AgNet DEMO

Author: Robinson

  • 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.

  • Stanley Culpepper: A leading voice for growers

    By Clint Thompson

    When University of Georgia (UGA) Cooperative Extension weed agronomist Stanley Culpepper speaks, Tift County grower Bill Brim listens. After more than two decades of Culpepper providing expertise regarding more than 20 different vegetable crops, there’s no reason for Brim not to pay attention.

    “He’s a great young man. He’s a hard worker and tries to get things done. He’s the best one out at the (experiment) station, as far as I’m concerned,” says Brim, co-owner of Lewis Taylor Farmers in Tifton, Georgia.

    Culpepper’s accomplishments are a big part of why growers like Brim have confidence in what the scientist says. A professor in the UGA Crop and Soil Science Department, Culpepper is a world-renowned scientist at one of the leading agricultural colleges in the country and has had a lot to say over his 20-plus years at the Tifton campus.

    Culpepper’s team is improving tactics for vegetable growers to better manage weeds. In the last couple of years, he has been very active in fruiting vegetables, like tomato, pepper and eggplant; cucurbits, like watermelon, squash, cantaloupe and cucumber; cole crops, like broccoli and cabbage; and leafy greens, like collard and mustard; as well as carrots.

    Whether it’s researching alternatives to methyl bromide or developing management strategies for overcoming palmer amaranth weeds, Culpepper has had far-reaching impact in commodities across the world.

    “My team’s research efforts have always and will always follow the needs of our growers, which are of course, very diverse,” Culpepper says. “Developing alternative systems to methyl bromide that our farmers continue to rely on today was certainly among our more impactful work. I also think it was my favorite personal project. That effort was so large that I had an opportunity to work with growers for an extended period of time early in my career. Those growers really helped teach me how to grow vegetables on plasticulture. And of course, what good is research if the researcher can’t grow a crop like a grower?”

    UGA 3-WAY

    Culpepper’s work with methyl bromide alternatives is considered among his most impactful contributions as a scientist. For decades, Georgia vegetable producers relied on methyl bromide as a soil fumigant to control weeds, insects and nematodes. It was phased out in the mid-2000s, though, when the Environmental Protection Agency deemed it harmful to the ozone.

    Culpepper devoted almost 10 years of research to finding suitable alternatives. Brim said an effective alternative that Culpepper was responsible for was the UGA 3-way system that implements Telone II, metam sodium and chloropicrin.

    “What he did was just a tremendous help for us as far as developing a new product that we could use” for weed, fungus and nematode control, says Brim. “Without that, we’d probably be out of business. Methyl bromide was such a forgiving chemical as far as helping us develop nematicide programs and weed control and disease control. When we lost methyl bromide, we thought we were just done. Stanley did research here on the farm on the 3-way … two years before we actually started using it completely before methyl bromide was taken away from us. We really didn’t know until years later (how effective it was going to be), and now we’re still using the 3-way.”

    EXPANDING HERBICIDE LABELS

    Another area Culpepper has had a major impact on is the development of new herbicide tools for vegetable growers. His efforts have led to more than 34 new herbicide uses in various vegetable crops for Georgia farmers. He has also assisted growers in other states to obtain these labels.

    “I absolutely love finding new effective herbicides for a vegetable grower and getting them labeled in a way that is safe for the user, the crop and our environment. Of course, this accomplishment is the result of an amazing team of people working together from the University of Georgia, industry, IR-4, The Georgia Department of Agriculture and the U.S. EPA,” says Culpepper. 

    DESTINED FOR AGRICULTURE

    Culpepper was destined for a career in agriculture. He grew up on a bicentennial family farm in North Carolina where his family produced corn, cotton, peanuts, soybeans and wheat. So much of his childhood influenced every step of his career. Culpepper remembers those hot summer days of pulling weeds when he was very young. He even recalls chopping them down with a hatchet as some were twice as big as he was.

    “I thought I might be able to make a difference studying weed science,” Culpepper remembers. “Hopefully, I have.”

    He received a bachelor’s degree in agronomy and his master’s and doctorate degrees in weed science from North Carolina State University.

    Culpepper began his professional career at UGA as a cotton, vegetable and small grain weed scientist in 1999 and continues with those same responsibilities today.  

    ACCOMPLISHED CAREER

    Culpepper’s awards and accomplishments speak volumes about how his colleagues view his work. He has been a guest speaker at more than 300 events across the globe; 686 Extension county meeting presentations and 66 in-service Extension trainings. He has authored or co-authored 106 refereed journal articles, four book chapters, 406 abstracts for presentations, 223 Extension publications and 222 newsletters/blogs.

