Several specimens of Asian citrus psyllid were found in three adjoining backyards in Dinuba, CA, in an area surrounded by commercial citrus groves, early in the week of Sept. 9, and the discovery is expected to trigger a quarantine, prohibiting the movement of citrus fruit or plant materials from anywhere within a five-mile radius of where the pests were found, according to Bob Blakely, director of industry relations for California Citrus Mutual in Exeter, CA.
Blakely told The Produce News that the boundaries of a quarantine area have not yet been set, "but we fully expect it is going to trigger a quarantine."
The U.S. Department of Agriculture and California Department of Food & Agriculture have been searching for additional pests within 800 meters of the initial find, but as of the morning of Sept. 13 no further finds had yet been identified.
"What we expect is once they finish the delimiting and they determine where the psyllids are, then there would be a five-mile quarantine around those," he said.
The previous week, a single adult psyllid was found in a trap in Wasco in Kern County, also in a backyard.
The finds in Dinuba were more serious, as "they actually found a breeding population," Blakely said. "They found all life stages at that location." The affected trees have been treated, and the agencies are "proceeding to treat all host material within 800 meters" even as they continue to search for additional infestations. "Growers are cooperating by treating any commercial groves within that 800 meters, and some growers even beyond that, on their own, respraying, so certainly it is being taken very seriously and the industry is acting quickly to try to knock down any populations that might be there."
The only citrus currently being harvested in the Central Valley of California is Valencia oranges, and only about 20 percent of that crop remains, Blakely said. The Navel harvest was expected to start in October.
A five-mile quarantine area would cover parts of Tulare and Fresno counties, he said.
The infestation was believed to have been caused by "something brought in from outside the area," he said. "We continue to stress that the public needs to be aware of the dangers of moving citrus from quarantine to non-quarantine areas. That is how this pest spreads, and it threatens the whole citrus industry."
Asian citrus psyllid is a serious concern to the industry because it is a vector for the devastating citrus disease huanglongbing that has caused tremendous losses to the citrus industry in Florida, Mexico and in many other places, destroying hundreds of thousands of acres of citrus groves.
Since the psyllid first crossed from Mexico into San Diego County several years ago, the industry and government agencies have worked hard to try to continue it and prevent further spread, and particularly to keep it out of the commercial citrus zones.
Last year, the dreaded huanglongbing showed up in Hacienda Heights in Southern California, but so far no further instances of the disease have been found in California.