California Ag Network

Category: Pest/Disease Management

  • Asian Citrus Psyllids Found in Fresno County

    The California Department of Food and Agriculture’s Plant Pest Diagnostic Center (PPDC) has identified two Asian citrus psyllids (ACP) on a glassy-winged sharpshooter trap from a packinghouse in the Orange Cove area of Fresno County. This has been the first time that the ACP has been detected in Fresno County since November 2019.

    Following confirmation of the ACP detections, agricultural staff from the Citrus Pest and Disease Prevention Division (CPDPD) began conducting a survey and subsequently collected additional suspect ACP adults and nymphs from trees on the packinghouse premises, which were sent to the PPDC for identification.

    All residential properties with host plants within 400 meters of the detections in Fresno County will be treated to prevent ACP population spread. Any growers who are located within 800 meters of the detection site will be notified by the Fresno County Grower Liaison Teri Blaser.

    Following an increase in recent ACP detections across the Central Valley, including in Tulare and Kern counties, growers, packers, haulers and all citrus industry members are encouraged to be extra vigilant in their ACP mitigation steps and adherence to regulatory practices.

    Questions?
    Contact your regional grower liaison for the latest information on detections near you and coordinated or area-wide treatment schedules. Find your grower liaison here.

    Citrus Pest & Disease Prevention Program

  • Growers Petition for a Sonoma County Winegrape Pest & Disease Control District

    Over the course of more than 18 months, a group of viticulturists and vineyard owners have been working together to research both the benefits of, and the process for establishing a Winegrape Pest and Disease Control District in Sonoma County. They have engaged in research and discussed an effort with elected and appointed Sonoma County Officials, University of California Cooperative Extension & UC-ANR, Napa County Agricultural Commissioner’s Office, Napa County Winegrape Pest and Disease Control District Board of Directors, State Legislators, and other Pest Control Districts throughout California.

    The California Winegrape Pest and Disease Control District Law enables owners of wine grape acreage within Sonoma County to petition the Sonoma County Board of Supervisors to acknowledge and establish a Wine Grape Pest and Disease Control District. The Sonoma County Winegrape Pest & Disease Control District Coalition is organizing this petition effort for the Sonoma County Board of Supervisors.

    Included is a petition of support and frequently asked questions about the functionality of the Special District. Please take a moment to read through the benefits of such a district, visit https://sonomacountypcd.org, review what Napa’s WGPDCD has been working on for the last 20 years, and give your support in petitioning the Board of Supervisors to allow the formation of one in Sonoma County, which would allow collaboration in ongoing pest control efforts, not only with each other, but with neighboring districts to form area wide protection from harmful pests.

    Coalition member and Grower Relations Manager at Jordan Vineyard & Winery Dana Grande shared, “I have been a part of the group working on this for the last 24 months. A Pest and Disease Control District (PCD) for Sonoma County winegrapes is something that I have thought we needed for a very long time. When I heard about the opportunity to assist in the exploratory committee, I jumped in… Ultimately, the dollars spent will be up to the discretion of the PCD Board, but we envisioned that those funds would be used for local research, augmenting pest monitoring, pest mitigation and exclusion, and mobilization of efforts should an exotic pest be discovered in our County. Our neighbors in Napa County have had a PCD for the last 20 years. We can look to their model to envision what might be funded in Sonoma County.

    Bryon Sheets from Doc’s Ranch Vineyard added, “With all the challenges us growers face, it just makes sense to have this additional community resource to help us fight the important battle against invasive pests.”

    Karina Maher, a grower and doctor in Glen Ellen shared her support of the district as well, quoting Benjamin Franklin, that “An ounce of prevention is worth a pound of cure.” She continued, “As a pediatrician, I know this to be true for human health. Similarly, the time to prevent and recognize wine grape pest and disease infestations is before they get out of control. The Winegrape Pest and Disease Control District in Sonoma County will help do just that. The time is now.”

    Sonoma County growers are invited to Download and sign the petition HERE. “Please return your completed petition to us as soon as possible,” requests Jason Saling, grower and leader of the Sonoma County Winegrape Pest Control District Coalition. ” Your support is appreciated. It is through this effort that winegrowers of Sonoma County can secure and protect their agricultural interests now and into the future.”

