The California Department of Food and Agriculture has expanded the boundaries of the quarantine it established in San Diego County after citrus greening disease was spotted on August 5, officials said on Wednesday.

The bacterial disease, also known as Huanglongbing, was detected in two citrus trees on a residential property in Oceanside. The disease is not harmful to people but is deadly to citrus and could be devastating to the county's citrus industry. 

California Department of Food and Agriculture officials said the 60-square-mile quarantine area will prohibit people and businesses from moving citrus nursery stock, plant parts and fruit outside the quarantine boundaries, with the exception of commercially cleaned and packed fruit that adhere to specific requirements.

The restrictions also prohibit people from moving residential citrus plants and plant parts off the properties on which they are grown.

The citrus greening quarantine area is bordered on the north by Vandegrift Boulevard; on the south by Carlsbad Village Drive; on the west by the Pacific Ocean; and on the east by Melrose Drive.

"Unfortunately, Huanglongbing is fatal to citrus," said San Diego Agricultural Commissioner Ha Dang, "so our goal is to stop this from spreading any farther. By working together, we can all protect San Diego County's $150 million citrus industry from this deadly disease."

The California Department of Food and Agriculture, the United States Department of Agriculture and San Diego County's Department of Agriculture, Weights and Measures are working together on the quarantine. Work includes treating the residential location where the disease was found, establishing the quarantine boundaries and notifying businesses and residents within the quarantine area.

Dang said this was a critical time for homeowners to protect their backyard citrus trees by searching for evidence of the Asian citrus psyllid and the disease.

Huanglongbing affects the vascular system of citrus trees and plants. Once a tree is infected, it cannot be saved and will die within a few years.