• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.419-427
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• 2012

This study was carried out to investigate the effect of two shading methods, shading agent spray on the glasshouse and internal shading screen treatment, on the growth and fruit quality of paprika (Capsicum annuum L. 'Cupra' and 'Coletti') in summer season cultivation. In the shading agent treatment, a commercial shading agent diluted with water at a ratio of 1 : 4 was sprayed on the roof of a glasshouse. In the internal shading screen treatment, a 10~20% shaded screen was used during the day time when the sun radiation was greater than $700W{\cdot}m^{-2}$. Compared to the unshaded control, photosynthetic photon flux density (PPFD) decreased in the greenhouse in the shading agent (SA) and shading screen (SS) treatments by 20% and 30%, respectively. Lower air temperatures and higher relative humidities were observed in the SA than in both the control and the SS treatment. Time to reach the break point of humidity deficit $8g{\cdot}m^{-3}$ was 2 hours late in the SA than in both the control and the SS treatment. Compared to control, both the SA and the SS treatments showed lower instantaneous temperatures of leaf, fruit, and flower by $2^{\circ}C$, $5^{\circ}C$ and $3^{\circ}C$, respectively. There were no differences in number of branches, stem diameter, and leaf size among treatments although both shading treatments promoted plant height in both cultivars. Botrytis infection ratio declined with the SA treatment by 14.7% in 'Cupra' and 22.1% in 'Coletti' as compared to that in the control. Shading increased fruit size in both cultivars, whereas no differences were observed in the number of locules and thickness of fruit tissue among treatments. Shading treatment increased mean fruit weight by a range of 10 to 15 g per fruit, while it decreased soluble solids contents as compared to that in the control. Similar Hunter values were observed among treatments, while fruit firmness increased slightly in shading treatments. Compared to the control, shading treatments improved marketable fruits by 11.7~22.6% and increased the number of fruits per plant by 4~9.2 in both 'Cupra' and 'Coletti'. The results of this study indicate that shading agent application on the roof of glasshouse would be one of the most effective options to reduce heat stress imposed on the paprika crop in summer cultivation, resulting in improved crop growth and fruit yield.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.249-254
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• 2016

This study was carried out to evaluate the efficiency of white shading agent for reduction of greenhouse air temperature and to develop cost-effective cooling strategies for strawberry seedling production during hot seasons. Experiment results showed that solar radiation ($W/m^2$) was reduced by 14~17% and 33~37% for 15% and 35% white wash shading treatments, respectively, in black shading net treatment solar radiation was reduced by 39~44% compared to non-shaded treatment. Measured greenhouse air temperatures in 15% and 35% white wash shading treatments were $38.4^{\circ}C$ and $36.5^{\circ}C$, respectively, whereas in black shading net covered greenhouses air temperature was $35.1^{\circ}C$, thereby 35% and 15% shading treatments showed 3.3 and $1.9^{\circ}C$ higher air temperatures than black net shading treatment. Crown diameter of strawberry plants in black net shading treatment was 7.5mm, and in 15% and 35% white wash shading treatments were 8.6mm and 8.3mm, respectively. Strawberry transplants grown in 35% white wash shading treatment produced the highest above ground fresh weight(7.8g), followed by 15% white wash shading(6.7g) and black net shading treatments(5.8g). Also, both 15% and 35% white wash shading treatments produced higher root fresh weight(4.1g and 4.3g) compare to black net shading treatments(2.7g).

• Journal of Bio-Environment Control
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• v.24 no.1
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• pp.34-38
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• 2015

This research was conducted to establish efficient methods to overcome high temperature and low humidity with light selective shading agent and two-fluid fogging system in greenhouses in hot season. There were four experimental treatments; not treated (Non), fogging by two-fluid fogging system (Fog), spraying onto the greenhouse surface with shading coating agent (Coat), and using fogging and coating together (F&C). The amount of solar radiation entered into the greenhouses was higher in Non, and then Fog, Coat, and F&C in descending order. Fog was more efficient to lower the air temperature and also raise relative humidity than Coat treatment. The crop temperature was about $6^{\circ}C$ higher in Control than the other treatments. F&C revealed as the most efficient method to control the environment inside the greenhouse, but fogging system seemed to be more economic. In stand-alone greenhouses spraying coating agent may be the appropriate choice because of their structural limitations, mainly eave height.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.31-38
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• 2014