    Culpepper has received 31 professional awards. Some of the highlights include:

    • Donnie H. Morris Award of Excellence in Extensionfrom the Georgia Fruit and Vegetable Growers Association (2003)
    • Montreal Protocol Award from the EPA for assisting in the preservation of the ozone layer (2010)
    • Walter Barnard Hill Award for Distinguished Achievement in Public Service and Outreach from UGA (2014)
    • Southern Region Excellence in Extension Award from the Association of Public and Land-grant Universities (2016)
    • Walter Barnard Hill Distinguished Public Service Fellow Award from UGA (2019)

    In addition, Culpepper is currently serving a third term as a member of the Agricultural Science Committee of the U.S. EPA Science Advisory Board.

    Culpepper attributes his success to working with others. “Success is really driven by cooperation, whether that is with Extension agents, farmers, consultants, industry partners, regulators, or usually with all of these groups. As we continue to move forward in agriculture, this is a priority for our sustainability,” Culpepper concludes.

  • Mulch Improves Water Conservation in Vegetable Production

    Sweet onions are shown growing in Tifton, Georgia, with two types of mulch: organic (wheat straw mulch) on the left and inorganic (plastic mulch film) on the right.

    By Juan Carlos Díaz-Pérez

    For centuries, horticulturists have modified the crop microenvironment to extend the production season and enhance crop growth, yield and quality. Some of the techniques to achieve environmental modification include the use of mulches, high tunnels, greenhouses, etc.

    Mulches are widely used in both conventional and organic vegetable production. According to Wikipedia, “a mulch is a layer of material applied to the surface of soil with the goal of conserving soil moisture, improving fertility and health of the soil, and reducing weed growth.”

    Mulch may be organic (straw, leaves, cover crop residue, newspaper, wood chips, etc.) or inorganic, such as plastic film. Mulch effects on crops may vary depending on different factors.

    Factors affecting organic mulches include source of organic material (plant or animal), size of the particle, thickness of the mulch (amount applied) and age of the material. Factors affecting plastic mulch films include color, thickness, composition and permeability.

    In a vegetable crop field, soil water may be: 1) evaporated from the soil, 2) evaporated from the surface of the leaves of the crop, in a process called transpiration, 3) lost from surface runoff or 4) lost by percolation. In this article, we will focus on ways to improve soil water conservation.

    SOIL WATER EVAPORATION

    Both organic mulches and plastic mulch films act as barriers to water evaporation from the soil. These two types of mulches differ, however, in how they diminish soil water evaporation.

    In bare soil, water tends to evaporate from the soil. Soil water evaporation is proportional to the evaporative demand. Evaporation increases with increasing air and soil temperatures and decreasing relative humidity.  The rate of soil water evaporation also decreases as the soil water content decreases.

    According to the Food and Agriculture Organization of the United Nations, organic mulches may reduce soil water evaporation from 40 to 90 percent relative to bare soil. A thickness of 2 to 4 inches is effective in reducing evaporation. Soil evaporation tends to decrease with decreasing particle size of organic residues.


    Plastic mulch films are, in general, more effective in reducing soil water evaporation compared to organic mulches. Plastic mulch films differ in permeability to gases due to differences in film composition. For example, virtually impermeable film and totally impermeable film provide greater fumigant retention compared to low-density and high-density polyethylene film. With respect to soil evaporation, however, all plastic mulch films seem to be effective in conserving soil moisture.

    Physical damage or deterioration decrease the effectiveness of a plastic film to reduce soil water evaporation. Biodegradable mulches may be more prone to rapid deterioration compared to plastic mulch films.

    RAINFALL PENETRATION INTO SOIL

    Water-use efficiency increases when the crop uses rainfall water. Although organic mulches reduce soil evaporation, they allow for water penetration to the soil after a rainfall event. In fact, by reducing water flow through the soil surface and improving soil structure, organic mulches improve the water penetration to the soil and reduce soil runoff compared to bare soil.

    In contrast to organic mulches, plastic mulch films are impermeable to liquid water. Thus, they do not allow rainfall water penetration into the soil covered by the film. Rainwater that reaches the plastic film flows to the soil area between the beds and may result in soil runoff and soil erosion.

    In conclusion, both organic mulches and plastic mulch films are useful tools that help growers conserve soil moisture and increase irrigation efficiency.

