Widespread herbicide-resistant weeds and severe insect pest infestations pose a challenge to the preplant pest management (PPPM) strategy currently in use in leaf vegetable fields in southern China. The aim of this study was to develop a new weed and insect control method for use before planting leaf vegetables in southern China. Two flaming machines (a tractor mounted and a trolley flaming machine) were designed, and their efficacies for the control of insect and weed pests were evaluated and compared in two field trials. With liquefied petroleum gas (LPG) at 101 kg·ha−1, flaming machines reduced plant numbers by 86.7% to 98.8% 2 days after treatment (DAT), which was equal to or higher than the reduction after application of paraquat at 900 g·ha−1. Some weed species, especially awnless barnyard grass (Echinochloa colona) and goosegrass (Eleusine indica), regrew at 7 DAT, resulting in a decrease in control efficacy. Flaming machines also reduced the number of diamondback moth (Plutella xylostella) larvae by 83.0% to 88.2% and the number of adult striped flea beetles (Phyllotreta striolata) by 64.9% to 80.9%. This is the first report on flaming treatment in China to show that this method is a promising alternative to chemical pesticides for PPPM in leaf vegetable fields.
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Wenlei Guo, Li Feng, Dandan Wu, Chun Zhang and Xingshan Tian
Kaitlin Barrios and John M. Ruter
Swamp sunflower (Helianthus simulans) is an underused perennial plant native to the southeastern United States that produces an abundance of golden yellow inflorescences in the fall. It is a vigorous grower and tolerates a wide variety of soil conditions, growing in wetland and nonwetland habitats. Swamp sunflower warrants wider use in perennial beds and landscapes, and research on production practices to make plants more suitable for shipping could promote its production. This study evaluated the effects of plant growth regulators (PGRs) on the growth and floral attributes of the swamp sunflower. Treatments were applied to rooted cuttings in 1-gal pots as a substrate drench of 1, 2, 4, or 6 mg/pot paclobutrazol; 0.5, 1, 2, or 4 mg/pot flurprimidol; or water (control)/pot for Expt. 1. A second experiment (Expt. 2) applied 4, 6, or 8 mg/pot paclobutrazol; 2, 4, or 6 mg/pot flurprimidol; or water (control)/pot. Six weeks after treatment (WAT) for Expt. 1, paclobutrazol applied at 4 and 6 mg/pot and flurprimidol at 2 and 4 mg/pot resulted in smaller plants (as reflected by growth index) by 29%, 34%, 22%, and 48%, respectively, compared with the control. Furthermore, at the termination (6 WAT) of Expt. 1, the highest rate of flurprimidol produced the smallest plants, with the exception of the highest rate of paclobutrazol. By 6 WAT, plants treated with the highest rate of paclobutrazol and flurprimidol had lower dry weights and higher chlorophyll measurements than control. All PGR treatments for Expt. 2 resulted in smaller plants than the control by 27% to 36% at 4 WAT and 23% to 41% at 6 WAT. Differences for internode length and flower diameter were observed for Expts. 1 and 2, respectively. Results from these experiments suggest a substrate drench application of 6 mg/pot paclobutrazol or 4 mg/pot flurprimidol can be used for producing smaller plants compared with nontreated plants for swamp sunflower under greenhouse conditions.
Urban horticulture is not as new as many people think. Throughout history, different techniques have been used to ensure sustainable urban agricultural production. A good example of this is the chinampa system, which was developed during the time of the Aztecs in the region of Lake Xochimilco, south of Mexico City. A chinampa is a raised field on a small artificial island on a freshwater lake surrounded by canals and ditches. Farmers use local vegetation and mud to construct chinampas. Fences made of a native willow [bonpland willow (Salix bonplandiana)] protect the chinampa from wind, pests, and erosion. The dominating crops are vegetables and ornamentals. The canal water that rises through capillarity to the crops reduces the need for additional irrigation. A considerable portion of the fertility in the soils is system-immanent and generated in the aquatic components of the chinampa. Complex rotations and associations allow up to seven harvests per year. Chinampas also provide ecosystem services, particularly greenhouse gas sequestration and biodiversity diversification, and they offer high recreational potential. Recently, research and community initiatives have been performed to try to recover the productive potential of chinampas and align this sustainable system with the needs of the 21st century. In other parts of the world, some with a history of raised field agriculture, similar efforts are being made. The chinampa model could help supply food and ecosystem services in large cities on or near swamplands, large rivers, or lakes.
John L. Griffis Jr.
