California Fruit and Vegetable

Category: Pest/Disease Management

  • Adding ACP-Effective Materials to Suppress Kern County HLB Vectoring Pest in Citrus

    ACP/HLB San Joaquin Valley Task Force – To Citrus Growers in the Kern County area: last fall and early this year, there has been a significant number of Asian citrus psyllid (ACP) trap detections (over 100) in Kern County. The detections occurred in residential properties, as well as commercial citrus areas in Kern County – especially the City of Bakersfield and areas south and east of it. Unfortunately, in addition to the trap detections, live breeding populations of ACP were discovered by CDFA survey crews in both residential and commercial citrus. Although these detection areas were treated, there is significant concern low level ACP populations may still exist undetected and left to build on the new spring flush. It is imperative for us to continue our efforts to protect Kern County citrus from the devastating effects of Huanglongbing (HLB) – especially in light of the significant level of HLB-positive citrus trees found just south in Los Angeles, Orange, San Bernardino and Riverside counties. An established population of ACP increases the threat of HLB but will also cause the need for additional insecticide treatments to try to suppress the population. Additionally, if HLB is detected and confirmed by CDFA, critical regulatory changes may affect everyone. Given the posed risks, it is important the San Joaquin Valley keep ACP populations as close to eradicated as possible.

    The San Joaquin Valley ACP/HLB Area-Wide Task Force has been tracking and analyzing all ACP detections to date in Kern County. After recent review of the data, the Task Force strongly recommends growers add an ACP-effective material to their pre-bloom or spring foliar treatments – the sooner, the better since ACP build populations on the young leaf flush.  Fortunately, this timing coincides with pre-bloom treatments and treatments for katydid, worms, thrips and other pests.  See below for material examples from the University of California.

    IMPORTANT: If there is any open bloom in the orchard, state bloom regulations and pesticide label pollinator protections must be followed.  Contact the Kern County Agricultural Commissioner’s Office for details at (661) 868-6300.

    WHAT WE NEED YOU TO DO:

    1. Consider treating ALL your citrus blocks in Kern County, especially if they are located east and south of Bakersfield – including non-bearing trees and blocks not normally treated at this time.
    1. Use an ACP-effective insecticide next time you are treating the block. The sooner, the better – click on the link below for a list of ACP-effective insecticides from the University of California: Asian Citrus Psyllid / Citrus / Agriculture: Pest Management Guidelines / UC Statewide IPM Program (UC IPM) (ucanr.edu)

    Examples of ACP-effective materials which also suppress Katydids (from the UCIPM Guidelines):

    • Danitol
    • Baythroid
    • Mustang
    • Micromite
    • Entrust

    Examples of ACP-effective materials that can be used during the bloom period – some with restrictions (ALWAYS check the pesticide label and state bloom regulations prior to use):

    • Sivanto
    • Sefina
    • Micromite
    • Beleaf
    • Fujimite
    • ** = Restricted use to only 1 hour after sunset until 5 hours before sunrise.
    • **Delegate
    • **Entrust
    • **Exirel
    1. Suggested Dilution – 100 to 300 g.p.a. for airblast sprayers. FYI – many nutritional products are compatible with ACP insecticides however you should always check with your PCA before tank mixing.
    1. Please treat the borders of the block first, if possible, since ACP tend to populate block borders first. This way ACP will be driven toward the center of the block where they will get treated instead of away from the block and miss treatment.

    By adding an ACP-effective material to your spring foliar treatment, we will greatly lower both the ACP population and the risk of HLB being transmitted into our trees. Please let me know if you have any questions or concerns regarding this important effort by the SJV ACP/HLB Area-Wide Task Force.

    Sincerely,
    The ACP/HLB San Joaquin Valley Task Force

    For additional information on Kern County operations, please contact:
    Judy Zaninovich
    ACP/HLB Grower Liaison for Kern County
    (559) 730-8691
    jsleslie@msn.com

  • Late-season Thrips Management in Lettuce

    Effective control of western flower thrips (WFT) to prevent cosmetic scarring and contamination is important in spring lettuce crops, and now that INSV has been found infecting plants in Yuma lettuce, management becomes even more important.  For most of the growing season, WFT numbers have been below average based on sticky trap counts, field reports and population densities here at YAC. However, in the past few weeks WFT populations have increased in most growing areas. This is not surprising as we typically observe “bioconcentration” of WFT during March and April on late lettuce as surrounding produce acreage declines. Each time a lettuce field is harvested, and disked, adult thrips disperse from these areas into the next available lettuce field.  As the number of lettuce acres becomes reduced near the end of the season, this creates a bottleneck effect that concentrates high numbers of thrips adults on the remaining fields under production. This can often make chemical control of WFT very difficult, particularly in March, as adults can continually re-infest fields following spray applications.   So, what management approaches can you take to manage thrips and hopefully reduce the potential incidence of INSV.  The first line of defense should be sanitation. Growers should disc under produce crops immediately following harvest. The longer a harvested crop remains above ground, the more insects that can build up and move to adjacent lettuce fields, especially with the dry, windy, and warm weather we typically have in March.   If only light INSV incidence is present in pre-harvest fields, PCAs should consider rogueing and removing suspect plants from the field.  Ultimately, this may curb secondary infection within the field. 

