Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.      

The following email question was routed to me from www.emeraldashborer.info. I am answering it here in the Landscape Alert because I am sure many others have similar questions.

From: Joel

Message: For the past three yrs. I've spent about $600 per year treating our 43 ash trees with Bayer Tree and Shrub Insect Control. Am I wasting my money? Should I also buy traps? From whom?

Dear Joel,

I can't tell where you are located, but assuming that you are in an emerald ash borer (EAB)-infested area, you have not wasted your money. The Bayer Tree and Shrub Insect control product works extremely well as an annual spring basal drench for trees less than 12-inch dbh (diameter at breast height). For trees greater than 12-inch dbh, you should treat twice (effectively doubling the rate). This will also work extremely well. For larger trees, it may be less expensive to hire an arborist to make trunk injections of TREEäge. Recent research indicates three years of control following a single trunk injection treatment made at the 0.4 lb ai/inch dbh rate. This means you could have the trunk injections made every thirdor fourth year for trees up to a 17-inch dbh. For trees with more than a17-inch dbh, I would have TREEäge injected every third year, until more research results are available. Tree care professionals also have the options of using Merit or Xytect as a basal soil drench, or imidacloprid as a trunk injection every 18 months. 

For more information on the best products to use to protect trees against EAB see: “Insecticide Options for Protecting Ash Trees from Emerald Ash Borer” Herms et al. 2009.   A regional Extension publication from Ohio, Michigan, Indiana, Illinois and Wisconsin. It can be read and downloaded on www.emeraldashborer.infoby choosing “Information for Homeowners” on the left side of the opening page. It is the first publication listed. 

And for the second question about using traps, it is not necessary to use traps. They will not help control EAB. Traps are for detection purposes only. If you live in an area where EAB has just recently been found, I would begin insecticide protection when the first ash tree dies from EAB within 10 miles of where you live.