Quarantine boundaries extend out from the Oceanside site where two diseased trees were found. Photo credit: cfda.ca.gov

The California Department of Food and Agriculture Thursday declared a quarantine in North County following the detection of the citrus disease Huanglongbing (HLB).

The disease, also known as citrus greening, was found in two trees on a single residential property in Oceanside.

This is the first time the disease – which does not harm people but is deadly to citrus – has been detected in San Diego County.

The state is working with the U.S. Department of Agriculture and the San Diego County Agricultural Commissioner on a mandatory 60-square-mile quarantine area around the site to restrict the movement of citrus fruit, trees and related plant material.

The quarantine area is bordered on the north by Vandergrift Boulevard at Camp Pendleton; on the south by Carlsbad Village Drive; on the west by the Pacific Ocean; and on the east by Melrose Drive on the eastern edge of Oceanside.

HLB quarantines currently exist in parts of Orange, Los Angeles, Riverside and San Bernardino counties, where more than 2,400 trees have tested positive and been removed.

The quarantine prohibits the movement of citrus nursery stock or plant parts out of the specified area. Provisions exist to allow the movement of commercially cleaned and packed citrus fruit.

Fruit that is not treated in such a way must not be moved from the property on which it is grown, although it may be processed and/or consumed on the premises. This includes residential citrus, such as oranges, lemons, grapefruit and kumquats.

Residents are urged to take steps to protect citrus trees:

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

HLB is a bacteria that affects the vascular system of citrus trees and plants. The Asian citrus psyllid can spread the bacteria as the pest feeds on citrus trees and plants. Once a tree is infected, there is no cure; the tree will produce bitter and misshapen fruit and die within a few years.

CDFA staff are scheduling removal of the infected trees and are in the midst of surveying citrus trees in a 250-meter radius around the detection site to determine if any other trees are infected.

A treatment program for citrus trees to reduce Asian citrus psyllid infestations will also be conducted within 250-meter radius of the find site.

The action is designed to remove a critical reservoir of the disease and its vectors, and is considered essential to protect surrounding citrus.

The agencies continue to pursue a strategy of controlling the spread of the Asian citrus psyllid while researchers work to find a cure for the disease.

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