    Controlling WFT with insecticides is the best approach to minimizing cosmetic feeding damage and may reduce spread of INSV within fields. For adults, which can easily be found on the leaf surface, your best choices of insecticide are methomyl (Lannate) or acephate at a high label rate.  They are the most efficacious products against adult WFT. Radiant is not as consistently efficacious against adults, but a 7 oz or higher rate will provide the best knockdown and residual control of WFT larvae.  Remember, the key to preventing cosmetic damage by WFT is to maintain larval populations at low levels.  The cryptic or thigmotactic behavior of thrips often makes them difficult to find on lettuce plants. Research has shown that if you can see a few adults and larvae on the plant, it means that there are likely 10-fold more thrips actually on the plant (hiding near the base of the plant between midribs).  This behavior also means that spray coverage is important, particularly with contact insecticides like Lannate. There are other insecticides such as Torac, Minecto Pro, Exirel, Movento and Assail that can provide suppression (50% control or less) against WFT larvae, but don’t expect much activity against adults. For more information on the identification, biology, ecology, and management of thrips on desert produce please visit Western Flower Thrips Management on Desert Produce. — By John Palumbo, University of Arizona Extension

  • Controlling Important Pests in Organic Strawberry Production

    A new study published in the journal Pest Management Science showed that semiochemicals can effectively manage one of the most economically damaging pests in organic strawberry production, the lygus bug (Lygus spp.). Semiochemicals are organic compounds that send signals to insects that alter their behavior, used either to attract them or repel them and can act as an alternative to insecticidal sprays.  In this study, the researchers simultaneously used a female sex pheromone in combination with phenylacetaldehyde to attract the lygus bugs away from the strawberry crops, and another semiochemical, hexyl butyrate that repels the lygus bug away from strawberry crops. They measured the abundance of lygus and the amount of lygus damage in treated and untreated strawberry field under either organic or conventional management. While the semiochemicals were effective under both management regimes, they were especially helpful in the organic strawberry fields. Organic strawberry fields treated with the semiochemicals had 80% fewer lygus bugs and a 50% reduction of lygus damage. These results suggest that semiochemicals used in combination as repellents and attraction agents to draw lygus away from crops can be an effective measure of pest control without the use of insecticides. — The Organic Center

  • CA Citrus Mutual Joins Group to Speed CA’s Shift to Safer Pest Management

    Yesterday, the California Department of Pesticide Regulation and California Department of Food and Agriculture launched a broad new work group to accelerate the systemwide adoption of safer, sustainable pest control practices.

    The 25-member Sustainable Pest Management Work Group includes farmers, community members, university researchers and representatives from commodity groups and the pesticide industry. They are charged with identifying pathways to minimize the use of toxic pesticides and expand the use of integrated pest management practices; better protect public and environmental health; and engage, educate and promote collaboration to achieve these goals.

     “Transitioning away from toxic pesticides requires us to speed up the development of effective alternatives,” said CalEPA Secretary Jared Blumenfeld. “By giving our farmers a suite of integrated pest management tools, we can better protect farmworkers and some of California’s most vulnerable communities. This dynamic task force will give us the roadmap to achieve this bold vision.”

    “California agriculture is recognized not only for its quality and quantity, but also for the sustainable, innovative, forward-thinking way it is grown,” said CDFA Secretary Karen Ross. “Our farmers have been leaders in adopting integrated pest management and partnering with universities and technical assistance providers to meet our high standards for food, environmental and worker safety. This work group represents a broad array of perspectives to inform the next decade of research and development investment and new partnerships to continue the production of nutritious, delicious food and high quality agricultural products with the least impact to our surrounding communities.” 

    Funded in last year’s budget, the group’s work will build upon the recommendations of the Alternatives to Chlorpyrifos Work Group whose 2020 report identified alternatives to the hazardous insecticide and outlined actions to further support agriculture and the health of local communities, farmworkers and the environment. A new status update details additional actions DPR has taken based on the 2020 report, and how DPR and CDFA are working together to provide additional funding to the University of California and California State University to expand integrated pest management research and education. California prohibited virtually all uses of chlorpyrifos as of Dec. 31, 2020.

