AgNet DEMO

Category: VSCNews magazine

  • Seed Selection Considerations

    Photo credit: © Ok / stock.adobe.com

    By Tiffany Bailey and Ida Vandamme

    Choosing vegetable varieties is probably the most important decision a grower can make and can be the difference between a crop failure or success. On our farm, we consider seed selection one of the most powerful and efficient tools as part of the cultural controls in an integrated pest management program. It takes no extra effort to plant a better variety, and huge results can be achieved in both yields and disease resistance.

    The planet we live on has many different climates and conditions, and yet people across the world all still want red tomatoes. This is where the wonderful genetic diversity of plants comes into play. A seed variety that produces a healthy, red cherry tomato commonly grown in the North may struggle in the South. A different variety with different genes, better suited for the South, may have an internal mechanism coded within to help the plant cope with intense heat and pest and disease pressures. An extra waxy cuticle, more vigorous growth to stay ahead of leaf loss, and quicker systemic responses are just a few of the many ways a plant can be better adapted to different conditions.

    DIVERSIFY FOR RESILIENCY

    In the beginning stages of an organic farm, a good practice to best protect against a crop failure is to plant several different crops and even varieties of crops. That way, if an unsuitable variety is planted, the loss will be small and other varieties can make up for it. Over time, the different seed varieties will show their strengths and weaknesses.

    Even after the stronger varieties are determined, it is still a good idea to trial new seed varieties because every year is different. What did well last year may have to make room for another variety to take the spotlight. Having a diverse crop plan will make your farm more resilient to changes and new stresses. Plants come with amazing genetic diversity, which should be used to the farmer’s advantage.

    CONSERVE RESOURCES

    A good variety is such an effective control because you will spend less time, energy, resources and tears on it. An unsuitable variety will cost you more money in labor, chemicals, and/or equipment to maintain it.

    On our farm, we have had experiences with weak seed varieties that needed to be sprayed more often with more expensive materials to keep the crop from succumbing to disease. On the flip side of that same coin, we have had solid varieties which seemed to be completely carefree with good management.

    KNOW YOUR SITE

    It is all about site-specific needs. There are hundreds of different conditions a farm could be planted under and, thankfully, hundreds of different varieties of crops available to choose from. Local Extension offices are a great tool to get started with. They will know which varieties perform best in your location, but farmers should do their own trials because every farm is different, and management strategies will affect which varieties perform the best.

    ORGANIC VS. NON-ORGANIC SEED

    National Organic Program rules state that non-organic seeds can be used only if organic seed cannot be found or is not commercially available in the quantities needed. A search record must be provided with three attempts to source organic seed if non-organic seed must be used.

    We have heard from both experienced farmers and university professors that crops grown from non-organic seeds perform better than crops grown from organic seeds. We have made our own observations on the matter and tend to agree with them.

    Photo credit: © eleonimages / stock.adobe.com

    However, others say it is a myth that organic seed crops do not perform as well. Organic seed undergoes the same rigorous disease testing as non-organic seed, according to our local Extension agent. She has assured us that there should be no difference. We encourage all farmers to see for themselves!

    Tiffany Bailey is owner and Ida Vandamme is farm manager at Honeyside Farms in Parrish, Florida.

  • Hope Springs Eternal

    Photo credit: © Wayne Smith

    By Ryan Atwood

    To be a farmer is to be an optimist. Farmers work long hours, deal with weather events, labor issues, trade issues and global pandemics that are beyond their control. The 2020 Florida blueberry harvest season was a tough one due to increased imports and the coronavirus pandemic. The government did provide some assistance to farmers through the Coronavirus Food Assistance Program, which will help them continue forward into the coming 2021 season.

    WINTER WEATHER

    Florida blueberry growers have hedged and regrown their bushes for the year. Fall season into winter is a time for flower bud development, which gives the first indication of the crop to come. It is too early to tell what size crop Florida will produce. The Florida industry has been pretty stable in production numbers (~20 million pounds) the last few years due to some decent amount of cooler weather in the late fall and early winter.

    During the last warm (no chill) winter, the state struggled to produced 15 million pounds. This winter, climate forecasters are calling for a La Niña weather cycle. La Niña events are predicted to produce warmer temperatures and less rainfall than on average. The Florida blueberry industry has been moving to more evergreen production, which warmer weather tends to favor in terms of crop timing. A warmer winter most likely will not have quite the negative effect on statewide volumes like it has in the past.

    November tends to be the slowest month in blueberry production. Most growers take a vacation, work on getting their overhead irrigation ready for cold protection and replant new or existing ground. Things start to ramp back up in December as plant growth regulators are typically applied to stimulate the plants into flowering in January.


    In January and February, growers battle cold weather events during pollination. This leads to the setting of their berries that will be harvested in the spring. The spring brings hope of good yields with excellent quality.

    MEXICAN COMPETITION

    The unknown challenge this spring will be the ever-increasing Mexican blueberry volume during the Florida harvest window.

    Mexican blueberry production has increased dramatically over the last decade. This has led to reduced prices and returns to Florida growers. Many Florida blueberry farms have thrown in the towel the past several years. Others have turned from commercial to u-pick operations.