  • New Findings on Growing Hemp in Florida

    By Tory Moore

    As the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Industrial Hemp Pilot Project research continues, growers around the state have begun growing hemp on their own farms. Researchers from the UF/IFAS Mid-Florida Research and Education Center (MREC) in Apopka have important considerations for Florida growers contemplating or currently growing hemp. Research lessons learned and new findings are the focus of this article.

    FLOWERING REQUIREMENTS

    Understanding hemp genetics, specifically flowering requirements, before you plant is vitally important.

    Hemp is predominantly a short-day, photoperiod-sensitive plant. In controlled environments like greenhouses, hemp is commonly grown under 18 hours of light to keep plants in a vegetative phase and then transitioned to 12 hours of light to initiate flowering. Supplemental lighting is necessary to maintain plants in a vegetative state when natural daylength is below the daylength that initiates flowering. Photoperiod requirements vary among hemp varieties and cultivars.

    Genetics determine whether flowering in a particular variety or cultivar is daylength dependent or daylength neutral (known as autoflowering).

    Daylength-dependent varieties and cultivars flower when daylength shortens to a critical threshold and triggers flowering. This is somewhere between 12 to 15 hours of daylight, depending on the variety or cultivar. Florida has between 13 to 14 hours of daylight on the longest day of the year, the summer solstice on June 21, which limits optimal planting time to within a few weeks of the solstice. Beyond optimal planting dates, plants can reach a desirable size if grown vegetatively under lights for three to six weeks prior to transplanting or removal from supplemental lighting. However, this is dependent upon the growth rate and plant architecture of the variety or cultivar.

    Daylength-neutral or autoflowering varieties and cultivars will flower after a specific maturity time, commonly 30 to 50 days after sowing. Autoflowering hemp plants are generally smaller and can be planted at higher densities, with some reports of seeding rates of up to 26,000 plants per acre.

    Take time to learn what the early stages of flowering look like so you can accurately track flower development. Flower bulking is noticeable starting around two to three weeks.

    Weekly or twice weekly, sampling of upper plant flowers and other plant tissue should be conducted after flowering has begun. Sample to ensure the crop does not exceed the 0.3 percent limit for total Delta-9 THC, commonly known as “going hot.” High floral density can be achieved by six to eight weeks after floral initiation.

    This illustration is representative of one cultivar’s flowering process. The transition can appear different across cultivars. Source: UF/IFAS Industrial Hemp Pilot Program

    Most high-cannabinoid hemp cultivars are dioecious, meaning plants are either male or female. Only female hemp plants produce desirable flowers and high-cannabinoid extract. When fertilized by male pollen, female plants produce seeds and produce less oil. It is critical to determine plant sex when cultivating essential oil-type hemp to prevent accidental production and pollination by male plants, which would reduce high-cannabinoid production ideal for CBD and CBG products.

    PEST MANAGEMENT

    Consider pest management early and evaluate pest pressure in your hemp crop often.

    You will encounter pests within your hemp crop. Commonly found pests include aphids, mites, arthropods (grasshoppers) and worms (tobacco budworm, corn earworm and beet armyworm).

    Weekly scouting for pests is recommended with special attention being made during flowering. Worm pressure is most noticeable during flowering and can devastate a hemp crop. If you identify your plants transitioning, be prepared for worm pressure.

    Pesticides available for use in hemp are limited. UF/IFAS recommends testing approved pesticides on a few plants to see if the products cause harm before treating the entire crop. Growers will want to be prepared to spray as soon as they see a need, so conducting this testing before a problem arises is critical. Since there are a lack of conventional pesticides available for use in hemp, be sure to know what pest control products are approved by the Florida Department of Agriculture and Consumer Services.

    Fungal issues in hemp have been observed both in greenhouse and field trials.

    IRRIGATION AND FERILIZATION

    Hemp needs adequate water for optimal growth but does not like “wet feet.” Hemp sitting in water for just a day or two can promote virulent fungi and kill plants.

    Selection of appropriate growth media or field space is critical to keep plants healthy. Keep in mind that hemp cultivars have varying water demands and tolerance. Dialing in your irrigation will be critically important for success.

    Preliminary findings for greenhouse-grown hemp suggest that plants can be grown in a wide variety of substrates. Hemp in container production seems to favor substrates with greater porosity (air space). Plants perform poorly in substrates that stay too wet, as root rot has been observed in other substrates.

    If fertigating, low fertigation on a consistent basis is advised to reduce leaching through the soil.

