California Ag Network

Tag: ACP

  • To all San Joaquin Valley Citrus Growers

    The ACP/HLB San Joaquin Valley Task Force called a meeting on October 8, 2020 due to the increased number of ACP trap finds in the southern part of Kern County. In the last month (September and into October), there

    have been a total of 35 ACP trap finds in the areas of the south part of Bakersfield, Arvin, Lamont, Mettler, and Maricopa. There were 15 residential and 20 commercial citrus sticky trap finds. While there have been finds in

    some of these areas in the past, the amount of detections in this last 30-day period is alarming. The Asian citrus psyllid, as a reminder, transmits Huanglongbing; the best way to avoid HLB is to control ACP which the valley has been successfully doing. 2020 has been a suspiciously quiet year for ACP finds but now, it is time to act.

    We are now in the late part of the season where most spray programs have already been executed. A coordinated spray is not recommended at this time. Kern County growers are encouraged to use an ACP effective material if they have not done so in the last six weeks. It is prudent for all growers to use ACP effective materials when treating other pests. Regarding the residential finds, CDFA is at various stages of treating them. Prior to these finds, CDFA had released Tamarixia radiata in certain residential areas of Kern County. Future Tamarixia releases are scheduled.

    The task force wants to convey the seriousness of what is being seen and what it means to our industry. Unfortunately, the suspicion is that these finds in commercial citrus are spilling over from residential properties. It is up to the citrus industry to deal with this threat. San Joaquin Valley citrus growers have done a good job using ACP effective materials when treating. The cooperation shown by growers during coordinated treatments reflects their commitment to keeping ACP suppressed. Nevertheless, task force members wished to highlight what should be done to help control the Asian citrus psyllid here in the valley.

    It is even more imperative to control the psyllid due to the find of a CLas positive ACP in commercial citrus down in the Riverside area. That was a wake-up call. We cannot, as an industry and in good conscience, dismiss that find. Growers and Pest Control Advisors need to be diligent. The following best practices must be a part of the regime tending to citrus groves.

    What do Growers and Pest Control Advisors need to do? It is easy to say, “follow the best practices”, but there are key elements that the task force believes is important. All the guidelines should be adhered to, but these are the key elements:

    A. Know When and Where Asian citrus psyllids might be present.
    – flush is what attracts the psyllid. Nice, tender leaves and stems. Like candy to an ACP.
    – citrus varieties matter. Lemons flush constantly. Grapefruit, oranges, and mandarins will have fewer flush cycles.
    – know when flushes occur. Spring, late summer for established trees. Younger trees have extensive, prolonged flush. Topping and hedging will produce flush. Spraying with kaolin stimulates flush also.

    – temperature determines how long a flush will last. Hot temps lead to quick hardening of the plant growth. Cooler temps prolong flush.

    1. Scout for Asian citrus psyllids (Yellow sticky traps are a passive method to determine presence of ACP).

      – use both visual and tap surveying.
      – survey along the borders, psyllids tend to not go deeper into groves unless the population is high (they do not like each other very much). If very wide plantings or very wide wind machine rows exist, then check along them too. Younger trees and shorter trees will allow the psyllids to travel farther into the grove.
      – do more frequent surveys during flush. Monthly surveys work when the vegetation is hardened off, unless the trees are close to a find, then sampling frequency should increase.

    2. Be aware of inadvertently transporting ACP.
      – clean equipment used before moving to the next property. Applies to anyone working in a grove; especially picking crews, trimming crews, irrigators, Pest Control Advisors, and the growers themselves.
      – check clothing and vehicles for insect hitchhikers. Shake out hats, bags, clothing. Sweep down vehicles.
      – do not park vehicles in the rows, park outside of the grove.

    3. If possible, use ACP effective materials when treating other pests, following label instructions.

    4. Follow the requirements when moving bulk harvested citrus.

    5. Be aware of developments!
      – receive newsletters from San Joaquin Valley Grower Liaisons.

    Fresno County Northern Tulare County Southern Tulare County Kern County

    – subscribe to industry publications.