    The American public is growing more aware of the increase in foreign food supply. As U.S. consumers become more aware of this, the #DemandAmericanGrown campaign will continue to gain traction. We as agricultural producers need to continue (or start if you have not already begun) to educate our fellow Americans on the importance of American agriculture.

    What happens if our country were to become dependent on a foreign supply for food? We would be at the mercy of those who produce that food. This seems absurd to many Americans, as food is relatively abundant for most of our population. However, one only needs to look at socialist countries such as Cuba, Venezuela and others to see the effects of a short food supply.

    America was built on its great agricultural history. If we want to continue to be a great country, we need to be committed to local agriculture. It is a matter of national security.

    Ryan Atwood is co-owner of H&A Farms in Mt. Dora, Florida

  • Georgia Blueberry Disease Management Update

    Orange-colored blueberry leaf rust pustules can be seen on leaf undersides. Photo by Jonathan Oliver.

    By Jonathan Oliver

    In 2020, mild winter conditions followed by a wet spring contributed to the development of significant disease issues on Georgia blueberries. Among other issues, growers faced difficulties with preharvest and postharvest fruit rots and continuing problems with spring blueberry leaf rust epidemics.

    The fruit pathology program at the University of Georgia (UGA) in Tifton conducts trials to determine fungicide efficacy and optimal application timings. Disease management information is provided to blueberry growers through the UGA Cooperative Extension Service, the Southeast Regional Blueberry Integrated Management Guide (smallfruits.org/ipm-production-guides/) and the free MyIPM smartphone app.

    FUNGICIDE-RESISTANT RIPE ROT

    During the 2020 growing season, Georgia blueberry growers faced challenges from fruit rots including ripe rot caused by the fungi Colletotrichum gloeosporioides and C. acutatum. Development of ripe rot (also called anthracnose fruit rot) is favored by warm, wet conditions. Fungal infection can occur from bloom up until harvest, though symptoms do not typically appear until fruit begin to ripen.

    The spores of the fungus that cause ripe rot can easily spread from berry to berry via rain splash, in packing lines or in clamshells. Typically, field applications of QoI (strobilurin) fungicides such as Abound (azoxystrobin), Pristine (pryaclostrobin + boscalid) and Quilt Xcel (azoxystrobin + propiconazole) provide excellent ripe rot control. However, in recent years, C. gloeosporioides isolates from blueberry with resistance to QoI fungicides have been identified in Georgia and elsewhere in the southeastern United States.

    Blueberry leaf rust damage is visible on the top of the fruit. Photo by Jonathan Oliver.

    To provide growers with needed information regarding alternative fungicides for ripe rot management, the UGA-Tifton Fruit Pathology Laboratory and UGA Cooperative Extension personnel conducted trials during 2020 to evaluate fungicidal spray programs for control of ripe rot and other fruit rot disease issues. In these trials, spray programs which incorporated applications of Switch (cyprodinil + fludioxonil), Captan (captan), Miravis Prime (pydiflumetofen + fludioxonil), Omega (fluazinam) and Ziram (ziram) were the most effective at reducing fruit rots in general and ripe rot in particular.

    To manage ripe rot, applications of effective fungicides beginning at early bloom and continuing every seven to 14 days through preharvest are recommended. Growers are reminded that rotations of the available modes of action (and/or tank mixes with multi-site products such as captan) are encouraged to reduce the chances of continued fungicide resistance development in the pathogen population.

    Ripe rot is also known as anthracnose fruit rot. Photo by Jonathan Oliver.

    In addition, when developing a spray program for fruit rots, growers should be aware of the preharvest interval (PHI) of these products, including Ziram (which should not be used more than three weeks after full bloom), Omega (which should not be used within 30 days of harvest) and Quilt Xcel (also a 30-day PHI). Consult the various labels for rates, recommendations and precautions.

    BLUEBERRY LEAF RUST

    Blueberry leaf rust (caused by the fungus Pucciniastrum vaccinii) is most frequently associated with causing leaf spots and premature defoliation after harvest. However, Georgia blueberry growers have also experienced significant spring epidemics of leaf rust in recent years that can directly impact developing fruit. These spring epidemics are likely the result of increasingly mild winters that allow blueberry leaves infected during the previous season to persist through the winter and serve as sources for disease spread early in the subsequent season.

    Recent trial work carried out by the UGA-Tifton Fruit Pathology Laboratory reinforces the importance of spring fungicide applications for leaf rust management. Applications of effective demethylation inhibitor (DMI) fungicides during the spring were found to significantly decrease the development of leaf rust throughout the growing season. Two spring applications of Proline (prothioconazole) were capable of controlling leaf rust and measurably reduced disease throughout the full season, regardless of whether effective fungicides were used after harvest.