    Don’t hesitate to reach out to Jason Saling at 707-328-5290 or SonomaCountyPCD@gmail.com for more information.

    FREQUENTLY ASKED QUESTIONS

    What is a Winegrape Pest & Disease Control District?

    A Pest & Disease Control District (PCD) is a grower funded, grower run Board serving the needs and priorities of the agricultural commodity that funds it.

    How is a PCD funded?

    As defined in the California Food and Ag Code, Section 6200-6290, funding is generated by a minor per planted wine grape acre assessment. The assessment is collected annually by the County Assessor as part of property taxes, and 100% of those funds are placed into a trust account specific for Pest & Disease Control District. The assessment is capped by State law at $5.00 per planted acre of wine grapes.

    Who forms the PCD Board? How do Growers/Owners know where the assessment dollars are spent?

    Wine grape landowners or their duly authorized representatives serve on the PCD Board. Meetings of the Board must comply with the Brown Act. Meetings are open to the public and agendas are posted ahead of the meeting. Agenda and non-agenda items can be addressed by growers at each meeting. Budgets are formed annually and formally presented at Board meetings. Directors, appointed by the Board of Supervisors serve a three-year term. The district is re-authorized by the BOS for 5-year terms.

    Why do we need a PCD now, can’t we wait until we discover a new pest threat in our vineyards?

    No. A PCD serves to manage both established pests, and works to avoid the establishment of new pest threats. A PCD is funded for a cohesive and coordinated system for detection and eradication. Without a PCD, individual expenses could be very high, and isolated eradication efforts may not banish the pest from our industry. Long-term effects could include increased costs for insecticides, increased labor costs for monitoring, establishment of new pest control compliance agreements, organic growers losing certification due to use of non-certifiable insecticides, fruit quality issues, and tarping/monitoring grape loads at harvest.

    A Sonoma County PCD will serve to promote and protect the long-term sustainability of our industry by ensuring that our integrated pest management activity remains resilient, protecting both our agricultural interests and our natural resources.

    How does a Sonoma County Wine Grape PCD add value to my vineyard?

    Over the last 20 years, Sonoma County wine grape growers have seen the introduction and establishment of Vine Mealybug (VMB.) Additionally, Light-Brown Apple Moth (LBAM), Virginia Creeper Leafhopper, Glassy-winged Sharpshooter, and European Grapevine Moth (EGVM) have all threatened the integrity of wine grape production in the County.

    A PCD will ensure that early activities for eradication of an invasive pest will be coordinated and can use funds to ensure that those costs don’t fall squarely on individual landowners.

    The PCD will:

    • – Establish a pool of funding dedicated solely for early detection, monitoring, and mitigation of wine grape pests and diseases

    • – Create an open forum and dedicated grower board to respond to grower / owner input to determine areas of greatest need, focusing on localized research and education/outreach

    • – Coordinate with UCCE / UC ANR, Sonoma County Ag Commissioner to leverage funding and labor resources

    • – Coordinate with neighboring regions, i.e. Napa, Mendocino, Lake, Marin and Solano Counties to extend a buffer zone around Sonoma County’s high value wine growing region

    • – Communicate, coordinate, and cooperate in establishing local research priorities to the UCCE / UCANR

    • – Establish a Board with a County level voice for requesting co-funding as required from Sonoma County BOS, and State and Federal Grant opportunities.

      Does Napa County have a Pest and Disease Control District?

      Yes. On January 4, 2022, the Napa County BOS renewed the NCPCD for its fifth consecutive 5-year term since its inception in 2002, when GWSS was first identified as an impending threat to the industry. The District was in place and ready when European Grapevine Moth was discovered, and quickly mobilized trapping efforts to successfully delimit and restrict the migration, and, within two years, eradicate the pest by working in tandem with and resources provided by the UCCE, Napa County Ag Commissioner, and CDFA.

