California Fruit and Vegetable

Tag: HLB

  • “Grove-First” Approach to Combat Citrus Greening

    Since the mid-2000s, citrus greening disease or Huanglongbing (HLB), has taken a toll on citrus fruits, causing significant crop and economic losses for citrus growers from Florida to Texas, and threatening to make its way to California — the nation’s #1 citrus state.

     

    An aerial view of the new APHIS-funded Grove-First test site. Here researchers can partner with ARS scientists to evaluate therapies to combat citrus greening disease. (Photo by Cody Estes, owner of Estes Citrus Inc., Vero Beach, FL).

    Photo Caption: An aerial view of the new APHIS-funded Grove-First test site. Here researchers can partner with ARS scientists to evaluate therapies to combat citrus greening disease. (Photo by Cody Estes, owner of Estes Citrus Inc., Vero Beach, FL).

    With citrus trees in all major U.S. citrus-producing states affected by the bacterial pathogen, the Agricultural Research Service (ARS) is working to combat the disease. Citrus greening affects a variety of citrus fruits — with the greatest damage occurring within Florida’s orange groves.

    Through the project “Grove-First,” ARS scientists Michelle Heck and Randall Niedz are working to stop citrus greening from overtaking these vital crops. Grove-First invites fellow researchers, citrus growers, and industry experts to test their scientific models to curb the effects of citrus greening directly in the field.

    Coordinated by molecular biologist Heck at ARS’ Emerging Pests and Pathogens Research Laboratory in Ithaca, NY, and geneticist Niedz, who is based at the U.S. Horticultural Research Laboratory in Fort Pierce, FL, Grove-First will support any researcher who wants to test possible solutions directly in the field.

    “We want to provide access to anyone in the research community to test their therapy against citrus greening,” said Heck. “This new project is going to open the door [to further research] and obliterate the barrier between the lab and the field. We are going to provide researchers with the ability to test their therapies directly in the field.”

    With the support of ARS and USDA’s Animal and Plant Health Inspection Service (APHIS), Grove-First will leverage a commercial grove in Vero Beach, FL, to evaluate different treatments on both mature and young trees.

    “The only way to determine if a treatment works is to actually see it work in the field,” added Niedz. “When you have a woody perennial like citrus trees, they are large, and therefore expensive to grow. Most researchers simply don’t have the resources, or access to the trees. With Grove-First, we now have a field site to welcome collaborations with some of the best researchers in the country.”

    Heck tributes citrus growers for bringing Grove-First to fruition as a collaborative project. She said that in the past, the only way growers could fight citrus greening disease was to deliver therapies to trees using broadcast sprayers or through irrigation lines.

    Because citrus greening disease attacks the vascular tissue of citrus trees, many growers have now turned to injecting individual citrus trees with an antibiotic treatment, such as oxytetracycline, which delivers more immediate treatment.

    “The innovation to open up field testing and Grove-First research came from grower willingness to treat each individual citrus tree by direct injection,” said Heck. “This was transformative.”

    Grove-First will welcome researchers with three important considerations.

    “We want the treatments to be safe … safe for the (citrus) trees and safe for the workers,” Heck said. “They also must be affordable for the grower, and they must be available. The treatments that are safe, affordable, and available will be prioritized for screening through Grove-First.” – By Tami Terella-Faram, USDA-ARS Office of Communications

  • HLB Funding Prioritized in Farm Bill Proposal

    California Citrus Mutual (CCM) commends Chairwoman Stabenow of the Senate Agriculture Committee and Chairman Glenn Thompson from the House Agriculture Committee for prioritizing the citrus industry’s fight against Huanglongbing (HLB) in each of their frameworks for the 2024 Farm Bill. Each Chair’s framework continues support of the Emergency Citrus Disease Research and Extension Program at $25 million per year for the life of the Farm Bill.

    “This is a significant step towards reaching a bipartisan Farm Bill compromise that will continue critical research to find a cure to Huanglongbing,” said CCM President/CEO Casey Creamer.  “While this isn’t the finish line, it clearly signals that Congress supports maintaining citrus funding.  We thank the Chairs of the Committee and our California Congressional delegation for championing our needs.”