    Sylvie Robillard Teri Blaser Jessica Leslie Judy Zaninovich

    FresnoACP@yahoo.com TBlaserSCI@ocsnet.net jess.leslie@hotmail.com jleslie@msn.com

    These were felt to be the most important points of the voluntary best practices. The ACP/HLB San Joaquin Valley Tack Force felt it was important to write this letter to all the valley citrus growers because as of this moment, the valley has not discovered a CLas positive Asian citrus psyllid or a CLas positive tree. The members of the task force believe that the industry must operate under the assumption that there are positive psyllids and trees in the valley; they just have not been found yet. If the industry relaxes its vigilance that is when Huanglongbing will become established and cause havoc. Thank you for taking the time to read this and may each and all stay safe and well.

    Sincerely,

    The ACP/HLB San Joaquin Valley Task Force 

  • CLas-positive Asian Citrus Psyllid Found in Riverside Commercial Grove

    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 Woodcrest area of Riverside County. Confirmed by Citrus Research Board’s Jerry Dimitman Laboratory, this single adult psyllid is the first CLas-positive ACP found in a commercial citrus grove in California.

    While a positive ACP detection in a commercial grove is cause for serious concern, as of today, HLB has not been detected in any California commercial groves. That said, it is more crucial than ever that we stop the disease from spreading by eradicating the Asian citrus psyllid in commercial groves. The cost to manage the Asian citrus psyllid is far less than any potential costs or loss to the industry should HLB take hold throughout our state.

    An expansion of the HLB quarantine zone will not be established as a result of the CLas-positive ACP detection and CDFA staff is swiftly conducting surveys and collecting samples per the ACP/HLB Action Plan  from the perimeter of all commercial groves and all 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 to apply insecticides to all HLB host material within the designated area with materials recommended by the University of California (UC).

    Currently, the best way to stop the disease from spreading is to stop the ACP. To stop the ACP, 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 pest and disease. All growers, packers and haulers must comply with all California Department of Food and Agriculture, county and federal regulations, including quarantines.

    Growers in Riverside County may contact 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 hotline. – By the Citrus Pest & Disease Prevention Program

  • Best Practices Video for Field Crew During Citrus Harvest for Pest/Disease Prevention

    To provide industry members, including field crews, with best practices to prevent the spread of the Asian citrus psyllid (ACP) in California’s citrus groves, the Citrus Pest & Disease Prevention Program has developed a mobile-friendly, Spanish-language field crew training video that can be used by field crew supervisors and farm labor contractors prior to harvest.
     
    This video, which stems directly from our in-person train-the-trainer workshops, provides an overview of best practices for field crews to prevent Huanglongbing (HLB) from threatening the California citrus industry’s livelihood and infecting commercial groves.
     

    A direct, downloadable version of this video is available here.

    We all must do our part if we’re going to protect California citrus from this disease – and field crews are at the forefront. For additional resources and videos, please visit CitrusInsider.org/Resources.

  • CA Detections of Citrus Disease HLB up 160 Percent

    HLB infected Tree

    Stakes at All-Time High for Backyard & Commercial Trees in 2019

    Detections of Huanglongbing (HLB), an incurable plant disease that kills citrus trees, increased by 160 percent in 2018 compared to the previous year, signaling the growing threat to the state’s iconic citrus trees, landscape and economy.

    HLB is spread by a small pest called the Asian citrus psyllid as it feeds on citrus tree leaves. The disease is not dangerous to humans or pets, but it is fatal for citrus trees and has no cure. Once a tree is confirmed with the disease, it must be removed from the property in order to protect neighboring citrus trees.

    The disease was first discovered in California in 2012 in Hacienda Heights. HLB was detected in 269 trees in 2017 and 699 trees in 2018, with a majority of these occurring in Los Angeles and Orange counties. The disease has not yet been detected in a California commercial grove.