    The Sustainable Pest Management Work Group is part of the State’s larger commitment to accelerating the transition away from hazardous pesticides. To support the move, Governor Newsom is proposing to fund additional support for the transition by replacing the current flat-fee mill assessment on pesticide sales with a new risk-based tiered mill assessment, where higher toxicity pesticides are assessed a higher fee.

    The members of the Sustainable Pest Management Work Group include:

     

    1. Jenny Broome, Driscoll’s
    2. Don Cameron, Terranova Ranch
    3. Casey Creamer, California Citrus Mutual
    4. Jim Farrar, UC Integrated Pest Management (IPM)
    5. Chris Geiger, City of San Francisco
    6. Kim Harley, UC Berkeley
    7. Lisa Herbert, Sutter County Agricultural Commissioner
    8. Nina Ichikawa, Berkeley Food Institute
    9. Dan Kaiser, Environmental Defense Fund
    10. Susan Kegley, Pesticide Research Institute
    11. Margaret Lloyd, UC Extension – small farm advisor
    12. Suguet Lopez, Líderes Campesinas
    13. Gabriele Ludwig, Almond Board of California
    14. Pam Marrone, Chestnut Bio Advisors, Formerly Marrone Bio Innovations
    15. Nayamin Martinez, Central California Environmental Justice Network
    16. John McKeon, Taylor Farms
    17. Cliff Ohmart, Pest Control Advisor (PCA)
    18. Scott Park, Park Farms
    19. Margaret Reeves, Pesticide Action Network
    20. Taylor Roschen, California Farm Bureau
    21. Sarah Ryan, Environmental Director Big Valley Band of Pomo Indians
    22. Daniel Sonke, Campbell Soup Company
    23. Paul Walgenbach, Bayer
    24. Ron Whitehurst, Pest Control Advisor (PCA)
    25. Houston Wilson, UC Organic Agriculture Institute

  • How to Prevent Crown Gall in the Orchard



    Keep getting crown gall in the orchard? Watch this brief interview with Kern County Area Orchard Systems Advisor Mohammad Yaghmour as shares a few simple steps on how to effectively prevent this detrimental infection.  Read more in Pacific Nut Producer and California Fresh Fruit Magazines.
    Please thank this video’s sponsor Trece for their industry support.

  • Novel Treatment Causes Killer Citrus Disease to Leak & Die

    New research affirms a unique peptide found in an Australian plant can destroy the No. 1 killer of citrus trees worldwide and help prevent infection. Huanglongbing, HLB, or citrus greening has multiple names, but one ultimate result: bitter and worthless citrus fruits. It has wiped out citrus orchards across the globe, causing billions in annual production losses.

    Untreated citrus plants on the left, as compared to treated ones on the right. (Hailing Jin/UCR)

    All commercially important citrus varieties are susceptible to it, and there is no effective tool to treat HLB-positive trees, or to prevent new infections. However, new UC Riverside research shows that a naturally occurring peptide found in HLB-tolerant citrus relatives, such as Australian finger lime, can not only kill the bacteria that causes the disease, it can also activate the plant’s own immune system to inhibit new HLB infection. Few treatments can do both.

    Research demonstrating the effectiveness of the peptide in greenhouse experiments has just been published in the Proceedings of the National Academy of Sciences.

    The disease is caused by a bacterium called CLas that is transmitted to trees by a flying insect. One of the most effective ways to treat it may be through the use of this antimicrobial peptide found in Australian finger lime, a fruit that is a close relative of citrus plants.

    “The peptide’s corkscrew-like helix structure can quickly puncture the bacterium, causing it to leak fluid and die within half an hour, much faster than antibiotics,” explained Hailing Jin, the UCR geneticist who led the research.

    When the research team injected the peptide into plants already sick with HLB, the plants survived and grew healthy new shoots. Infected plants that went untreated became sicker and some eventually died.

    Arrows point to areas of fluid leakage from the bacterial cell after treatment with the antimicrobial peptide. (Hailing Jin/UCR)

    “The treated trees had very low bacteria counts, and one had no detectable bacteria anymore,” Jin said. “This shows the peptide can rescue infected plants, which is important as so many trees are already positive.”

    The team also tested applying the peptide by spraying it. For this experiment, researchers took healthy sweet orange trees and infected them with HLB-positive citrus psyllids — the insect that transmits CLas.

    After spraying at regular intervals, only three of 10 treated trees tested positive for the disease, and none of them died. By comparison, nine of 10 untreated trees became positive, and four of them died.