      Additional examples of work funded by the NCPCD:

    – Vine Mealybug mapping identifying hotspots and published a GIS web map,
    o Public, Grower, and Field worker training and education on VMB,
    o Coordinated mating disruption to decrease insect population, and
    o Funded and Coordinated Anagyrus wasp release to augment biological control;

    – Glassy-Winged Sharpshooter (GWSS) –
    o Supplementing funding to ensure that 100% of nursery shipments are inspected,
    o Increasing trapping and seasonal monitoring now that GWSS is established in Solano County

    – Pest Identification workshops for all manner of pests, new and exotic threats to the industry

    But our Agricultural Commissioner already does plant inspections. Why do we need a PCD?

    The Sonoma County Department of Agriculture administers exclusion programs to keep invasive and injurious pests out of Sonoma County. In 2020, staff inspected 1069 nursery stock shipments for GWSS. Additionally, they deployed trap programs for other invasive insects and those 6531 traps were serviced 52,721 times. As robust as our AC’s programs are, their priorities are directed at specific pest species and ratings as defined by CDFA. As State and County funding for specific pest management/exclusion programs diminishes over time, PCD’s can step in to further fund prevention and monitoring for a wine grape specific pest, disease, or research not addressed by State or County priority.

  • “Cautiously Optimistic” about Leaffooted Bug Lure & Trap

    Almond Board of California — With the rise of leaffooted bug damage showing up in almond kernels at the handler, the bottom line of growers is at stake. Research funded by the Almond Board of California and conducted at UC Riverside, is expanding much needed tools for effective IPM monitoring protocol to combat the pest.

    Across the industry, handlers have seen higher rates of brown spot damage caused by leaffooted bug – and true bugs, such as stink bug – which has led to increased rejection rates.

    Growers are limited to the best monitoring protocols available today, but they can be time and labor intensive, often pointing out damage after it’s too late to act.

    leaffooted bug on Almond (Photo Courtesy of the Almond Board of California)

    A multiyear effort led be UC Riverside Entomology Professor Jocelyn Millar – and funded by the Almond Board of California – has worked to improve the monitoring options for the pest.  

    “You can take beat samples of the crop canopy to look for adults or nymphs, but we’ve never established any kind of treatment threshold for that practice,” said Houston Wilson, assistant cooperative extension specialist in the Department of Entomology at UC Riverside and collaborator on the project. “You can look for signs of feeding damage, which manifests in gummosis, which can also be caused by a number of things.”

    Wilson said growers can cut gummy nuts open to look for evidence of leaffooted bug penetration of the kernel.

    “Identifying gummosis is easier because you can look for the signs, but it’s an artifact – by the time you see it, the leaffooted bug has already damaged the nuts,” Wilson said. “We don’t have a passive sampling system for leaffooted bug, like for navel orangeworm, where a pheromone attracts the insect to a trap,” Wilson said. “What we’re trying to develop is a lure – a pheromone – and a better trap.”

    leaffooted bug damaged nuts (Photo Courtesy of the Almond Board of California)
    First, the pheromone

    Over the past five years, Millar and his team have been isolating and identifying compounds that make up the leafooted bug pheromone. Nine compounds were identified, and the team began work to synthesize each one. Wilson said that some of the compounds were relatively easy to identify, but others were not, “the last pheromone compound we identified was entirely new to science.”

    In the latest project update, Millar noted that this new compound was a relatively small part of the overall pheromone composition but it packed the biggest punch, triggering the strongest responses from the bugs. Over the last two years, Millar’s team has been able to collect enough material to identify the compound and effectively synthesize it.

    Second, the trap

    At the same time as the pheromone work, the team at UC Riverside – and other collaborators such as Cooperative Extension Specialist Kent Daane – began looking at the best trap for the application. They tested multiple styles of traps and colors, ultimately identifying that a hanging cross-vane panel trap coated with a sticky substance – yellow or blue in color – performed the best for trapping leaffooted bug.

    With a fully recreated pheromone and an effective trap, the team ran trap trials in commercial almond, pistachio and pomegranate orchards in the Central Valley. Based on in-field trials, the team concluded that the trap and pheromone were both very effective and will look to the private sector to commercialize the new monitoring system.

