Asian citrus psyllids
Asian citrus psyllids on a citrus leaf. Courtesy County News Center

The California Department of Food and Agriculture declared a citrus quarantine in a 95-square-mile area of Rancho Bernardo Tuesday after detecting a potentially threatening citrus tree disease during routine inspections.

The disease, known as Huanglongbing, is a major threat to San Diego’s $115 million annual citrus crop, county officials said. Trees infected with the bacterial disease can produce misshapen, bitter fruit and the disease can eventually kill the tree.

The quarantine announced Tuesday comes after HLB was found in a residential lime tree in the area and is in addition to the existing HLB quarantine in the city of Oceanside. It covers the area bordered on the north by the intersection of Interstate 15 and Auto Park Way; to the south by Poway Road; to the west by Via De Las Flores; and to the east by Lake Ramona.

“Unfortunately, Huanglongbing is fatal to citrus,” San Diego Agricultural Commissioner Ha Dang said. “Our goal is to prevent this disease from spreading any further. By working together, we can all protect our food supply, local agriculture, and environment from this devastating disease.”

The quarantine is intended to protect the region’s food supply and agriculture by restricting people and businesses from moving citrus nursery stock, plant parts and fruit outside the quarantine boundaries and off their properties. According to a county statement, the only exception is for agricultural businesses that must adhere to specific requirements for treatment, cleaning, and packing commercial fruit prior to movement.

HLB is not harmful to people or animals and is spread by the Asian citrus psyllids, tiny insects who can carry the bacterium when they feed on citrus trees.

The county Department of Agriculture, Weights and Measures is partnering with state and federal regulators to limit the impact on the public and help prevent the spread of the disease.

County officials are also proactively notifying local citrus growers, plant nurseries and other related businesses.

Samples from trees on the affected property and the surrounding area are undergoing tests for HLB. If it is detected in additional citrus trees in the quarantine area, state agricultural officials will follow up with treatment and removal of the infected trees.

City News Service contributed to this article.