    In addition to its efficacy against the bacterium, the stable anti-microbial peptide, or SAMP, offers a number of benefits over current control methods. For one, as the name implies, it remains stable and active even when used in 130-degree heat, unlike most antibiotic sprays that are heat sensitive — an important attribute for citrus orchards in hot climates like Florida and parts of California.

    In addition, the peptide is much safer for the environment than other synthetic treatments. “Because it’s in the finger lime fruit, people have eaten this peptide for hundreds of years,” Jin said.

    Hailing Jin, research leading UC Riverside geneticist

    Researchers also identified that one half of the peptide’s helix structure is responsible for most of its antimicrobial activity. Since it is only necessary to synthesize half the peptide, this is likely to reduce the cost of large-scale manufacturing.

    The SAMP technology has already been licensed by Invaio Sciences, whose proprietary injection technology will further enhance the treatment.

    Following the successful greenhouse experiments, the researchers have started field tests of the peptides in Florida. They are also studying whether the peptide can inhibit diseases caused by the same family of bacteria that affect other crops, such as potato and tomato.

    “The potential for this discovery to solve such devastating problems with our food supply is extremely exciting,” Jin said. — By Jules Bernstein, UC Riverside

  • National Cucurbit Project Reupped for $7.1 Million

    The Cucurbit Coordinated Agricultural Project (CucCAP), a multi-institution, nationwide research and outreach initiative led by Michigan State University and dedicated to cucurbit crops — cucumbers, squashes, melons and watermelon — has been awarded $7.1 million from the U.S. Department of Agriculture’s (USDA) Specialty Crop Research Initiative.

    The new funding extends the project that began in 2015 for four years. The goals of CucCAP, which is led by Rebecca Grumet, a professor in the MSU Department of Horticulture, are to harness genomic resources for disease resistance and management in cucurbit crops.

    “Producers and processors of cucurbit crops throughout the country consistently identify diseases as one of their most serious and costly problems,” Grumet said. “The diseases cause severe reductions in yield and crop quality, sometime causing total crop loss.

    “Control measures are expensive due to chemical costs, time and labor. The most cost-effective and environmentally desirable solution is disease-resistant varieties in combination with effective integrated disease management strategies.”

    To address these problems, the CucCAP team, with members from 10 institutions around the country combines expertise in genomics, bioinformatics, plant breeding, genetics, plant pathology, outreach and economics.

    The partners are: Boyce-Thompson Institute, Clemson University, Cornell University, North Carolina State University, University of Florida, University of Georgia, University of Puerto Rico, USDA Agricultural Research Service, and West Virginia State University.

    The project’s new phase, CucCAP2, will focus on the development of advanced genomic, bioinformatic and breeding tools; disease resistant materials; disease management strategies and economic analyses for critical diseases threatening cucurbit production.

    Genomics, which helps researchers understand the genetic makeup of cucurbit species and breed disease-resistant varieties, is one CucCAP scientists’ most important approaches. Tools developed through the project have allowed identification of genetic regions associated with resistance to important diseases.

    Grumet has worked with Michigan specialty crop growers for decades on disease management issues. Her research has concentrated on reproductive development and disease resistance in cucurbits — particularly cucumbers.

    This research is especially relevant to Michigan, as the state is home to the nation’s largest pickling cucumber industry, valued at nearly $50 million per year.

    Through CucCAP, researchers have been addressing two devastating diseases threatening cucumbers — downy mildew and Phytophthora fruit rot, caused by a pathogen called Phytophthora capsici. Grumet said these diseases cost U.S. cucumber growers roughly $5 million annually.

    Mary Hausbeck, a University Distinguished Professor in the MSU Department of Plant, Soil and Microbial Sciences, is also a part of the CucCAP team. Her work for the project includes development of effective practices and timely extension resources for management of cucurbit diseases and resistance to Phytophthora fruit rot in processing squash. Additionally, researchers at partner institutions are working with a variety of fungal, oomycete and viral pathogens infecting the different cucurbit crops throughout the country.

    CucCAP projects are geared toward the entire production process, from breeding and pathology to economic analysis and outreach. Commodity organizations and seed industry representatives from around the world assist in setting research priorities.

    Getting information to growers about research findings is also a fundamental part of CucCAP. Outreach is conducted through meeting with growers and providing easily accessible online resources, such as disease control information on the CucCAP website. In addition, the team created a cucurbit genomics database website to serve as a central portal for genomics data and research.

