California has expanded the HLB quarantine zone with the detection of a single infected tree in San Bernardino County. ( Courtesy CDFA )

The California Department of Agriculture has declared a quarantine after detecting huanglongbing in a single citrus tree near Montclair, Calif., in San Bernardino County.

The quarantine, announced by the department on Nov. 22, follows the first case of HLB detected in San Bernardino County. The CDFA is working with the U.S. Department of Agriculture and agricultural commissioners in San Bernardino and Los Angeles counties, according to a CDFA news release.

A 93-square-mile quarantine links with existing zones in Los Angeles and Orange counties, making a contiguous 1,015-square-mile area, according to the CDFA release. A map on the state’s agriculture department website shows HLB quarantine areas.

Under the quarantine, citrus nursery stock or plant parts are prohibited from leaving the area. Commercially cleaned and packed citrus can be moved from quarantine zones under certain provisions, but fruit that’s not commercially cleaned and packed must remain on the property where it was grown. That includes oranges, lemons, grapefruit and kumquats, although they can be eaten or processed on the premises, according to the CDFA.

The department is removing the infected tree and are treating trees to kill Asian citrus psyllid infestations within 400 meters of the tree. The psyllids spread HLB.
HLB has not been detected in commercial citrus groves in California.

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