    HLB has devastated commercial citrus production in Florida. Over the course of 10 years, Florida’s commercial citrus industry lost $7.8 billion in revenue, 162,200 citrus acres and more than 7,500 jobs due to HLB. Should the disease spread from backyard trees in Southern California to nearby commercial citrus groves, the livelihood of California’s citrus production could impact about 3,900 farmers and 292,000 acres of citrus production in the state. Commercially grown citrus contributes $7 billion in economic impact to the state and employs more than 22,000 individuals.

    “The livelihood of California’s commercial citrus industry and the generations of families it supports is at risk because of HLB,” said Jim Gorden, a citrus grower in the San Joaquin Valley and chair of the Citrus Pest & Disease Prevention Committee. “We are at a crossroads, and we must all work together to do what is necessary to protect our citrus.”

    Asian Citrus Psyllid Adults

    The California Department of Food and Agriculture (CDFA) has established quarantines throughout the state that limit the transport of citrus across state and international lines, and between areas where the psyllid and disease have been found. Additionally, CDFA has agriculture crews canvasing the state to inspect backyard citrus trees for the Asian citrus psyllid and HLB.

    “The Department is committed to our partnership with California’s commercial citrus industry and residential citrus growers to fight HLB,” said Victoria Hornbaker, interim director of the citrus program at CDFA. “With more than half of California residences estimated to have a citrus tree on their property, and California citrus production supporting billions of dollars in our state’s economy, we all play an instrumental role in protecting our citrus.”

    California residents play an important role in protecting the state’s citrus trees. Residents should: 

    • Proactively inspect their citrus trees for the Asian citrus psyllid and HLB monthly, and whenever watering, spraying, pruning or tending trees.
      • Adult Asian citrus psyllids are brown, about one-eighth of an inch long, and feed with their body at a 45-degree angle on citrus leaves.
      • Symptoms of HLB include blotchy and yellowing leaves, premature and excessive fruit drop, lopsided fruit, and bitter, inedible fruit.
    • Call the state’s pest hotline at 800-491-1899 if the pest or disease is spotted.
    • Cooperate with agriculture officials who may ask to inspect or treat their citrus tree.
    • As part of tree maintenance, visit a local nursery or garden center to get advice on products that can help protect citrus trees.
    • When pruning citrus trees, be sure to dry out citrus clippings or double bag them before removing the plant material from the property.
    • Refrain from moving citrus plants, foliage or fruit as doing this may unknowingly spread the pest.

    More information and photos of Asian citrus psyllids and HLB symptoms are available at CaliforniaCitrusThreat.org.

  • Research Reveals a New Direction for Halting the Citrus Greening Epidemic

    Ithaca, New York, (April 2, 2018) – New clues to how the bacteria associated with citrus greening infect the only insect that carries them could lead to a way to block the microbes’ spread from tree to tree, according to a study in Infection and Immunity by Agricultural Research Service (ARS) and Boyce Thompson Institute (BTI) scientists.

    Citrus greening, also known as “huanglongbing,” is a serious disease dramatically affecting citrus production across the world. Trees with this disease all die after only a few years. Citrus greening has been detected in every citrus-producing county in Florida, throughout the southern citrus growing states and in isolated spots in southern California. There is no effective prevention or cure.

    The disease is associated with the bacterium Candidatus Liberibacter asiaticus, CLas for short, which is spread from tree to tree only by a tiny insect vector—the Asian citrus psyllid. If CLas cannot infect the psyllid, its ability to spread citrus greening is halted.

    With the long-term goal of disrupting this CLas-Asian citrus psyllid interaction, research molecular biologist and BTI professor Michelle Heck, with the ARS Emerging Pests and Pathogens Research Laboratory, and BTI researcher Marina Mann focused on an important point: not all psyllids spread CLas equally well.

    To be spread by the Asian citrus psyllid (ACP) effectively, the bacteria must pass through the cells lining the insect’s gut and multiply. Scientists in Heck’s lab had previously shown that the gut cells of adult ACP show severe stress responses when infected by CLas. The cell nuclei become fragmented, and some cells react to the point of dying, allowing the bacteria to move out of the psyllid and into the tree.

