Huanglongbing Detection Triggers Citrus Quarantine Expansion in San Bernardino County


A citrus quarantine expansion has been declared following the detection of the citrus disease Huanglongbing (HLB) in one residential citrus tree in the City of San Bernardino. This is the first confirmed find of the citrus disease in the city and follows the recent detections of several HLB-positive trees located in Colton, Montclair and Ontario. The California Department of Food and Agriculture (CDFA) is working with the San Bernardino County Department of Agriculture to remove the HLB-infected tree and prevent the spread of HLB into neighboring areas.

HLB is a bacterial disease that affects the vascular system of citrus trees and plants. While not harmful to humans, the disease kills citrus trees and has no cure. A small insect called the Asian citrus psyllid (ACP) can spread the bacteria as it feeds on citrus tree leaves. Once a tree is infected, there is no cure; the tree will produce rancid-tasting fruit and die.

The expanded 52-square mile square mile quarantine area expansion will place more than 1,327-square miles of Southern California into the HLB quarantine area. The newly expanded portion in San Bernardino County is bordered on the north by Palm Avenue and Kendall Drive; on the east by Sterling Avenue; on the south by Santa Ana Avenue; and on the west by Palmetto Avenue.

HLB maps for San Bernardino and Riverside counties are available online at: Please check this link for future expansions within the county, should they occur.

The citrus quarantine prohibits the movement of all citrus nursery stock or plant material out of the affected area. Provisions exist to allow the movement of commercially cleaned and packed citrus fruit. Growers within the new expansion area should contact CDFA’s Citrus Division at 916-654-0317 for information on these provisions.

Fruit that is not properly cleaned and/or packed, including fruit grown from commercial operations and residential citrus trees must not be moved from the property on which it is grown, although it may be processed and/or consumed on the premises.

San Bernardino residents are urged to take several steps to help protect citrus trees:

  • Do not move citrus plants, leaves, or foliage into or out of the quarantine area or across state or international borders. Keep it local.
  • Cooperate with agricultural officials placing traps, inspecting trees, and treating for the pest.
  • If you no longer wish to care for your citrus tree, consider removing it so it does not become a host to the pest and disease.

CDFA staff have scheduled removal of the infected tree and are in the midst of a treatment program for citrus trees to suppress Asian citrus psyllid infestations within 400 meters of the find site. By taking this action, a critical reservoir of the disease and its vectors will be removed, which is essential to protect other citrus trees on the property, neighbors’ trees and the community’s citrus from this deadly disease. CDFA, in partnership with USDA, local county agricultural commissioners, and the citrus industry, continues to pursue a strategy of controlling the spread of the Asian citrus psyllids while researchers work to find a cure for HLB.

Questions? If you are a citrus grower in San Bernardino County and have questions about this detection, please contact your grower liaison Sandra Zwaal at

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