HLB-positive psyllid a First in Commercial Citrus

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The first HLB-vectoring Asian citrus psyllid was found in a commercial citrus block in Riverside County (photo courtesy USDA ARS.)


The first Asian citrus psyllid (ACP) carrying the bacteria that causes citrus greening or Huanglongbing was found this summer in a commercial citrus grove in Riverside County.

The infected ACP was found in an older, certified organic orange grove in Woodcrest, Anmol Joshi of California Department of Food and Agriculture, confirmed August 21 at a virtual grower meeting. The positive ACP was confirmed July 31 by the Citrus Research Board’s Dimitman Lab.

Prior to this find, all confirmed infected ACP and infected HLB trees were found in residential areas in southern California.

The tree where the infected ACP was found and adjacent trees were sampled along with all trees along the perimeter of the grove. The property also had a newly planted grove and 48 trees in that grove were sampled. A total of 286 plant and nine insect samples were taken. At the meeting, CDFA reported that results from all but 20 of the samples were found negative for CLas, the bacteria that causes HLB. Results from the final samples are expected.

If an ACP nymph is confirmed as CLas positive CDFA will initiate abatement procedures to remove the tree where the nymph was collected.

Growers of all citrus groves in the 250-meter area will be expected to treat their trees with a UC recommended foliar or systemic insecticide.

Expansion of the HLB quarantine zone will not be established as a result of the CLas-positive ACP detection.

Enforcement activities by the Riverside County Agricultural Commissioner’s office will include orchard inspection, transporter inspections, and inspection of fruit sellers at farmers markets and flea markets.

Daniel Delgado, deputy agriculture commissioner in Riverside, said that inspectors at groves will be watching for practices that could lead to transport of ACP on plant materials as well as documentation of all measures required for transport from the field to the packing house.

CDFA is requiring that fruit moved from an orchard to a packinghouse within an HLB quarantine area be field cleaned, grate cleaned or sprayed prior to harvest. It also must be tarped and be accompanied by an HLB mitigation form. Citrus fruit moving to a packinghouse outside an HLB quarantine area must be wet washed or grate cleaned or sprayed before harvest. It also must be completely tarped and be accompanied by an HLB mitigation form. Grate cleaning refers to a portable machine that separates out all leaves and stems from the fruit.

A CDFA technician installs psyllid traps in Southern California (photo by Citrus Pest and Disease Prevention Program.)
Cecilia Parsons
Associate Editor at JCS Marketing, Inc. | cecilia@jcsmarketinginc.com