State officials scramble to contain huanglongbing, identify source


For the Capital Press

A collective shudder went through California's citrus industry as state ag officials announced the detection of the fatal citrus disease huanglongbing.

Both an infected citrus tree and a vector of the disease -- Asian citrus psyllid -- were confirmed March 31 in the Hacienda Heights area of Los Angeles. They were the first detections of the disease in the state.

The closest commercial citrus grove is 14 miles away from the detection site.

Citrus industry officials have been bracing for this detection since 2008 when the first psyllid was found in California. Robert Leavitt, director of Plant Health and Pest Prevention at CDFA, said samples of plant material and the insect were confirmed positive at the USDA laboratory in Beltsville, Md.

The state said it plans to take immediate action with treatments to knock down populations of the psyllid in the immediate area of the infected tree. The state is also placing hold notices on all citrus nursery stock within a 5-mile radius of the find. Additional testing of plant material and trapping for the psyllid is also under way.

Researchers are trying to determine where the tree came from, whether it already was infected, whether an infected graft was placed on it, or if the bug transmitted the disease to it. An infected psyllid spreads the disease by feeding on leaf shoots, and a healthy bug can become a carrier by feeding on a diseased tree.

Huanglongbing is a bacterial disease that attacks the vascular system of plants. The Asian citrus psyllid is an efficient vector of the disease and can spread the bacteria from tree to tree. The disease can also be spread by infected budwood.

Leavitt said the USDA would investigate whether the tree was infected at the site or by a graft.

There is no treatment for huanglongbing. Infected trees produced bitter and misshapen fruit and die within a few years.

One of the biggest problems agriculture officials face is homeowners who smuggle in plant material from other countries, not realizing the potential threat to California's $38 billion agriculture industry.

Huanglongbing has cost the Florida citrus industry 6,600 jobs and billions in lost revenue since it appeared there in 2005, eight years after that state's first detection of the Asian citrus psyllid that transmits it.

The Associated Press contributed to this report.

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