    While postharvest applications are still recommended to prevent premature defoliation due to blueberry leaf rust, this trial work highlighted the particular importance of spring fungicide applications for leaf rust management in conditions of high disease pressure. Growers should be aware that leaf rust epidemics can start early following mild winter conditions and consider early-season applications with DMI fungicides for rust management. DMI fungicides with very good to excellent efficacy against rust include Proline, Quash (metconazole) and Quilt Xcel. Consult the various labels for rates, recommendations and precautions.

  • Chilli Thrips: An Increasing Threat for Blueberry Growers

    Figure 1. Chilli thrips cause leaf bronzing.

    By Oscar Liburd

    Chilli thrips, Scirtothrips dorsalis, was first detected in southern highbush blueberries in Florida in Orange, Sumter and Hernando counties during the summer of 2008. It is a major pest of many host plants, including vegetable, ornamental and fruit crops.

    Figure 2. Deformed leaves are the result of chilli thrips feeding.
    FEEDING DAMAGE

    In blueberry, chilli thrips feed on young leaves, causing leaf bronzing (Figure 1) and shoot dieback in late spring to early summer shortly after the bushes are pruned. Some infestation symptoms include the edges around younger leaves and stems are eaten, and bushes become pale green with deformed leaves (Figure 2). During a heavy infestation, blueberry cupped leaves are quite noticeable, with larger leaves curving inward (Figure 3).

    Overall, chilli thrips affect plant vigor and reduce the number of berries the following season.

    IDENTIFICATION AND LIFE STAGES
    Figure 3. Blueberry cupped leaves are a symptom of chilli thrips infestation.

    Chilli thrips are smaller than flower thrips and are approximately 0.04 of an inch long. They have dark fringed wings and dark spots across the back of the abdomen (Figure 4).

    Chilli thrips have four life stages: egg, larva, pupa and adult, including two actively feeding larval instars and two non-feeding pupal instars. Female thripsinsert their eggs into blueberry tissues, and the eggs hatch in about six to eight days. Females are capable of laying between 60 to 200 eggs.

    Newly hatched larvae pass through two larval stages (first instar and second instar). These larval instars last for about six to eight days, during which time they feed on blueberry tissues. They then pass through a prepupal and a pupal stage, during which time they do not feed. Chilli thrips complete their life cycle in 17 to 21 days under ideal conditions.

    In Florida, most of the chilli thrips outbreaks in blueberries were recorded from late May to September on new growth. 

    Figure 4. Adult chilli thrips have fringed wings. Photo by Lyle J. Buss, University of Florida
    MANAGEMENT METHODS

    Chemical insecticides including the use of Delegate® (spinetoram), Apta® (tolfenpyrad), Rimon® (novaluron), Assail® (acetamiprid) and Sivanto® (flupyradifurone) are the primary means to manage chilli thrips populations in blueberries.

    Delegate® is effective in controlling larvae and adult chilli thrips. Apta® inhibits feeding of larval and adult thrips. Rimon® affects egg and larval development due to its growth regulator characteristics. Assail® is a neonicotinoid insecticide that can control larvae and adults due to systemic qualities. Sivanto® also controls larval and adult thrips and behaves similarly to neonicotinoids.

    In organic production, Entrust® (spinosad) is the primary insecticide tactic. However, Azera® (pyrethrins + azadirachtin) and PyGanic (pyrethrins) can also be used in organic production.

    Management for chilli thrips includes eliminating host plants, including weeds, that support their growth and development. Beneficial insect predators such as Geocoris spp. and Orius insidiosus feed on thrips and need to be considered when using chemical pesticides.

  • Sneak Peek: January 2021 VSCNews Magazine

    By Ashley Robinson

    The January issue of VSCNews magazine will be the blueberry grower’s handbook heading into the 2021 season.

    Chilli thrips are a growing threat for blueberry growers. Without proper management of the pest, overall plant vigor and yields can be affected. Oscar Liburd, a professor at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) in Gainesville, Fla., shares conventional and organic management tactics that growers can implement to help control these pesky pests.

    UF/IFAS has unveiled its newest blueberry variety, Sentinel, named in honor of UF alumna, Alto Straughn. It is a low-chill southern highbush variety and offers increased yields for growers. Brad Buck, UF/IFAS public relations specialist, mentions that Sentinel was ranked “high” in flavor among flavor panels.

    America was built on its rich agricultural history. Ryan Atwood, co-owner of H&AFarms in Mt. Dora, Florida, shares the struggles blueberry growers faced in 2020 and growers’ optimism for the year to come. Atwood also discusses the increasing Mexican blueberry volume during the Florida harvest window and its impact on the U.S.

    In 2020, mild winter conditions followed by a wet spring contributed to the development of significant disease issues on Georgia blueberries. Jonathan Oliver, an assistant professor at the University of Georgia in Tifton, Georgia, updates Georgia growers on disease management strategies.

    Outside of the blueberry spotlight, Kimberly Morgan, an associate professor and Extension economist, and Tara Wade, an assistant professor, both at the UF/IFAS Southwest Florida Research and Education, share how growers could benefit from enterprise budgets.

    Morgan is also joined by Jessica Ryals, a sustainable food systems agent for UF/IFAS, for another article in this month’s issue. These two discuss how an imperfect market system can yield profitable market opportunities for growers.

