Signs of citrus greening

Symptomatic yellowing of citrus leaves can be a tell-tale sign of Huanglongbing, or citrus greening disease.

HLB continues to spread in suburban Los Angeles

CDFA establishes 180-square mile quarantine zone for HLB in southern California Four trees in San Gabriel confirmed with the disease Officials continue to scour area for more diseased trees

Two new confirmed cases of Huanglongbing were revealed in the same San Gabriel, Calif. neighborhood, bringing the total to five the number of trees infected by the bacterial disease in citrus since 2012.

Four of those cases were confirmed within days of each other in July.

The announcements forced the California Department of Food and Agriculture (CDFA) to effectively double its regulatory quarantine within the region to 180 square miles. That region now effectively covers a zone from Pasadena to LaHabra in the counties of Los Angeles and Orange.

According to the CDFA, HLB was confirmed July 10 in a kumquat tree in San Gabriel using standardized testing procedures. A lime tree in a neighbor’s yard was confirmed within a couple days and shortly thereafter confirmations were made in nearby calamondin and mandarin trees.

So far the disease has been limited to residential neighborhoods with non-commercial citrus.

All citrus trees testing positive for HLB were removed and destroyed by the CDFA.

The quarantine prohibits the movement of a long list of citrus plant materials from the zone. Quarantine regulations even addresses equipment used in the harvesting, processing and hauling of host plant materials.

The quarantine maintains existing provisions allowing the movement of only commercially cleaned and packed citrus fruit.

Any fruit that is not commercially cleaned and packed, including residential citrus, must not be removed from the property on which it is grown, although it may be processed and consumed on site.

“The success of any quarantine depends on cooperation from those affected,” said CDFA Secretary Karen Ross. “The stakes couldn’t be higher for California citrus. We urge residents in the San Gabriel-area to do all they can to comply.”

Surveys continue

Additional information, including a map of the quarantine zone, is available online.

The HLB quarantine zone is part of a much larger quarantine already in place for the Asian citrus psyllid (ACP) in southern California. The ACP is the pest that spreads bacteria causing HLB.

In addition to the positive results in various trees for HLB, state officials found psyllids that were infected with the bacteria that causes HLB.

CDFA, the USDA and the Los Angeles County Agricultural Commissioner’s continue to survey and test for the disease throughout the Los Angeles Basin. Officials continue with ground treatment of citrus trees within 800 meters (about one-half mile) of the find sites. In the long term, the strategy is to control the spread of the ACP, which is known to spread HLB.

Huanglongbing is known to be present in Mexico and parts of the southern U.S. Florida first detected the disease in 2005. The University of Florida estimates that the disease causes an average loss of 7,500 jobs per year and has cost Florida growers nearly $3 billion in lost revenue since then.

For the latest on western agriculture, please check out Western Farm Press Daily and receive the latest news right to your inbox.

Huanglongbing has also been detected in Georgia, Louisiana, South Carolina and Texas, as well as Puerto Rico and the U.S. Virgin Islands.

The ACP was first detected in California in 2008 and quarantines for the pest are now in place in 17 California counties. California residents who believe they have seen evidence of HLB in local citrus trees they are asked to call the CDFA’s toll-free pest hotline at 1-800-491-1899. More information on the ACP and HLB can be found online.

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.