    The $25 million in funding will go to the U.S. Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA) to fund research to find a cure for HLB. The funding is overseen by grower representatives from California, Texas, and Florida.

    This is a big win for the citrus industry as there were significant headwinds with the current fiscal battles in Washington, D.C., including escalating Farm Bill baseline expenditures and competing priorities within agriculture.  It proves the strength of the advocacy partnership with Florida and Texas Citrus Mutuals in addition to the strong support received from allied industry organizations.

    About California Citrus Mutual (CCM)

    CCM is a voluntary, non-profit trade association representing California citrus growers on the economic, regulatory, and political issues that most impact them.

  • California Citrus Breeding Program Expanding with Congressional Support

    Today, Presidents of California Citrus Mutual (CCM) and Citrus Research Board (CRB) issued statements applauding Congressional leaders for recently approving additional funds for the new citrus breeding program in Parlier, California. Congress is allocating an additional $500,000 in federal funding on top of the $1 million granted last year to expand the program into California. The program will now receive $1.5 million in federal funds on an annual basis along with the $500,000 that CRB provides the program with annually.

    “CRB was instrumental in developing the concept for the California based program and was also involved in efforts to establish the nationwide program while CCM advocated to secure funding,” said CRB President Marcy Martin. “Our two organizations working together on behalf of the industry has been instrumental in getting this program off the ground.”

    “On behalf of the industry, I would like to thank our congressional leaders and the Committee for their continued support of this program, which will help us find solutions to issues specific to our growers located in California,” said CCM President and CEO Casey Creamer. “I would like to specifically extend our gratitude to Congressmen Costa and Valadao and Senator Padilla for championing the need for this program in D.C.”

    The California citrus breeding program will focus on fresh market citrus. Funding will go towards research and development of high-quality, superior citrus selections well suited to California growing regions, changing climatic pressures, consumer taste preferences, and resistance to pest and diseases, such as huanglongbing (HLB).

    The California program is an expansion of the existing national USDA Agricultural Research Service (ARS) citrus breeding program located in Fort Pierce, Florida, which is focused primarily on varieties that are optimized for Florida growing conditions. Work done through the Florida program has resulted in new varieties with higher yields, increased disease resistance, improved color, and a longer shelf life.

    The Florida and California breeding programs along with the continued support from the University of California citrus breeding program at UC Riverside will work together to deliver results for California based growers.

    The California citrus breeding program is located at the USDA-ARS field station in Parlier. Thanks to funds that have already come in, forward progress continues to be made with the addition of a dedicated scientist, developing plans for construction of a greenhouse and laboratory, and securing additional ground for the program.

    About California Citrus Mutual (CCM)
    CCM is a voluntary, non-profit trade association representing California citrus growers on the economic, regulatory, and political issues that most impact them.

    About the Citrus Research Board (CRB)
    The CRB administers the California Citrus Research Program, the grower-funded and grower-directed program established in 1968 under the California Marketing Act as the mechanism enabling the State’s citrus producers to sponsor and support needed research. More information about the Citrus Research Board may be found at www.citrusresearch.org.

  • Update to ACP and HLB Bulk Citrus Movement Requirements

    Effective March 12, 2024, the Citrus Pest and Disease Prevention Division (CPDPD) has updated the requirements for moving bulk citrus fruit from an Asian citrus psyllid (ACP) quarantine zone to a packer/processor in a Huanglongbing (HLB) quarantine area. Citrus fruit may now be moved from any ACP quarantine zone to an HLB quarantine area for packing or processing without a mitigation, such as a pre-harvest treatment or field cleaning. One mitigation was previously required.

    Listed below are some examples of potential bulk citrus movement that is now allowed without mitigation, per the CPDPD’s Citrus Grower/Grove Manager Information page:

    • Tulare County to HLB quarantine zone in Riverside County
    • Imperial County to HLB quarantine zone in Ventura County
    • Kern County to HLB quarantine zone in San Diego County

    Please note, safeguarding all fruit in transit is still required for all bulk citrus ACP/HLB quarantine movements, and all other quarantine requirements, such as those for invasive fruit fly quarantines, still apply. Trucks must be fully tarped or the vehicle must be fully enclosed.

    In the instance that HLB is detected in new areas, this regulatory update may be revisited and revised by CPDPD.

