Treating for Emerald ash borers

Asked June 23, 2019, 9:20 AM EDT

I’m hoping you can offer some expertise (or point me in the right direction) about best practices for treating an ash tree with emerald ash borers. The trunk is about 25” in diameter but is still in pretty good shape—a few low dead branches but the top is pretty healthy. We have had a company quote on the treatment and they have recommended an application of Imidacloprid as well as feeding with Mycorrhizae. And treating annually after that. A friend in another region, who works in the field, mentioned that usually Emmamectin benzoate is more effective for trees over 20” diameter and only needs to be done every 2 years. I was just hoping to get some local expertise about what has been working best in our region and whether feeding is necessary/recommended. Many thanks.

Baltimore County Maryland

1 Response

There are a number of different recommended ways to treat and protect trees from emerald ash borer. And there are professional tree companies in Maryland that use emamectin benzoate. Actually, the new information coming out shows that trees treated with emamectin benzoate are protected for 3 years.
The following is a booklet for homeowners/professionals that goes into detail about treatments for EAB. This is the most current edition,

One item to bring to your attention this booklet recommends imidacloprid for homeowner use. That is not the case in MD as imidacloprid is now only available for professional use. Refer to the following page from our website explaining about pollinators and pesticides.