Seven entities recently received $21.7 million to conduct research into combating and preventing HLB at the farm level. The funding is from the U.S. Department of Agriculture's National Institute of Food and Agriculture (USDA NIFA) Emergency Citrus Disease Research and Extension program.
The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) received the majority of the funding, more than $16 million.
PROJECTS LED BY UF/IFAS The largest grant, at approximately $8.6 million, is for development, evaluation and delivery of citrus HLB management approaches by targeting its nature as a pathogen-triggered immune disease. The principal investigator is Nian Wang. The goal is to develop HLB management approaches for existing groves and non-transgenic HLB-resistant and HLB-tolerant citrus varieties.
Other UF/IFAS projects are:
A coordinated network for the improvement of HLB research and Extension outputs, funded at $2 million. Megan Dewdney is the principal investigator. The project tackles the task of gathering and organizing the research findings available to growers.
Targeted production of non-transgenic HLB-tolerant trees through complementary approaches, funded at approximately $1.5 million. Zhonglin Mou is the principal investigator. The first goal of this project is to produce non-genetically modified HLB-tolerant citrus trees by editing or silencing the promising target genes.
HLB-resistant rootstock candidates for the citrus industry: Validating and understanding disease resistance, funded at approximately $1.2 million. The principal investigator is John Chater. This project will advance knowledge about why some rootstocks appear to be more tolerant to HLB than others.
Providing individual protective covers and brassinosteroids to prolong health and improve fruit yield and quality in newly planted trees, funded at $800,000. Fernando Alferez is the principal investigator.
Toward a reliable insect cell culture-based technique for culturing CLas bacteria (the causative agent of HLB), funded at approximately $793,000. Kirsten Pelz-Stelinski is the principal investigator. The project aims to have a culture system that serves as an essential research tool for increased understanding of CLas biology and for effective, rapid screening of antimicrobial agents against CLas.
Accelerating the delivery of conventionally developed HLB-tolerant citrus scions and rootstocks as pathogen-free budlines for replicate multi-site testing, funded at approximately $536,000. The principal investigator is Jude Grosser. Successful adoption of this technology will reduce the current clean-up time by 1.5 to 2 years, and significantly increase the number of selections that can be processed.
PROJECTS LED BY OTHER INSTITUTIONS
Virus-induced gene silencing using insect specific viruses to manipulate psyllids as a strategy to control HLB is a University of California-Davis project led by Yen-Wen Kuo.
A method for generating an optimally attractive scent for Asian citrus psyllid biocontrol is a University of Connecticut project led by Alexander Aksenov. UF/IFAS' Lukasz Stelinski is a co-investigator.
Endophytes as sources of antimicrobials to control HLB is being led by Kateel Shetty of Florida International University.
Scalable low-cost organic nanocarriers for efficient foliar uptake of registered anti-HLB agents is a Purdue University project led by Kurt Ristroph.
Citrus yellow vein-associated virus induced gene silencing vector for vaccinating seedlings and controlling HLB in infected fruit-bearing trees is a University of Maryland project led by Anne Simon.
Molecular strategies to block psyllid transmission of the HLB pathogen is a USDA Agricultural Research Service project led by Michelle Heck.
Winter and spring rains have given us a robust growing season this year. Tender new citrus flush is ideal habitat for ACP to feed, lay eggs and build new populations. An increase in ACP numbers and feeding can increase the risk of HLB spreading and building up. University of California recommends growers monitor trees regularly for ACP, paying careful attention to new flush, and treat when populations reach the detection threshold. The UC IPM website lists a range of materials effective against ACP, including organic options. Growers are also encouraged to work with a pest management professional to better detect and manage ACP.
Advanced notification of nearby beekeepers is required before pesticide treatments. Use the BeeWhere BeeCheck system, or contact the County Agricultural Commissioner's office, 805-681-5600, for more information. Always follow label instructions for bee safety.
If your citrus is no longer being cared for or is not worth the resources required to protect it from ACP and HLB, consider removing it.
HLB Quarantine Update
As of May 5, a total of 5.007 trees and 709 ACP have been confirmed positive for the bacterium that causes HLB. Trees confirmed positive are treated for ACP and removed, and the HLB quarantine may be 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, with the majority of detections in Orange County. 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.
CPDPP Full Committee, Wednesday August 9 (agenda pending)
All meetings are free and open to the public to listen to or make public comment. Meetings are currently in person and accessible via phone and/or webinar. Links to register for and join meetings are included in agendas when posted.
For a list of current committee members, click here.
To ensure California citrus growers are well prepared in the event of a potential commercial grove detection of Huanglongbing (HLB), the deadly citrus plant disease that can be spread by the Asian citrus psyllid (ACP), the Citrus Pest and Disease Prevention Program (CPDPP) has developed a response guide for growers to utilize and educate themselves on the California Department of Food and Agriculture's (CDFA) action plan.
The actions in the response guide represent the most effective tools known to the citrus industry at this time and are meant to protect California's citrus groves and support CDFA's current required regulatory response. While, as of today, there have been no positive detections of HLB in a commercial citrus grove, the CPDPP recognizes the importance of proper preparation.
In addition to the requirements outlined in the guide, growers are encouraged to use as many methods as feasible for their operation in order to limit the spread of the ACP and HLB.
To read or download the response guide, please click here. If you have any questions or would like to order physical copies of this response guide, please visit our Resources page.
Response Guide for a Confirmed HLB Positive Detection
The Asian citrus psyllid is the insect vector for the bacterium that can cause huanglongbing disease. Photo credit: UC Regents
Preliminary results indicate 3.5% of ACP collected showed signs of bacterium that can cause huanglongbing
An ongoing study in the commercial citrus groves of coastal Southern California is looking at whether Asian citrus psyllids – the insect vector of huanglongbing “citrus greening” disease – are carrying the bacterium that can cause HLB.
Thus far, the project has tested more than 3,000 adult ACP collected from 15 commercial citrus sites across the region, of which 138 – just over 3.5% – had some level of the bacterium present, according to researchers from UC Agriculture and Natural Resources, UC Davis, UC Riverside and the University of Arizona, Tucson.
“While the results are a cause for concern, the situation in California is much better than in Florida and Texas, where ACP carrying the bacterium make up the majority of the population and HLB is widespread in commercial citrus,” said Neil McRoberts, a UC Davis plant pathologist and UC Integrated Pest Management program affiliate advisor. “The results indicate that there is no room for complacency, but also no cause for panic.”
Since the first HLB-infected tree in California was found in 2012, nearly 4,000 infected trees have been detected and removed from residential properties in Southern California, mainly in Orange and Los Angeles counties. According to McRoberts, “to date, no HLB has been found in commercial citrus” in California.
He stressed, however, that the aforementioned ACP study – funded by the HLB Multi Agency Coordination Group and managed by USDA-APHIS – does not involve any testing of trees for HLB and focuses only on looking at the insect which spreads the bacterium.
McRoberts also emphasized that the project's detections of the bacterium cannot be considered “official” because the researchers' lab procedures differ from the official testing protocols of the California Department of Food and Agriculture.
“Follow-up sampling by CDFA staff would allow official samples to be collected for further investigation, but is entirely voluntary for the growers involved,” he said, adding that his research team is currently wrapping up the sampling phase of the project, with data analysis continuing into 2023.
While commending the “huge coordinated effort” by the California citrus industry, California Department of Food and Agriculture, UC ANR and other partners to suppress the ACP vector and slow the spread of HLB, McRoberts also urged continued vigilance.
“Our study results indicate that it is not time to declare the emergency status for ACP/HLB in California over – the situation is still evolving,” he said.
For further information about the research, contact Neil McRoberts at nmcroberts@ucdavis.edu or (530) 752-3248.
UCR ARGENTINE ANT & CITRUS PEST MGT FIELD DAY (NOV. 1 & 2) Citrus growers and affiliates are invited and encouraged to attend one of the upcoming Argentine Ant and Citrus Pest Management field day events hosted by the University of California (UCR & UCCE) at the Prospect Park Carriage House in Redlands on Nov. 1 and in Saticoy on Nov. 2 from 8am - noon. Attendees will have the opportunity to see and hear about Argentine Ants at designated stations in small groups, and to hear from UCR and UCCE Researchers and your local CPDPP ACP/HLB Grower Liaison. 2 DPR CEUs (other) have been requested. Water, coffee, pastries, and snacks provided for attendees. There is no cost to attend the event, but registration is required. CLICK HERE FOR THE AGENDA & TO REGISTER.
CRB STILL ACCEPTING APPLICATIONS FOR THE CA-CRaFT PROGRAM The California Citrus Research and Field Trials (CA-CRaFT) program is still 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. . . READ MORE
SPANISH LANGUAGE ACP/HLB PRESENTATION LINKS On September 27, 2022, a Spanish language presentation on ACP/HLB was given by Francisco Macias, a local pest control advisor, and a presentation on inspections given by Rafael Raygoza with the Ventura County Agricultural office. The event was moderated by Maureen McGuire from the VC ACP/HLB Task Force and Farm Bureau CEO. Thanks to our presenters and moderator for providing this valuable information in Spanish. Here are the links to the presentations. Video presentation Audio-only recording
ACP/HLB UPDATES There have been NO confirmed positive HLB trees or ACP detected in Ventura County. As of 10/21/2022, the total HLB residential trees reported in California is 3,919. Growers are encouraged to work with your pest control companies and remain diligent with the ACP area-wide treatments. Research shows that keeping ACP populations low in generally infested areas such as Ventura County, reduces the risk of citrus trees acquiring the bacteria that causes the deadly HLB disease. The Ventura Co. ACP/HLB Task Force 2022/2023 area-wide treatment schedule can be found here. UPCOMING EVENTSCitrus Pest & Disease Prevention Program (CPDPP) Meetings The Citrus Pest and Disease Prevention Program (CPDPP) meetings are free and open to the public. The virtual meeting agendas, minutes and schedules are posted in www.cdfa.ca.gov/citruscommittee/.
University of California Cooperative Extension Ventura County 669 County Square Drive, Suite 100 Ventura, CA 93003 Phone: 805.645.1451 Fax: 805.645.1474