Since EAB was discovered in the U.S., researchers have focused much of their efforts towards finding effective control treatments.  Experimental results are variable – some treatments are highly effective, but others are less so.  The latest research results can be found in the 2^nd edition of ‘Insecticide Options for Protecting Ash Trees from Emerald Ash Borer’, which came out in 2014: http://www.emeraldashborer.info/files/multistate_EAB_Insecticide_Fact_Sheet.pdf.  A summary is listed below. Note that new research results are coming out all the time, so recommendations may change is the future. As always, follow all pesticide label directions carefully.  

Spray-type treatments with traditional broad-spectrum insecticides have been the least effective at controlling EAB. Quite simply, EAB adults can be active through most of the summer, and the insecticides didn’t last long enough to provide enough control. Additionally, obtaining a thorough spray coverage is very difficult, especially with larger trees.

Tree injection system.

The most effective insecticide treatment by far has been stem injections with the active ingredient ‘emamectin benzoate’. Test results have shown that this product provides better than 99% control of EAB larvae – and that level of protection lasts for at least two years. Many communities in the Midwest have found that a combination of insecticide treatments, along with timely removal of low-value trees, is incredibly useful in managing the ash trees in their urban forests.

Additional information about EAB is available from the ND Department of Agriculture at: https://www.nd.gov/ndda/plant-industries/pest-survey-and-outreach/emerald-ash-borer-eab.  For more information about tree pests such as Dutch elm disease, gypsy moth, and others, please visit the ND Invasives website at: http://www.ndinvasives.org/.