If the trees are still in good health and structurally sound, they can be treated. If you decide to move forward with the treatments, please realize that depending on the insecticide, they will need to be treated every one to two years until EAB leaves the area; which is typically around 8 years.
There are various treatment options, but our go to method is using direct injection into the tree. A small hole is drilled into the tree through the bark into the cambium layer and then a pressurized capsule is placed into this hole in the tree and the insecticide is taken up and spread throughout the tree. This limits insecticides being placed in the ground or on the trunk. We feel it is the most environmentally friendly approach.