California

Golden mussel (Limnoperna fortunei), an invasive, non-native freshwater bivalve, was recently discovered in the Port of Stockton by California Department of Water Resources staff while conducting routine operations. This discovery is the first known occurrence of golden mussels in North America. The species poses a significant immediate threat to the ecological health of the Delta and all waters of the state, water conveyance systems, infrastructure and water quality. Please report organisms observed in California suspected to be golden mussels to CDFW’s Invasive Species Program.

In a study recently published in the journal Ecology, "Long-term drought promotes invasive species by reducing wildfire severity," University of California, Irvine scientists uncover the intricate dance between drought, wildfires and invasive species in Southern California’s coastal sage scrub ecosystems.  Titled “Long-term drought promotes invasive species by reducing wildfire severity,” the research, led by Sarah Kimball, Ph.D., director of the Center for Environmental Biology at UCI, sheds light on the critical interplay of these factors and its profound implications for ecosystem health.

Divers monitoring Lake Tahoe have discovered invasive New Zealand mudsnails in areas off the South Shore, the Tahoe Regional Planning Agency (TRPA) and Tahoe Resource Conservation District (Tahoe RCD) announced today. This is the first time the species has been detected in the Tahoe Basin.

Following rapid response protocols under the federally approved Lake Tahoe Aquatic Invasive Species Management Plan, TRPA convened an incident team comprised of staff from TRPA and Tahoe RCD and partner experts. The team is rapidly deploying scientists, beginning with lake-wide dive surveys to determine the extent of the infestation and sharing all available information with state and federal wildlife managers through the Lake Tahoe Aquatic Invasive Species Coordinating Committee. Get up-to-date information on the response and potential protocols for management of the infestation on the TRPA New Zealand mudsnail page.

A portion of Los Angeles County has been placed under quarantine for the Tau fruit fly (Zeugodacus tau group) following the detection of more than 20 flies in the unincorporated area of Stevenson Ranch, near the city of Santa Clarita.

This the first Tau fruit fly quarantine ever in the Western Hemisphere. The fly is native to Asia and is a serious pest for agriculture and natural resources, with a very wide host range, including numerous fruits and vegetables as well as a select range of native plants in California.

The Port of San Diego, along with the Southern California Caulerpa Action Team (SCCAT), the City of Coronado, and the Coronado Cays Homeowners Association (CCHOA), are responding to the discovery of an invasive seaweed scientifically known as Caulerpa prolifera in the Coronado Cays area of San Diego Bay.

In late September, divers found a small patch of Caulerpa prolifera while conducting an in-water pre-construction eelgrass/Caulerpa dive survey as a permit condition for a dock replacement project. Additional patches were discovered nearby during follow-up surveys. The total find within the Cays is about one-quarter of an acre. The SCCAT has prepared a Rapid Response Eradication Plan to address the immediate need to eradicate this invasive species.

A state exterior quarantine has been declared to prohibit the introduction of the spotted lanternfly (SLF), Lycorma delicatula, into California. Spotted lanternfly was first detected in North American in 2014 in Pennsylvania and has now spread to nine states. The quarantine prohibits the entry into California of SLF, its host plants, and a variety of articles, including conveyances, originating from any area where an SLF infestation exists.

If you believe you have seen the spotted lanternfly, please contact CDFA's Invasive Species Hotline at 1-800-491-1899, via Report a Pest, or by contacting your local County Agricultural Commissioner.

The 2025-2030 Strategic Plan outlines a bold vision focused on science-based conservation, empowering land stewards, and advocating for strong public policies to stop the spread of invasive plants. Provides a plan summary overview, as well as the full report for a detailed breakdown of their proposed steps to achieve this vision.

The goals of the California Invasive Species Action Week (June 1-9, 2024),  are to increase public awareness of invasive species issues and promote public participation in the fight against California's invasive species and their impacts on our natural resources.

Prevention is the most effective strategy in managing invasive species. However, hundreds of invasive plants and animals have already established in California and are rapidly spreading each year. These invaders are negatively impacting our waters, our native plants and animals (some of them rare, threatened, or endangered), our agriculture, our health, our economy, and our favorite recreational places. Help us celebrate California's Invasive Species Action Week, and more importantly, help stop the spread of invasive species, by volunteering to take action.

Learn how invasive species are affecting California, with Invasive Species Action Week Lunchtime Talks. Webinars are part of California Invasive Species Action Week, organized by the California Department of Fish & Wildlife. Webinars were recorded and available for viewing.

Landowners, we need your help: CDFW has deployed nutria survey teams from the Delta through the San Joaquin Valley and needs written access permissions to enter or cross private properties for the purposes of conducting nutria surveys and, where detected, implementing trapping efforts. Landowners and tenants, see Nutria: The Triple Threat to California's Future [PDF, 598 KB]; so CDFW can survey for and remove destructive nutria from your properties, complete and submit the Nutria Project Temporary Entry Permit [PDF, 207 KB].

The Asian citrus psyllid and citrus greening (Huanglongbing) could be a death sentence for California citrus trees - but with support from California residents, we can save the citrus trees that we all know and love.