Emerald Ash Borer Insecticide

Asked July 2, 2014, 8:55 PM EDT

Hi. We have an awesome Black Ash tree in front of our home which we planted ourselves 15 years ago. It is about 30 inches in circumference at the base of the trunk, and is very healthy this year. We live in Fargo, ND. The nearest Emerald Ash Borers are approximately 300 miles away in the Minneapolis/St. Paul area, but I understand that at this point it is a question of WHEN they come, not IF they come. I would like to be proactive and have some insecticide on hand so I can treat it right away when they arrive within the 15 mile radius recommended for treating with chemical. I have been trying to read about what type of insecticide to buy, but there is a lot of info out there, and it is a little confusing to me. Any recommendation would be appreciated. Thank you!

Cass County North Dakota

1 Response

Good morning,

Most of the damage done to ash trees by EAB is from the insect's larvae, which live under the bark. Therefore, we usually recommend some type of systemic insecticide that will move throughout the tree.

Two products (active ingredients) that are available to homeowners are those with the chemicals 'imidacloprid' or 'dinotefuran'. There are many different formulations or commercial products of both these chemicals; therefore, I can't give highly specific recommendations. Nevertheless, they are both simple to use. Mix the product with water and apply at the base of the tree (both products), or spray on the bark (some dinotefuran formulations). Both chemicals are about equally effective. They have about a 12-month residual, so must be re-applied annually. As always, follow all label instructions.

One professional-grade treatment, not available to homeowners, is the chemical emamectin benzoate. This chemical is injected into the tree stem with special equipment. This chemical is highly, highly effective and has a 2-year residual. I know of one tree-care company in Fargo that makes these treatments, though there may be other companies that I'm unaware of that offer this service.

Imidacloprid can also be injected with professional injection equipment.

I hope this answers your questions. If you need more information, please let me know. Best wishes,