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Effective November 16, 2021, the Animal and Plant Health Inspection Service (APHIS) and the California Department of Food and Agriculture (CDFA) established a Mediterranean fruit fly (Medfly) quarantine area in San Bernardino and Los Angeles Counties, California. APHIS is applying safeguarding measures and restrictions on the interstate movement or entry into foreign trade of regulated articles from this area. This action is in response to the CDFA’s confirmation of a mature, unmated female Medfly on October 25, and a subsequently confirmed male Medfly on November 9 from Jackson traps placed in backyard citrus trees in residential areas of Upland, California. There are 15.75 acres of commercial agricultural production in the quarantine area. Currently, the quarantine area encompasses 95 square miles.

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 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.

 The Coast Guard Office of Commercial Vessel Compliance was notified by the State of California on the detection and identification of golden mussel (Limnoperna Fortunie) in the Port of Stockton. To minimize the spread of the golden mussel it is recommended that operators continue to ensure that ballast water management systems are operational and used in accordance with the Operational Manual for that system.

Multiple federal, state and local agencies have been notified of an invasive algae species discovered in Newport Bay, California in March 2021. The algae, which is native to Florida and other subtropical and tropical locales, is scientifically known as Caulerpa prolifera. It can grow quickly, choking out native seaweeds and potentially harming marine life through lost habitat.

A similar species of invasive algae, Caulerpa taxifolia, was identified in California in 2000 and was successfully eradicated through a comprehensive joint local, state and federal effort in 2006. Due to the similarity between these two species, scientists believe this algae species may pose a serious threat to our local coastal ecosystems.

However, it is imperative that the public avoid contact with the plant due to its extreme ease of recolonizing from just tiny fragments. If you believe you have seen this invasive algae, please complete a sighting report. Please do not collect a specimen, as this may lead to further spread.

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.

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.

Alligator weed works it's way into Northern California. ARS researchers are seeking biocontrol agents to control the invasive weed.

Native species in California's estuaries are expected to experience greater declines as invasive species interact with climate change, according to a study from the University of California, Davis. The study "Biological Invasions Alter Consumer-stress Relationships Along an Estuarine Gradient," published in the Ecological Society of America's journal, Ecology, said these declines are expected not only because of climate-related stressors, but also because of the expanding influence of new invasive predators whose impacts are occurring much farther up the estuary.

A portion of Los Angeles County has been placed under quarantine for the Mediterranean fruit fly following the detection of two wild flies in the Leimert Park neighborhood in the City of Los Angeles. The USDA, the Los Angeles County Agricultural Commissioner, and California Department of Agriculture are working collaboratively on this project.

Under International Plant Protection Convention (IPPC) standards, Ceratitis capitata  is a transient pest under eradication that is present only in one area in California.  This species is not widely distributed and is under official control in the U.S.

A portion of San Diego County has been placed under quarantine for the Mexican fruit fly following the detection of six flies and one larva in and around the unincorporated area of Valley Center. The United States Department of Agriculture (USDA), the San Diego County Agricultural Commissioner, and the California Department of Food and Agriculture (CDFA) are working collaboratively on this project.

The Mexican fruit fly can lay its eggs in and infest more than 50 types of fruits and vegetables, severely impacting California agricultural exports and backyard gardens alike. For more information on the pest, please see the pest profile at: www.cdfa.ca.gov/plant/go/MexFly. Residents who believe their fruits and vegetables may be infested with fruit fly larvae are encouraged to call the state’s toll-free Pest Hotline at 1-800-491-1899.

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.

A portion of Los Angeles County has been placed under quarantine for the Oriental Fruit Fly following the detection of 14 flies in the San Fernando Valley in the North Hills area. To prevent the spread of fruit flies through homegrown fruits and vegetables, residents living in the quarantine area are urged not to move those items from their property. However, they may be consumed or processed (i.e., juiced, frozen, cooked, or ground in the garbage disposal) on the property where they were picked or disposed of by double bagging and placing in the regular trash, not green waste. Residents with questions about the project may call CDFA’s Pest Hotline at 1-800-491-1899. Additional information may be found here: www.cdfa.ca.gov/plant/off.

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.

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.

The U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS), and the California Department of Food and Agriculture (CDFA) in collaboration with County Agricultural Commissioners, are proud to announce that after a year of hard work we have eradicated all populations of invasive fruit flies from California. This significant achievement is a testament to the hard work of our agencies and the critical support from the public. 

The United States Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed the presence of virulent Newcastle disease in a small flock of backyard exhibition chickens in Los Angeles County, California. It is important to note that the presence of the disease is not a food safety concern. This is the first case of virulent Newcastle disease, previously referred to as exotic Newcastle disease, in the U.S. since 2003.