    In potted studies, significant losses were seen at soil electrical conductivity of 1.9 or greater. If fertigation is not possible, consistent results can be achieved with appropriate amounts of granular fertilizer.

    ADDITIONAL ADVICE

    If taking vegetative cuttings of the crop, the selection of proper rooting media is critical. Always use a rooting hormone to increase rooting success. Hormone concentrations that are too high can reduce rooting success; 1,000 parts per million indole-3-butyric acid tends to work well.

    Florida has unique growing conditions and pressures that make producing any new crop a challenge. Along with UF/IFAS Industrial Hemp Pilot Project information, rely on those successfully growing hemp in your area to provide data-driven and specific production advice. If you have not yet begun to grow hemp, consider the rules and regulations as well as the inherent risks of growing any new crop. 

    Hemp production lacks a body of knowledge validated by years of scientific research and data, much of which the UF/IFAS Industrial Hemp Pilot Program actively seeks to develop. UF/IFAS researchers recommend growers make hemp cultivation and management decisions and choose genetics based on information appropriate to their region and backed by science.

    UF/IFAS Extension agents across the state are available for support and to answer questions tailored to your region and farm. The UF/IFAS Industrial Hemp Pilot Project website (programs.ifas.ufl.edu/hemp) is updated regularly with the latest research results and ways to learn more about growing hemp in Florida.

    Acknowledgments: Steven Anderson, Brandon White, Brian Pearson and Roger Kjelgren contributed to this article.

  • Smart Irrigation Tools for Blueberry Growers

    Figure 1. A: The University of Georgia Smart Sensor Array (UGA SSA) node is installed in blueberries. The electronics are housed in the white PVC container. The spring allows the antenna to bend when farm vehicles pass overhead. B: The UGA SSA sensor probe integrates three Watermark sensors and can be customized to any length.

    By Vasileios Liakos

    One of the goals of the University of Georgia College of Agricultural and Environmental Sciences (UGA CAES) is to develop new irrigation methods and tools for crops. Researchers, including myself, Erick Smith, George Vellidis and Wes Porter, have been developing smart irrigation scheduling tools for blueberry growers in Georgia since 2015. Smart irrigation is a new method of irrigation that uses technology and information to make more accurate and faster decisions.

    UGA has developed two smart irrigation tools for blueberries — the UGA Smart Sensor Array (SSA) and the Blueberry App.

    SYSTEM RECORDS SOIL MOISTURE

    The UGA SSA is a system that records soil moisture within fields. It consists of a monitoring system, a commercial server that receives soil moisture data wirelessly, and a website that presents soil moisture data and recommends irrigation rates. The monitoring system consists of smart sensor nodes and a gateway. Each node has a circuit board, a radio frequency transmitter, soil moisture sensors, thermocouple wires and an antenna (Figure 1a). Each node accommodates two thermocouples for measuring temperature and a probe that consists of up to three Watermark® soil moisture sensors (Figure 1b).

    “Soil moisture sensors record soil water tension, and we realized very soon that farmers could not make irrigation decisions based on the sensor readings. It was necessary to convert sensor readings into amount of irrigation,” said UGA precision agriculture specialist George Vellidis.

    To overcome this problem, we utilized soil properties and a model to convert soil water tension numbers into inches of irrigation that is needed to saturate the soil profile. Additionally, farmers can see in real time their soil moisture data to make irrigation decisions for each location in fields using a web-based interface that was developed by UGA.

    IRRIGATION SCHEDULING APP
    Figure 2. Left: The main screen of the Blueberry App tells growers how many hours they need to run their irrigation systems and how many gallons they are going to use. It also allows them to check accumulated rainfall from the past seven days and the expected crop evapotranspiration for the next seven days. Right: Blueberry growers do not have to check the app daily since it notifies users if there is rain at the field and how much irrigation they need to apply.

    Blueberry growers can also use the Blueberry App on their smartphones to schedule irrigation (Figure 2). The app runs a model that uses reference evapotranspiration (ETo) data and the Penman-Monteith equation to calculate the irrigation needs of blueberries.

    The innovation of the Blueberry App is that it is programmed to receive forecasted ETo data for the next seven days for every location in the United States from the Forecast Reference Evapotranspiration service of the National Oceanic and Atmospheric Administration. Precipitation data are received from the Georgia Automated Environmental Monitoring Network and the Florida Automated Weather Network (FAWN).

    UGA has developed a crop coefficient curve that shows the water needs of blueberries in Georgia every year. The goal is to include more coefficient curves from other states. This will be capable if more blueberry growers use the app.

