This is a valid question for anyone considering treating their ash trees instead of removal. While time will tell for certain, I nevertheless believe this is NOT the case. I have been involved with Emerald Ash borer treatment in Michigan, Ohio, Indiana, Illinois, and Wisconsin since 2002. Over this time I have become more experienced treating for this insect than any other arborist in America. There are many customers that I treated in the very beginning that are no longer treating, and their ash trees are still there. We started in the beginning with aggressive treatments of imidacloprid both in the soil and trunk injected. But after a few years we have started to wean these trees off treatment by reducing the treatments first to soil only and then finally to skipping a year. In many cases the homeowners have taken over by applying the homeowner version of the treatment as insurance to help maintain the insecticide levels we built up over the years.
When the Emerald Ash Borer kills all of the untreated ash trees in any given localized area, it runs out of food. Some people think that they then “move on” but that is not the case. The only EAB life stage that can “move” are the adults once they emerge, but they do not fly that far. Perhaps ½ mile to 1 mile. They are capable of hitching rides on vehicles to move longer distances but the main body of the population simply dies off from lack of food.
The EAB is classified as a phloem feeder. When the eggs hatch, the larvae burrow under the ash bark looking for actively growing sapwood. They do not have that much energy stored up when they hatch and certainly cannot go very far looking for living tissue. If they do not find any in a short distance they will die, ending the life cycle at that point. They will not become an adult beetle the following year.
This means they CANNOT live on dead ash trees NOR any part of an ash tree that has already died from prior attacks. Removing ash trees not planned to be treated as soon as you can will also slow the spread of this insect by removing their food source. Many cities have adopted this removal method as part of their overall Emerald Ash Borer management plan. This is a good idea even if they are treating many other specimen ash trees that they wish to keep.
The team at Emerald Tree Care, LLC including our Board Certified Master Arborist and some of the nation’s leading experts on Emerald Ash Borer. If you are in an area where the Emerald Ash Borer has been or might be soon, we implore you to call. Even if you are outside our treatment area we share treatment ideas with many other Certified Arborists and can help you find one in your area. Let us know how we can help!