- Author: Ben Faber
California Citrus Research and Field Trials (CA-CRaFT) Grower Applications Now Being Accepted VISALIA, CALIF. – August 16, 2022 – The California Citrus Research and Field Trials (CA-CRaFT) program is now accepting grower applications. The CA-CRaFT project aims to demonstrate at the commercial grower level the effectiveness of additional mitigations to control Asian citrus psyllid (ACP), the vectoring agent of Huanglongbing (HLB). All California commercial citrus producers are eligible to participate in the CA-CRaFT Project.
The CRB will be hosting webinars on the CA-CRaFT program and application process on September 8 and 14, 2022. For more information about the California-focused CRaFT Project, program requirements, and webinar schedule, visit the CRB website at www.citrusresearch.org or contact Ariana Gehrig at craft@citrusresearch.org. |
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- Author: Ben Faber
CLas-positive Asian citrus psyllid found in commercial grove in Pauma Valley, San Diego County
An Asian citrus psyllid (ACP) sample confirmed positive for Candidatus Liberibacter asiaticus (CLas) – the bacteria that causes Huanglongbing (HLB) – was collected from a commercial citrus grove in the Pauma Valley area of San Diego County. This confirmation marks the first CLas-positive ACP found in a commercial grove in San Diego County and only the second grove detection in California.
The ACP sample was collected during a routine commodity survey conducted by Citrus Pest and Disease Prevention Division (CPDPD) staff. Five adult psyllid samples were pooled and tested for CLas, resulting in confirmation of the bacteria by Citrus Research Board's Jerry Dimitman Laboratory, and later verified by the U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS).
An expansion of the HLB quarantine zone in San Diego County will not be established as a result of the CLas-positive ACP detection and CPDPD staff are swiftly conducting intensive surveys and collecting samples per the ACP/HLB Action Plan from the perimeter of all commercial groves and residential HLB host plants that are located within a 250-meter radius around the find.
While treatment is not mandatory as a result of the detection, all growers within 250 meters of the find site will be notified by their local Grower Liaison and encouraged to apply insecticides to all HLB host material within the designated area with materials recommended by the University of California (UC).
It is more crucial than ever that we prevent HLB from potentially impacting commercial citrus groves by working to eradicate ACP populations now. The cost to manage the ACP is far less than any potential costs or loss to the industry should HLB take hold in our commercial groves and throughout our state.
Currently, the best way to prevent HLB from infecting California's citrus groves is to stop the spread of the ACP. To do so, we must restrict its movement and suppress existing psyllid populations. It is critical to follow best practices and review recommendations from the UC on how to protect commercial citrus groves from HLB. Regulations are in place to help prevent the spread of the deadly pest and disease. All growers, packers, haulers and nurseries must comply with all California Department of Food and Agriculture (CDFA), county and federal regulations, including quarantines.
Growers in San Diego County may contact their local Grower Liaison Sandra Zwaal, the County Agricultural Commissioner's office or the CDFA Pest Hotline at 800-491-1899 for additional information. If you see or suspect ACP or HLB symptoms in your grove, please notify the CDFA .
HLB Quarantine Update
As of July 8, a total of 3,546 trees and 443 ACP have tested positive via PCR for the bacterium that causes HLB. Trees that test positive are treated for ACP and removed, and the HLB quarantine is expanded. Additional ACP treatments and HLB detection surveys are conducted on a recurring basis to remaining citrus within 250 meters of each detection. Counties where HLB has been detected via PCR testing are Los Angeles, Orange, San Diego, Riverside, San Bernardino and San Diego. To see a map of the current HLB quarantine areas, and other details of locations and numbers of HLB detections, please visit maps.cdfa.ca.gov/WeeklyACPMaps/HLBWeb/HLB_Treatments.pdf.
For information on regulatory and treatment requirements growers can expect when HLB is detected in or near your citrus grove or packing house, please refer to CDFA's Information for Citrus Growers/Grove Managers, Action Plan for ACP and HLB or this summary flier.
Additional ACP/HLB Resources
- New and improved CDFA Citrus Division website: https://www.cdfa.ca.gov/Citrus/
- General ACP/HLB
o Information on the state ACP/HLB program including maps, quarantine information, and a signup option for email alerts: citrusinsider.org/
o Biology of ACP and HLB, detection maps and recommendations for monitoring, eradication and management: ucanr.edu/sites/acp/
o UC IPM recommendations for ACP
o Web-based map to find out how close you are to HLB: ucanr.edu/hlbgrowerapp
o Video on Best Practices in the Field, available in English and Spanish
- Research
o UC Ag Experts Talk presentations on management of various citrus pests and diseases are available for viewing here and here on YouTube.
o Summaries of the latest research to combat HLB: ucanr.edu/sites/scienceforcitrushealth/
o Science-based analyses to guide policy decisions, logistics, and operations: www.datoc.us
- Regulatory/Quarantine
o Sign up for program updates from the Citrus Pest and Disease Prevention Division at www.cdfa/signup-email-updates.
