The pest was fist found in Michigan in 2004 and started spreading across the United States. Several years ago, the Green and Golf Committee toured the club looking at our ash tree population. At that time we designated 75 trees that we wanted to protect and called them high value trees. Since then we have treated 141 trees on a biannual basis. The Iowa DNR recommended that we not treat those trees until a detection was within 15 miles of your property.
Here is a map showing where EAB is in Iowa as of January 2020.
Once it was discovered within 15 miles of the club we started treating those high value trees to protect them. This is a treatment that is done every 2 years. We will be doing it again this year. None of the trees that we have been treating are showing any sign of EAB infestation. Once trees start to leaf out we will have a better idea of damage but for now we believe our treatments are protecting those trees. Treatments are not cheap and once started you have to continue them to protect the tree.
We have been pruning trees throughout the property this past winter and this spring. We have found Emerald Ash Borers in some of our ash trees. On #2 North we found 2 ash trees that were devastated by EAB. There are a few tell tale signs of EAB.
First is the exit hole of the adult insect. It leaves a very significant "D" shaped hole in the bark of the tree. The following photos show this "D" shaped hole.
The next sign is "S"-shaped galleries between the bark and the wood caused by larvae feeding. While you can see galleries in ash trees from other types of borers the Emerald Ash Borer leaves that "S" shaped pattern. Here is a photo from one of our trees.
If caught early enough treatments can help save a tree. However if the infestation is more than 30% of the tree, then the recommendation is to remove the tree. We will be discussing our issues at the next Green and Golf Committee meeting. I am sorry to say that I truly believe we will see more damage this year from this pest.
To recap we have 346 ash trees on property. We are treating 141 of these trees, which is about 40% of the population of ash trees.