MODESTO, Calif. — If the $2.4 billion California citrus industry is to survive, it must maintain Asian citrus psyllid detection and control programs to buy time until fixes for the deadly citrus disease it carries are discovered.
Representatives of the citrus industry, county agriculture commissioners, the U.S. Department of Agriculture and the University of California delivered that message to state Sen. Cathleen Galgiani, chair of the Senate Committee on Agriculture, Nov. 14. During a 2 ½-hour hearing, they highlighted collaborative efforts.
In both Florida and Texas, huanglongbing — also known as HLB or citrus greening — arrived in the state about five years after the psyllid was first detected, said Joel Nelsen, president of Exeter-based California Citrus Mutual.
So far, California has bucked the trend, he said. Only one tree has been found positive for HLB in California, in Hacienda Heights, Los Angeles County. That tree was removed by the homeowner.
But the psyllid continues to move north, with the latest finds this fall in Santa Clara and San Joaquin counties, said Bob Wynn, senior advisor to California Department of Food and Agriculture secretary Karen Ross. Much of the southern part of the state from Fresno to the Mexican border remains under a citrus psyllid quarantine.
The discovery individual of psyllids in Lodi and Manteca this fall sent the San Joaquin County agriculture commissioner’s department scrambling, said commissioner Tim Pelican.
Although the county only has 9 acres of citrus, he said crews treated infested properties to protect nurseries in neighboring Stanislaus County and the entire San Joaquin Valley citrus industry.
The county hadn’t trapped for citrus psyllid during 2013 because of lack of funding. In fact, the traps that picked up the pest this season were being used for the grape pest, glassywinged sharpshooter, Pelican said.
“One of the things we really need to look at is the state of California is a little bit remiss for not providing any more to any of the pest-detection programs in the state,” he said.
Much of the statewide survey and detection effort is being funded by the California Citrus Pest & Disease Protection Program, which collects an 8-cent-per-box assessment from the state’s citrus growers. Kingsburg citrus grower Nick Hill chairs the 16-member industry committee that advises CDFA on program expenditures.
Along with the roughly $15 million from annual box fees, the USDA contributes another $9.5 million as part of the Citrus Health Response Program.
CDFA, working with county agriculture commissioners, conducts an extensive insect trapping program and targets high-risk areas where the pest is likely to be found, Wynn said.
But the yellow stick traps, also used to detect glassywing sharpshooters, are not the most efficient at attracting pests if they are present, several people said.
Instead, they called them “bumble” or “blunder” traps that tend to catch pests if they happen to fly into them.
“One of the problems we have is trying to detect this insect because we don’t have very good tools to use,” Pelican said.
Once a psyllid is trapped, the state and county follow a protocol for treating infested properties and enacting a quarantine.
To move citrus to packinghouses, commercial citrus growers within quarantines can opt to remove all plant material and leaves from fruit in groves or spray groves with an approved insecticide before harvest.
Hill said most growers, including himself, have chosen the “spray and move” program. But treatment has increased his production costs by $70 to $80 annually per acre.
One of the concerns has been from organic growers, who are frustrated about the lack of organically approved insecticides for psyllids, Nelsen said.
Wynn said researchers continue to look for organic compounds but with little luck so far.
“This is one of (Ross’) top priorities is to find organic solutions,” Wynn said. “We’ve searched not just products that are registered for citrus and ACP but all other organic products that are out there. We’re doing everything we can.”
Researchers also are seeking better ways to identify infected trees earlier so growers can remove them along with the disease inoculum they carry.
“When we saw what happened in Florida when they first detected their first trees infected with citrus greening, they found the disease was so widespread,” said Mary Lou Polek, vice president of science and technology for the Visalia-based Citrus Research Board. “They were waiting for visual symptoms. Once you see symptoms, it’s much too late.”
At its Nov. 12 meeting in Ventura, the Citrus Pest & Disease Program approved $65,000 in funding so University of California-Davis scientists can conduct trials with promising early disease-detection methods in infected Texas groves this winter, Hill said.
“We’re very hopeful that these detection methods will find the disease before it becomes symptomatic on the tree,” he said.