    To receive future issues of VSCNews magazine, click here.

  • New BMP Record-Keeping Requirements for Florida Growers

    By Ajia Paolillo

    Rows of watermelon in North Florida, trees, leaves. UF/IFAS Photo: Thomas Wright.

    On July 1, 2020, new record-keeping requirements went into effect for nitrogen and phosphorus amounts applied by growers enrolled in the Florida Department of Agriculture and Consumer Services (FDACS) Best Management Practices (BMP) program. These records are required due to the passage of Senate Bill 712, the Clean Waterways Act.

    Growers have been asking many questions about this new requirement and what they must do to be in compliance with the law. This article is comprised of questions and answers designed to help growers understand their requirements as a FDACS BMP program participant, and the records submission process moving forward.

    Matt Warren, environmental manager with the FDACS Office of Agricultural Water Policy in Hardee County answers some of the common questions from growers:

    Q: Who does this new law apply to?

    A: Any grower enrolled in the FDACS BMP program, regardless of whether or not they are located in an area with a Basin Management Action Plan (BMAP).

    Q: The new requirement states that growers must submit their application records for nitrogen and phosphorus to FDACS. When do I submit my records?

    A: You will submit your records of nitrogen and phosphorus applications only when requested by a FDACS representative during an implementation verification visit. These visits are done by FDACS to verify that a grower is in compliance with the program, by properly implementing the BMPs they committed to in their Notice of Intent to Implement BMPs. 

    Q: When will these implementation verification visits take place?

    A: The visits will be done once every two years. Initially, priority will be focused on visits to growers located in BMAP areas, but every grower enrolled in the BMP program will be visited.

    Q: Who will be conducting the implementation verification visits, and how will I be notified when I am receiving a visit?

    A: A FDACS field representative will contact the grower to schedule a visit. The visits are not unannounced.

    Q: I received a letter in the mail with record-keeping examples and instructions. Do I need to submit my records online?

    A: The letter was to inform you of the new requirements and offer a form that you may use to record your nitrogen and phosphorus application information. Do not submit any records at this time. You will only be required to submit your records to the FDACS field representative during your implementation verification visit.

    Q: What information am I required to record for submission?

    A: Growers are required to keep a record of the total pounds of nitrogen and phosphorus (in the form of P2O5) that are applied to their fields on a monthly basis. Total pounds of nitrogen and phosphorus must be accounted for from all sources applied, including biosolids. Growers do not need to submit records of other nutrient applications, such as minor elements or soil amendments such as lime.

    Important note: Growers must continue to keep records for their own files on all nutrient and soil amendment applications, in order to be in compliance as stated in their Notice of Intent to Implement BMPs and BMP checklist requirements.  

    Q: What form do I use to record my nitrogen and phosphorus application information?

    A: FDACS has provided a suggested form for you to use. You are not required to use this form, but it is easy to follow and clearly shows what information is needed and where to input it. FDACS has this form available as a hard copy, printable PDF or in electronic form as an Excel spreadsheet. The Excel spreadsheet is recommended, as the information can be uploaded automatically.

    Q: Do I have to give them my only copies of my records?

    A: No, you must keep your original copies of your records. Give the FDACS representative a copy of the form mentioned above, or something similar, as your records submission.

    Q: How far back do my records need to go for this new requirement?

    A: You must submit nitrogen and phosphorus monthly totals for the past two years from the date of your scheduled implementation verification visit. For example, if you have an implementation verification visit scheduled for Dec. 20, 2020, you must submit nitrogen and phosphorus application records dating back to Dec. 20, 2018.

    Q: How does FDACS determine if I am in compliance? Is it based on University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) recommendations for crop production? What about soil and leaf samples?

    A: UF/IFAS recommendations are used to determine if a grower is in compliance. For more information, please refer to these FDACS publications at fdacs.gov/Agriculture-Industry/Water/Agricultural-Best-Management-Practices:

    • Water Quality/Quantity Best Management Practices for Florida Vegetable and Agronomic Crops 
    • Water Quality/Quantity Best Management Practices for Florida Specialty Fruit and Nut Crops

    Soil and leaf samples are a requirement under the FDACS BMP program, and the results will also be used to determine if a grower is in compliance with the BMP program. Be sure to keep up with soil and leaf samples, as they may also be needed for justification. 

    Q: What if I do not have this information available for my FDACS field representative at the time of the implementation verification visit?

    A: You will have to work with your FDACS representative. You may be placed in remedial action and given a certain time period to submit your records. If you choose not to submit your records, you may be referred to the Florida Department of Environmental Protection for regulatory action.

    Q: Are my nitrogen and phosphorus application totals considered public records once they are submitted? 

    No, they are not considered public record. But, FDACS must provide them to the Florida Department of Environmental Protection, if requested, as long as the confidentiality specified for the records is maintained.

    See blogs.ifas.ufl.edu/clue/2020/08/31/from-senate-bill-712-to-the-clean-waterways-act-and-agricultural-best-management-practices for more details and information about the Clean Waterways Act.

