Posts Tagged: Huanglongbing
The California Department of Food and Agriculture (CDFA) and the United States Department of Agriculture (USDA) have confirmed the detection of the citrus disease known as Huanglongbing (HLB), or citrus greening, in Riverside County. The disease was detected in plant material taken from a grapefruit tree in a residential neighborhood in the city of Riverside near I-215.
The infected tree has been removed and agriculture officials are moving swiftly on mandatory surveying in an 800-meter area. Mandatory treatments will soon follow. CDFA staff will visit all regulated entities in the quarantine area, including retail and production nurseries and packinghouses. Additionally, 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.
Riverside County Agricultural Commissioner/Sealer Ruben Arroyo plans to take an aggressive stance on any abandoned groves in the area, and the Citrus Pest & Disease Prevention Program outreach team is already working with the City of Riverside to inform residents of the actions needed to stop HLB's spread.
Please read the full press release shared on July 25 by Riverside County.
For more information about ACP or HLB, Riverside County residents may call the Agricultural Commissioner's Office at (951) 955-3045 or CDFA's toll-free pest hotline at 1-800-491-1899 or visit: www.cdfa.ca.gov/plant/acp//span>
California citrus farmers have their ears perked for all news related to Asian citrus psyllid (ACP) and huanglongbing (HLB) disease, but the very latest advances have been available only in highly technical research journals, often by subscription only.
UC Cooperative Extension scientists are now translating the high science into readable summaries and posting them on a new website called Science for Citrus Health to inform farmers, the media and interested members of the public.
“The future of the California citrus depends on scientists finding a solution to this pest and disease before they destroy the industry,” said Beth Grafton-Cardwell, UC Cooperative Extension citrus entomology specialist. “Our farmers want to stay on top of all the efforts to stop this threat.”
Grafton-Cardwell and UC Cooperative Extension biotechnology specialist Peggy Lemaux are the two scientists behind the new website. When scientists make progress toward their goals, Grafton-Cardwell and Lemaux craft one-page summaries with graphics and pictures to provide readers with the basics.
For example, the website outlines scientific endeavors aimed at stopping the spread of huanglongbing disease by eliminating the psyllid's ability to transfer the bacterial infection. This section is titled NuPsyllid, and contains summaries of three research papers including one by UC Davis plant pathologist Bryce Falk.
Falk is collecting viruses found in Asian citrus psyllid; so far he has identified five. He is looking into the potential to utilize one of the viruses as is or modify one of the viruses to block the psyllid's ability to transmit the bacterium. For example, the virus might out compete the bacterium in the psyllid's body.
Another focus of the website is HLB early detection techniques (EDTs). If HLB-infected trees are found and destroyed before they show symptoms, ACP is less likely to spread the disease to other trees. EDT research described on the website includes efforts to detect subtle changes in the tree that take place soon after infection, such as alterations in the scents that waft from the tree (studied by UC Davis engineer Cristina Davis), changes in the proteins in the tree (studied by UC Davis food scientist Carolyn Slupsky) and starch accumulation in the leaves (studied by UC farm advisor Ali Pourreza).
As more research is published, more one-page descriptions will be added to the website. The website contains a feedback form to comment on the science and the summaries.
Photo: ACP traps
The proceedings of the 5th International Conference on Huanglongbing (IRCHLB V) is now published, available and citable online through the Journal of Citrus Pathology: http://escholarship.org/uc/iocv_journalcitruspathology
Joseph (Josy) M. Bové - Selected Photos
Joseph (Josy) M. Bové Dedication
Tribute to Prof. Dr. Joseph Bové
If you download the Bové Dedication pdf file, there is a link near the top of page 3 that will redirect you to the video interview of Prof. Bové. This is the video that we could not show during the meeting due to audiovisual technical difficulties. You must download the pdf for the link to be active. The link is not active when simply viewing the publication online.
The keynote speakers are working on their contributions. These will be available shortly and we will send another email announcement when they become available as well.
sIn the bottom left corner is the Search box for finding authors and topics of the abstracts.
Every year growers get together to learn what is being done in the citrus research world that could affect their operations. This June, University of California and the Citrus Research Board are bringing some good talks to three different growing areas. All growers are invited, but RSVPs are appreciated.
This is a reminder of the complexity of huanglongbing and the bacterial infection it causes. This abstract is from the HLB Conference in Florida last fall.
4.a.5 Symptom variations and molecular markers that illustrate the HLB complexity
Yongping Duan, Marco Pitino, and Cheryl Armstrong
USHRL-ARS-USDA, Fort Pierce, FL 34945, USA
Huanglongbing (HLB) is a devastating bacterial disease of citrus worldwide due to its intracellular and systemic infection. Various HLB symptoms are observed on different species/varieties of citrus plants: from yellow shoots to blotchy mottle on the leaves, from vein yellowing/vein corky to mosaic/green islands similar to zinc deficiency on the leaves, from whitish discoloration to stunted green leaves, etc. These variations of symptoms, which result from a combination of biotic and abiotic stresses, are not only present on individual plants from a variety but also exist on individual branches of an infected plant. Our results indicated that the adaptation of the bacterial populations, such as the dynamics of ‘Candidatus Liberibacter asiaticus' (Las), plays an important role in the induction of various symptoms and that Las mutations as well as the number and recombination events of Las prophages/phages affect this phenomenon. In addition, the selection of the host plants (resistance/tolerance) for the bacterial populations is also critical for symptom expression during disease progression. Based on severity, we divided HLB symptoms into four grades. It is worth noting that the grades of HLB symptom severity show a positive correlation with our newly identified biomarkers from host plants, and that gene expression profiling of different grades of infected leaves rationalized the differentiation based on the dynamics of these biomarkers. Because of these findings, we propose new approaches that allow for rapid selection of variant citrus plants, including bud sports with greater HLB resistance/tolerance.
Non-Technical Summary: Various symptoms of citrus huanglongbing display in different species/varieties of infected citrus plants. These variations of symptoms are not only present on individual plants from a variety, but also exist on individual branches of an infected plant. We have identified some molecular markers from the citrus plants and Las pathogen that illustrate the HLB complexity. Therefore, we propose new approaches that allow for rapid selection of variant citrus plants, including bud sports with greater HLB resistance/tolerance.