I am frequently asked this question by homeowners concerned that an infested tree next door will somehow doom their ash tree even if they treat for Emerald Ash Borer. I thought it important to not only explain why this is not true but also show some pictures that speak for themselves.
The neighbor on the left has had me treat their ash tree for a couple of years now. The insecticide is systemic, meaning it gets absorbed by the plant tissue it comes in contact with and moves throughout the treated tree into and through the exact areas that Emerald Ash Borer feed. As this is a PREVENTATIVE treatment in place before the Emerald Ash Borer attempts to feed on the ash tree(s), then any ash borer that touch a treated ash tree (either by feeding on the leaves as adults or burrowing under the bark as newly hatched larvae) cannot survive and complete their life cycle. The ash tree on the right has not been treated and any ash borer that go after it are not affected at all and will complete their life cycle and emerge as new adults the following season. As we continue treating the tree on the left it is easy to understand that no future Emerald Ash Borer will survive there and the tree on the right will continue to be attacked until it is completely dead in about 2 years.
Here in another neighborhood of hundreds of dead and dying ash trees, another customer of mine has been treating for Emerald Ash Borer for three years. When we started treatment there was no visible signs of infestation in the area but within two years it just exploded. In my opinion there are no other ash trees in this subdivision that can be saved at this point. Treatment needs to begin when your trees still look healthy and the insect has been confirmed within 15 miles of your ash trees. DON”T WAIT UNTIL IT IS TOO LATE TO TREAT!!!! If your trees already look like those in the background behind this treated ash tree, then you have waited too long. They cannot be saved at this point! Contact us now to get your trees inspected!