    What’s next?

    “We demonstrated in field trials last summer and this spring that the synthetic pheromone blend is highly attractive to females,” Wilson said. “Now we’re looking at what minimal blend of compounds are needed to attract the pest. If we want this to be a commercially viable lure, we have to find the most cost-effective composition. In many cases, it’s not necessarily required to have the full bouquet of compounds in a pheromone blend to have a functional lure.”

    Once the right balance is determined for a synthetic blend that lures leaffooted bugs to a trap the next step is understanding what trap catch means on population density in an orchard. This will define treatment thresholds, giving growers guidance on timing to combat leaffooted bug before damage occurs on kernels. Private industry will likely takeover at this point to develop the traps for the industry. For Wilson, this prospect has him cautiously optimistic.

    “We’re very fired up with this pheromone blend, but I’m also trying not to get ahead of myself before we know what the cost will be for a commercial and scalable lure.”

    More information about best management practices of leaffooted bug is available at the UC Statewide IPM website.

  • CA to Hold Public Workshops on Statewide Pesticide Application Notification System

    The California Department of Pesticide Regulation will hold three public workshops on June 27, 28 and 29 to collect feedback to inform the next phase of design and development for the state’s pesticide application notification system.

    California will be the first state in the nation to develop a statewide system to provide the public more transparent and equitable access to information in advance of pesticide applications.

    The workshops will be hosted online via Zoom and facilitated by the UC Davis Center for Regional Change. Each workshop will follow the same format, including a brief overview of the proposed design for the statewide notification system and an opportunity for the public to provide input. The proposed system design has been informed by broad stakeholder feedback provided in public focus groups and webinars convened by DPR in 2021. The information collected during the workshops will further inform the design of the statewide notification system.

    The workshops will be held at the following times:

    Monday, June 27: 1-3 p.m.
    Tuesday, June 28: 10 a.m.-12 p.m.
    Wednesday, June 29: 6-8 p.m.

    Registration is not required to attend. Spanish interpretation will be provided at all workshops. A copy of materials presented during the workshops will be made available on DPR’s website following the workshops.

    DPR began developing the statewide notification system in mid-2021, after the state budget allocated $10 million to DPR for system development.

    DPR has partnered with four County Agricultural Commissioners to launch pilot projects to inform the department’s development of the statewide system. These county-led pilot projects have launched in communities within Riverside, Stanislaus and Ventura counties. The Santa Cruz community pilot will launch this summer. The UC Davis Center for Regional Change will conduct independent evaluations of the pilot programs.

    For more information and updates on statewide notification, please visit DPR’s website.

    ABOUT THE DEPARTMENT OF PESTICIDE REGULATION

    The California Department of Pesticide Regulation protects human health and the environment by fostering safer and sustainable pest management practices and operating a robust regulatory system to evaluate and register pesticides and monitor and regulate their sale and use across the state.

    DPR’s work includes conducting scientific evaluations of pesticides to assess and mitigate potential harm to human health and the environment prior to and following registration, registering all pesticides prior to sale or use in California, monitoring for pesticides in the air and water, and enforcing pesticide laws and regulations in coordination with 55 County Agricultural Commissioners and their combined 400 field inspectors across the state’s 58 counties. DPR invests in innovative research, outreach, and education to encourage the development and adoption of integrated pest management tools and practices and conducts outreach to ensure pesticide workers, farmworkers and local communities have access to pesticide safety information.

  • Citrus Growers Encouraged to Increase Vigilance Following Recent ACP Detections in Central Valley

    Following recent Asian citrus psyllid (ACP) detections in the Central Valley over the last few weeks, growers, packers, haulers and all citrus industry members are encouraged to be extra vigilant in their ACP mitigation steps and adherence to regulatory practices.

    Recently, multiple ACP were detected on traps at a packinghouse in the Woodlake area of Tulare County. Upon confirmation, visual delimitation surveys began the following day. Live adults or nymphs were found and collected at two more adjacent properties, including an abandoned parcel with citrus host plants. CDFA is working closely with the packinghouse to ensure regulatory compliance. Treatment of host plants on residential properties within 400 meters of the detection will be conducted by CDFA once all necessary notifications, emergency proclamations and public meetings have been held. Commercial citrus operations within 800 meters of the detections will be asked to conduct treatments as well.

