Ash trees and the Japanese emerald borer

Asked September 7, 2019, 4:53 PM EDT

Thank you for providing this service. 8+ years ago, the Japanese Emerald Ash Borer had destroyed all the 25+ mature Ash trees on our and our neighbor’s property- a total of 5 acres. On our property we now have 3 Ash saplings (we are amateurs but feeling confident of this) on our woodland edges with a DBH ranging from approximately 3/4- 2 inches. Our questions: 1. Are the borers still here in the area? 2. Should we let the saplings grow or cut them down? 3. It is cost prohibitive for us to pay for treatment with commercial pesticide for their entire life. We are wondering if we let them grow, will they encourage the survival of any borers in the community? 4. If we let them be, are they doomed to succumb to the borer as they mature? Thanks for your advice. Jane

Montgomery County Maryland

3 Responses

Hi -- Unfortunately, damage to ash trees from emerald ash borer has been extensive in Maryland, with the exception of a few places on the Eastern Shore. Yes, emerald ash borers are present in Montgomery County. If you want your trees to survive, they will have to be treated with a systemic insecticide every 2 to 3 years. They are not likely to survive if they are not treated. You can contact a certified arborist to apply the treatment (by soil drench or injection). You can ask first for an estimate of the cost and then you can make a decision. You can find a certified arborist near you using this website.

There is good information on our website about emerald ash borer and treatment options.

Also, see the Homeowner's Guide to Emerald Ash Borer:


Thank you!