    For complete information regarding the mitigations required for fruit movement, please visit the CPDPD’s Citrus Grower/Grove Manager Information page.

    For questions regarding citrus fruit movement requirements, please contact your local County Agricultural Commissioner or contact Keith Okasaki at Keith.Okasaki@cdfa.ca.govor 916-274-6300.

  • Citrus Greening (HLB) Impacting Brazilian Citrus Crop – Annual Report

    The Brazilian orange crop for Marketing Year (MY) 2023/24 is forecast at 408 million 40.8-kg boxes (MBx) – standard reference, equivalent to 16.5 million metric tons (MMT), a decrease of 1.03 percent compared to the estimate of current crop MY 2022/23 (around 412.3 million boxes or 16.67 MMT), due to the incidence of greening, which has been affecting Brazil’s citrus belt. Meanwhile, the average fruit weight is expected to be 158 grams for MY 2023/24, as a result of unfavorable climate and diseases, with expectations of lower production and fruit quality. FCOJ 65 Brix equivalent production for MY 2023/24 is forecast at 1.05 MMT, a decrease of 1.64 percent vis-à-vis the estimate for MY 2022/23 (1.12 MMT), due to downward expected availability of fruit for processing provoked by extremely high temperatures and the greening incidence. A significant share will keep supplying the U.S. market due to limited juice availability from Florida provoked by hurricane Ian.

    FRESH ORANGES

    PS&D Table

    The following table provides total Brazilian fresh orange production, supply, and distribution (PS&D) for Brazilian (BR) marketing years (MY, July-June) 2022/23, 2023/24, and 2024/25. The MY mentioned above are equivalent to U.S. MY 2021/22, 2022/23, and 2023/24, respectively.

    Table 1

    Production, Supply and Distribution for Brazilian Fresh Oranges

    Note: There is a one-year lag between the BR MY and the U.S. MY. For example, BR MY 2023/24 is equivalent to U.S. MY 2022/23. To ensure data continuity, the current Brazilian MY 2023/24 will be referred to as U.S. MY 2022/23 throughout this report.

    General

    Post forecasts the total Brazilian orange crop for MY 2023/24 (July/June) at 408 million 40.8-kg boxes (MBx) – standard reference, equivalent to 16.5 million metric tons (MMT), a decrease of 1.03 percent compared to current Post estimate for MY 2022/23 (412.3 million boxes or 16.67 MMT), due to greening incidence.

    The commercial area of the state of São Paulo and the western part of Minas Gerais (known as “Triângulo Mineiro”) should produce 307 million 40.8-Kg boxes (12.52 MMT) for MY 2022/2023, a projection based on the most recent data released by the Defense Fund for Citriculture (Fundecitrus) in December 2023. Considering the total citrus belt estimated production, approximately 27.60 million boxes should be harvested in the Triângulo Mineiro region, as reported by Fundecitrus, and 280 million boxes in São Paulo.

    Around 30 percent of Brazil’s orange production is destined to the market and 70 percent is used for juice processing. The main orange varieties that Brazil produces are Hamlim, Westin, Rubi, Valencia Americana, Seleta, Pineapple, BRS Alvorada, Pera Rio – pear orange, Valencia, “Folha Murcha” Valencia, and Natal. The citriculture chain in Brazil is highly industrialized.

    Figure 1

    Orange Production History in the Brazilian Citrus Belt

    The graph above (Figure 1) shows the orange crop production history in the Brazilian citrus belt, reflecting significant oscillations over the course of twenty-four years, ranging from 450 million 40.8Kb boxes in BR MY 1999/00 to 250 million BR MY 2010/11. During its big harvests, the Brazilian citrus belt produced an average of 400 million boxes, particularly in BR MY 2011/12, 2012/13, 2017/18, 2019/20. However, in the past four market years, the average has fallen around 100 million to an average of 300 million.

    According to Post contacts, the current average of orange boxes produced in the Brazilian citrus belt reaches 915 boxes per hectare, even though some larger citrus growers produce 2,000 boxes per hectare due to the following reasons: 1- adapted varieties (more productive plants) and a mix of varieties (early oranges are very productive, compared to the others, mid-season and late); 2- densification of orchards (in the 1980s there were around 250 trees/ha. now there are about 700 trees/ha); 3- pruning and management techniques for better productivity and more day-to-day management. Today, 70 percent less pesticides are used in each pesticide application.

    Data from Fundecitrus shows an estimate to the weight of oranges at 160 grams (255 fruits per box) upon the current harvest, representing an increase of 3.77 percent in relation to the average weight recorded in the previous crop MY 2021/22, and a 1.23 percent growth in average weight when compared to the last ten crops.

    Production

    According to data from the Brazilian Institute of Geography and Statistics – IBGE in November 2023 citrus is produced in Brazil on 584,443 hectares. The citrus belt accounts for approximately 83 percent of the cultivated area in Brazil. Taking into account the estimated 307 million of boxes produced in the Brazilian citrus belt in MY 2022/23, post contacts inform that 300 million are produced in São Paulo and Minas Gerais regions, of which 50 million are in natura and 250 million are used for processing. According to Fundecitrus, the second half of 2023 has observed Minas Gerais producing more than Florida. Approximately 27.02 million boxes are expected to be produced in the Triângulo Mineiro region for MY 2022/23, against 16 million boxes in Florida.

    In Brazil, citrus growers plant and sell according to market demand, many of them through juice industry contracts. The citrus belt, however, also has the highest incidence of plants with symptoms of the main citrus disease, greening (or Huanglongbing – HLB). According to data published by Fundecitrus in 2023, 38 percent of the plants in the citrus belt have symptoms of the disease.

    Rainfall was frequent and voluminous from January to April 2023 throughout the São Paulo citrus belt, making MY 2022/23 orange crop produce fruit with good size development. Moreover, the decrease in the estimated production of pear orange in the citrus belt is being offset by an increase in the production of early varieties. Recent data from Fundecitrus reports that oranges of the early varieties benefited from the abundant rainfall in the beginning of 2023, which resulted in an estimate of 2.27 million boxes. The other varieties (Pera Rio, Valencia, Valencia Folha Murcha and Natal) have an estimate down by 4.39 million boxes, due to the size of the fruit, smaller than expected.

    Throughout 2023, temperatures reached astonishing numbers, ranging from 95°F to 104°F. The process known as “evapotranspiration”, by which the land transfers water and plants transfer transpiration to the atmosphere, is higher as the heatwave increases. With the arrival of the dry season from May 2023 to August 2023, rain became scarce in the citrus belt region in São Paulo, falling 26 percent below the average, causing the trees to suffer from drought stress.

    According to the Brazilian Economic Research Center (CEPEA), throughout 2023, many oranges were withered and sunburned, varieties that consumers do not usually buy. To avoid those fruit conditions and premature fruit fall, many producers anticipated the harvest of late varieties, mainly Valencia and Natal. Abundant rain in October 2023 relieved drought stress, but the availability of oranges on the fresh market remained restricted.

    A heatwave that hit the state of São Paulo in November 2023 caused partial fruit abortion, which is when the fruit falls off before the final filling stage. This happens so that the tree does not die. At high temperatures, the fruit’s stomata close – the structure that ensure gas exchange -, automatically reducing photosynthesis and negatively impacting the production.

    In irrigated areas damages tend to be mitigated, since orange flowers are more advanced. These areas are in the north of São Paulo state, where temperatures are usually higher. Irrigation facilitates planting, since the regular rainfall cannot always be proper for crops, and it can reduce the risk of high temperatures. According to Fundecitrus, the practice of irrigation is considered a complementary strategy. There are around 36 percent of irrigated hectares in the citrus belt and 63 percent of non- irrigated hectares, or hectares without information on irrigation.

    Fundecitrus emphasized in its most recent orange crop forecast from December 2023 that the citrus belt harvest reached 82 percent of production in the middle of November 2023, 26 percent faster compared to previous years. To produce oranges all year round, nine months of harvest are needed, which runs from May to February.

    With El Niño in Brazil, heat waves started in June 2023. High temperatures and rain shortage in the Brazilian citrus belt is expected to continue to be a cause of concern for the next harvest (MY 2023/24), according to Post contacts. According to the U.S. National Oceanic and Atmospheric Administration (NOAA), along with its National Weather Service and funded U.S. institutions, an El Niño forecast from November 2023 has a 62 percent probability of continuing until April or June 2024.

