Monday, December 10, 2001 -

Invasion and biological control of Spartina alterniflora in Willapa Bay, WA

Fritzi Grevstad1, Dino Garcia-Rossi2, Donald Strong3, and Miranda Wecker1. (1) University of Washington, Olympic Natural Resources Center, Spartina Biocontrol Program, 2907 Pioneer Road, Long Beach, WA, (2) Bodega Marine Laboratory, PO Box 247, Bodega Bay, CA, (3) University of California, Davis, Evolution and Ecology, Storer Hall, University of Calfornia, Davis, CA

Spartina alterniflora is a perennial grass native to intertidal salt marshes along the east coast of North America. On the Pacific coast it is introduced, and its invasion of intertidal mudflats threatens birds, shellfish, and other organisms dependent on the wide open mud that is characteristic of Pacific estuaries. In Willapa Bay, Washington, S. alterniflora has turned approximately 5000 acres of mudflat into densely vegetated meadows. The infested area continues to grow 20% per year. With current control methods unable to keep pace with the invasion, biological control may be the best hope for a large-scale reduction in the impacts of spartina on the Willapa Bay ecosystem.

During the summers of 2000 and 2001, we introduced the delphacid planthopper, Prokelisia marginata into Willapa Bay for biological control of S. alterniflora. Past research demonstrated that this insect is particularly effective at killing S. alterniflora from Willapa Bay. Here we present early results of the biocontrol project in Willapa Bay including a review of host specificity trials, initial establishment, spread, and preliminary impacts of P. marginata on S. alterniflora in Willapa Bay.

Species 1: Poaceae Spartina alterniflora (smooth cordgrass, spartina)
Species 2: Homoptera Delphacidae Prokelisia marginata
Keywords: biological control

The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA