Project : USDA ARS

ARS Home » Midwest Area » Wooster, Ohio » Application Technology Research » Research » Research Project #438340

Research Project: Sustainable Production and Pest Management Practices for Nursery, Greenhouse, and Protected Culture Crops

Location: Application Technology Research

2024 Annual Report

Objectives
1: Develop growth models integrating light, temperature, carbon dioxide, and other environmental factors into decision-support software tools to reduce energy costs or increase yield and quality of ornamental and edible crops grown under controlled environment. 2: Develop nutritional and substrate amendment guidelines that improve crop quality and yield or reduce environmental impacts of food and ornamental plants grown in protected horticulture. 3: Develop new hydroponic and container-culture technologies that improve substrate chemical, physical, or biological properties and reduce nutritional, water, and agrichemical inputs. 4: Identify alternative control agents and develop and/or improve methods and strategies for managing pests (insects, other arthropods, and weeds) in horticultural (food and ornamental) crops through improved knowledge of pest biology, ecology, & behavior in order to reduce pesticide usage.

Approach
Ornamental, nursery, and protected culture crops represent about one-fourth of the farm gate value of all specialty crops, and about 15% of the total value of U.S. crop production (USDA NASS Horticultural Crop Census 2014). Production value of nursery and greenhouse crops was estimated at $19 billion in 2013 (USDA NASS Horticultural Crop Census 2014). This project brings together the expertise of USDA-ARS research scientists with cooperators at other universities to focus on ornamental, nursery, and protected culture research. The project is a science-based, outcome-driven, economically motivated program that is already assisting growers in improving the quality of their food and ornamental crops. This project will continue to further our knowledge base in protected culture crops by: 1) integrating light, temperature, carbon dioxide, and other environmental parameters into growth models that enhance decision support in greenhouses and controlled environments, 2) continue developing silicon and other substrate amendments to enhance crop quality and mitigate biotic and abiotic stress, 3) engineering substrates to improve nutrient and water use efficiency, and 4) developing novel management strategies for insects and weeds that integrate knowledge of pest biology with cultural practices and management tools. This project integrates the mission and expertise of the Application Technology Research Unit with other researchers in disciplines critical to the overall success of the project.

Progress Report
In support of Objective 1, Objective 1. Sub-Objective1A: Photosynthetic response curves to light and carbon dioxide (CO2) were developed for five culinary herbs (basil, cilantro, mint, parsley, and sage). Sub-objective 1C: Further improvements have been made to Virtual Grower 4 to improve accuracy of greenhouse heat balance calculations. These include differential equation solvers for heat transfer, in particular heat gain from solar radiation. Instrumentation has been set up to collect multi-year solar spectrum and weather data from ARS-leased greenhouses in Toledo. Sub-Objective 1D: We continue to make improvements to the design and prototype of a near-field radiometer used to characterize the spatial distribution of horticultural lighting. Using belt-driven linear actuators we can move the sensors over a larger distance than can be achieved with lead screw designs. In support of Objective 2, Sub-objective 2A: Progress continues to retrofit and program growth chambers capable of providing a low CO2 environment for research studies. Development of silicon (Si) fertilization guidelines for protected horticulture crops continued. Wollastonite had an almost-equivalent impact on substrate pH as dolomitic limestone, whereas rice hulls had a minimal impact on substrate pH. We are evaluating the effectiveness of Si to mitigate chilling injury in culinary herbs. Preliminary data indicate Si may be beneficial to some, but not all, of the herbs evaluated. Sub-objective 2B: We evaluated nutrient management strategies to increase strawberry daughter plant production. Another study showed daughter plant number was greatest when a fertilizer concentration 1.7x to 2.7x higher than the recommendation for fruit production was applied. ‘Albion’ was more sensitive than ‘Monterey’ to high fertilizer concentrations. Sub-Objective 2C: Experiments were completed to determine how soilborne pathogens recolonize soils treated with anaerobic soil disinfestation. Quantitative PCR (qPCR) was completed to quantify Pseudopyrenochaeta lycopersici (corky root rot) and Colletotrichum coccodes (black dot root rot), but a new qPCR assay needs to be troubleshot for Verticillium dahliae. Once completed, soil microbial communities can be assessed with high throughput sequencing for pathogen suppressive soils. Evaluation of gasses in sulfur supplementation experiments was delayed due to instrument failure and repair time. Field trials on anaerobic soil disinfestation were established at four farms in Ohio. These trials will be completed in Fall 2024. In support of Objective 3, Sub-Objective 3A: All textured bark research is complete. Peer refereed papers have been published or are in preparation. Research compared and contrasted gas diffusivity, nitrogen emissions, relationship between water storage and water potential, unsaturated hydraulic conductivity, and solute transport in various textured substrates alone or in combination, providing insights both to the basic science of soil physics and substrate design and their application in CEA. Research is ongoing to investigate different size fractions of biochar and hazelnut shells as a substrate amendment. Sub-Objective 3B: Completed and published practitioner methodology for extracting pore- water when utilizing stratified substrates or altering fertilizer placement. Sub-Objective 3E: Conventional water quantity and quality data collected at two Ohio nurseries, comparing the effect of irrigation type and regime is being submitted to a peer reviewed publication. Operational water collected at nursery and greenhouse facilities in Ohio, North Carolina, South Carolina, and Louisiana are being analyzed for emerging contaminants. Concurrently, intensive water hydrology analyses and sampling are taking place at a cooperating nursery in southeastern U.S. coastal plain across open and closed production systems.. Sub- Objective 3F: Biostimulant experiments for leafy greens were completed using spinach and Phytophthora pseudocryptogea but no biostimulant effectively reduced disease. Final experiments on the combination of biological control agents with chitin and chitosan will be completed in tomato-Fusarium bato bucket systems. In support of Objective 4, Sub-objective 4B, Hypothesis 4B.1: Research was conducted to compare the influence of drought stress vs. flood stress on predisposing ornamental trees to mass infestation by ambrosia beetles. Flood stress induced the emission of ethanol, which is a strong attractant for ambrosia beetles. Hypothesis 4B.2: A third season of seasonal flood tolerance is underway on species-1 (dogwood) and the second season on species-2 (apple) with the ‘early season’ portion of experiment completed. We are continuing with one of the contingencies to examine factors in addition to ethanol that may affect colonization of trees by ambrosia beetles. A third year of investigating the influence of acetic acid on ambrosia beetle colonization has started. Sub-Objective 4B.3: Research evaluated portable devices for detecting the emission of ethanol from stressed trees. A 3-D printed sensor mounting device was designed and tested for use with a commercially available sensor. The emission of ethanol from stressed trees, was characterized over time after initiating flood stress as a tool for monitoring tree health. Sub-Objective 4B.4: Field research continued to test a proprietary compound for reducing the attraction and colonization of ambrosia beetles to ornamental trees. Sub-Objective 4B.5.1: Gas chromatography- electroantennographic detection (GC-EAD) were used to characterize the antennal sensitivity of ambrosia beetles to stress-induced attractants (i.e., acetic acid and ethanol). Laboratory experiments demonstrated the benefits of stress-induced compounds within trees on the offspring production of ambrosia beetles, which has applications for management tactics and rearing beetles for research purposes. Sub-objective 4C, Goal 4C.1: We completed 2 years of testing monitoring techniques for red-headed flea beetles but found no suitable monitoring devices and thus were unable to develop a reliable seasonal activity profile. Goal 4C.2: We have not been able to find a reliable source to collect sufficient beetles in the field to run experiments for screening control materials. Therefore, we are working to develop methods for maintaining a colony of red-headed flea beetles to use in future research and reveal more information about their ecology. Sub-Objective 4D.1: Portable techniques were compared to reveal the presence of insect infestations of food crops grown within controlled environments. Volatiles were detected using a portable gas chromatograph (i.e., z-nose) following infestations by aphids and whiteflies. Research was completed to characterize the species complex and seasonal activity of dipteran pests infesting gourmet mushrooms, along with variability in the defenses of different oyster mushroom species to fungus gnats. Sub- Objective 4D.2: Research was completed to evaluate the repellent activity of plant-based essential oils and reduced risk insecticides against fungus gnats that infest oyster mushrooms. Analytical studies were conducted to determine the composition of active and inactive essential oil formulations against fungus gnats. Sub-Objective 4E: We successfully rescued and stabilized the mycovirus, determined the host range, and prepared the viral particles for transmission electron microscopy image analysis as the confirmation of viral replication in S. sclerotiorum, also known as white mold. Greenhouse and field trials have been carried out and showed promising results. When grown in soil mixed with SlaGemV-1-infected S. sclerotiorum, plant displays a resistant phenotype to virus-free pathogenic S. sclerotiorum infection, known as the “biopriming” effect. We also have advanced the spray-induced gene silencing (SIGS) technology in the control of white mold. We developed the SIGS to silence S. sclerotiorum argonaute 2, a crucial part of the fungal gene regulation and defense system. We have obtained promising results from greenhouse trials and will proceed to do field trials.