    “Using modern genomic tools, we can more efficiently introduce and combine genes for different resistances while maintaining high yield and important fruit quality traits,” Grumet said. “This is critically needed given the tremendous losses that can be caused by these destructive diseases.” – By Cameron Rudolph, Michigan State University

  • CDFA Seeking New Grower Representative for Citrus Pest & Disease Prevention Committee

    The California Department of Food and Agriculture (CDFA) is seeking a grower representative with operations in the Fresno County area to sit as a member 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.

    Committee members receive no compensation but are entitled to payment of necessary travel expenses in accordance with the rules of the Department of Personnel Administration. The term for one grower representative from Fresno County expires on Sept. 30, 2023. 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 resume by Feb. 15, 2021 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 on the committee vacancy, contact: David Gutierrez, Branch Chief, Citrus Pest and Disease Prevention Division at (916) 274-6300, or e-mail David.Gutierrez@cdfa.ca.gov.

  • First CLas-Positive Asian Citrus Psyllid Found in San Diego

    An Asian citrus psyllid (ACP) sample – confirmed positive for Candidatus Liberibacter asiaticus (CLas), the bacteria that causes Huanglongbing (HLB) – was collected from a residential property in the Fallbrook area of San Diego County. Confirmed by Citrus Research Board’s Jerry Dimitman Laboratory, this adult psyllid sample is the first CLas-positive ACP found in San Diego County.

    While the first confirmation of a CLas-positive ACP in San Diego County is concerning, as of today, HLB has not been detected in any San Diego County trees but surveying and sampling of area trees is ongoing. This find signals a critical time for homeowners and growers alike to continue to control ACP populations to stop the potential spread of this deadly disease, as oftentimes a CLas-positive ACP precedes the detection of an HLB-positive tree.

    The HLB quarantine zone will not be expanded as a result of this CLas-positive ACP detection and CDFA staff is swiftly conducting surveys and collecting samples from HLB host plants that are located within a 250-meter radius around the find, per the ACP/HLB Action Plan.

    While treatment is not mandatory for area commercial growers as a result of the detection, San Diego County commercial growers who have additional questions can contact Sandra Zwaal, San Diego County Grower Liaison, at szwaal2@gmail.com.

    CLICK HERE for additional information from Citrus Pest and Disease Prevention Program (CPDPP) Citrus Insider.

    Source: Citrus Pest and Disease Prevention Program (CPDPP) Citrus Insider

  • After 100 years, Cornell University Plant Pathologists Revisit Fire Blight Hypothesis

    Historically credited as being the first bacterium ever characterized as a plant pathogen, fire blight is a bacterial disease that leads to significant losses of pear and apple. The role of insects in the spread of this disease has been long studied. In a new study, plant pathologists based at Cornell University and Cornell AgriTech take a hypothesis that has been more or less ignored for 100 years and provided support for its validity.

    Fly feeding on the ooze droplet in the experimental chamber (Photo by Matthew Boucher).

    According to first author Matthew Boucher, the study describes a long hypothesized but never experimentally supported transmission mechanism for fire blight. Boucher and colleagues show that flies in an apple orchard can acquire the bacterial agent (Erwinia amylovora) of fire blight from sugary droplets exuding from diseased apple trees and subsequently transmit the bacterium to uninfected shoots so long as those shoots are damaged in some way.

    “This transmission mechanism is mechanical, the bacterium does not appear to have a close evolutionary relationship with any given insect and may seem inefficient to an unsuspecting observer,” explained Boucher. “However, we show that the massive populations of E. amylovora in the sugary droplets exuding from trees allow flies to acquire enough bacteria for the population to persist in and on flies for as long as seven days in some cases.”

    Flies can continually shed bacteria over the course of those seven days, resulting in multiple opportunities for a single insect to initiate an infection.

    “Demonstrating that bacterial populations can survive within the insect is important because previous research largely discounted E. amylovora survivability within an insect.” More research is needed, especially under field conditions, but this is an exciting step toward understanding the diversity of interactions between plants, insects, and phytopathogens.

    “We also show that insects do not need to have intimated, co-evolved relationships with plant pathogens to be important agents in the disease cycle. There are only one or two similar pathogens in documented research, but there are likely more out there that need to be studied to advance our knowledge of this end of the disease-vector spectrum,” Boucher said when asked what makes his work groundbreaking. “As a collective work, we show the importance of integrating historical literature into modern research and revisiting topics and hypothesis that may not have been technologically feasible to investigate when they were first proposed.”

    This work is a foundational study that will provide excellent context for future researchers interested in the topic. For more information, read “Interactions Between Delia platura and Erwinia amylovora Associated with Insect Mediated Transmission of Shoot Blight” published in PhytoFrontiers.