State announces four-county quarantine on citrus plants after disease detected

A leaf from an orange tree that is showing signs of "citrus greening" that is caused by the Asian citrus psyllid that carries the bacterium causing disease, "citrus greening" or huanglongbing. ( Joe Raedle/Getty Images )

The citrus plant quarantine already in place in Los Angeles and parts of Orange counties was expanded Friday by the California Department of Food and Agriculture to include 93 square miles of San Bernardino County.

The DFA made the announcement after finding the disease Huanglongbing, also known as HLB or citrus greening, in a single tree near Montclair.

The area will link up with the existing quarantines in Los Angeles and Orange Counties, creating a contiguous 1,015-square-mile area. Quarantines are also already in place for HLB in portions of Riverside County.

The new portion is bordered on the north by I-210; on the south by Chino Airport; on the west by Highway 57; and on the east by Ontario International Airport.

Quarantine maps are available at www.cdfa.ca.gov/plant/hlb/regulation.html.

HLB is a bacterial disease that affects the vascular system of citrus trees and plants, but it does not pose a threat to humans or animals, the DFA said.

The disease is carried by the Asian citrus psyllid insect that spreads the bacteria as it feeds on citrus trees and plants. Once a plant or tree is infected, there is no cure. The tree will produce bitter and misshapen fruit and die within a few years.

DFA said this is the first time the plant disease has been detected in San Bernardino County, and officials are working with the United States Department of Agriculture and San Bernardino County and Los Angeles County agricultural commissioners to address it.

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

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 and/or consumed on the premises.

DFA said it is urging residents with citrus plants to take several steps to help protect those plants:

--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.

DFA staff have scheduled the removal of the infected tree and are in the midst of a treatment program for citrus trees to knock down Asian citrus psyllid infestations within 400 meters of the find site.

By taking this action, DFA said, a critical reservoir of the disease and its vectors will be removed, which is essential to protect surrounding citrus from this deadly disease.