    Additionally, one ACP was recently detected on a trap at a juice plant in Visalia, and upon completion of the visual delimitation survey of the find site and adjacent properties, there were no additional finds.

    In Kern County, three ACP trap detections have been identified in the last week. One in the city, and two in rural residential locations in Southwest Bakersfield. These are the first ACP detections found in Kern County since November 2021. CDFA teams have already begun delimitation surveys and treatments will be conducted on residential properties with host plants within a 50-meter area around the detections once proper notifications, emergency proclamations and public meetings have been held. There are no commercial operations for several miles around the Kern County detections.

    These detections are a resounding reminder to continue to follow ACP mitigation best practices and regulatory requirements to efficiently suppress ACP populations and prevent the spread of Huanglongbing to the Central Valley.

     

    If you suspect ACP or Huanglongbing in your orchard, please notify the California Department of Food and Agriculture Pest Hotline at 1-800-491-1899. For questions, contact Kern County Grower Liaison Judy Zaninovich at jsleslie@msn.com, Northern Tulare County Grower Liaison Teri Blaser at tblasersci@ocsnet.net or Southern Tulare County Grower Liaison Jessica Leslie at jess.leslie@hotmail.com.

  • Mating Disruption Research to Combat Spotted Lanternfly Included in CDPR’s $3.75 Million Investment

    The California Department of Pesticide Regulation (DPR) today awarded $3.75 million to fund 10 research projects that explore Integrated Pest Management (IPM) tools for urban, non-agricultural and agricultural pest management. The 2021-2022 DPR Grants Programs funded by the state budget represent a 617% increase from the previous year’s funding to accelerate the transition to safer, more sustainable pest management.

    “The grant projects we are funding today are critical to developing and expanding innovative practices and biological, non-chemical and physical tools to manage pests in agriculture, urban and other non-agricultural communities,” said DPR Director Julie Henderson. “The research will support the state’s work to accelerate a systemwide transition to safer, more sustainable pest management and better protect human health and the environment.”

    DPR’s Research Grants Program funds projects that advance IPM, an approach that uses the least-toxic, effective method to solve pest problems. In the last decade, DPR has awarded $9,702,819 in research grants.

    Research projects funded for agricultural pest management:

    • Investigating a pesticide-free mating disruption approach using vibrational signals to control the spotted lanternfly, which presents particular risk to grapes, hops, apples and stone fruit, along with maple, poplar, walnut and willow trees. Spotted lanternfly is one of the most damaging invasive insects nationwide and has already caused significant harm to crops and landscapes across 11 states. This research will be led by Dr. Rodrigo Krugner at the United States Department of Agriculture – Agricultural Research Service (USDA ARS).

    • Evaluating an IPM approach that will disrupt insect behavior by targeting and interfering with a pest’s biological processes and minimizing possible unintended effects to other organisms. The project will evaluate the use of this tool for controlling diamondback moth and western flower thrips that impact California vegetable crops such as lettuce. This research will be led by Dr. Daniel Hasegawa at USDA ARS.

    • Assessing a biocontrol system for the management of tadpole shrimp in rice. Tadpole shrimp usefully eat some early season weeds but can cause damage to rice later in their lifecycle. To preserve their role in controlling weeds but diminish the shrimp’s later impact on the rice harvest, predator mosquito fish will be introduced mid-season to control the shrimp’s population when necessary. This research will be led by Dr. Ian Grettenberger at UC Davis.

    • Testing two emerging IPM technologies for agricultural use, the automatic release of biocontrol organisms using flying drones, and precision spray application technology, which uses much less pesticide than applying pesticide sprays using current techniques. This research will be led by Dr. Ian Grettenberger at UC Davis.