In most highly developed countries, landscaping and ornamental plants are routine components of the urban environment. However, in many Third World countries, this is not the situation outside of the larger cities. Landscaping and ornamentals are associated with hotels, public parks, offices, government buildings, and wealth; they are not significant commodities in rural settings. However, as urban areas in these countries—such as Senegal—expand and modernize, there is an increased demand for ornamental plants. Senegal’s urban population has almost doubled during the past five decades, increasing from 23% in 1960 to 43% in 2013. New jobs and sources of income are available for individuals who are properly trained in ornamental plant production and maintenance. Senegal has several rural training centers where some courses in agronomy and vegetable production are taught, but ornamental plant production is not included in the curriculum. This U.S. Agency for International Development (USAID) Farmer-to-Farmer project was conducted at one of those rural training centers at Djilor to introduce ornamental horticulture into the curriculum and to make students aware of ornamental plant production practices and the opportunities available to them if they become involved in a horticulture business.
Mary Rogers, Illana Livstrom, Brandon Roiger and Amy Smith
Growing North Minneapolis (GNM) is an urban agriculture and youth development summer program sited in the North Minneapolis, MN, neighborhood. The program is a university–community partnership between faculty at the University of Minnesota (UMN) and North Minneapolis community partners. We leverage resources from the city of Minneapolis Step-Up program to recruit, train, and employ youth (14–15 years old) who face barriers to employment—particularly youth from low-income families, youth of color, youth from immigrant families, and youth with disabilities. Youth interns are placed in a 10-week-long summer program and are matched with undergraduate student mentors from the UMN and North Minneapolis gardener mentors. The undergraduate students and garden mentors work together to lead teams of youth and work in multiple urban garden sites located in North Minneapolis, a designated low-resource community in the metro area. One of our goals is to develop leadership experience for UMN undergraduate students and improve food and horticultural skills among urban youth through garden-based education. Learning is experiential and contextualized in the various community garden sites through activities focused on food justice and accessibility, food production systems, and horticultural science. Youth learning and development outcomes are reported based on written postprogram qualitative survey questions prompting youth to identify what they learned throughout the program, what they enjoyed the most, and what challenged them after the summer program in 2018. Our results show that youth participants learned across multiple domains of knowledge and valued the social interaction offered by the intergenerational mentorship structure. The GNM program can serve as a model for garden-based experiential learning with early high school youth.
Xuan Wu, Shuyin Liang and David H. Byrne
Criteria to determine the horticultural quality of ornamental plants include plant architecture, flower characteristics, and resistance to biotic and abiotic stresses. The architecture of a rose (Rosa sp.) bush is linked to flower yield and ornamental value. The Texas A&M University (TAMU) Rose Breeding and Genetics program has the objective of developing garden rose cultivars that flower heavily and exhibit a compact full shape. To determine which architectural traits are key for the development of this desired shape, five rose seedlings with a desirable compact growth habit and five with an undesirable growth habit were selected from TAMU diploid rose breeding germplasm. This comparison indicated that the key traits for the selection of compact growth habit are the number of primary shoots followed by the number of secondary and tertiary shoots produced.
Hui-Shan Chan, Hui-Ying Chu and Mei-Fang Chen
In floriculture design, “shaping” is the use of floral materials as media for expressing ideas. Common floriculture techniques include tying, pasting, winding, connecting, overlapping, and weaving. Shaping is also a key factor in the appeal of the final product. Therefore, this study recruited 149 university students to explore how their floriculture material-shaping skills are affected by factors such as creative personality traits, spatial abilities, and shaping creativity. Students were allowed to use three different leaf materials in their floriculture works: planar leaf, linear leaf, and amorphous leaf materials. Representative planar, linear, and amorphous floriculture materials used in the current study were yellow palm (Chrysalidocarpus lutescens), veitch’s screw pine (Pandanus baptistii), and tree fern (Asparagus virgatus), respectively. The average score for creativity in shaping floriculture material was (±sd) 3.26 ± 0.84 (range, 1.33–4.67). Comparisons of the three leaf materials showed that the score for shaping creativity was highest for the planar leaf material (3.70 ± 1.23), followed by the amorphous leaf material (3.18 ± 0.99) and the linear leaf material (2.91 ± 0.94). The chi-square test results indicated that creative personality traits affected the number of shaping skills used, and that spatial abilities and floriculture material-shaping creativity further enhanced skills in floriculture material-shaping. Suggestions for floriculture educators and practitioners are provided accordingly.
