HLB detected in Riverside tree
Officials moving quickly to control spread
The spread of the deadly citrus disease Huanglongbing (HLB) took a giant leap this week with the discovery of an HLB infected tree in the city of Riverside, about 50 miles from the outbreak in the San Gabriel area of Southern California.
The disease is carried by the Asian citrus psyllid which has been found for years in Tulare County and other areas of the state, but so far the disease the tiny pest can carry has only been found in parts of Los Angeles and Orange counties, until now.
The California Department of Food and Agriculture (CDFA) and the United States Department of Agriculture (USDA) on Wednesday confirmed the detection. The disease was detected in plant material taken from a grapefruit tree in a residential neighborhood in the city of Riverside near I-215.
Alyssa Houtby with California Citrus Mutual, said the find is definitely disturbing because of the distance from the current outbreak of HLB. She said 78 trees in the San Gabriel and Anaheim areas have been found to be infected.
“It’s a huge jump and much closer to commercial citrus groves,” she said of the latest find. She said the expected quarantine will take in one citrus packing house, two nurseries which grow citrus and the University of California, Riverside, the lead university doing HLB research.
“You can assume the psyllids did not fly there on their own, so they had some help,” she said of likely hitchhikers or the homeowner bought in a tree already infected. She added the homeowner has been extremely cooperative.
Infected trees are immediately removed and agriculture officials are moving swiftly on mandatory surveying in an 800-meter area. Mandatory treatments will soon follow. Local, state and federal agriculture authorities are working together to determine potential implications to the University of California, Riverside, which will fall within the 5-mile quarantine area.
Houtby said they have been told the find should not impact the university. “UCR does have a plan in place,” she said.
Houtby will join representatives from CDFA, CPDPP, and UCR on Aug. 8 to provide an update to the Riverside City Council. Riverside City staff are heavily engaged in this issue to encourage homeowner cooperation with CDFA treatments and surveys. Additionally, the city is assisting with outreach to hobby farmers within the nearby “greenbelt” and will be partnering with CCM and the CPDPP to host a grower meeting in the coming weeks.
She added CDFA is doing a “thorough investigation” and should be able to determine how the disease got to Riverside. One test will determine the strain of HLB to determine if it is a new strain, or the same found in the other infected areas.
Houtby also said they have not found any infected psyllids in the area.
Abandoned groves are a significant challenge in Riverside County and adjacent San Bernardino County — an issue that CCM has been working with local growers, elected officials, and County Ag Commissioners to address. Riverside County Agricultural Commissioner/sealer Ruben Arroyo plans to take an aggressive stance on any abandoned groves in the area, and has the support of the board of supervisors to begin the process of abatement.
The disease was detected in a CDFA sample collected July 10 from the tree. Houtby said ag officials are routinely sampling trees all over, including Tulare County, on a regular basis to be on the lookout for the spread of HLB.
The bacterial disease attacks plants’ vascular system but does not pose a threat to humans or animals. The Asian citrus psyllid can spread the bacteria when the pest moves from one location to another, feeding on citrus trees and other plants. Once a tree is infected there is no cure and it typically declines and dies within a few years.
“The discovery of this disease means all citrus trees are at risk — including homegrown trees enjoyed by residents and thousands of acres of trees cared for by citrus farmers,” said Arroyo. “It’s important for residents, growers and agricultural officials to work together to quickly find this disease and stop its spread. I encourage everyone to visit Californiacitrusthreat.org to review symptoms of the disease and report disease sightings,” he added.
Riverside has a storied history of citrus production and is home to California Citrus State Historic Park, which preserves the cultural landscape of the citrus industry and tells the story of the industry’s role in the history and development of California. Though not affected by this HLB quarantine, the historic park and all citrus throughout Riverside are threatened by any presence of the disease.