A Candidatus Liberibacter asiaticus (CLas)-positive Asian citrus psyllid (ACP) sample has been collected from a residential property in California’s Ventura County. CLas is the bacterium that causes HLB. The Citrus Research Board’s Jerry Dimitman Laboratory confirmed the positive sample. This is the first confirmed CLas-positive ACP sample found in Ventura County.
The positive sample, comprised of 12 adult psyllids from a residential citrus tree in the southwest area of Santa Paula, was collected on Sept. 6 as part of the Multi-Pest Risk Survey. It was confirmed positive for CLas on Sept. 19.
An HLB quarantine zone will not be established as a result of this CLas-positive ACP detection. California Department of Food and Agriculture (CDFA) staff are swiftly conducting surveys and collecting samples from the property and all HLB host plants that are located within a 250-meter radius around the find, per the ACP/HLB Action Plan.
While the first confirmation of a CLas-positive ACP in Ventura County is concerning, HLB has not been detected in any Ventura County citrus trees. However, a CLas-positive ACP sometimes precedes the detection of an HLB-positive tree. So, it is more crucial than ever that ACP populations continue to be controlled properly in order to stop the disease from spreading.
No nymphs were observed at the time of collection on Sept. 6, but during resampling efforts, CDFA collected 15 nymphs from the find site property on a different host plant. CDFA crews will be surveying for any additional adult or nymph psyllids as part of the 250-meter survey that is being conducted.
This CLas-positive ACP detection is not associated with the research that was conducted last year in Southern California, including Ventura County. That research was part of a program funded by the HLB Multi-Agency Coordination Group. It was conducted by researchers from University of California (UC) Agriculture and Natural Resources, UC Davis, UC Riverside and the University of Arizona. These studies’ laboratory tests vary from the federally approved testing methods and procedures required by CDFA labs that would allow the state to take any regulatory action. Therefore, this is the first CLas-positive ACP detection recognized by CDFA.
While treatment is not mandatory for area commercial growers as a result of the detection, Ventura County commercial growers who wish to take proactive steps to protect their groves or who have additional questions can contact Ventura County Grower Liaisons Sandra Zwaal or Cressida Silvers.
Source: Citrus Pest & Disease Prevention Program
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