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 quarantine boundaries for Huanglongbing (HLB), also known as citrus greening disease, in multiple counties across Southern California. The affected regions now include parts of Riverside, Los Angeles, San Diego, and Orange counties.
The latest expansion, effective April 22, 2025, adds the Riverside area of Riverside County (grid 472) and the Valley Center area of San Diego County (grid 500) to the quarantine zone. These areas also fall under the Asian Citrus Psyllid Bulk Citrus Regional Quarantine Zone 6, aligning them with the HLB containment efforts.
HLB is considered a major risk to California's $3.4 billion citrus industry. A 2012 University of California study projected that an uncontrolled spread of the disease could cost the state up to $2 billion over 20 years and result in the loss of approximately 22,000 jobs. With 267,000 acres of lemons, oranges, grapefruits, and mandarins in production, California supplies about 80% of the nation's fresh citrus.
To address the threat, the USDA's National Institute of Food and Agriculture has allocated over $11 million for research into disease mitigation. The funding supports three projects currently underway at UC Riverside, focused on citrus disease management.
Florida's citrus industry has experienced long-term impacts from HLB, which was first detected there in 2005. Since then, the state has seen a 26% reduction in orange acreage and a 42% drop in yields. California growers and regulators are monitoring developments closely to avoid similar outcomes.
In San Diego County, the quarantine affects more than 450 businesses, including over 100 growers managing 830 acres of commercial citrus. Four nurseries and a farmers' market in the Fallbrook area are also located within the impacted zone.
Officials continue to expand monitoring and containment efforts to limit the spread of the disease, while research institutions and government agencies explore long-term solutions to protect the state's citrus industry.
For more information:
Western Growers
Tel: +1 949 863 1000
Email: [email protected]
www.wga.com