EMERALD ASH BORER BIOLOGICAL CONTROL PROGRAM
Emerald ash borer (EAB) or Agrilus planipennis is a small Asian beetle killing ash trees
throughout urban, forested, and riparian areas of Michigan, Ohio, Indiana, Illinois, Pennsylvania,
Maryland, and West Virginia. Currently there are no effective management tools, other than tree
removal. The USDA’s Animal and Plant Health Inspection Service (APHIS) and Forest Service
have established a 5-year plan for developing and testing possible biological control techniques
for this pest.
Research on EAB biological control began in 2002 when this destructive beetle was first found
in Michigan. Much of the biocontrol research was done in China, where studies of EAB led to
the discovery of three specific insect natural enemies: Spathius agrili, Oobius agrili and
Tetrastichus planipennisi. These natural enemies are tiny stingless wasps that seek and kill EAB
eggs and larvae. Five years of research led to an environmental assessment1 of field release of
these natural enemies. After a 60-day public comment period and a Finding of No Significant
Impact, APHIS and the State of Michigan approved release of these wasps for control of EAB.
Small-scale releases were completed in Michigan in 2007. The sites will be monitored for
establishment of the natural enemies and their potential to control and slow the spread of EAB in
the United States.
An EAB biocontrol laboratory is being established at the APHIS facility in Brighton,
Michigan. With oversight from APHIS and the Forest Service, the laboratory will be responsible
for rearing these three natural enemies for scheduled releases. The releases will start in
Michigan and progress to other states as determined by program needs, regulatory approval, and
production capabilities. Release sites will be determined by APHIS and the Forest Service in
consultation with State partners. The challenges of rearing these natural enemies will limit their
availability for release un