Misinformation relating to horticulture can spread quickly among laypersons. Although some misinformation may be harmless, such as the myth that bell pepper (Capsicum annuum) fruit can be either male or female, other misinformation is generated to sway consumer decisions. The demand from Cooperative Extension Service (CES) agents for support to combat the spread of horticultural misinformation, horticulture specialists at the University of Arkansas System Division of Agriculture Cooperative Extension Service (UACES) created a “Horticulture Fact or Fiction” series of blog posts that targeted common horticulture myths with science-based explanations and used graphics interchange format (GIFs) to promote the blog posts on social media. The integrated social media campaign was shared on the authors’ UACES Horticulture social media accounts and by eight UACES agents during 2021. The effort reached 13,397 social media users, and the blog posts had a total of 45,544 pageviews. Although social media was not the major driver of traffic to the blog post series, GIF-based outreach on social media did direct more than 1000 additional users to the blog posts. Through this integrated approach of using social media and GIFs shared by both specialists and CES agents, we were able to connect a large number of stakeholders to research-based content, resulting in higher average traffic to our webpage-based blogs than the average UACES webpage. This type of integrated approach using multiple online means of communication including GIFs, blogs, and social media to create a toolkit of resources for CES agents may be useful for extension professionals targeting stakeholders online.
Sarah Cato, Amanda McWhirt, and Lizzy Herrera
Catherine G. Campbell, Jorge Ruiz-Menjivar, and Alia DeLong
Florida, like much of the southeastern United States, is rapidly urbanizing. With this urbanization, there is an increasing interest in commercial urban agriculture (CUA) as an important sector for agriculture in the state. The U.S. Department of Agriculture Census of Agriculture does not report data about CUA operations, thus limiting the knowledge about the status of CUA operations regarding basic features such as farm size, operator demographics, production systems, sources of revenue, barriers to business operations and profitability, and future opportunities for development. Because previous research has found differences in urban farmers’ demographics and their perceptions of barriers and opportunities, the purpose of this research was to characterize CUA operations in Florida and to understand the urban farmers’ perceptions of the primary needs, barriers, and opportunities for developing CUA, as well as CUA operators’ informational needs and preferred informational formats. We performed a cluster analysis to identify salient groups of urban growers in Florida to identify subgroups based on shared characteristics that revealed three distinct groups of urban farmers with differing perceptions of barriers, opportunities, informational needs, and preferred informational formats.
Sandhya Neupane and Fulya Baysal-Gurel
Phytophthora root rot, caused by Phytophthora nicotianae Breda de Haan, is one of the destructive diseases of boxwood (Buxus sempervirens L.) and can affect all growth stages of field- and container-grown boxwood plants. Management is a problem and is only possible through an integrated approach. In this study, the efficacy of fungicides, biofungicides, host-plant defense inducers, and fertilizer were evaluated to manage Phytophthora root rot of boxwood. The objective of this experiment was to develop fungicide and biofungicide recommendations for Phytophthora root rot management in boxwood production. Field and greenhouse experiments were conducted in 2019 (Trial 1) and 2020 (Trial 2). The field experiment was arranged in a completely randomized design with four plots per treatment with five single ‘Green Velvet’ boxwood plants per plot. The greenhouse experiment was arranged in a completely randomized design with five single ‘Green Velvet’ container-grown boxwood plants per treatment. Plots/containers were inoculated with P. nicotianae grown on rice grains. Plant growth data such as height and average width were recorded at the beginning and end of the experiments. Total plant fresh weight and root fresh weight were recorded at the end of the experiments. Roots were assessed for root rot disease severity using a scale of 0% to 100% roots affected. Treatments used in both experiments were fungicides—ametoctradin + dimethomorph, fluzapyroxad, mefenoxam, oxathiapiprolin, pyraclostrobin, pyraclostrobin + boscalid; host-plant defense inducers—aluminum tris-drench, aluminum tris-foliar, potassium salts of phosphoric acid; biofungicides—Trichoderma harzianum Rifai strain T-22 + Trichoderma virens strain G-41, Bacillus amyloliquefaciens Priest; fertilizer—water-soluble nitrogen (nitrogen 5%) and soluble potash; and combination of water-soluble nitrogen, soluble potash, and T. harzianum Rifai strain T-22 + T. virens strain G-41. All treatments were drench applied except one of the aluminum tris, which was applied as foliar. The controls were nontreated, inoculated and nontreated, and noninoculated boxwood plants. In the greenhouse experiments, treatments that effectively reduced disease severity were pyraclostrobin, ametoctradin + dimethomorph, and oxathiapiprolin. In the field experiments, treatments such as pyraclostrobin, oxathiapiprolin, mefenoxam, fluzapyroxad, and combination of water-soluble nitrogen (nitrogen 5%), soluble potash, and T. harzianum Rifai strain T-22 + T. virens strain G-41 effectively reduced Phytophthora root rot severity. Oxathiapiprolin and pyraclostrobin are the chemical fungicides that were effective in both field and greenhouse experiments.
