Treating the Ash Tree for EAB

On Friday, the day finally arrived to treat my ash tree for Emerald Ash Borer. In early spring I had noticed the D shaped exit holes a sign of  Emerald Ash Borer infestation on the ash tree on the side of my house. I love that tree and wanted to save it if possible. Fortunately, I noticed the infestation while there was still hope.

I engaged a tree service recommended to me by my friends at the local Extension Office and listened to their recommendations. What they told me also mirrored what the Forest Service had told me: The protocol for treating Ash trees in areas were groundwater is used for drinking water is for either emamectin benzoate or a specific formulation of imidacloprid to be injected directly into the base of the tree trunk. The insecticide will hopefully be transported within the vascular system of the tree from the roots and trunk to the branches and leaves- if it works. This reduces hazards to groundwater and to other plants from drift and protects the applicator from exposure, and has less impact on beneficial insects and other non-target organisms (like me).

So I engaged SavATree to do the work, and ended up waiting several months until they were able to perform the service. During the early summer I had watched as more of the tree’s canopy withered and worried that they might not get here until it was too late.  Ash trees with greater than 50% canopy loss should be removed and destroyed in accordance with established state guidelines. Friday, the technician arrived to treat the tree and there was still enough canopy to try and save it.

Trunk injections require physically drilling into a tree during the application of the insecticide. The technician arrived with his bucket of tools in hand. First he exposed the base of the tree. Then, he measured the circumference of the tree at about four and a half feet up. The technician, Scott, proceeded to drill a hole for ever five inches of the circumference fairly evenly spaced and attached a tubing system to the holes with a valve on each tie in. Using gloves, safety glasses and pouring  over the plastic bucket he carefully measured out the Imidacloprid and poured it into the bottle connected to the tree tubing and then used a hand pump to create a vacuum. Within minutes all the pesticide had been drawn into the tree’s vascular system.

This is not a due it yourself project. Only licensed professionals can buy this strength of the pesticide and drilling the holes has the potential to cause injury to trees (especially smaller trees), and may provide entry points for certain disease-causing fungi like the Nectria, the cause of Nectria canker. It is a good sign that the pesticide was so easily taken up and that the tree still had so much canopy left. I am hopeful that the tree will be saved. It is reported by the Forest Service that tree injections are tolerated in still healthy ash trees, especially if treatments are applied once every two years, small volumes of product are injected, and injection holes are small and shallow.