There are no known pesticides or other methods to combat the disease. It can only be eliminated by finding and eliminating the insect carrier.
California growers have taxed themselves to fund a psyllid trapping program that aims to eliminate the bacteria carrier before it can spread the disease, Nelson said.
Huanglongbing is hard to detect visually because the bacteria can be present in a tree for a year or longer before symptoms can be spotted. Once infected, a tree dies within five years. Typically, a healthy citrus tree can be productive for decades.
The psyllid was first detected in Southern California in 2008 and is known to exist in the region mostly in ornamental or backyard trees.
Since then, the state has recorded nearly 43,000 reports of psyllid detection — some with multiple insects — in Southern California, all without the bacteria, Lyle said.
One tree infected with the disease was discovered in the Hacienda Heights area of Los Angeles County — but scientists found no infected psyllids.
Tulare County has 119,000 acres of citrus, 61 citrus packing sheds and four juice plants.