o Regulatory requirements for moving bulk citrus: Information for Citrus Growers
o Summary of regulatory requirements in the event of an HLB detection in commercial citrus: citrusinsider.org/Regulatory-Flyer
- Author: Ben Faber
From:
Cressida Silvers
CA Citrus Pest and Disease Prevention Program
ACP/HLB Grower Liaison
Ventura, Santa Barbara and San Luis Obispo Counties
805 284-3310 (phone or text)
ACP/HLB Resources
- New and improved CDFA Citrus Division website: https://www.cdfa.ca.gov/Citrus/
- General ACP/HLB
o Information on the state ACP/HLB program including maps, quarantine information, and a signup option for email alerts: citrusinsider.org/
o Biology of ACP and HLB, detection maps and recommendations for monitoring, eradication and management: ucanr.edu/sites/acp/
o UC IPM recommendations for ACP
o Web-based map to find out how close you are to HLB: ucanr.edu/hlbgrowerapp
o Video on Best Practices in the Field, available in English and Spanish
- Research
o UC Ag Experts Talk presentations on management of various citrus pests and diseases are available for viewing here and here on YouTube.
o Summaries of the latest research to combat HLB: ucanr.edu/sites/scienceforcitrushealth/
o Science-based analyses to guide policy decisions, logistics, and operations: www.datoc.us
- Regulatory/Quarantine
o Sign up for program updates from the Citrus Pest and Disease Prevention Division at www.cdfa/signup-email-updates.
o Regulatory requirements for moving bulk citrus: Information for Citrus Growers
o Summary of regulatory requirements in the event of an HLB detection in commercial citrus: citrusinsider.org/Regulatory-Flyer
- Author: Ben Faber
New ‘Candidatus Liberibacter' Pathosystems Focus Issue from APS (American Phytopathological Society) |
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Read the great review of the bacteria that causes Citrus Huanglongbing and then the abstracts of the articles in this edition of Phytopathology. The review itself is pretty comprehensive, however you can't read the full articles contained in the editon without paying. But this gives you an idea of the extent of work being done, even though the language may be quite technical. The 18 articles in this Phytopathology Focus Issue showcase the enormous research efforts made by the scientific community, giving rise to major advances and achievements in a short time often through multidisciplinary approaches applied to the bacterium, psyllid vector, and plant host. Preview two editors' pick below or see the full Focus Issue. |
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Transcriptome Profiling of ‘Candidatus Liberibacter asiaticus' in Citrus and Psyllids |
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Alves et al. explored Huanglongbing (HLB) presence and absence over 13 years in citrus orchards in Brazil and compared two hierarchical Bayesian modeling approaches to link climatic factors to the spatial distribution of HLB prevalence. They found an inverse relationship between HLB prevalence and mean temperature during the dry season, but wind speed, rainfall, and proximity of other HLB contributed to HLB prevalence. The results further our understanding of environmental factors associated with disease distribution and spread and assists policymakers in defining regions at risk of HLB outbreaks to help guide monitoring strategies that mitigate further spread of HLB. |
HLB symptoms
/table>- Author: Ben Faber
A $1.5 million emergency grant is enabling UC Riverside scientists to find plants impervious to a disease threatening America's citrus fruit supply.
Citrus Greening Disease — also known as Huanglongbing, or HLB — results in fruit that is bitter and worthless. It has crippled Florida's citrus industry and has already been detected in California, which grows 80% of America's fresh citrus. An estimated 267,000 acres of Golden State oranges, lemons, grapefruits, and mandarins are at stake.
For these reasons, the National Institute of Food and Agriculture is supporting scientists at UCR, the University of Florida, and the U.S. Department of Agriculture's Agricultural Research Service in their search for plants with natural tolerance to HLB.
“If you find a disease affecting your crops, a good first step is to look for plants that are able to grow and produce despite infection,” said UCR geneticist Danelle Seymour. “Then you can start to identify the genetic basis of the disease tolerance and make sure the next generation of plants includes these genes.”
Following this recipe, Seymour and UCR plant pathologist Philippe Rolshausen will examine a set of 350 citrus hybrids developed and grown by project collaborators in Florida. All trees in the set are already infected with HLB, yet they live longer, are healthier, and yield more fruit than their infected relatives.
While there are a number of projects searching for different solutions to the threat of HLB, this project is different because the plants being tested were all grown in an environment endemic to the disease. Additionally, the number of plants they're able to test is unusually large.
“The environment in which these plants were grown means we can be confident that these rootstocks will enhance tree health and yield in HLB-affected areas,” Seymour said. “Also, because our data set is so large, we've got the opportunity to identify plants with levels of tolerance that exceed current commercial varieties.”
In addition to searching for parts of the hearty hybrids' genomes responsible for their tolerance to HLB, scientists will also be checking for plants that have resistance to other pathogens that are already in California.
Citrus in the state is also threatened by nematodes that chew up roots, preventing plants from taking up nutrients, and by phytophthora, a type of water mold that causes rotting roots.
By searching not only for a solution to the looming threat of HLB but also to problems that have already taken root in California, scientists are hoping to ensure that citrus won't need to be imported from HLB-free countries and costs stay low for both local growers and consumers.
“This way, we're making sure the next generation of rootstocks will include the right genes and that we're being as efficient as possible in our breeding practices,” Seymour said.
ACP nymph image by Sam Droege, USGS