    Figure 2

    Maximum Daily Temperate in Brazil, Dec 4-10, 2023

    A compilation of surveys by Brazilian institutions, including the Brazilian National Institute of Meteorology, released in November 2023 a newsletter on El Niño. The climate forecast for December 2023/January-February 2024 indicates a greater likelihood of temperatures above the normal range in most of the country, including the citrus belt area.

    The Brazilian map in Figure 2 on the left highlights the current behavior of high temperatures in Brazil (Dec 4-10), showing evidence that El Niño may worsen the temperature oscillations in most of Brazil. In the citrus belt area, red color shades on the map indicate temperature ranging from 86°F to 104°F.

    Area

    Post forecasts the area planted for oranges at 590,000 ha for MY 2023/24, 10,000 ha downward compared to Post current estimate for MY 2022/23 (600,000 ha), due to densely cultivated plants.

    São Paulo is the only state that compiles trees planted and tree inventory data. According to Crop Forecast Survey data from Fundecitrus (PES in Portuguese) from May 2023, bearing trees total 169.29 million and cover an area of 399,415 hectares in the citrus belt. This represents an increase of 0.41 percent in the number of trees over the previous, released in 2022.

    Even though the whole country produces oranges, the Brazilian map in Figure 3 bellow shows the main citrus-growing regions in Brazil, according to data from IBGE (2022). It denotes the states of Bahia (3.39 percent); Paraná (3.88 percent) and Rio Grande do Sul (2.11 percent) as the main orange production states outside of the Brazilian citrus belt (76.94 percent in São Paulo and 6.44 percent in Minas Gerais).

    Figure 3

    Main Citrus-Growing Regions in Brazil

    Data on the map in Figure 4 below covers the area of land planted with orange trees in each of the twelve regions that make up the five sectors of the citrus belt: North, Northwest, Central, South and Southwest. Variation in area is indicated by colors. The darkest color, for example, in navy blue, denotes regions where there are the most land in used for orange tree planting, including, among other municipalities, Avaré, with 58,824 ha and Duartina, with 60,446 ha. Meanwhile, there are 12,169 ha in Altinópolis and 11,570 in Brotas, highlighted in the map by the lightest shade of orange.

    Figure 4

    Brazilian Citrus Belt per Region

    Currently in Brazil there are a total of 5,134 orange grove properties, most of them large producers with high productivity. In addition to pests, high production costs and an insufficient labor force has driven many small producers away from the industry. As reported by Post contacts, it costs around BRL 40 million to invest in a citrus farm.

    The current scenario makes it increasingly likely that citrus farming, especially on small and medium farms, will be converted to other crops, such as sugar cane in the São Paulo region or livestock farming. The main reason is because the production of sugar cane in São Paulo is less risky than that of oranges. Moreover, there are already mills in the São Paulo region, making it easier to switch the production to a new commodity. Thus, prices of other crops may define the fate of the Brazilian citrus industry in the coming months. Fundecitrus highlights, however, that the production of oranges requires a smaller area for production, compared with other crops. Orange production compared with sugarcane, for example, has an area 14 times smaller and a profitability of around 2.5 times higher.

    In the long term, Post contacts report that the trend of the orange industry expanding outside the São Paulo and Minas Gerais area is likely to continue. In the state of Bahia, for example, the greening disease does not exist, due to the climate and the distance from the main region of the citrus belt.

    The next couple of years will be crucial to determine which new areas Embrapa considers to be promising for citrus planting in the so-called expanded citrus belt. Besides taking climate risk into account, agricultural planning for planting and producing citrus in new areas must include the use of healthy seedlings produced in a protected environment.

    Recent studies conducted by Fundecitrus and Embrapa funded by Innocent Drinks, a British-based company that produces smoothies and juice, have found that the entire citrus belt holds a stock of approximately 36 million tons of carbon, equivalent to 133.4 million tons of carbon dioxide (CO2). This is the same emitted by the city of São Paulo in around eight years. The absorption of the gas can contribute to reducing the impacts of global warming, according to Embrapa, since the agricultural land functions simultaneously as the source and the drain for carbon, while stabilizing and securing fauna in the citrus farming areas.

