Using the Slow Ash Mortality Strategy as a Response to the Introduction of Emerald Ash Borer in Oregon

Emerald Ash Borer (EAB), Agrilus planipennis, is an invasive wood-boring beetle that has caused extensive damage to ash trees across North America for the last 2 decades. Ash trees play a vital role in ecosystems, providing habitat in wetland forests and riparian zones. The first detection of EAB in Oregon occurred in 2022 in Forest Grove, marking the first confirmed sighting of this pest West of Colorado. In response, the Oregon Department of Agriculture (ODA) spearheaded efforts to contain the pest through the Slow Ash Mortality (SLAM) program. The SLAM strategy combines insecticide treatments, specifically trunk injections of emamectin benzoate, with the use of trap trees to monitor and control the spread of EAB. Trap trees are artificially stressed by removing a strip of bark, making them more attractive to EAB, and are subsequently felled and inspected for evidence of infestation. A "Ring of Fire" was established around Forest Grove, where clusters of treated and trap trees were selected every quarter mile to prevent further spread. This approach was implemented in 2023 and 2024, with the goal of assessing EAB's distribution and determining the effectiveness of containment efforts. Results from this study provide critical insights into the management of EAB populations and the future of ash tree preservation in Oregon.