Optimizing the Effectiveness of a Biocontrol Agent against Spartina Species in Washington

Fritzi S. Grevstad and Miranda S. Wecker, Olympic Natural Resources Center, University of Washington

R/ES-63

Two species of non-native Spartina cordgrass have invaded Washington’s estuaries, degrading shoreline habitats and altering sites for shellfish aquaculture.  In an effort to control the plants’ spread, a host-specific herbivorous insect, Prokelisia marginata, has been introduced into Spartina-infested areas. This project will compare the performance of four ecotypes of P. marginata and determine which is most effective as a biocontrol. The best performing ecotype will be made available to resource managers, landowners and school groups for use in the field. The project will also quantify and document the impacts of P. marginata on Spartina in Willapa Bay and Puget Sound.  Through a series of field experiments, the project team will explore the feasibility of combining biocontrol measures with chemical and mechanical strategies for eradicating Spartina in Washington.