    Tree Inventory and Yields

    For MY 2023/24, Post forecasts 1.80 boxes/tree, a decrease of 1.1 percent from the estimate for MY 2022/23 (1.82 boxes/tree) due to the potential negative impacts of greening and El Niño. Total Brazilian tree inventory for MY 2023/24 is forecast by Post at 240 million trees and estimated at 240.5 million trees for MY 2022/23. The decrease is mainly expected in the São Paulo commercial citrus belt.

    The graph from Figure 5 below shows the current yield estimate from Fundecitrus for MY 2022/23, with a total of 1.83 boxes/tree embracing all five regions of the citrus belt. The north stands out as the most productive region, with 2.26 boxes/tree estimated.

    Figure 5

    Yield Estimate in the Brazilian Citrus Belt

    Post forecasts the average fruit weight in the Brazilian citrus belt for MY 2023/24 to be 158 grams, as a result of unfavorable climate and disease impact, with expectations of lower production and fruit quality. Moreover, Post forecasts 258 fruits to fill a 40.8-Kg/90-pound box. Considering all orange varieties, Fundecitrus reports that it is estimated 255 fruits to make up a 40.8-kg box for MY 2022/23 in the citrus belt. For that amount, oranges weight is estimated at 160 grams, in contrast to the previous projection of 165 grams…

    Read the full USDA Foreign Ag Service report HERE.

  • Updates to Bulk Citrus HLB Quarantine Requirements

    Effective Nov. 22, 2023, the Citrus Pest and Disease Prevention Division (CPDPD) has officially updated the requirements for moving bulk citrus fruit within and from a Huanglongbing (HLB) quarantine area to a packer/processor.

    Listed below is an overview of the newly updated requirements, per the CPDPD’s Citrus Grower/Grove Manager Information page:

    • If you are moving bulk citrus within a contiguous HLB quarantine zone, there is now no mitigation required.
      • If you are moving bulk citrus within a contiguous HLB quarantine area, but out of the original ACP regional quarantine zone (i.e., Orange County to Riverside County), one HLB mitigation is required.
    • If you are moving bulk citrus between two non-contiguous HLB quarantine zones (i.e., Riverside County to Ventura County), there is now one HLB mitigation required.
    • If you are moving bulk citrus outside of an HLB quarantine area, but within the same county (i.e., San Diego HLB quarantine zone to San Diego ACP regional quarantine zone), there is one HLB mitigation required.
    • If you are moving bulk citrus fruit to an area outside of the HLB quarantine zone and outside of the origin county (i.e., Ventura HLB quarantine Zone to Kern County), two HLB mitigations or a wet wash are required.All fruit, no matter of its origin or destination, must be completely safeguarded with a tarp or enclosed vehicle while in transit per requirements listed in the compliance agreement. The CPDPD will be signing revised compliance agreements with growers within an HLB quarantine, as well as packers/processors receiving fruit from a quarantined area.For complete information and details regarding the mitigations required for fruit movement, please visit the CPDPD’s Citrus Grower/Grove Manager Information page.For questions regarding citrus fruit movement requirements, please contact your local agricultural commissioner, email Keith Okasaki at Keith.Okasaki@cdfa.ca.gov or call 916-274-6300. — By the California Citrus Pest & Disease Prevention Program

  • Detection of Deadly Citrus Disease Triggers Quarantine in Ventura County; First HLB Detection in County

    The California Department of Food and Agriculture (CDFA) has declared a quarantine in Ventura County following the detection of the citrus disease Huanglongbing (HLB), or citrus greening, in two citrus trees on one residential property in the city of Santa Paula. These detections are the first HLB-positive trees in Ventura County. CDFA is working with the United States Department of Agriculture and the Ventura County Agricultural Commissioner on this cooperative project.

    The disease was detected in plant material taken from one orange and one lime tree in a residential neighborhood in the Santa Paula area of Ventura County. These detections follow the confirmation of a Candidatus Liberibacter asiaticus (CLas)-positive Asian citrus psyllid (ACP) sample taken from the find site.

