Bug in Baja a risk to California citrus trade

A tiny insect that can carry a disease that kills citrus trees has been discovered just blocks south of the border in Tijuana, sending shock waves through the California citrus industry.

The disease, known as citrus greening, has already killed tens of thousands of acres of orange groves in Florida and has the potential to ruin much of California’s $1.2-billion citrus growing business, industry officials said.

Mexican agricultural officials found the Asian citrus psyllid in orange trees growing near homes in the vicinity of the California border.

But the officials are annoyed at the alarm sounded by California citrus farmers, saying there’s no evidence that these bugs have come into contact with the bacterium that causes the disease, also known as huanglongbing or yellow dragon disease, or that citrus greening is infecting Mexican citrus groves.

State and federal agriculture officials are surveying San Diego and Orange County citrus ranches and homes, trying to learn whether the pest has jumped the border.

“This has the potential to be incredibly destructive,” said Mike Wootton, senior vice president of Sunkist Growers, the giant California and Arizona citrus marketing cooperative based in Sherman Oaks.

The industry and state officials plan to launch a public awareness campaign today. They want to alert homeowners and commercial landscapers to be on the lookout for the insect and will encourage them to call the California Department of Food and Agriculture’s exotic-pest hotline at (800) 491-1899 if they spot anything suspicious on citrus trees. More information can be found at www.californiacitrusthreat.org.

California supplies about 85% of the nation’s fresh orange crop and nearly all of domestically grown fresh lemons. The Golden State also ships a third of what it grows overseas, a lucrative business that could be threatened if the insect establishes itself here and trading partners block California citrus exports, Wootton said.

Most likely, the bug has already skipped across the border in shipments of cut flowers or oranges surreptitiously brought to California and headed for swap meets, and it’s just a matter of time before it’s discovered, said Beth Grafton-Cardwell, a UC Riverside Extension entomologist.

The psyllid alone won’t do much damage to California orange groves, Grafton-Cardwell said. The situation becomes dangerous when the insect lands on a tree that’s already infected with the germ that causes the disease. The bugs would then spread the bacteria to other trees.

“We might not have the disease in the state or we might have it sitting in some backyard tree that someone brought in from Asia. It could be a time bomb just waiting for a psyllid,” Grafton-Cardwell said.

That’s what has agriculture officials worried.

Since it was discovered in 2005, the disease has rapidly spread to the 32 counties in Florida that grow citrus commercially, said Andrew Meadows of Florida Citrus Mutual, the state’s grower trade group.

In Florida, growers have found that a grove’s 5% infection rate can explode to 40% to 80% in just four years. Greening disease is always fatal. The trees can’t be treated and have to be uprooted and burned.

Citrus greening is exceptionally hard to detect during the first several years of infection, said Ted Batkin, president of both the California Citrus Research Board and the California Invasive Pest Coalition. After four to five years, the tree will have yellow leaves and stunted, bitter-tasting fruit.

By the time symptoms appear, feeding psyllids have infected nearby groves.

Mexican officials said the disease had not been detected in any part of Mexico. But Grafton-Cardwell and other U.S. experts believe the bacterium is starting to affect trees in eastern Mexico.

In years past, the psyllid was detected in some fruit-growing regions in central Mexico. But officials said this latest appearance in the state of Baja California Norte is odd because it is not a commercial citrus-producing area.

Mexican authorities suspect that the insects or their larvae were carried to Tijuana by a traveler.

“We don’t even cultivate citrus here,” said Genaro Lopez Bojorquez, the regional head for Mexico’s secretary of agriculture in northern Baja.

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jerry.hirsch@latimes.com

marla.dickerson @latimes.com

Hirsch reported from Los Angeles and Dickerson from Mexico City. Cecilia Sanchez of The Times’ Mexico City Bureau contributed to this report.