Detection of Citrus Disease, Huanglongbing, Triggers Quarantine Expansion in San Diego County; First HLB Detection in County


The California Department of Food and Agriculture (CDFA) has declared a quarantine in north San Diego County following the detection of the citrus disease Huanglongbing (HLB), or citrus greening, in two citrus trees on one residential property in the City of Oceanside. These detections are the first HLB-positive trees in San Diego County. CDFA is working with the United States Department of Agriculture and the San Diego County Agricultural Commissioner on this cooperative project.

The disease was detected in plant material taken from one orange and one lemon tree in a residential neighborhood in the Oceanside area of San Diego County. CDFA crews have removed and disposed of the infected trees and are conducting a mandatory survey of every residential property within 250-meters of the detection site. After the survey is complete, all host plants in the 250-meter area around the detection site will be treated to suppress the disease vector, the Asian citrus psyllid. By taking these steps, a critical reservoir of the disease and its vectors will be removed, which is essential to protect the surrounding citrus from this deadly disease.

These detections establish a mandatory five-mile citrus HLB quarantine area around the find site. The quarantine prohibits the sale of all host nursery stock and the movement of all host plants within a five-mile radius of the find. Fruit grown in the area must undergo additional mitigation steps before it can be transported into or out of this area. This quarantine applies to residents and commercial operations alike. The 68-square mile quarantine area is bordered on the north by Stagecoach Road in Camp Pendleton; on the south by Tamarack Avenue in Carlsbad; on the west by the Pacific Ocean; and on the east by North Santa Fe Avenue in Vista. Production and retail nurseries within the five-mile quarantine are being contacted by CDFA and will be issued a hold notice preventing the sale of nursery stock host plants. Visit CDFA’s Map and Quarantines page for more details.

Growers in San Diego County should contact Grower Liaison Sandra Zwaal at for additional information about these detections and for information on upcoming area-wide treatments expected to begin mid-August into early September. In response to the HLB detections in Oceanside, a grower meeting will be held on Thursday, Aug. 26 at 9 a.m. at the Fallbrook Public Utility Office and via Zoom. Stay tuned to Citrus Insider for details on how to R.S.V.P.

An HLB quarantine area currently exists in parts of Orange, Los Angeles, Riverside and San Bernardino counties, where more than 2,400 trees have tested positive for the disease and have been removed.

To read the full press release, please visit the CDFA website.

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