Hello,

Emerald ash borer is still a threat to any ash trees in Michigan. Only Ontonagon, Iron and Gogebic counties were not yet affected in 2016. 

Have a certified arborist come and diagnose the trees. To find a certified arborist search by your zip code here--- www.treesaaregood.org

If you value your ash trees, they should be treated to protect them. Depending on which treatment you choose, you may treat once per year or, with a professional treatment that can last 2 or more years.

If the trees are less than 12 inches in diameter at the trunk, 4 feet up from  the ground, you can treat them each year with a soil drench. Some studies show that homeowner applied soil drenches are effective on trees as large as 15 inches in diameter. The details on this are here---

http://msue.anr.msu.edu/news/emerald_ash_borer_treatments_for_homeowners

https://counties.uwex.edu/wood/files/2016/04/Homeowner-EAB-Guide-Wood-County.pdf

Trees with a diameter trunk larger than 12-15 inches should be treated by a certified tree professional. They have access to chemicals that are more effective, and some will last 2 years before re-treatment is necessary. Trees less than 12 inches diameter  can be treated this way, too, if you want.

You can read a complete discussion of what you can do in this article. There is a chart of chemicals on pdf page 11 (printed page 9).  

http://www.emeraldashborer.info/documents/Multistate_EAB_Insecticide_Fact_Sheet.pdf

Compare the homeowner drench product (note that you will have to read the label and calculate how much product to buy for all trees) with the cost of having a professional treatment. The professional treatment may be less expensive.

Treatment will be necessary every 1-5 years for the life of the tree, unless some new treatment is discovered by scientists. Research is still going on. "EAB" updates can be found here--- http://www.emeraldashborer.info

Thank you for using our service.