    Now, the researchers have found that, unlike adult psyllids, young psyllid nymphs appear to be resistant to the effects of exposure to CLas, and their nuclei rarely reach the same level of disruption. This means CLas cannot enter psyllid gut cells to multiply.

    The next step will be to identify the mechanism for this resistance in the nymphs so that it might be manipulated to also halt the spread of CLas by the adults. An important clue lies in how psyllid nymphs interact with symbiotic bacteria in their gut, especially Wolbachia pipientis.

    Many insects are hosts for Wolbachia and often depend on these bacteria for important benefits—much like how human health depends on gut bacteria. In their study, Mann and Heck showed that in psyllid nymphs, Wolbachia and CLas are commonly found within the same cells.

    The authors hypothesize that, in accommodating the beneficial bacteria, the nymphs also let in more CLas. This is supported by their finding that CLas levels in psyllid nymphs are strongly correlated with Wolbachia levels. Though this link remains to be tested directly, understanding its mechanism could yield an important target for disrupting CLas-psyllid interaction.

    “CLas exploits the way nymph and adult psyllids differ in their guts to gain entry into its insect vector,” Heck said. “We may be able to use this new foothold in our understanding to develop ways to block transmission by insects in the citrus grove.”

    If this works, “citrus growers will be in a much better situation in terms of disease control and saving the U.S. citrus industry,” said Dan Dreyer, Chairman of the California Citrus Research Board, which funds this and other research aimed at developing a management strategy for citrus greening.

    “There are still many unanswered questions about CLas, how it is acquired and transmitted via the Asian citrus psyllid, and how it causes the disease,” continued Dreyer. “The more we learn about CLas and its vector, the closer we will get to moving citrus production past the threat of citrus greening.”

    The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $20 of economic impact.

  • California Citrus Nursery Society 2017 Annual Meeting Rec

    Temecula, Calif., (November 29, 2017) – The 2017 California Citrus Nursery Society (CCNS) annual meeting was held at the Embassy Suites in Temecula, CA on November 2, 2017. CRB Associate Research Scientist, Dr. Mojtaba Mohammadi and CRB Director of Communications, Carolina Evangelo attended the meeting which was led by CCNS Executive Director, Tom Delfino. The meeting featured talks from the following speakers:

    • Bob Atkins,of the California Pest and Disease Prevention Program (CPDPP), provided an update on program outreach efforts.
    • Dan Willey, of com, delivered a proposal on how to improve quarantine labeling.
    • Chandrika Ramadugu,of UC Riverside, gave a presentation on HLB resistant rootstocks.
    • Kelsey Schall, of the Hoddle Lab at UC Riverside, discussed how better Argentine ant control in citrus groves can result in improved ACP control by Tamarixia radiata, a parasitic wasp.
    • Frank Byrne, of UC Riverside, gave an update on ACP management in retail nursery stocks through neonicotinoid use.

    A Panel Discussion on the effects of the new HLB Quarantine Zone on UC Riverside was a highlight of the meeting. Panel participants included Dr. Tracy Kahn, Dr. Peggy Mauk, Dr. MaryLou Polek, Dr. Mike Roose and Dr. Georgios Vidalakis.

    The meeting concluded with a banquet and speech by Dr. Mike Roose highlighting the genetic relationships between citrus species.

    On Friday, November 3, a group of meeting attendees headed to UC Riverside where Dr. MaryLou Polek, led a tour of the USDA-ARS National Clonal Germplasm Repository for Citrus & Dates. Drs. Tracy Kahn and Mike Roose followed up with a tour of the Citrus Variety Collection (CVC) at UC Riverside. Dr. Chandrika Ramadugu led participants on a tour of ongoing field trials evaluating the horticultural traits of hybrid citrus trees developed for HLB resistance. After lunch, participants traveled to the Citrus Clonal Protection Program’s Rubidoux facility in Riverside.  Dr. Georgios Vidalakis, the CCPP director, gave a presentation on the history of CCPP including its mission and ongoing research activities.

