State declares citrus quarantine in Fallbrook: Here’s what that means

SAN DIEGO (FOX 5/KUSI) — A citrus quarantine has been declared in Fallbrook after officials detected the presence of a citrus tree disease in a mandarin tree, adding to the quarantines already in place in Oceanside, Rancho Bernardo and Valley Center.

The California Department of Food and Agriculture (CDFA) and the United States Department of Agriculture (USDA) have confirmed a new citrus quarantine in Fallbrook started on Sept. 16, 2024 after agriculture officials detected the fatal citrus tree disease — Huanglongbing (HLB).

HLB is one of the most destructive citrus diseases known worldwide and is caused by phloem-restricted bacteria, according to the CDFA and USDA. It is caused by the Asian citrus psyllid insects that spread the bacteria when they feed on the citrus trees.

If left unchecked, fruit from HLB-infected trees can be small, uneven, and poorly colored, while the juice becomes high in acids and bitter, eventually killing infected trees, according to the Center for Invasive Species Research at University of California Riverside .

There is no cure for the disease and tree removal is necessary to prevent it from spreading to other trees.

Agriculture officials detected the citrus tree disease in one mandarin tree in a residential neighborhood in Fallbrook on Sept. 10 during regular inspections, according to San Diego County officials. There is now a five-mile quarantine in place surrounding the positive citrus tree.

According to the county, the infected tree is being treated and removed and officials are surveying and treating a 250-meter area around the site.

The county says this disease posses a major threat to San Diego County’s $138 million annual citrus crop, potentially affecting nearly 500 businesses, over 100 growers, 830 acres of commercial citrus, four commercial nurseries and a farmer’s markert in downtown Fallbrook.

View an interactive map of current citrus quarantines online here .

“Unfortunately, Huanglongbing is fatal to citrus,” said San Diego Agricultural Commissioner Ha Dang. “So our goal is to prevent this disease from spreading. By working together, we can all protect our food supply, local agriculture, and environment from this devastating disease. Partnering with state and federal regulatory partners, we are working closely with residents and agricultural operators and ask for everyone’s cooperation with the ongoing regulatory activities.”

San Diego County officials say the citrus disease is fatal to trees but not harmful to humans or animals.

The California Department of Food and Agriculture (CDFA) says it will work with nearby residents to treat their citrus trees as a proactive measure. County officials are also working to notify area citrus growers, plant nurseries and any other impacted businesses.

Some noticeable symptoms of the tree disease are mottled yellow leaves and asymmetrical fruit that may be partially green.

Fallbrook residents in the quarantine area are urged by county officials to take the following precautions now that a citrus quarantine is in place:

• Do not bring citrus plants in or out of the quarantine area
• Wash any citrus grown in a backyard and remove all leaves and stems
• Dry or double bag plant clippings
• Work with officials inspecting trees, taking samples and treating for pests
• Residents can contact a tree removal service if they no longer want to care for a citrus tree
• Buy citrus trees only from reputable local nurseries
• Report citrus trees that seem to be sick or dying by contacting CDFA’s toll-free Pest Hotline at 800-491-1899 or visit www.cdfa.ca.gov/plant/acp
• Visit CaliforniaCitrusThreat.org to learn more
• For questions on moving commercial citrus and HLB quarantine regulations, contact the San Diego Department of Agriculture, Weights and Measures at 760-752-4700 or visit www.sdcawm.org .

The only exception to the citrus quarantine is if agricultural businesses follow specific requirements for treatment, cleaning, and packing commercial fruit before it can be transported into or out of the area.

An HLB quarantine is currently also in place in the Oceanside, Rancho Bernardo, and Valley Center areas, as well as in parts of Los Angeles, Orange, Riverside, San Bernardino and Ventura counties, where more than 8,600 trees have tested positive for the disease and have been removed since 2012.

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