Detection of Huanglongbing Triggers Quarantine Expansion in San Bernardino and Los Angeles Counties


A quarantine expansion has been declared following the detection of the citrus disease Huanglongbing (HLB), or citrus greening, in five residential citrus trees located in Rancho Cucamonga. This is the first time the disease has been confirmed in Ranch Cucamonga, marking the fifth city in San Bernardino County to have had a positive detection of HLB. The California Department of Food and Agriculture (CDFA) is working with the United States Department of Agriculture (USDA) and San Bernardino County to remove the HLB-infected tree and prevent the spread of HLB into neighboring areas.

The expanded quarantine area will merge with the existing quarantines in San Bernardino and Los Angeles Counties. The expanded portion is bordered on the north by Big Tree Cucamonga; on the west by Pauda Avenue in Claremont and Mount Baldy Road; on the east by Interstate 15; and on the south by Foothill Boulevard and Interstate 10 in San Bernardino County.

The updated HLB quarantine maps for San Bernardino and Los Angeles counties are available online. Please check this link for future quarantine expansions in these counties, should they occur.

The quarantine prohibits the movement of all plant parts or citrus nursery stock out of the quarantine area. Provisions exist to allow the movement of commercially cleaned and packed citrus fruit. If you are a grower within the new quarantine expansion area, please contact CDFA’s emergency quarantine response program at 916-654-0312 for information on these provisions.

Fruit that is not commercially cleaned and packed, including residential citrus, such as oranges, lemons, grapefruits and kumquats, must not be moved from the property on which it is grown, although it may be processed (removal of stems and leaves, and a thorough washing) and/or consumed on the premises.

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 within 250-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, continue 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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