Location: Invasive Species and Pollinator HealthTitle: Cape-ivy galling fly established and thriving along the California Coast
Submitted to: California Invasive Plant Council
Publication Type: Trade Journal
Publication Acceptance Date: 7/31/2020
Publication Date: 9/1/2020
Citation: Portman, S.L., Moran, P.J. 2020. Cape-ivy shoot-galling fly established and thriving along the California Coast. California Invasive Plant Council. 28(2):8,14.
Technical Abstract: The Cape-ivy galling fly (Parafreutreta regalis) was permitted for release as a biological control agent against invasive Cape-ivy (Delairea odorata) in California in 2016, and releases by the USDA-ARS, Invasive Species and Pollinator Health Research Unit began in September of that year in northern California. Since then, over 80 releases of the fly, consisting of over 5,000 flies, have been made at 18 field sites in riparian, forest and scrub habitats along the coast where Cape-ivy is invasive, choking out vegetation and threatening water resources. Surveys in 2019 and the first half of 2020 indicate that the fly is established at at least four sites, including Coast Dairies State Park (Santa Cruz County), Garrapata State Park and Glen Deven/Big Sur Land Trust (Monterey County), and the San Luis Obispo Land Conservancy (San Luis Obispo County). Gall density has increased 40-fold at these sites since initial post-release surveys. The USDA-ARS will continue to release, monitor and evaluate the impact of the Cape-ivy fly.