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A new report by entomologists studying Emerald Ash Borer (EAB) indicates effective measures can be taken to slow EAB’s spread and preserve ash trees. Cowritten by several university researchers, “Insecticide Options for Protecting Ash Trees from Emerald Ash Borer (2014)” provides a status update on ongoing scientific research conducted to evaluate chemical treatments used to kill EAB.

“Government agencies and homeowners should take solace in the fact that science has honed in on technologies effective at managing EAB in small geographies which includes cities and towns,” said Dan Herms, Ph.D., professor and chairperson of the entomology department at The Ohio State University (OSU) and the study co-author. “Treatment can be implemented for a fraction of the cost of cutting and replacement and provides a longer time horizon to deal with this, important given the rapidity at which EAB overtakes and kills a local ash population.”

The new report is an extensive update of the first edition, published in 2009, and is on EAB’s origins and the various technologies and approaches used to combat it. The researchers provide reports on studies used to evaluate different pesticides and explain the practical and environmental trade-offs for each treatment option.

Highlights from the 2014 edition include:

• Research that shows treating landscape ash trees with effective systemic insecticides is much less costly than removing trees;
• Even large ash trees can be effectively and consistently protected over multiple years, even when EAB density is high;
• In studies conducted by OSU and Michigan State University (MSU), the best performing insecticide provided nearly complete EAB control for two years;
• Infested trees that show signs of decline when treatments are initiated may continue to decline the first year after treatment but then begin to improve the second year as the trees recover.  Effectiveness of products varies and depending on the product applied and the pest pressure, some trees may not recover despite treatment; and
• Studies have found that as EAB population declines, it seems likely that surviving ash trees can be managed with less frequent treatments.

“The challenge for homeowners and large municipalities is the same: what is the best approach to manage through an EAB infestation,” said Deb McCullough, Ph.D., a professor at MSU and report co-author. “The financial costs are significant, as is the potential loss of tree benefits with removal. Treatment tools provide options which allow urban foresters to manage this issue so that the effects on communities are minimized.”

Additional report co-authors include David Smitley, Ph.D., MSU; Clifford Sadof, Ph.D., Purdue University; and Whitney Cranshaw, Ph.D., Colorado State University.