    • Developing an IPM software decision-making tool for pistachio growers that helps reduce pesticide use by guiding more precise pesticide applications when chemical use is necessary. This IPM tool leverages smart technology to help growers transition from routine preventative spraying to more limited threshold-based chemical use. This research will be led by Dr. Themis Michailides at UC Davis.

    Research projects funded for urban and agriculture pest management:

      • Studying the use of a reduced-risk ”attract-and-kill” approach as an effective alternative to urban and agricultural pesticide spray programs for managing South American palm weevils, a pest that damages date palms in urban and agricultural environments. “Attract-and-kill” strategies use pheromones that attract the target pest to a small amount of pesticide that kills the insect, as opposed to spraying a large quantity of pesticide over an area to control pest populations. This research will be led by Dr. Mark Hoddle at UC Riverside.

      • Studying the impact and potential of using insect growth regulators that target Argentine ants for pest control in urban and agricultural environments. Insect growth regulators are new, safer pest management tools that pose a much lower risk of causing unintended damage to beneficial insects when compared to many traditional insecticides. This research will be led by Dr. Dong-Hwan Choe at UC Riverside.

    Research projects funded for urban and nonagricultural pest management:

    • Testing non-chemical entrapment methods for trapping, monitoring and eliminating bedbugs, a significant public health pest that disproportionately affects low-income Californians. This research will be led by Dr.Catherine Loudon at UC Irvine.

    • Creating a new set of guidelines for effectively identifying and managing biting mites, a common, but poorly understood indoor pest that is often misidentified and incorrectly managed. This research will be led Dr. Andrew Sutherland at UC Agriculture and Natural Resources (UCANR).

    • Assessing a baiting system for detecting western drywood termites to reduce the number of unnecessary fumigation treatments in California homes, especially in Southern California where termites represent a significant pest problem. This system would indicate when active termite infestations have returned and if preventative treatment is needed, greatly decreasing the amount of high-risk pesticide use in homes. This research will be led by Dr. Dong-Hwan Choe at UC Riverside.

      For more information on past recipients of DPR’s Grants Program, please visit DPR’s Grants Program webpage.

      ABOUT THE DEPARTMENT OF PESTICIDE REGULATION

      The California Department of Pesticide Regulation protects human health and the environment by fostering safer and sustainable pest management practices and operating a robust regulatory system to evaluate and register pesticides and monitor and regulate their sale and use across the state.

      DPR’s work includes conducting scientific evaluations of pesticides to assess and mitigate potential harm to human health or the environment prior to and following registration, registering all pesticides prior to sale or use in California, monitoring for pesticides in the air and water, and enforcing pesticide laws and regulations in coordination with 55 County Agricultural Commissioners and their combined 400 field inspectors across the state’s 58 counties. DPR invests in innovative research, outreach, and education to encourage the development and adoption of integrated pest management tools and practices and conducts outreach to ensure pesticide workers, farmworkers and local communities have access to pesticide safety information. More information about DPR.

  • USDA-ARS and Weed Science Society of America Present Weed Science Webinar Series

    The USDA’s Agricultural Research Service (ARS) and Weed Science Society of America (WSSA) today announced the launch of a free webinar series focusing on current research and advancements in managing weeds and invasive plants.

    “ARS scientists have worked in a wide range of agricultural and natural ecosystems that include agronomic and horticultural crops, pastures, forests, rangelands, wetlands and riparian areas,” said Steve Young, USDA-ARS National Program Leader for Weeds and Invasive Pests. “Our scientists have made contributions to discoveries in the newest fields of robotics and genetics as well as the traditional and fundamental subjects of weed-crop competition, physiology, and integration of weed control tactics.”

    By collaborating with WSSA, ARS scientists aim to highlight the important research that has contributed to the development of sustainable practices to control weeds and invasive plants.

    “WSSA is excited to host a series of webinars to highlight the contribution of ARS scientists to our discipline,” said Stanley Culpepper, WSSA president. “Their efforts to advance the knowledge of managing weeds and invasive plants is a crucial component of long-term management success.”

