Treatment successes shared at emerald ash borer field day

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.

At an MSU Extension Field Day at BayPointe Golf Club on August 16, over 120 attendees had the opportunity to walk the golf course to observe ash trees of all sizes that have been treated each year with a basal soil drench of imidacloprid since 2004. 

Results of this test with 52 ash trees, half of which were treated, show that if treatments begin when trees are still healthy most (92 percent) of the trees can be saved.  However, if treatments don’t begin until trees show obvious symptoms of borer infestation, only about half (62 percent) of the trees will survive.  Therefore, the best chance of saving infested ash trees is to use both a basal soil drench of imidacloprid and and imidacloprid trunk injection the first year, followed by one or the other treatment each year afterwards.

After the walking tour of the golf course, tree care professionals from the Detroit area shared their success in saving ash trees.  Several professional arborists reported successes using an imidacloprid trunk injection, an imidacloprid basal soil drench (or basal soil injection), or both.  They also emphasized the need to start treating trees before they are compromised from borer damage.

emerald ash borer infection
Canopy thinning and dieback ratings for
ash trees infected with Emerald ash borer.

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