Rooting agents and shading treatments were tested in two different experiments to determine their effects on the establishment success of hardwood cuttings of three highbush blueberry varieties 'Bluecrop', 'Duke' and 'Sunrise'. For the experiment with rooting agents, one-cm long bases of the cuttings were dipped into solutions of IBA or NAA for 5 s, both at 0, 500 and $1000mg{\cdot}L^{-1}$ in 50% ethanol, and were also treated with Rootone$^{(R)}$ powder. Determined 90 days after cutting, the percent rooting and root weight were increased by NAA at $500mg{\cdot}L^{-1}$ in 'Bluecrop' and 'Sunrise', while in 'Duke' IBA at $500mg{\cdot}L^{-1}$ was effective. These auxin treatments were found to work better than a commercial product Rootone$^{(R)}$. The rooting agent-induced increases in root development resulted in better shoot growth of the cuttings in all three varieties, as determined after 90 days of further growth in individual containers. In the experiment with shading treatments, different levels of the shading treatment (30 to 90%) were imposed over the cutting bed under no mist. In all three varieties, 30% shading increased the percent rooting and root and shoot growth, compared to no shading control. However, shading levels higher than 50% shading were found to be inhibitory for hardwood cuttings of highbush blueberries, especially under the environmental conditions with no mist system.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.304-311
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• 2021

This Experiment was conducted to determine the effects of light shield materials when melon grown inside a plastic greenhouse in summer season. The average temperatures were 36.6℃, 34.5℃ and 34.0℃ respectively for the control(non-shield), coating agent, and the white net. The light transmittances were 69% and 75%, respectively inside the greenhouse treated with the coating agent and white net immediately after applicants, compared with that inside the control greenhouse. At the 40 and 80 days after treatment, the light transmittances for the coating agent were 92% and 98%, respectively, indicating it was slowly decomposed and removed, but there was no change in the transmittance for the white net. While the leaf number did not differ among the treatments, the plant height was higher in the white net and shading agent than in control. The weight of the leaves, fresh-weight and dry-weight were no different from that of shading, but it became heavier in the later stages. The marketable fruit yield was increased by 6% for white nets and 5% for the coating agent compared to control, there was no statistical significance. Therefore, coating agent is considered as an effective method to lower temperature during high temperature period, but it is preferable to use it in consideration of cultivation period, because the coating agent is gradually removed.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.166-170
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• 2012

Most of Cudriania tricuspidata Bureau saplings in Korea have been produced by crown division. But the production of Cudriania tricuspidata B. saplings by this method is very low in efficiency and in uniformity. Therefore, to develop Cudriania tricuspidata B. saplings production system by cutting method which is suitable for mass production, several conditions on rooting and growth of cuttings were investigated. The rooting ability of cuttings varied according to temperature on the bed, length, thickness of the hard wood cutting and rooting agent application. Of different concentration of rooting agent, the 5,000 ppm of 1-naphthalenacetic acid(NAA) and Indole butyric acid(IBA) were found to be the highest in rooting of hardwood cuttings; other concentration were in order as follows; 2,500, 1,000 and 10,000 ppm in concentration of rooting agents. The shading ratio of polyethylene film showed the highest rooting ratio of the softwood cuttings at 55%.

• Journal of Ginseng Culture
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• v.6
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• pp.51-79
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• 2024

In the 1970s and 1980s, during the nascent phase of ginseng disease research, efforts concentrated on isolating and identifying pathogens. Subsequently, their physiological ecology and pathogenesis characteristics were scrutinized. This led to the establishment of a comprehensive control approach for safeguarding major aerial part diseases like Alternaria blight, anthracnose, and Phytophthora blight, along with underground part diseases such as Rhizoctonia seedling damping-off, Pythium seedling damping-off, and Sclerotinia white rot. In the 1980s, the sunshade was changed from traditional rice straw to polyethylene (PE) net. From 1987 to 1989, focused research aimed at enhancing disease control methods. Notably, the introduction of a four-layer woven P.E. light-shading net minimized rainwater leakage, curbing Alternaria blight occurrence. Since 1990, identification of the bacterial soft stem rot pathogen facilitated the establishment of a flower stem removal method to mitigate outbreaks. Concurrently, efforts were directed towards identifying root rot pathogens causing continuous crop failure, employing soil fumigation and filling methods for sustainable crop land use. In 2000, adapting to rapid climate changes became imperative, prompting modifications and supplements to control methods. New approaches were devised, including a crop protection agent method for Alternaria stem blight triggered by excessive rainfall during sprouting and a control method for gray mold disease. A comprehensive plan to enhance control methods for Rhizoctonia seedling damping-off and Rhizoctonia damping-off was also devised. Over the past 50 years, the initial emphasis was on understanding the causes and control of ginseng diseases, followed by refining established control methods. Drawing on these findings, future ginseng cultivation and disease control methods should be innovatively developed to proactively address evolving factors such as climate fluctuations, diminishing cultivation areas, escalating labor costs, and heightened consumer safety awareness.