive environment in which to grow.

This stress factor, combined with the constant onslaught from the Emerald Ash Borer, makes it more difficult to save these Ash trees. All of these Ash are under the same degree of Borer infestation but look how much stronger those on the right are…… temporarily. All of these trees, on both sides of the parking lot, will eventually succumb to the EAB without treatment; but obviously those on the left will die a year or two sooner.

Tree Green has had remarkable success treating Ash trees for Emerald Ash Borer.  Give us a call, and we’d be happy to give you a free evaluation.