Accomplishments
1. More profitable containerized crops using stratified substrates. Container growing media has gone from soil-based to soilless culture over the past 70 years, always filling the container uniformly resulting in a wet or saturated container bottom or inefficient use of applied water and fertilizer resources. ARS scientists in Wooster, Ohio developed a novel and paradigm-shifting approach to filling containers in stratified layers with two or more substrates to increase functionality and reduce costs. Substrate stratification has been shown to increase root growth, decrease water use and fertilizer, shorten crop time to market, and reduce costs by 40%. Additionally, stratification can extend peat-based substrates by 50%, providing the most ideal solution to the reoccurring Canadian sphagnum peat shortage. This new approach of stratifying substrates is now taught as part of undergraduate horticultural production crops across the United States. Greenhouse and nursery growers throughout the U.S. are now adopting substrate stratification in both greenhouse and nursery crops. Growers have begun to implement automation to streamline use of substrate stratification.

2. Increasing profits by decreasing pot temperature for horticultural crops grown in containers. Container growing media often exceeds 120ºF when producing horticultural crops in black containers, with temperatures staying above ambient air temperature until the next day. High media temperatures slow or stop crop growth, damage or kill roots, increase incidence of crop death, shrink the number of marketable plants, and increase the rate of fertilizer release. ARS scientists in Wooster, Ohio and McMinnville, Tennessee, found that white pots decreased substrate temperature by 8 to 12ºF, increased crop health and growth by up to 130%, and retained 35% more fertilizer. This research led to the adoption of white containers throughout the nursery industry. One early adopter (a ~1,000-acre wholesale nursery) found that switching to white containers saved 40% on container costs and reduced production time by 30%. This equates to an estimated cost savings of up to $7,300 per acre per year.

3. Flood stress, but not drought stress, induces ambrosia beetle infestations of trees. Invasive ambrosia beetles infest trees in ornamental nurseries and orchards weakened by physiological stress. Flood stress predisposes trees to infestations, but the influence of drought stress has not been studied. ARS researchers in Wooster, Ohio, in collaboration with researchers at Tennessee State University and North Carolina State University, showed that flood stress, but not drought stress, predisposes trees to mass attack by ambrosia beetles. Ambrosia beetles were more likely to land on flood-stressed trees than drought-stressed ones. These results will aid growers of horticultural trees in understanding how water stress predisposes trees to infestation by ambrosia beetles and in developing a management plan based on tree health.

4. Flight activity of invasive ambrosia beetles increases the risk window to horticultural tree crops. Wood- boring ambrosia beetles are among the most successful invasive species on a global scale, which poses challenges for producers of horticultural tree crops in the U.S. ARS researchers in Wooster, Ohio, demonstrated that invasive species of ambrosia beetles fly earlier and for much longer durations compared to native species. The peak flight activity of Anisandrus maiche, a newly established exotic species, follows the peak activity of other long-established species. This extended flight activity increases the risk window to tree crops, whereby trees stressed by extreme climatic events in spring and mid-summer can be mass attacked by ambrosia beetles. Producers of trees in ornamental and orchard systems will be able to better manage ambrosia beetle pests through an improved understanding of their seasonal flight activity.

5. Improved energy use efficiency in indoor farms. Energy use in controlled environment agriculture is usually the highest cost category after labor. Energy models can be used to estimate these costs and environmental control system optimizations can have a large impact. A steady state energy model and crop growth model using machine learning were developed by ARS researchers in Toledo, Ohio. Energy use efficiency (EUE) of simulated indoor farms was shown to be improved by shifting photoperiod and corresponding electrical loads to nighttime off-peak periods and using higher temperature setpoints when using cultivars that aren’t as sensitive to higher temperatures. Facilities located in climates with lower outside air temperatures, particularly at night, were shown to have significantly lower energy consumption. These models allow growers to choose sites with smaller carbon footprint and lower operating costs due to energy savings.

6. Improved nutrient management guidelines for strawberry daughter plant production in controlled environments. Strawberry fruit production in greenhouses has rapidly expanded in recent years. This has increased the need for healthy, disease-free starting plant material for fruit producers. Propagation of strawberry plants in the U.S. typically consists of removing and rooting the “daughter plants” that develop on a plant. ARS researchers in Wooster, Ohio developed improved nutrient management strategies for greenhouse-grown strawberry plants that optimize the formation of daughter plants rather than strawberry fruit. Relative to optimal fertilizer recipes for strawberry fruit production, increasing the fraction of nitrogen supplied as nitrate and increasing the fertilizer concentration individually increased daughter plant production by up to 50% more than current industry practices. The increased yields will help improve profitability for propagators and increase the supply of rooted plants for the greenhouse strawberry industry.

U.S. DEPARTMENT OF AGRICULTURE

Application Technology Research: Wooster, OH