    If you have more questions or would like a copy of the suggested record-keeping form, contact your FDACS Office of Agricultural Water Policy field representative or your UF/IFAS Extension agent.

  • Safety Training Program Protects Ag Workers During the Pandemic

    By Kimberly L. Morgan

    Throughout the food supply chain, producers, processors, distributors, wholesalers and retailers seek economies of scale and scope to improve profit margins, while delivering safe, consistent, reliable and relatively low-cost foods to consumers. At the farm level, owners make decisions to minimize production and harvesting costs, relying on human resources and scientific advances to address the dynamic uncertainties unique to the agricultural industry.

    During the 2020 global pandemic, every individual, household, company and government had to adjust day-to-day behaviors. Yet nationwide, few food shortages occurred, and minimal increases in prices have been documented to date. The U.S. agricultural industry continued to provide healthy and safe food, due in large part to the adaptability of farmworkers, supervisors and owners.

    Workers labor long hours in physically demanding conditions, with paychecks dependent on speedy, accurate and careful handling of fruits and vegetables to ensure high-quality, safe produce is delivered to buyers. The economic implications of the highly transmissible coronavirus range from short-term negative impacts on worker health and farm profitability to the immeasurable losses of life.

    To proactively educate farm owners, supervisors and workers on how best to do their jobs under pandemic conditions and preserve their health and livelihood, the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Farm Labor Supervisor COVID-19 Safety Training program was developed.

    With decades of experience educating nearly 1,500 farm labor supervisors on how best to protect farmworkers’ lives, the training team has delivered six webinars in both Spanish and English to 775 participants. The training consists of three sections:

    PART 1: WHAT IS THE CORONAVIRUS OR COVID-19?

    Motivated by the trainers’ observations that farmworkers tend to distrust technology used in the fields (for instance, the scan systems that track production), this section addresses their concerns by sharing information regarding the COVID-19 testing and health-monitoring procedures specific to agricultural operations.

    Picnic benches with barriers help protect farmworkers from COVID-19 during lunch breaks.

    Farmworkers often fail to recognize COVID-19 symptoms and/or don’t think it is a problem that will affect their health as many are relatively young and work primarily outdoors. To mitigate this prevailing mindset, general information is included about the virus, whom it targets, Florida statistics, typical symptoms, case studies and transmission examples.

    Ag-related COVID-19 cases are shared to relay facts that the disease is a real and persistent threat to the health and wellbeing of farmworkers, and to communicate that there are things workers can do to protect themselves and others. Florida Department of Health statewide COVID-19 infection and mortality rates by ethnicity, age and county are shared to show the real-time relevance and impact of the virus on communities.

    PART 2: COVID IN AGRICULTURE

    Building on Centers for Disease Control (CDC) guidelines, UF/IFAS experts apply their firsthand knowledge of the day-to-day working environment on Florida’s farms and share best practice recommendations to help protect farmworkers’ lives. As local and state agencies work to provide farmworker access to COVID-19 testing sites, this information is shared. Supervisors are encouraged to adopt prevention and control tips and to post CDC-approved worker education resources in appropriate languages. The training stresses the importance of practicing social distancing, wearing masks and handwashing both on and off the farm.

    PART 3: PROTECTING SUPERVISORS AND WORKERS

    Farmworkers are typically paid hourly. Time off due to COVID-19 symptoms or quarantining for 14 days after exposure to a COVID-19-positive coworker results in costs to both the worker and the employer. The employers may need to provide sick pay and find and hire a replacement.

    The training provides information on financial support programs from various agencies that are available for both farmworkers and owners to address these concerns. Since harvest practices usually are built around teams working in proximity, creative ways are suggested to complete the work while maintaining social distancing. This includes forming groups that share work assignments and living arrangements to minimize exposure during shift changes.

    Also included in this section of the training is the latest CDC general guidelines and the Agricultural Employer Checklist for Creating a COVID-19 Assessment and Control Plan. Other topics covered are:

    • How to screen workers
    • The importance of employees reporting to their employers if they begin to feel sick
    • Areas that put workers at most risk and how to make them safer
    • Handling sick time
    • Assigning responsibility to ensure practices are followed
    • Numerous resource websites

    Dates for future training and responses to frequently asked questions related to protecting farmworkers from COVID-19 will be posted on the UF/IFAS Farm Labor Supervisor Training Facebook page (www.facebook.com/FLSTraining15).

  • Treading the Produce Safety Rule Agricultural Water Requirements

    By Taylor Langford, Matt Krug and Michelle Danyluk

    The Food Safety Modernization Act’s Produce Safety Rule (PSR) highlights the need to reduce risks associated with agricultural water (e.g., irrigation, fertigation, foliar sprays, frost protection, etc.) that will contact fresh produce. The PSR requires some growers to monitor the quality of their agricultural water by analyzing generic E. coli populations through sampling frequently enough to establish a microbial water-quality profile. This testing is applicable to growers who use agricultural water from surface or ground water sources that contacts the harvestable portion of produce covered by the PSR.

