Biological agent type
root boring beetle
Plant species attacked
Click on image to view larger photo.
Images by Eric Coombs,
Oregon Department of Agriculture.
Impact on target plant
The larvae bore into the root and lower stems, and often cause plant mortality.
Collection and release
Sweep netting the adults during the cool of the morning in the late-flowering period (late June-July) is the most productive. Sort adults from debris using an aspirator. Numbers are usually few, making this a difficult insect to work with. Release 50 – 100 adults per site.
This beetle has been released in 8 counties and is established in 4, primarily in NE Oregon.
History and comments
The root-boring beetle Agrilus hyperici was introduced in Marion County in 1986, and failed to establish. It occurs in the eastern half of Wallowa County where it spread naturally from populations in Idaho and Washington. The first release of adults collected in Oregon was made in Umatilla County in 1992, which were recovered in 1994 and is now widespread in NE Oregon. The beetle has been released in other counties, and was recovered in Jackson County in 2005. An extended effort was made in 2011 with APHIS to collect beetles in NE OR for redistribution into the central and SW part of the state.