The three species of parasitoid wasps released in Minnesota (Tetrastichus planipennisi, Spathius galinae and Oobius agrili) are reared in a specialized USDA facility in Michigan. They are provided at no charge to state cooperators such as the Minnesota Department of Agriculture to release. A fourth species, Spathius agrili, was released in Minnesota from 2010 – 2012. Releases of S. agrili were discontinued for northern regions because this species was unlikely to establish.
We initiated releases in 2010 in southeastern Minnesota with adult parasitoids. To increase the efficiency of parasitoid rearing we began receiving and releasing immature stages of the parasitoids in 2013. They are in protective structures that are placed in the field then the adult wasps emerge within the next few weeks. There are now over 30 release sites in the Twin Cities and southeastern Minnesota. Releases at new and select existing sites will continue. View locations of EAB finds and biocontrol agent releases.
After a viable biological control site is identified, coordination by the MDA with local natural resource managers, property owners and the USDA EAB Parasitoid Rearing Facility are necessary. At each site one has to obtain permission, guarantee access and ensure other management objectives won’t interfere with implementation. Special permits may be necessary depending on the ownership and designation of land. Long term site access is important for follow-up monitoring of ash health and documenting parasitoid establishment.
Not all sites fit the criteria for biological control. Once an EAB infestation is identified, several steps need to be completed to determine if biological control is viable:
Chris Mallet, EAB Biological Control Coordinator
Jonathan Osthus, Project Manager
Plant Protection Division