Search for Emerald Ash Borer Control Continues
Published: Friday, June 7, 2019
The following is from Jeff Burbrink, Elkhart County Extension educator.
It seems hard to believe that only 15 years ago, the Emerald Ash Borer (EAB) was found in Indiana. Since 2004, nearly every large ash tree in our county has died, unless they were treated with an insecticide. The remaining living ash trees are mostly small saplings. Once they approach 3-4 inches in diameter, the borer attacks, killing the tree in 2 to 4 years.
EAB continues to make its way south and west, killing millions of trees in the process and endangering people because of the brittle, dead trees they leave behind. It's a heartbreaking case of an invasive, non-native species causing millions of dollars of damage.
I am occasionally asked if ash trees will make a comeback in our area. I think they eventually will. Researchers have been scouring forested areas in the Midwest and eastern states, collecting seed from ash trees that are still alive despite being surrounded by forests full of dead ash. These legacy trees may have some sort of resistance built into their genetic code that is transferable to the next generation of ash trees. Ash trees in China, for instance, have built in defensive mechanisms to counter the feeding of EAB.
Researchers in the region are also looking into biological control of EAB. At least four different parasite species of wasps have been identified with some potential to attack the borer. These are not wasps that we need to worry about. They are tiny little creatures, which most people would not recognize as a wasp, much less sting someone.
The key to making a successful biological control work is that the introduced species needs to be able to survive our climate, and do so without creating another issue with other native species. It also needs to be acceptable to people. Can you imagine the uproar if lions or wolves were introduced to control deer in our region?
If you have a living ash tree that you have kept alive by treatments, it is wise to continue those treatments for a while longer. Fortunately, the researchers have developed new techniques that require less pesticide and treatment every other year, which saves money and helps with the environment.
For now, I would not consider planting ash trees in Elkhart County. Hopefully in my lifetime, that will change. I am fairly confident we will someday see EAB resistant ash trees in our community.
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