    Presentations will be given by USDA-ARS weed science research experts every Tuesday from 2-3p.m. ET and include an interactive Q&A session:

    Theme I: Tactics

    April 19 – Non-Crop Systems: Advancements in Weed Biocontrol Tools: Melissa Smith, Research Ecologist at the Invasive Plant Research Laboratory in Fort Lauderdale, FL

    April 26 – New Technology for Weed Identification and Control: Steven Mirsky, Research Ecologist at the Sustainable Agricultural Systems Laboratory in Beltsville, MD

    Theme II: Mechanisms 

    May 3 – Role of Plant Physiology in Weed-Crop Competition: Dave Horvath, Research Plant Physiologist at the Sunflower and Plant Biology Research Unit in Fargo, ND

    May 10 – Molecular Basis for Controlling Invasive Plants: Matt Tancos, Research Plant Pathologist at the Foreign Disease-Weed Science Research Unit in Fort Detrick, MD

    May 17 – Addressing Herbicide Resistance with Alternative Chemistries: Scott Baerson, Molecular Biologist at the Natural Products Utilization Research Unit in Oxford, MS

    Theme III: Impacts 

    May 24 – Spread and Distribution of Invasive Plants: John Madsen, Research Biologist at the Invasive Species and Pollinator Health Unit in Albany, CA

    May 31 – Climate Change Effects on Weeds and Management: Dana Blumenthal, Ecologist at the Rangeland Resources & Systems Research Unit in Fort Collins, CO

    June 7 – Restoration for Managing Invasive Plants: Roger Sheley, Ecologist at the Range and Meadow Forage Management Research Unit in Burns, OR

    To attend the webinar, please register in advance. This webinar is open to the public, and WSSA membership is not required.

    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 $17 of economic impact.

  • Aphid ‘honeydew’ May Promote Bacteria that Kill Them

    The word ‘honeydew’ sounds benign, but the sugary waste product of aphids can promote growth of bacteria that are highly virulent to the pests, according to a new study.

    The research takes a step towards understanding how some strains of the bacteria Pseudomonas syringae that live on leaves and are pathogenic to aphids might one day be used to control the pests. Aphids transmit plant viruses when they feed on sap, costing billions of dollars in annual crop damage around the world.

    The paper, “Context Dependent Benefits of Aphids for Bacteria in the Phyllosphere,” published Jan. 12 in The American Naturalist, assessed the virulence of different strains of P. syringae to aphids. The researchers also investigated how well the bacteria survive on leaf surfaces without aphids, and whether bacteria benefited from the presence of aphids.

    “For one of the experiments, we actually took the aphids out of the picture entirely,” said Melanie Smee, the paper’s first author and a postdoctoral researcher in the lab of co-author Tory Hendry, assistant professor of microbiology in the College of Agriculture and Life Sciences.

    “We literally just sprayed fake honeydew on to leaves, and we still saw the same increase for the bacteria [as when aphids were present], so it’s really just the honeydew that’s helping the bacteria,” Smee said.

    In the study, Smee and Hendry identified 21 strains of varying virulence to aphids. They then chose eight of those strains. For each strain, they sprayed bacteria onto plants with aphids and other plants without aphids, to see if the bacteria benefited from the aphids presence. They measured bacterial growth on leaves and found that half of the strains benefited significantly.

    The next step was to try to understand the source of that benefit. They knew the bacteria are consumed and then grow within aphids and then are excreted out, so they wanted to see if passage through the aphids helped bacterial populations thrive. They set up a new experiment, with the aphids suspended above leaves that had been sprayed with bacteria. They fed one set of aphids an artificial diet with bacteria, and another set without bacteria, and the aphids then excreted honeydew onto the leaves below.

    They found it didn’t matter whether aphids were fed bacteria; all the bacteria on the leaves did better in the presence of aphids. It turned out that the honeydew was the only factor that boosted bacterial populations.

    They also found that benefits from honeydew to bacteria were not correlated to strain traits, but they were affected by the initial population densities, such that smaller populations increased more with honeydew, compared with large populations, which increased less.

    More work is needed to determine which P. syringae strains are pathogenic to plants, an important consideration if bacteria are used for pest control. The researchers are also interested in investigating the role of the interaction of bacterial communities.