    CDFA crews will be working to remove and dispose of the infected trees and are conducting a mandatory survey of every property within 250 meters of the detection site. After the survey is complete, all host plants in the 250-meter area around the detection site will be treated to suppress the disease vector, the ACP. By taking these steps, a critical reservoir of the disease and its vectors will be removed, which is essential to protect the surrounding citrus from this deadly disease.

    These detections establish a mandatory five-mile citrus HLB quarantine area around the find site. The quarantine area is bordered on the north by Ojai Road; on the south by E Los Angeles Avenue; on the west by Wells Road; and on the east by Balcom Canyon Road. The quarantine prohibits the sale of all host nursery stock and the movement of all host plants or plant parts within a five-mile radius of the finds. The quarantine applies to residents and commercial operations alike. These detections will also place parts of Ventura County into Bulk Citrus Regional Quarantine Zone 6, which will require any commercial citrus growers to apply an additional mitigation step(s) to move fruit within or from this zone. Production and retail nurseries within the five-mile quarantine are being contacted by CDFA and will be issued a hold notice preventing the sale of nursery stock host plants. Visit CDFA’s Map and Quarantines page for more details.

    Growers in Ventura County should contact Grower Liaisons Sandra Zwaal at szwaal2@gmail.com or Cressida Silvers at cressidasb@gmail.com for additional information about these detections. In response to the HLB detections in Santa Paula, a grower meeting was held on Wednesday, Oct. 4. Stay tuned to Citrus Insider for details or reach out to the Grower Liaisons for more information.

    An HLB quarantine area currently exists in parts of Los Angeles, Orange, Riverside, San Bernardino and San Diego counties, where more than 6,300 residential trees have tested positive for the disease and have been removed. — California 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.

  • Could Stingrays be the Key to Saving Citrus from Deadly HLB Disease?

    Imagine a devastating plant disease that sweeps the land, decimating crops. For Florida’s citrus growers, that apocalyptic vision is not a horror movie, but a reality: since it was first identified in the Sunshine State in 2005, citrus greening disease has reduced Florida’s citrus production by a whopping 70%, and threatened other major citrus producing states such as California and Texas. Without any treatment or cure available, desperate growers have cut down infected trees or abandoned their groves entirely. Scientists have been racing to come up with a solution. Now, one enterprising team believes it may have one, in the form of: stingrays.

    Like other organisms, stingrays have an immune system. Unlike most organisms, however, the rays’ system produces an antibody with a functional domain that is both far smaller and more stable than most. These special antibodies, or nanobodies – termed “mantabodies” by the research team – are specialized proteins that can help other organisms fight off infection. Essentially, the researchers plan to treat the rays as a sort of all-purpose pharmacy, where they can introduce a novel pathogen like the citrus greening bacteria, and the rays will generate an immune response specific to that pathogen. The genetic material (gene) encoding this specifically-targeted antibody can then be placed in modified plant cells that grow as a symbiont – an organism that lives in a close, mutually beneficial relationship with the diseased organism.

    Alternatively, researchers can culture the modified plant cells in large vessels and then harvest the antibodies that the cells produce for inoculation into citrus trees. The resulting antibody therapy would prevent or cure disease development in the trees. The approach could, in theory, be applied to other organisms too, and the researchers plan to use the technology to target pathogens that invade farmed fish, honey bees, and more.

    This project was a 2022 winner of ARSX, an annual competition that asks ARS scientists to propose innovative, high-risk, high-reward ideas that cross disciplines and break boundaries to solve our most pressing challenges.

    A southern stingray, Hypnum americanus, swims along the seabed. (Photo courtesy of Matt Ajemian, Ph.D., director of the Fisheries Ecology and Conservation Lab at FAU-HBOI)

    The project team includes researchers from ARS, the Florida Atlantic University Harbor Branch Oceanographic Institute, in Fort Pierce, FL, and the and U.S. Department of Energy Oak Ridge Institute for Science and Educationin Oak Ridge, TN. Team member and ARS research molecular biologist Michelle Heck is using USDA’s SCINet high performance computing clusters to analyze the stingray genomes, and she is applying a powerful artificial intelligence (AI) approach called AlphaFold to identify the mantabody genes.