    As of January 2020, the compliance dates for all operations covered under the PSR have passed, excluding the requirements on agricultural water. In March of 2019, the Food and Drug Administration (FDA) announced new compliance dates for agricultural water. Compliance is currently scheduled to begin in January of 2022, 2023 and 2024 for large, small and very small farms, respectively.

    The delay in compliance for water was based on feedback from the industry that the written standards are too complex to implement. In response, FDA is currently exploring alternatives to simplify microbial quality and testing standards while still protecting public health.

    OUTBREAK OUTCOMES

    However, not long after FDA’s announcement to delay compliance dates and review requirements, a multistate outbreak of E. coli O157:H7 involving romaine lettuce was announced by the FDA and Centers for Disease Control and Prevention. This outbreak came on the heels of two other outbreaks related to romaine in April and November of 2018.

    An executive summary published by the FDA on May 21, 2020, announced the findings of the outbreak investigation. The findings pointed toward contamination of surface water used for irrigation combined with close proximity to cattle feeding operations and unusual weather events (frost and wind) as the most likely culprits.

    The investigation also revealed that the surface water implicated in the outbreak was tested by growers and met the water quality criteria in the PSR. This has added another layer of complexity to the process of identifying suitable strategies and realistic expectations for ensuring the safety of water used during crop production.

    The revelations that the agricultural water provisions of the PSR were being delayed and that there was a produce outbreak related to pre-harvest water that met the current PSR requirements resulted in various efforts to identify appropriate risk reduction strategies. In response, FDA developed the Leafy Greens STEC (Shiga toxin-producing E. coli) Action Plan that included public and private stakeholders. The plan is designed to expedite actions to prevent future outbreaks associated with leafy greens.

    One of the goals of the 2020 Leafy Greens STEC Action Plan is to “advance agricultural water safety.” Recognizing the diversity among agricultural production systems, the plan is focused on identifying standards that are workable across a variety of farms, water sources and uses. One of the actions identified by the plan is to advance a proposed rule for agricultural water for covered produce other than sprouts.

    Following the outbreaks involving romaine in 2018, the United Fresh Produce Association and the Produce Marketing Association developed a diverse Romaine Task Force that consisted of over 100 industry, academic and regulatory stakeholders. Some recommendations were developed specific to romaine, and others were broader recommendations. The task force recommended adoption of the new California/Arizona Leafy Greens Marketing Agreement (LGMA) water treatment metrics, which require surface water applied via overhead to leafy greens plants within 21 days of harvest to be treated.

    California has recently approved the new LGMA water metrics, which included over 50 changes to strengthen food safety requirements in areas of farm water use and field/equipment sanitation. The new requirements for water are focused on ensuring the safety of water used in overhead crop sprays, enhancing water-monitoring requirements, and minimizing the risk of water applied with furrow irrigation from coming into contact with the edible portion of the crop. These newly adopted changes are in addition to the metric that was added last year.

    As previously seen, food safety standards adopted by, or developed for, certain commodities or segments of the produce industry often shape broader market-driven and regulatory standards that apply across the board. It is still unknown how newly adopted standards and decisions made by agreements and task forces will shape FDA’s thinking on revisions to the PSR.

    GROWER GUIDANCE

    The Florida produce industry should remain engaged in the process to identify and adopt strategies that satisfy general concerns around use of agricultural water. Although the compliance dates of the PSR water-testing provisions have been delayed, growers who have not previously tested their agricultural water should consider implementing testing now to better understand the microbial quality of their water sources.

    Produce Safety Rule inspections, conducted by the Florida Department of Agriculture and Consumer Services (FDACS), after a pause at the beginning of the COVID-19 pandemic, have resumed and are continuing throughout the state. Scheduling of inspections generally follow the patterns of produce production across the state. The initial round of inspections is intended to be educational in nature, but inspectors are obligated to take measures to protect public health if serious issues are observed.

    To prepare for inspections, growers, harvesters and packers should, at a minimum, follow Good Agricultural Practices and attend a Produce Safety Alliance (PSA) grower training. The PSA grower trainings continue to be offered at the highly subsidized price of $25 through collaborations with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) and FDACS. Due to the COVID-19 pandemic, PSA trainings are being offered remotely and capacity is limited. See crec.ifas.ufl.edu/extension/events/ for the list of upcoming PSA grower training events.

    The On-Farm Readiness Review (OFRR) program is another way to help growers prepare for a PSR inspection. The OFRR is a personalized site visit in which UF/IFAS and FDACS representatives can address questions about practices or conditions at a specific farm or packinghouse, including discussions related to agricultural water use. There is no cost associated with an OFRR. Sign up at fdacs.gov/FSMA for an OFRR.

  • Freeze Protection for Fruits and Vegetables

    Chard and cauliflower crops show signs of freeze injury.

    By Pam Knox and Tim Coolong

    Untimely freezes can cause tremendous problems for fruit and vegetable crops.

    Fall freezes quickly put an end to the growing season for most fruits and vegetables. If freezes come earlier than expected or before the crops are ready for harvest, they can provide a devastating blow to yields and reduce the value of the crops. Spring freezes may destroy blossoms on plants that have recently broken dormancy, reducing yield by eliminating potential fruit or destroying young plants.