Emily E. Braun, Sarah Taylor Lovell, Mohammad Babadoost, Frank Forcella, Sharon Clay, Daniel Humburg and Sam E. Wortman
Weeds are a top management concern among organic vegetable growers. Abrasive weeding is a nonchemical tactic using air-propelled abrasive grit to destroy weed seedlings within crop rows. Many grit types are effective, but if organic fertilizers are used, this could integrate weed and nutrient management in a single field pass. Our objective was to quantify the effects of abrasive grit and mulch type on weed suppression, disease severity, soil nitrogen availability, and yield of pepper (Capsicum annuum L. ‘Carmen’). A 2-year experiment was conducted in organic red sweet pepper at Urbana, IL, with four replicates of five abrasive grit treatments (walnut shell grits, soybean meal fertilizer, composted turkey litter fertilizer, a weedy control, and a weed-free control) and four mulch treatments (straw mulch, bioplastic film, polyethylene plastic film, and a bare soil control). Abrasive weeding, regardless of grit type, paired with bioplastic or polyethylene plastic mulch reduced in-row weed density (67 and 87%, respectively) and biomass (81 and 84%); however there was no significant benefit when paired with straw mulch or bare ground. Despite the addition of 6 to 34 kg N/ha/yr through the application of soybean meal and composted turkey litter grits, simulated plant N uptake was most influenced by mulch composition (e.g., plastic vs. straw) and weed abundance. Nitrogen immobilization in straw mulch plots reduced leaf greenness, plant height, and yield. Bacterial spot (Xanthomonas campestris pv. Vesicatoria) was confirmed on peppers in both years, but abrasive weeding did not increase severity of the disease. Pepper yield was always greatest in the weed-free control and lowest in straw mulch and bare soil, but the combination of abrasive weeding (regardless of grit type) and bioplastic or polyethylene plastic mulch increased marketable yield by 47% and 21%, respectively, compared with the weedy control. Overall, results demonstrate that when abrasive weeding is paired with bioplastic or polyethylene mulch, growers can concurrently suppress weeds and increase crop N uptake for greater yields.
Yuji Yamada, Masayoshi Nakayama, Hiromitsu Shibata, Sanae Kishimoto and Takashi Ikeda
During development, the fruit of some paprika (Capsicum annuum L.) cultivars shows a change in color from green to dark purple (e.g., ‘Mavras’) or lilac (e.g., ‘Tequila’). However, this purple coloration is rare among paprika cultivars and disappears in ripened fruit, which are red. Therefore, we investigated the mechanism causing this color change in the cultivars Mavras and Tequila to better understand how purple ripened fruit could be generated. High-performance liquid chromatography (HPLC) analyses of the anthocyanin contents of the fruit indicated that anthocyanin was undetectable in green fruit, accumulated in dark purple or lilac ones, and then decreased again in red ones in both cultivars. Furthermore, expressions of most of the analyzed anthocyanin biosynthesis–related genes and genes for their transcription factors increased in dark purple or lilac fruit and decreased in red ones, i.e., it was synchronized with the changes in anthocyanin contents. Furthermore, anthocyanin degradation activity as a result of peroxidases was detected at all stages but increased when the lilac or dark purple color started to fade. Thus, the development of purple coloration is caused by increased anthocyanin biosynthesis, whereas the fading of this coloration is a result of both a decrease in anthocyanin biosynthesis and an increase in anthocyanin degradation. At the ripening stage, the green pigment (chlorophyll) contents decreased, whereas the red pigment (carotenoid, particularly capsanthin) contents increased. However, these timings did not completely coincide with the timing of anthocyanin degradation, suggesting that the content of each pigment is individually regulated, and so purple, green, and red coloration could be freely expressed in mature paprika fruit.
Matthew H. Kramer, Ellen T. Paparozzi and Walter W. Stroup
A key characteristic of scientific research is that the entire experiment (or series of experiments), including the data analyses, is reproducible. This aspect of science is increasingly emphasized. The Materials and Methods section of a scientific paper typically contains the necessary information for the research to be replicated and expanded on by other scientists. Important components are descriptions of the study design, data collection, and statistical analysis of those data, including the software used. In the Results section, statistical analyses are presented; these are usually best absorbed from figures. Model parameter estimates (including variances) and effect sizes should also be included in this section, not just results of significance tests, because they are needed for subsequent power and meta-analyses. In this article, we give key components to include in the descriptions of study design and analysis, and discuss data interpretation and presentation with examples from the horticultural sciences.