In an effort to prevent the spread of the Asian citrus psyllid in California, the California Department of Food and Agriculture (CDFA) and the United States Department of Agriculture (USDA) have placed part of southern San Diego County under a quarantine that regulates the movement of citrus and closely-related plants. The county’s major citrus-producing region lies to the north of the boundary and is not included in the quarantine, which is designed to protect California’s citrus-producing regions from the pest.

The quarantine follows the detection of more than 250 Asian citrus psyllids in the South Bay Terrace area of San Diego over the last two weeks, as well as the detection of a single psyllid in the community of Dulzura, 23 miles away, which was confirmed this morning. CDFA and USDA are working with county officials and growers to implement the quarantine.

The Asian citrus psyllid can carry the disease huanglongbing (HLB), also known as citrus greening disease. There is no indication that the psyllids detected in San Diego carried HLB. However, to ensure the pests are disease free, the USDA is running additional tests.

“We are taking this preventive measure to stop the spread of this pest and protect our citrus crops,” said CDFA Secretary A.G. Kawamura. “This pest can carry a very serious disease that has the potential to cripple citrus plants beyond repair, so we are moving swiftly with this preventive measure to quarantine the area where the pest was found.”

All citrus and closely related plant species are susceptible host plants for both the Asian citrus psyllid and HLB. There is no cure for HLB once a citrus tree becomes infected. The diseased tree will produce inedible fruit and decline in health until it dies.

The states of Texas, Georgia, Mississippi, South Carolina and Alabama have all detected the Asian citrus psyllid but not the HLB disease. Florida and Louisiana have detected both the pest and the disease. Since the disease was first detected in Florida in 2005, it has spread to all 32 citrus-producing counties throughout the state. A population of the pest just south of the international border, in Tijuana, is not carrying the disease.

The quarantine area includes 1,181 square-miles and extends from the international border with Mexico up the coast to Highway 78, east to Ramona, and south along local roads and highways to the international border at Tecate, Mexico. A detailed map of the quarantine boundary is available online at http://www.cdfa.ca.gov/phpps/acp/maps/quarantine/ACP_QUAR_SANDIEGO_08_web.pdf.

All harvested citrus in the quarantine area must be commercially cleaned and packed before it can be moved out of the area. Nursery host plants may not be moved out of the quarantined area and the movement of cut greens, green waste and citrus fruit will be regulated and enforced by federal, state and county quarantine officials. Residents are urged to consume back yard citrus fruit at home and to refrain from transporting their back yard citrus, as well as citrus plants, out of the area.

California’s $1.1 billion citrus industry ranks second in the U.S. after Florida. California’s total citrus production has averaged 3.2 million tons per season over the past three seasons, about 24 percent of the nation’s total. California is the nation’s main source (80 percent) of fresh-market oranges, while Florida grows oranges mainly for juice. California also supplies 87 percent of the nation’s lemons (Source: USDA Economic Research Service).