    Growers are sometimes able to reduce the impact of freezes by using frost- and freeze-protection measures to increase temperatures near the crops and prevent damage due to freezing temperatures.

    TYPES OF FREEZES

    There are two main types of freeze that can occur in fields, and freeze-protection methods depend in part on what type of freeze is expected to occur.

    Mustard greens that were cultivated prior to a freeze resulted in some plant damage.

    An advection freeze is caused by cold and dry air moving (“advecting”) into the production area, replacing the warmer, moister air that was already in place. An advection freeze is commonly associated with moderate to strong winds, a well-mixed air mass that does not have a temperature inversion, and low humidity. Temperatures will drop below freezing and may stay that way for an extended period.

    It is difficult to protect against an advection freeze because the wind blows added heat away from the crops and makes formation of protective ice from sprinklers difficult. The lack of a temperature inversion means that wind-moving devices like tall fans or helicopters do not have access to a warmer layer of air to mix with surface air. The dry conditions also mean that irrigation is often not effective at keeping temperatures above freezing, which can lead to ice loading on the plants as the sprinklers try to keep up.

    Radiation freezes occur when the sky is clear and winds are calm to light. Temperatures drop because with clear skies, radiation from the earth’s surface can quickly allow energy to escape to space. The coldest air tends to flow downhill because it is denser than the air around it, pooling in the lowest-lying areas (sometimes known as “frost pockets”). Radiation freezes are often accompanied by a temperature inversion aloft. This is a layer of air above the surface that is warmer than the air near the ground.

    One freeze-protection method is to mix warmer air down to the ground using fans or helicopters, keeping the surface air warmer. Frost-protection methods are generally more effective in radiation freezes than in advection freezes, especially when strong inversions with plenty of warm air are present. Sometimes a night with cold air blowing into an area results in an advection freeze occurring the first night followed by a radiation freeze the second night when the winds die down. Therefore, growers may need to be prepared for both types of freezes.

    FREEZE-PROTECTION METHODS

    If temperatures are not expected to be much below freezing, heating at ground level can be employed to keep temperatures higher. This can be done using orchard heaters or even burning debris or bales of hay in open areas of the field to be protected. This method can be helpful when a radiation freeze is occurring, especially when a strong inversion is present to trap the heat near the surface, but it loses effectiveness with strong winds. It also puts out a lot of pollution and can be expensive to maintain because of the fuel and labor needed to keep the heaters burning.

    If a strong inversion is present, methods for mixing the warmer air down to the surface can be used. This can include both wind machines such as large fans or helicopters. Helicopters have the advantage of being portable but are expensive to operate. Wind machines can be permanent installations or can be mobile, but only cover a limited area. If the inversion is weak, a wind machine could make matters worse by increasing evaporative cooling through the movement of the air.

    Irrigation can be an effective tool for freeze protection if it is able to be applied at a rate that “keeps up” with the freezing conditions. The irrigation is applied continuously to the crops, forming ice on the crops which releases heat to the air around those crops by the latent heat released by changing liquid water into solid ice. The plant material under the ice is kept near freezing by the ice cover and transfer of energy into the plant.

    Row covers can provide plants with some protection from frost, wind and insects.

    If the air conditions are windy, air will mix with the ice, forming cloudy ice that is less effective at protecting the plants, which reduces their ability to survive the frost. Clear ice is a sign that the freeze protection is likely working. If the air is low in humidity, irrigation is not very successful because most irrigation systems cannot put out water at a high enough rate to keep up with the effects of the cold air. If the dew point temperature of the incoming air is below about 22° F, then irrigation is unlikely to be effective. Even higher dew point temperatures are no guarantee that irrigation will work, especially in an advection freeze where wind is a factor.

    Sometimes growers will use center pivots to irrigate prior to a freeze event. Center pivots move far too slowly to directly protect a crop as described above. However, in some cases when the soil is dry, adding moisture to the soil can help it retain heat from the day, which can provide some protection in the evening. When the soil is already wet, further irrigating it will not help.

    Covering plants with plastic tarps or row covers has been used with varying success. A plant can be covered by mulch or a cover overnight to keep the cold air from hitting the plant. The cover (particularly clear plastic) must be removed the next day or sunlight will heat the cover, causing potential damage to the plant from excessive heat. Floating row covers that allow 2 to 4° F of freeze protection and have various degrees of light transmission can be purchased and easily moved around fields. Row covers also provide some protection from wind and insects. Mulch or plastic covers will be most effective when the ground has been warmed by the sun during the day. They are also aided by moist soil conditions, which help hold heat in the ground.

    Other methods such as cultivating ahead of a frost or spraying chemicals to prevent frost formation on the leaves have been tried by some growers. However, they have not proven to be effective in field trials and could cause additional damage to the plants, so should be undertaken with caution. In some cases, cultivation can expose roots to freezing temperatures and cause further damage.

    See secure.caes.uga.edu/extension/publications/files/pdf/B%201479_1.PDF for more information about freeze-protection methods and how to run a frost protection irrigation system.