  • Karen Ross To Headline California Citrus Conference

    Visalia, Calif., (October 10, 2017) – The California Citrus Conference, scheduled for October 11, will feature California Department of Food and Agriculture (CDFA) Secretary Karen Ross as its keynote speaker.

    All those associated with the California citrus industry are invited to attend the free one-day event of presentations and demonstrations sponsored by the Citrus Research Board (CRB) at the Wyndham Hotel in Visalia, California. The conference will share the “best of the best” in research developments, according to CRB President Gary Schulz, and will emphasize work being done to combat huanglongbing (HLB).

    “HLB, which has decimated the citrus industry in other growing regions throughout the world, has now been found in over 150 residential trees in California,” said Schulz. “Secretary Ross will convey to growers that the CDFA understands the urgency of finding a cure for this devastating disease and stands foursquare behind the CRB’s wide-reaching research efforts.”

    “This disease is fatal to citrus trees,” Ross said. “It has no cure, so the solution must come from research – research that is already well underway, thanks to foresight and funding from growers and our state and federal leaders.”

    Ross has served as CDFA Secretary for nearly seven years. She previously was chief of staff for U.S. Agriculture Secretary Tom Vilsack and also had been president of the California Association of Winegrape Growers and vice-president of the Agricultural Council of California. Under her stewardship, the CDFA has worked diligently to track, contain and slow the spread of Asian citrus psyllids (ACP) and HLB by setting traps, treating trees in infested areas and removing HLB-positive trees.

    Other featured topics and speakers at the conference will include:

    • “The Very Latest in ACP and HLB Treatment Strategies and Detection Challenges” presented by Beth Grafton-Cardwell, Ph.D., director of the Lindcove Research and Extension Center and research entomologist, University of California, Riverside, and Carla Thomas, plant pathologist and epidemiologist, University of California, Davis.
    • “Exploration and Exploitation of the Microbial Communities That Associate with Citrus Trees” presented by Johan Leveau, Ph.D., professor of plant pathology, University of California, Davis.
    • “Improving Nitrogen Management of Citrus” presented by Steve Petrie, Ph.D., of Yara North America Inc.
    • “Being Active Is Not Being Bold” presented by Joel Nelsen, president of California Citrus Mutual.
    • “An Update from the Citrus Pest and Disease Prevention Committee (CPDPC)” presented by Nick Hill, CPDPC chairman.
    • “Priority Post-Harvest Research to Control Insect Pests of California Citrus” presented by Spencer Walse, Ph.D., research chemist with the U.S. Department of Agriculture (USDA)-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center.
    • “Panel Discussion: Biological Control Program for Asian Citrus Psyllid in California and Arizona” presented by Greg Simmons, Ph.D., entomologist with USDA-Animal and Plant Health Inspection Service, David Morgan, Ph.D., biocontrol specialist with CDFA and Richard Stouthamer, Ph.D., entomologist with the University of California, Riverside.
    • “Citrus Breeding for California: New Tools to Meet the Challenge of HLB” presented by Mikeal Roose, Ph.D., professor of genetics at the University of California, Riverside.
    • “Streamlining the Introduction of Citrus Varieties from HLB-infested Areas into California. A Case Study – Florida” presented by Georgios Vidalakis, Ph.D., professor and UC extension specialist in plant pathology, University of California, Riverside and director of the Citrus Clonal Protection Program.

    The event also will feature scientific poster presentations, networking opportunities and continuing education units, which have been approved by the Department of Pesticide Regulation.

    A complimentary breakfast buffet will be served from 6:30-9:00 a.m. Morning conference sessions are scheduled from 9:00 a.m.-noon, and will be highlighted by the keynote address from Secretary Ross. Following a free luncheon, afternoon sessions will run from 1:15-5:00 p.m.

    To register or request additional details, contact the CRB on line at www.citrusresearch.org  or by phone at 559.738.0246.

    Additionally, a special session, “Train the Trainer: Best Practices for Citrus Field Crews to Prevent the Spread of ACP/HLB” will be conducted in Spanish only from 7:00-9:00 a.m. Pre-registration for this seminar is required through www.citrusinsider.org or by phone at 559-592-3790.