Over the past six months, the USDA’s Animal and Plant Health Inspection Service (APHIS) and the California Department of Food and Agriculture (CDFA) have expanded the quarantine boundaries for Huanglongbing (HLB), also known as citrus greening disease, in several counties including Riverside, Los Angeles, San Diego and Orange.  

The latest expansion, effective April 22, 2025, includes the Riverside area of Riverside County (grid 472) and the Valley Center area of San Diego County (grid 500).  A map of the expanded boundary can be found here.  The expansion also includes the Asian Citrus Psyllid Bulk Citrus Regional Quarantine Zone 6 in these areas to reflect the HLB quarantine boundary expansion. A map of the expanded boundary can be found here.

HLB poses a significant threat to California’s $3.4 billion citrus industry. A 2012 UC study estimates that the disease could cost the state up to $2 billion over 20 years and result in the loss of 22,000 jobs. California supplies the country with 80% of its fresh citrus, with 267,000 acres of Golden State lemons, oranges, grapefruits and mandarins at stake if operations are permanently lost. The USDA National Institute of Food and Agriculture is making an emergency investment in citrus disease research with three projects at UC Riverside totaling more than $11 million. 

Florida’s citrus industry has long been an example of what could happen in California. Since HLB was first found in 2005, orange acreage and yield in Florida have decreased by 26% and 42%, respectively. In San Diego County alone, the quarantine has affected over 450 businesses, including 100+ growers managing 830 acres of commercial citrus. Additionally, four nurseries and a farmers’ market in Fallbrook fall within the impacted zone. 

California Code of Regulation allows interested parties to be notified of quarantine area boundary changes, as well as the opportunity to submit quarantine boundary appeals. If you are interested in receiving notifications, please sign up for regulatory updates here.