disease

Citrus Disease Forces Fruit Quarantine for Residents in Rancho Bernardo

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The California Department of Food and Agriculture has declared a new citrus quarantine in a 95-square-mile area of Rancho Bernardo after a citrus tree disease was discovered during routine inspections.

The disease known as, Huanglongbing, or HLB, isn't harmful to humans or animals, but it can cause citrus trees to produce misshapen or bitter fruits and eventually kill them, according to San Diego County.

Alex Muniz, a senior environmental scientist for the California Citrus Pest and Disease Prevention Program, told NBC 7 in a phone interview that HLB was first discovered on a lime tree in the backyard of a home in Rancho Bernardo. Muniz explained that the team routinely surveys areas that are predetermined to be at high risk of diseases like HLB, which is what led them to the infected tree.

“So any properties that are located within that 250-meter area will receive a special survey so that staff can take samples from any citrus trees on the property or closely related plants to citrus that can still be a host for this disease,” said Muniz.

They are just at the beginning of this process and, Muniz said, agricultural officials will be going door-to-door asking residents if they can survey their trees.

“Let’s say you have an orange tree, we will walk to the backyard and take 20 leaves from the citrus tree and then those leaves get sent up to our state lab where they can test it for this disease,” said Muniz.

Residents of the quarantine area should follow these rules:

  • Do not move citrus plants or leaves outside of the quarantine area
  • Cooperate with agricultural officials and inspectors as they take samples and treat trees
  • Remove your citrus tree if you no longer need it
  • Purchase citrus trees from reputable nurseries
  • Report sick or dying citrus trees to the San Diego Department of Agriculture, Weights and Measures at (760) 752-4700 or visit sdcawm.org
  • Residents can also call CDFA’s toll-free Pest Hotline at (800) 491-1899 or visit cdfa.ca.gov/plant/acp

The quarantine zone in Rancho Bernardo covers the area bordered on the north by the intersection of I-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. Inspectors are looking at trees in the area and may treat or remove infected trees.

The area of a Huanglongbing quarantine in Rancho Bernardo issued in February 2023.
San Diego County
The area of a Huanglongbing quarantine in Rancho Bernardo issued in February 2023.

This quarantine is in addition to another quarantine in effect in Oceanside since 2021. That quarantine was the result of the county's first-ever case of citrus HLB, according to the county.

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

David Ross is a local expert when it comes to all things plants and gardening. Ross manages Walter Andersen Nursery in Poway, which he says is not included in the quarantine area, but they have had to make some changes to their citrus tree sales. The nursery has had to make all orange, lemon, lime, grapefruit, kumquat-- anything that is considered citrus-- final sale items with no room for refunds, exchanges, or store credit.

“Everybody has a tree in San Diego, everybody has a backyard tree, [but] not everybody takes as good of care of them as others,” said Ross. He added that commercial citrus properties typically do an effective job of growing their trees in a way that protects them from diseases like HLB. However, it is the private residences, with one or two trees, that he said are the real concern.

According to the county, HLB is a significant threat to San Diego County's citrus crop, generating $115 million annually.

HLB is spread by Asian citrus psyllids, which can carry the disease and spread it to citrus trees while feeding.

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