Ash Borer Trapping Explained

Purple boxes showing up along roadways.

Published on: Aug 20, 2008

A new way of monitoring the spread of emerald ash borer has been introduced to Ohio and visitors to Ohio State University's Farm Science Review will learn more about the method.

Amy Stone, an Ohio State University Extension educator for Lucas County, will explain the EAB trapping program, a national effort led by USDA-APHIS designed to monitor and trap the insect in previously undetected areas. Stone will present "What are Those Purple Things? The New EAB Traps" at 11 a.m. on Sept. 18 at the Woodland Amphitheatre of the Gwynne Conservation Area.

"We want to keep people updated with what's happening in the world of emerald ash borer and continue to raise awareness about the insect and the damage it does to ash trees," says Stone, who has been involved in EAB outreach efforts for several years.

The biggest component of the EAB trapping program is a purple trap and lure, which is hung in the canopy of ash trees. Motorists traveling throughout parts of southern, southeastern and northeastern Ohio may have already caught a glimpse of these traps.

"The traps replace the older survey method where live trees were girdled to be more attractive to the insect. The girdled tree method was very expensive, labor intensive, and could only be used once," said Stone. "This new method is more cost-effective."

The trap contains manuka oil, a lure that smells like ash trees to the insect. Stone said that the traps are purple because research has shown that particular color is attractive to the insect. Once the emerald ash borer is lured to the trap, a sticky substance coating the outside traps the insect.

Nearly 7,500 traps have been placed in or near ash trees throughout Ohio. Stone said that the traps have been in place beginning in mid-May and, to date, no insects have been found in undetected areas.

USDA and the Ohio Department of Agriculture are leading Ohio efforts in the EAB trapping program. If a suspect beetle is found on a trap, it will be sent to USDA for identification. Counties with new finds will be quarantined to regulate the movement of ash trees, parts of an ash tree and all hardwood firewood out of the quarantined area.

Ohio residents are encouraged to assist in EAB detection and education by allowing trap placement on their property. For more information, call (888) OHIO-EAB or e-mail For more information on OSU Extension efforts in EAB education and detection, log on to