Official: Psyllid may become permanent

Agricultural Research Service The adult Asian citrus psyllid, Diaphorina citri, is 2 to 3 millimeters long.

CDFA expands psyllid quarantine in Riverside County


Capital Press

A state pest-control official says the Asian citrus psyllid may soon take up permanent residence in California.

The psyllid is the only known carrier of the dreaded huanglongbing, or citrus greening disease. Up to now, the state has focused on trying to eradicate the insect, said Larry Bezark, chief of the Integrated Pest Control branch of the Department of Food and Agriculture.

But the state is nearing a tipping point at which eradication becomes impossible, and Bezark said his department's efforts may soon switch to control mode, working only to contain the psyllid's spread.

"We are right at the point in California where there might be too many to eradicate," he said.

On Tuesday, Nov. 24, CDFA announced it had expanded its psyllid quarantines in Riverside and San Bernardino counties. There are additional quarantines in Los Angeles and Orange counties and parts of San Diego and Imperial counties.

A total of 14,201 square miles, or 8.5 percent of the state, is now under quarantine.

The psyllid was believed to have spread from northern Mexico, where it is established. Once it takes hold, "there's no way we're going to eradicate this pest, it's simply not possible," Bezark told the state Board of Food and Agriculture on Nov. 18. "So we need to control the populations as much as possible."

Despite those efforts, it's also likely that the psyllid will eventually make its way to the San Joaquin Valley, home of the state's citrus industry, Bezark said. In July, two psyllid larvae were found in luggage at the FedEx terminal in Fresno, one tested positive for huanglongbing.

One ray of hope: The psyllid is known as a tropical pest, so the valley's relatively cold winters could help control it.

Huanglongbing is one of the most feared diseases facing citrus and nursery producers and state regulators. It attacks and kills citrus trees, in the process spoiling the taste and appearance of their fruit. It has shown up in South Carolina and Louisiana and has caused extensive damage in Florida.

The state hopes it can keep the psyllid at bay, thus delaying the appearance of huanglongbing, until state researchers can develop treatments, Bezark said.

The disease has wreaked havoc since appearing in Florida citrus in 2005. In Florida, the psyllid preceded huanglongbing by seven years, Bezark said.

While that suggests the possibility of California contracting the disease in the next few years, the outcome is unpredictable. Researchers have yet to find greening in Texas, eight years after the psyllid showed up there, and lag time from insect to disease is unknown in other countries, Bezark said.

"We've got a whole (bunch) of people on the ground looking for crooked leaves," Bezark said, referring to the misshapen appearance of leaves on which psyllids have fed.

"You could find the disease in San Diego County tomorrow," he said. "Or it could take 10 years."

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