    “Using AlphaFold, which was just released two years ago, we can rapidly and accurately predict the shape of all the stingray proteins,” explained Heck, who works at ARS’s Robert W. Holley Center in Ithaca, NY, “And we can find the ones that look most like what we think a mantabody protein should look like.”

    The researchers are also taking advantage of other advances in biotechnology, like the mRNA technique that was used to deliver Covid-19 vaccines. They believe that their project could, in turn, advance biotechnology even farther.

    “You can modify almost anything with an antibody treatment,” said Joseph Krystel, a team member and research biologist at the ARS U.S. Horticultural Research Lab (USHRL) in Fort Pierce, FL. “You could stimulate the immune system of a citrus tree, or you could suppress a particular set of genes if you wanted to. The reason we don’t do it now is that it’s cost-prohibitive. But the mantabody platform could give us a more cost-effective way to do it.”

    It could also provide farmers with more sustainable biological alternatives to many current practices. Robert Shatters, a team member and research molecular biologist at the USHRL, explained that, “Mantabodies could be applied to veterinary aspects of agriculture, and a number of plant pathogen issues. We think this project would have a really broad impact, and that’s why we’re excited about it.” – By Kathryn Markham, USDA-ARS Office of Communications

  • Federal Funding for New Citrus Breeding Program in Parlier, California

    California Citrus Mutual (CCM) and the Citrus Research Board (CRB) welcome more than $1 million in new federal funding for critical research programs that support the U.S. and California citrus industries.

    The 2023 Appropriations bill passed by Congress recently includes continued funding to help stop the deadly citrus plant disease Huanglonging (HLB) that has devastated citrus production in Florida and other parts of the country. Additionally, $1 million in new funding was approved to establish a citrus breeding program at the USDA Agriculture Research Service (ARS) field station in Parlier, California. This funding will be re-appropriated annually.

    Championed by California Senator Alex Padilla and Representatives Jim Costa and David Valadao, the new California citrus breeding program will identify new citrus varieties that are best suited for changing climatic pressures such as drought, consumer taste preferences, and resistant to pests and diseases such as HLB.

    The program is an expansion of the existing national USDA ARS citrus breeding program located in Florida, which is focused primarily on varieties that are optimized for Florida growing conditions. The Florida program has resulted in new varieties with higher yields, increased disease resistance, improved color, and a longer shelf life.

    With such promising advances being made in Florida, CCM and the CRB saw the need for a similar program in California to breed fresh citrus varieties that are better adapted to the unique environmental conditions of California’s production regions.

    The CRB, which is a grower-funded organization aimed at furthering the industry’s research priorities, has committed $500,000 toward establishing the new breeding program in Parlier, with the goal of bringing additional representation to California’s industry.

    “The commitment of the citrus industry to delivering quality research and innovation for all farm use has taken a big step forward with the support of congress funding the citrus breeding program in Parlier,” said Justin Brown, CRB Chairman.

    Marcy L. Martin, CRB President, added, “Expanding the current national citrus breeding program into California will have a significant impact on California’s citrus industry as growers aim to mitigate the evolving issues that affect production and increase yield through varietal research.”

    The Florida and California breeding programs along with the continued efforts of the University of California citrus breeding program at UC Riverside will work together to deliver the best results for California citrus growers.

    “The addition of the breeding facility in Parlier will make the ARS Citrus Program a truly national project,” said CCM President and CEO Casey Creamer. “We look forward to watching the growth of this program and its collaboration with the UC breeding program to find solutions to the issues California citrus growers are faced with every day.”

    Additionally, the 2023 Federal budget includes continued funding for the Citrus Health Response Program, which supplements industry and state funding for on-the-ground efforts aimed at preventing the spread of the HLB and continued funding for the Huanglongbing Multi-Agency Coordination group, which funds research programs aimed at identifying short term solutions to HLB.

    About California Citrus Mutual (CCM)

    CCM is a voluntary, non-profit trade association representing CA citrus growers on the economic, regulatory, and political issues that impact them most.

    About the Citrus Research Board (CRB)

    The CRB administers the California Citrus Research Program, the grower-funded and grower-directed program established in 1968 under the California Marketing Act as the mechanism enabling the State’s citrus producers to sponsor and support needed research. More information about the Citrus Research Board may be found at www.citrusresearch.org.