Barbara J. Smith, Amir Rezazadeh, Eric T. Stafne, and Hamidou F. Sakhanokho
Supplemental lighting is frequently used to extend daylength for strawberries (Fragaria ×ananassa) grown in greenhouses and high tunnels; however, information is limited on the effect of these lights on disease development. We evaluated the effect of ambient light and six supplemental light treatments [red, blue, and white light-emitting diodes (LEDs), separately; a combination of red, blue, and white LEDs; wide-spectrum fluorescent (WSF); and WFS + ultraviolet B (UV-B)] on plant growth and disease response of strawberries grown in a greenhouse. Plants were exposed to supplemental light treatments for 17 h each day. In the WSF+UV-B treatment, plants were exposed to WSF light during the day and to UV-B light for 3 hours during the night. Two trials were conducted; each trial contained five or six cultivars and was replicated three times. Twice during each trial, detached leaves from each cultivar in each light treatment were inoculated with a conidial suspension of the anthracnose crown rot pathogen, Colletotrichum gloeosporioides and rated for disease severity 10 days later. There was a significant difference due to light treatment and to cultivar in relative chlorophyll content and plant growth parameters. Plant injury ratings were lowest in the white LED, WSF, and WSF+UV-B treatments. Plants in the combination LED and red LED light treatments received higher injury, lower vigor scores, and lower relative chlorophyll content values than plants in all other light treatments. After inoculation of detached strawberry leaves with C. gloeosporioides in Trial 1, there was a significant effect due to light treatments on disease severity ratings (DSRs) after 18 weeks’ exposure to light treatments with the DSRs in the WSF+UV-B treatment being lower than those in all other treatments except those in the red LED treatment. There was not a significant effect in DSRs due to light treatments after 24 weeks in Trial 1 or after 4 or 22 weeks in Trial 2. There were significant effects due to cultivar on DSRs in both trials: ‘Strawberry Festival’, ‘Pelican’, and ‘Seascape’ received the lowest DSRs. This study showed an effect of supplemental light on several strawberry plant growth parameters, including a harmful effect of high-intensity red LED irradiation.
Sofía Gómez and Celina Gómez
Biostimulant products have various reported benefits for plant production in the field or using hydroponic systems in protected structures. However, limited information is available describing their potential use for indoor farming applications. Considering that lettuce (Lactuca sativa) is one of the most popular crops produced in commercial indoor farms, the objective of this study was to compare growth and quality of lettuce grown indoors using nine biostimulant products derived from humic substances, amino acids, hydrolyzed proteins, or seaweed extracts. ‘Monte Carlo’, ‘Fairly’, and ‘Lalique’ lettuce were grown hydroponically for 30 to 33 days under a daily light integral, day/night temperature, relative humidity, and carbon dioxide concentration of ≈13 mol·m‒2·day‒1, 22/21 °C, 70%, and 800 µmol·mol‒1, respectively. There were no positive effects from using any of the biostimulant products evaluated in our study as growth (leaf area, leaf number, shoot diameter, and shoot and root dry weight), yield (shoot fresh weight), and quality (bolting, tipburn index, leaf color, and SPAD index) of treated plants were generally similar to those from the untreated control. Applications from one seaweed extract caused slight negative growth effects, possibly due to phytotoxicity. Cultivar differences showed that Fairly plants had the highest susceptibility to tipburn and bolting, and none of the biostimulant products countered these symptoms. Overall, the products evaluated provided marginal advantages for indoor hydroponic lettuce production.