    The study was funded by the U.S. Department of Agriculture’s National Institute of Food and Agriculture and by Cornell. — By Krishna Ramanujan, Cornell College of Agriculture & Life Sciences

  • Citrus Canker in Nursery Stock Sold to CA, CDFA & USDA Take Action to Identify & Destroy Affected Plants

    Citrus Pest & Disease Prevention Program — The United States Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) has confirmed the presence of citrus canker disease in a nursery in South Carolina. The nursery sells plants to consumers through online sales, including four locations in California since August 2021. Retail nurseries did not receive these plants.

    Citrus canker causes citrus leaves and fruit to drop prematurely, and results in lesions on citrus leaves, stems and fruit. Fruit infected with the bacterium that causes citrus canker (Xanthomonas axonopodis) is safe to eat, but it may not be marketable because of the lesions. The disease affects all citrus varieties. Citrus canker is not harmful to people or animals.

    Together with state partners, APHIS is working to collect and destroy the plants shipped to consumers in 11 states and trace plants that were sold to determine additional locations of potentially infected plants. The states include Alabama, California, Florida, Georgia, Louisiana, Mississippi, Nevada, Oregon, South Carolina, Texas and Washington.

    The California Department of Food and Agriculture (CDFA) was notified that four residential properties throughout the state had ordered citrus nursery stock from the South Carolina nursery. Upon being notified of the recall, CDFA staff successfully verified that one order was not filled, removed and destroyed the recalled trees from two of the three remaining residential properties and is working to connect with the recipients of the final shipment (as of March 9). All additional host plants on these properties were surveyed and sampled for citrus canker disease and submitted for analysis, and delimitation surveys will also be conducted around these locations. These swift actions by APHIS and CDFA are focused on protecting the citrus industry as well as nurseries and other establishments that sell citrus plants wholesale and direct to consumers.

    Currently, citrus canker is found throughout Florida and in limited areas of Louisiana and Texas. APHIS is working with state partners to contain the disease, and federal and state quarantines exist in these states. Additionally, citrus canker was recently confirmed in Alabama, and APHIS is working with state partners to establish a federal quarantine to parallel the state quarantine.

    If you live in one of the 11 states and bought citrus plants online that came from South Carolina between Aug. 5, 2021 – Feb. 17, 2022, please keep your plants for now. If you purchased a plant or plants that might be infected, APHIS and/or state officials will contact you in the next several days to collect and properly dispose of any plants purchased from the nursery. You can also call your local USDA office with additional questions. Contact information can be found at www.aphis.usda.gov/planthealth/sphd.

    To learn more about APHIS’ regulations for citrus canker, please visit https://www.aphis.usda.gov/aphis/ourfocus/planthealth/plant-pest-and-disease-programs/pests-and-diseases/citrus/citrus-canker.

    For questions about citrus canker in California or other pests or diseases, please call CDFA’s toll-free Pest Hotline at 1-800-491-1899.

  • Fresno County Vacancy on Citrus Pest & Disease Prevention Committee

    The California Department of Food and Agriculture is announcing one vacancy on the Citrus Pest and Disease Prevention Committee. The Committee advises the CDFA Secretary on activities associated with the statewide citrus specific pest and disease work plan that includes, but is not limited to, outreach and education programs and programs for surveying, detecting, analyzing, and treating pests and diseases specific to citrus.

    The members receive no compensation but are entitled to payment of the necessary travel expenses in accordance with the rules of the Department of Personnel Administration.

    The Committee member vacancy exists for one grower representative from Fresno County, the member term expires on September 30, 2022. Applicants should have an interest in agriculture and citrus pest and disease prevention.

    Individuals interested in being considered for a committee appointment should send a brief resume by March 31, 2022 to the California Department of Food and Agriculture, Citrus Pest and Disease Prevention Division, 1220 N Street, Sacramento, California 95814, Attention: David Gutierrez.

    For additional information, contact: David Gutierrez, Branch Chief, Citrus Pest and Disease Prevention Division at (916) 274-6300, or e-mail David.Gutierrez@cdfa.ca.gov.