Ask Mr. Answer Person: "Why isn't the Decorah Park-Rec Department using chemicals on ash trees to prevent Emerald Ash Borer?

Mary e-mails: Why are ash trees (in city parks) being cut down without at first trying to kill the borer?  I heard from a local nursery that ash trees can be treated with a chemical which kills the borer.  It is applied around the base of the tree and is absorbed through the root system and kills the larvae/bugs.  Can't that treatment be used in Decorah? Or at least looked into?

Mr. Answer Person says: "It would be great if there were a magic bullet to use against the Emerald Ash Borer, but there isn't.  Researchers from Ohio State, Purdue, the University of Wisconsin, University of Illinois and the University of Minnesota have all been studying the Emerald Ash Borer as part of "The Cooperative Emerald Ash Borer Program."  They have reported that insecticides have been effective in some cases, but have been ineffective in other cases.  Just one product, emamectin benzoate, has been proven to control EAB for more than one year.  And even the best chemical treatments have some side effects, such as insecticide drift, which can do damage to other plants in the area.

Another factor against using the chemicals is that information on EAB treatment is changing almost on a daily basis.  Decorah Parks & Recreation is trying to stay on top of the research and would change its approach if a promising new treatment is discovered. 

Then there's the issue of cost.  Decorah Park-Rec officials say the treatment they studied would cost $240 per tree.  In other words, treating just 40 trees would cost around $10,000.   Decorah Park-Rec will consider treating some ash trees, depending on the value of what they offer.  But it would be very expensive to treat them all, which is why Park-Rec will be removing some trees, starting with the less desirable ones. 

In the end, the Park-Rec Department consulted with Iowa officials, who recommended beginning to cut down some ash trees so that other trees could be planted now in their place.  This is not a perfect solution, but then again, nothing involving Emerald Ash Borer is perfect at this point.