Asmita Paudel and Youping Sun
Albizia julibrissin (mimosa tree) and Sophora japonica (Japanese pagoda tree) are drought-tolerant landscape plants; however, salinity responses of these two species are not well documented. The objective of this study was to investigate the morphological and physiological responses of these two species to three salinity levels in greenhouse conditions. Two studies were conducted in the summer/early fall of 2020 and the spring of 2021. In 2020, uniform plants were irrigated weekly for the first 2 weeks and every other day for the following 3 weeks with a nutrient solution at an electrical conductivity (EC) of 1.2 dS·m−1 as a control or saline solution at ECs of 5.0 or 10.0 dS·m−1. In 2021, plants were irrigated weekly for 8 weeks with the same treatment solutions as described previously. Albizia julibrissin and S. japonica survived in both experiments with minimal foliar salt damage (leaf burn or necrosis). Irrigation water at ECs of 5.0 and 10.0 dS·m−1 reduced plant height and dry weight (DW) of both species. In the fall experiment, A. julibrissin irrigated with a saline solution at an EC of 10.0 dS·m−1 had the highest reduction in plant height (61%) compared with the control. Albizia julibrissin and S. japonica irrigated with a saline solution at an EC of 10.0 dS·m−1 had 52% and 47% reductions in shoot DW compared with the control, respectively. In the spring experiment, compared with the control, there were 72% and 45% reductions in height of A. julibrissin and S. japonica, respectively, when irrigated with saline solution at an EC of 10.0 dS·m−1. In addition, compared with the control, A. julibrissin and S. japonica had 58% and 64% reductions in shoot DW, respectively, when irrigated with saline solution at an EC of 10.0 dS·m−1. Increasing salinity levels in the irrigation water also reduced leaf greenness [Soil Plant Analysis Development (SPAD)], leaf net photosynthesis rate (Pn), stomatal conductance (g S), and transpiration rate (E) of both species. Furthermore, sodium (Na+) and chloride (Cl−) concentrations in leaves were affected by elevated salinity levels in the irrigation water. Visual score, Pn, g S, and E negatively correlated to Na+ and Cl− concentrations in leaves. But Cl− accumulation had more impact on the growth of A. julibrissin and S. japonica. In summary, both species were tolerant to saline solution irrigation up to 5.0 dS⋅m−1 and moderately tolerant to saline solution irrigation up to 10.0 dS⋅m−1.
Haruna Kobayashi, Kiyomi Hashimoto, Erika Ohba, and Yohei Kurata
Light-emitting diodes (LEDs) are known to affect plant morphology. In this study, we examined the relationship between changes in stem and root morphology in Populus sieboldii × Populus grandidentata induced by irradiation with blue (450 nm), red (630 nm), and white (combination of red, blue, and green; 525 nm) LED lights. Populus samples were reared for 36–55 days in separate LED incubators, and changes in their appearance were observed. After rearing, the main stem of each seedling was cut, leaving a section of stem extending from the roots to ≈20 mm above the medium surface; this part was used for tensile testing. The tensile tests were performed to clarify the relationship between the tensile force and displacement until 100 mm. Irradiation with blue light produced the tallest seedlings. The highest dry weight (root and stem) and largest stem diameter were obtained under red light. The results of the tensile tests showed that the work required to displace seedlings 100 mm was highest in plants reared under red light, followed by white and blue light. Numerous root branches developed under red light, and taproots were longest in saplings reared under blue light. The observed differences in root system morphology that were induced by rearing under light of different wavelengths were reflected in the tensile force required to extract the trees from the medium. The morphological changes observed in roots are important given the role of roots in forests after landslides, earthquakes, and other disruptions.
Katherine Brewer, Mary Hockenberry-Meyer, Susan Galatowitsch, and Stan C. Hokanson
Prairie dropseed [Sporobolus heterolepis (A. Gray) A. Gray] is a critical North American native grass that is often not incorporated into prairie restoration seed mixes due to its low survival and growth rates. This project investigated using hydrogels, landscape plugs, and native field soil to improve the survival and growth of prairie dropseed. At three tallgrass prairie restoration sites at the Minnesota Landscape Arboretum, we planted prairie dropseed plugs in Fall 2019, Spring 2020, and Fall 2020. When grown in the field from 42 to 94 weeks, we found that potting mix–grown plugs had increased growth as measured by dry weight compared with plugs grown in native soils. Soil medium did not influence survival rates. The use of hydrogels did not demonstrate increased survival or growth compared with plugs planted with water. We recommend land managers and restorationists use plugs grown in commercial potting mix rather than grown in native soils, and we found no advantage in using hydrogels over watering at planting.