Emerald Ash Borer - is there a reliable preventive treatment for large Ash trees?

Asked April 12, 2015, 6:36 PM EDT

I have four large Ash trees on my property in Bethesda, MD. I was told by an arborist that the Emerald Ash Borer is now in Montgomery County, but there is an injection treatment that will protect the trees for about three years. My questions are two-fold: Is the Emerald Ash Borer really in Montgomery County, and if so, how fast is it spreading, is it a real threat in Bethesda this summer? If the Ash Borer is now a threat, are there reliable preventive treatments, and roughly how much should they cost?

Montgomery County Maryland

1 Response

Yes, emerald ash borer (EAB) is in Montgomery County. We cannot say how soon it will arrive in Bethesda, it has not been found extensively. Maps of trapping results on are on our website in Invasives > Invasive Insects > EAB. Considering that it has killed all the ash trees in the upper midwest and has killed everything in its path on its way here, sadly enough, there is no reason to suspect that it will stop now.

You can treat your trees. There is extensive information on management of EAB on our website in the Invasive species section in the publication on Management Options: :http://extension.umd.edu/hgic/invasives/emerald-ash-borer

We'd recommend that you familiarize yourself with everything on this page, including the Decision Key. Keep in mind that EAB is not going away. Any management option you choose will be a lifetime commitment, although once most ash trees are dead there will be less food for the EAB to infest and EAB numbers should go down.

We don't have specifics on cost.