California Ag Network

Tag: Citrus Pest & Disease Prevention Program

  • Confirmed CLas-positive Asian Citrus Psyllid Found in Ventura County

    Citrus Pest & Disease Prevention Program — A Candidatus Liberibacter asiaticus (CLas)-positive Asian citrus psyllid (ACP) sample has been collected from a residential property in Ventura County in the Santa Paula area and has been confirmed by the Citrus Research Board’s Jerry Dimitman Laboratory. 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 and confirmed positive for CLas on Sept. 19. This is the first confirmed CLas-positive ACP found in Ventura County.

    A Huanglongbing (HLB) quarantine zone will not be established as a result of this CLas-positive ACP detection and 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, as of today, HLB has not been detected in any Ventura County citrus trees. However, it is more crucial than ever that populations of the ACP continue to be controlled properly in order to stop the disease from spreading, as oftentimes a CLas-positive ACP precedes the detection of an HLB-positive tree. Additionally, there were no nymphs observed at the time of collection on Sept. 6., however, during resampling efforts this week, CDFA collected 15 nymphs from the find site property but on a different host plant. CDFA crews will be surveying for any additional adult or nymph psyllids as part of the 250-meter survey being conducted this week.

    This CLas-positive ACP detection is not associated with the research that was conducted last year in Southern California – including Ventura County – as a part of a program funded by the HLB Multi Agency Coordination Group by researchers from UC Agriculture and Natural Resources, UC Davis, UC Riverside and the University of Arizona, Tucson. 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 protecting their groves or who have additional questions can contact Ventura County Grower Liaisons Sandra Zwaal or Cressida Silvers.

  • Protect Citrus from Sweet Orange Scab and Lime Swallowtail Butterfly

    Citrus Pest & Disease Prevention Program — While limiting the spread of the Asian citrus psyllid and Huanglongbing are the highest priority for the California citrus industry and the Citrus Pest & Disease Prevention Program, the program continually monitors for a number of threats to the industry and has recently detected sweet orange scab (SOS) in new areas of the state. Additionally, an unofficial Lime Swallowtail Butterfly (LSB) sample was identified from Los Angeles County and several LSB sightings have been uploaded onto the iNaturalist application, including sightings in Los Angeles and San Luis Obispo counties.

    Sweet Orange Scab
    Sweet Orange Scab

    SOS is a cosmetic fungal disease that impacts the marketability of the fruit and effects all citrus, not just oranges. SOS is caused by the fungus Elsinöe australis, which is dispersed by water. You can recognize SOS by the scab-like lesions on fruit, and less frequently on leaves and twigs. SOS can cause premature fruit drop and stunt young nursery trees and new field plantings but has little impact on fruit quality.

    A positive detection of SOS was found during a commodity survey on the west side of Riverside County, the fourth detection in California within the last year and a half. To help protect citrus from SOS, growers and packinghouses within five miles from an SOS detection, and packinghouses throughout the state receiving fruit from groves within five miles from an SOS detection, are currently required to follow the below measures:

    • Sign an SOS compliance agreement with California Department of Food and Agriculture (CDFA).
    • Disinfect all fruit and field bins.
    • Collect and appropriately dispose of green waste.

    Per the Citrus Pest & Disease Prevention Committee’s direction, CDFA is also reviewing SOS impacts and analyzing the need to establish SOS interior quarantine regulations. Currently the program regulates areas within a five-mile radius from each SOS detection, following the United States Department of Agriculture’s quarantine protocols.

    Working hand in hand with growers, CDFA is exploring the rulemaking process to create state interior quarantines, which will avoid a broader statewide quarantine that would be more burdensome to the industry.

    Lime Swallowtail Butterfly

    There was one unofficial detection of LSB in Los Angeles and several reported sightings in Los Angeles and in San Luis Obispo counties.

    LSB in the larval stage eat citrus leaves and have been very damaging to nursery stock in other parts of the world. The larva looks similar to bird guano before maturing into green caterpillars. As butterflies, they are largely black with irregular yellow spots on the outer wings.