    By knowing the total ETo for the next seven days and the crop coefficient values of the blueberries, the crop evapotranspiration of blueberries can be calculated, and irrigation events adjusted accordingly.

    EVALUATION OF SOIL MOISTURE SENSORS

    Another interesting project, involving soil moisture sensors and blueberries, began a few months ago. The objectives of the project are to 1) compare different commercially available soil moisture sensors in blueberry soil, 2) determine the accuracy of each type of soil moisture sensor in blueberries and 3) determine which soil moisture sensor type is best for use in blueberries.

    Figure 3. Field trials are testing four different soil sensor types in blueberry fields.

    The soil moisture sensors used in this project are Watermarks, Irrometer tensiometers, Aquachecks and Decagons (ECHO EC-5). The selection of these sensors was made based on their popularity in the United States. Table 1 shows advantages and disadvantages of different types of soil moisture sensors.

    This study takes place at a UGA blueberry farm in Alapaha and at two commercial blueberry farms in Alma and Manor. At each site, the four different soil moisture sensor types have been installed close to each other along the beds to collect data to meet the objectives of the project (Figure 3).

    Source: Practical use of soil moisture sensors and their data for irrigation scheduling by R. Troy Peters, Kefyalew G. Desta and Leigh Nelson, 2013, Washington State University.

  • New Disease Threatens Florida Strawberries

    By Natalia A. Peres

    Pestalotia fruit rot lesions on ripe fruit; symptoms are very similar to those of anthracnose fruit rot caused by Colletotrichum accutatum.
    Photo by UF/IFAS GCREC

    Pestalotiopsis is not necessarily new to strawberry. A strawberry fruit rot caused by Pestalotia longisetula (or Pestalotiopsis) was reported for the first timein Florida in 1972. However, the fungus has always been considered a secondary pathogen. But this was not the case during the past two strawberry seasons (2018–19 and 2019–20), when severe outbreaks were reported in Florida commercial fields. Root, crown, petiole, fruit and leaf symptoms were observed. Yield was severely affected, and several acres of strawberry fields were destroyed before the end of the season.

    University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) studies indicate that isolates from the recent outbreaks are more aggressive and may belong to a new species of the genus Neopestalotiopsis.

    Many growers consider the disease a new threat to strawberry production. Several questions are being asked: Where did this come from? Why is it so aggressive? How does it spread? What are the conditions for the spread? Will it survive in Florida fields? How can it be controlled? UF/IFAS researchers are working hard on trials to understand the new disease and develop best management practices to control it.

    SUSCEPTIBILITY AND SPREAD

    UF/IFAS studies found the disease apparently originated from other hosts around strawberry nursery fields. Thus, strawberry cultivars do not seem to have any immunity to it, and all cultivars that are currently grown commercially in Florida (Florida Beauty, Florida Brilliance, Florida Radiance and FL127 SensationTM) are susceptible.

    The fungus is favored by high temperatures (77 to 86º F) and produces spores on the surface of infected tissues that are spread by water. Extended rainy periods or overcast conditions with prolonged leaf wetness during the strawberry season, such as those that occurred last December, are problematic. To minimize dispersal from field to field, growers are advised to limit their operations (such as harvesting or moving equipment through fields) when plants are wet. Current studies are focusing on sampling other hosts and weeds around Florida strawberry fields during the off-season to determine whether the fungus could become endemic in Florida. 

    MANAGEMENT METHODS

    Growers want to know how to manage the disease, and many different fungicide products have been screened in the laboratory and evaluated in field trials at the UF/IFAS Gulf Coast Research and Education Center (GCREC). In the field trials, the fungicide pre-mix of fludioxonil + cyprodinil (Switch® 62.5 WG) and thiram (Thiram® SC) significantly reduced disease incidence.

    Only a few other fungicides that are not currently labeled for strawberry use were somewhat effective. Since the overuse of fungicide products can lead to increased selection for fungicide resistance, applications need to be limited to the maximum the label recommends, and research needs to continue to seek alternatives.

    For the upcoming season, growers should closely scout plants arriving from nurseries for leaf spot symptoms. Unfortunately, there are many leaf spot diseases that look alike, so it is important to get the correct diagnosis. If caught early and at low levels, removing the symptomatic plants from the fields is advisable.

    The current seasonal forecast is for La Niña, which is known to bring a warmer than normal and dry climate pattern to Florida and the Southeast. The dry weather during La Niña years is usually not conducive to fungal diseases such as pestalotia leaf spot as well as anthracnose and botrytis.