  • Managing Root-Knot Nematodes in Vegetables

    Yellowing of pepper caused by root-knot nematodes

    By Johan Desaeger

    Root-knot nematodes (Meloidogyne spp.) are one of the most rapidly spreading of all pests and pathogens. The southeastern United States (Florida, in particular) is a paradise for these parasites. Nematodes cause damage to vegetables all over the world, and anyone who has had to deal with root-knot nematodes knows how difficult they are to control.

    Root-knot nematode damage is often not recognized and is frequently confused with other biotic or abiotic problems, such as disease, nutritional and watering issues. When nematode populations are high and weather and soil conditions are favorable, root-knot nematode damage can become so bad that total crop loss occurs. This is especially the case when soils are already warm at planting or when a double crop is planted on the same bed.

    Soil fumigants like Telone-chloropicrin mixtures and metam-based products like K-Pam are the most effective products when nematode pressure is high. Deep-shank (18-inch) injections of Telone can provide additional control in problematic fields by targeting nematodes that hide in the subsoil. Fumigants must be applied at least three weeks before planting to avoid phytotoxicity to the crop.

    NEW NEMATICIDES

    In the past, when beds were not fumigated, nematicide options for vegetable growers were limited to Vydate (oxamyl) and a few biological products. Over the past years, two new nematicides, Nimitz and Velum, have become available for vegetable growers in the Southeast. The new nematicides are less toxic and have a safer label (caution instead of danger) than previous products. They can easily be applied through drip irrigation systems. These nematicides should not be considered fumigant replacements, as they will target only nematodes. Additional measures need to be taken to manage soil diseases and weeds.

    Nimitz should be applied seven days before planting to reduce the risk of phytotoxicity to the crop, while Velum can be applied before and after planting. Fluopyram, the active ingredient in Velum, is the same as in the fungicide Luna, although no clear evidence of soil disease control was observed for Velum in University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) experiments. Care should be taken not to exceed the maximum annual use rate of fluopyram when using both Luna and Velum.

    Both Nimitz and Velum have been extensively tested at the UF/IFAS Gulf Coast Research and Education (GCREC) farm and are currently being evaluated in commercial fields. Their performance against root-knot nematodes on a variety of vegetables such as tomato, cucumber, squash, cantaloupe and watermelon was generally good and comparable to Vydate. Unless nematode pressure is too high, these products are a good alternative for growers that cannot or do not fumigate, or they may provide additional nematode control after fumigation when nematode pressure is high or long-season control is required.

    ORGANIC OPTIONS

    For organic growers, several biological products are available. They can be toxins derived from plants, bacteria or fungi while others are biocontrol organisms such as several species of bacteria and fungi. Some product names are ProMax, Kyte Gold, Ecozin, Dazitol, Majestene, DiTera and MeloCon. Typically, organic nematicides require multiple applications. In conventional production, they can be used as part of a program with chemical nematicides. Research into organic nematicides’ potential is ongoing at the GCREC and will be reported in future updates.

    Root-knot nematode damage on tomato

    Cover crops can also be good options to include in a nematode management plan. Summer cover crops like sunn hemp and sorghum-sudan grass can help reduce populations of most species of root-knot nematodes. The most common species in the Southeast are the southern (M. incognita), Javanese (M. javanica) and peanut (M. arenaria) root-knot nematodes. Often, vegetable fields will harbor more than one of these species. However, many more species exist.

    In Florida, more than 15 root-knot nematode species have been found, including seven in vegetables. One particularly virulent and aggressive species is the guava root-knot nematode (M. enterolobii). This nematode has become a serious concern for the sweet potato industry in the Southeast and can cause severe damage to almost all vegetables grown in the region.

    RESISTANT CULTIVARS

    Vegetable growers that fumigate may not care much what species of root-knot nematode they have in their field as fumigants probably kill all species equally. However, knowing your root-knot species does matter when cover crops or nematode-resistant tomatoes are part of the nematode management plan. Research at the GCREC has shown that while some cover crops, like cowpeas, may be poor hosts to certain species of root-knot nematodes, they may be good hosts to other species.

    Also, when root-knot nematode-resistant tomato cultivars are used, it is important to realize that while these cultivars are resistant to the three most common species mentioned above, they are not resistant to other root-knot species (including guava root-knot). Nematode-resistant tomato cultivars performed very well in root-knot nematode infested fields in recent trials in Florida. Root gall damage was negligible, and yields were increased compared to a susceptible cultivar. Fears, based on earlier reports that the nematode resistance gene in these cultivars might break down in the warm soils of Florida, were unjustified in GCREC trials.

    The resistant cultivars also greatly reduced nematode reproduction and root-knot soil numbers by the end of the crop. This is often not the case when only a fumigant is used, as the fumigant will protect the crop from early nematode damage and yield loss, but nematode populations often increase by the end of the crop. Nematode-resistant cultivars are the easiest and cheapest method to manage root-knot nematodes, but unfortunately nematode resistance is rarely a priority in tomato and vegetable breeding programs.