TULARE, Calif. — The confirmation May 22 that three Asian citrus psyllids were trapped in the San Joaquin Valley drove home the point that the citrus pest is expanding its presence in the state’s largest citrus-producing region.
If the psyllid behaves in the Central Valley as it did in Southern California, where it is well established, populations will continue to build until eradication is no longer practical, said Beth Cardwell-Grafton, a University of California-Riverside research entomologist and director of the Lindcove Research and Extension Center.
In preparation for that day, University of California entomologists and the Citrus Pest & Disease Prevention Program are developing an area-wide management program.
When the plan would be implemented is unknown and will depend on how long San Joaquin Valley growers can keep the psyllid at bay, she said.
“We’re not expecting this to roll out until the populations are so high we can’t eradicate them,” Grafton-Cardwell said.
Vicky Boyd(from left to right) Citrus grower Nick Hill talks with Victoria Hornbaker, citrus program coordinator for the Citrus Pest & Disease Prevention Program, and Katie Rowland, public relations account manager with Nuffer, Smith, Tucker, before the start of the packinghouse meeting.But Nick Hill, a Dinuba area citrus grower and chairman of the citrus pest program, said the most difficult part of this type of plan is getting growers lined up and in place.
Borrowing from Florida’s Citrus Health Management Areas, also known as CHMAs, Grafton-Cardwell said the goal is to have all of the growers in a large area spray for psyllids at the same time to maximize treatment efficacy. That way the pest can’t jump from a treated grove to an untreated grove to escape the chemicals.
In Florida, CHMAs have been successful in significantly reducing psyllid numbers.
Grafton-Cardwell outlined the program at a meeting designed for packinghouse personnel, May 22.
“The main goal is to slow the spread of psyllid and buy time for the scientists to find a cure,” she said.
Psyllids can carry hunglongbing, also known as HLB or citrus greening. The bacterial disease, which is harmless to humans, can weaken and even kill citrus trees. In Florida, where the disease is entrenched, it has caused more than $3.6 billion in lost revenue, she said.
Although only one tree has been confirmed with the disease in California, and that was in the Los Angeles basin, she said most experts believe there are other infected trees that just haven’t been identified.
Eradication is no longer possible in Southern California because of high psyllid numbers and large urban centers. In the San Joaquin Valley, the California Department of Food and Agriculture and the citrus industry continue to work toward localized eradication when a psyllid is trapped.