• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.176-181
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• 2010

Brown patch (Rhizoctonia solani AG1-1), dollar spot (Sclerotinia homoeocarpa), pythium blight (Pythium spp.), anthracnose (Colletotrichum graminicola), yellow patch (Rhizoctonia cerealis) and Zoysia patch (Rhizoctonia solani AG2-2) are the major turfgrasses diseases in Korea. In this study, 23 medicinal plant extracts were tested for antifungal activities against turfgrass pathogenic fungi. In paper disk diffusion method, 12 medicinal plant extracts, including Sophora flavescens, showed antifungal activity. Also, in the test of antifungal activity on media contained the extracts of S. flavescens, Curcuma longa, Rheum undulatum, Coptis chinensis and Asiasarum sieboldi showed above 80% inhibitory effects on the mycelial growth in 110 mg/10 ml concentration of the extracts. S. flavescens, in particularly, showed antifungal activity against the six turfgrass pathogenic fungi. The inhibition rate of S. homoeocarpa was 100% in 10 mg/10 ml, 5 mg/10 ml and 2 mg/10 ml concentrations of C. longa extract. In case of Pythium spp., the extracts of S. flavescens, R. undulatum and C. chinensis showed 100 % inhibition rate on the test media.

• Fisheries and Aquatic Sciences
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• v.22 no.12
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• pp.30.1-30.11
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• 2019

Marine natural products isolated from the sponge Fascaplysinopsis cf reticulata, in French Polynesia, were investigated as an alternative to antibiotics to control pathogens in aquaculture. The overuse of antibiotics in aquaculture is largely considered to be an environmental pollution, because it supports the transfer of antibiotic resistance genes within the aquatic environment. One environmentally friendly alternative to antibiotics is the use of quorum sensing inhibitors (QSIs). Quorum sensing (QS) is a regulatory mechanism in bacteria which control virulence factors through the secretion of autoinducers (AIs), such as acyl-homoserine lactone (AHL) in gram-negative bacteria. Vibrio harveyi QS is controlled through three parallel pathways: HAI-1, AI-2, and CAI-1. Bioassay-guided purification of F. cf reticulata extract was conducted on two bacterial species, i.e., Tenacibaculum maritimum and V. harveyi for antibiotic and QS inhibition bioactivities. Toxicity bioassay of fractions was also evaluated on the freshwater fish Poecilia reticulata and the marine fish Acanthurus triostegus. Cyclohexanic and dichloromethane fractions of F. cf reticulata exhibited QS inhibition on V. harveyi and antibiotic bioactivities on V. harveyi and T. maritimum, respectively. Palauolide (1) and fascaplysin (2) were purified as major molecules from the cyclohexanic and dichloromethane fractions, respectively. Palauolide inhibited QS of V. harveyi through HAI-1 QS pathway at 50 ㎍ ml^-1 (26 μM), while fascaplysin affected the bacterial growth of V. harveyi (50 ㎍ ml^-1) and T. maritimum (0.25 ㎍). The toxicity of fascaplysin-enriched fraction (FEF) was evaluated and exhibited a toxic effect against fish at 50 ㎍ ml^-1. This study demonstrated for the first time the QSI potential of palauolide (1). Future research may assess the toxicity of both the cyclohexanic fraction of the sponge and palauolide (1) on fish, to confirm their potential as alternative to antibiotics in fish farming.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.437-443
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• 2016

In this study Streptomyces strains were isolated from soils and their antifungal activities and involved mechanisms were investigated. Among over 400 isolates of actinomycetes, Streptomyces costaricanus HR391 was selected as a potential antagonist to control several plant-pathogenic fungi. S. costaricanus HR391 inhibited mycelial growth of Fusarium oxysporum f. sp. raphani, F. oxysporum f. sp. niveum, F. oxysporum f. sp. lycopersici, and Rhizoctonia solani by 26.5, 26.2, 21.2, and 23.8%, respectively compared to those of uninoculated control after 7-day incubation on PDB medium. S. costaricanus HR391 produced $89{\mu}M$ of siderphore, and showed fungal cell wall-degrading activity including $0.46{\mu}mol/min/mg$ of chitinase and $0.83{\mu}mol/min/mg$ of ${\beta}$-1,3 glucanase. S. costaricanus HR391 secreted 87.49 mg/L of rhamnolipid, and produced 9.49 mg/L and 4.3 mM of lipopeptide, iturin A and surfactin, respectively, all they are membrane-disrupting biosurfactants. It also produced antimicrobial peptide and antibiotics phenazine. In addition to antifungal substances, S. costaricanus HR391 secreted plant growth-promoting phytohormones, zeatin, gibberellins and IAA. These results suggest that S. costaricanus HR391 may be utilized as an environment-friendly biocontrol agent against some important pathogenic fungi.

• Research in Plant Disease
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• v.14 no.2
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• pp.112-116
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• 2008

Powdery mildew of Paprika caused by Leveillula taurica has been a serious problem in greenhouse. It is an unusual endophytic powdery mildew because the mycelia grow inside the leaf, such that the pale yellow lesions on adaxial surfaces appear first and the white powdery lesion/signs develop later on the corresponding to the spots of the abaxial leaf surface, where the conidiophores are typically emerge through the stomatal opening. Although one foliar application of cooking oil and yolk mixture(COY) to the foliage was not practically effective enough, two or three, weekly application of COY to the foliage at either 0.3 or 0.5% concentration resulted in excellent control against powdery mildew with disease index less/lower than 1, respectively. This treatment could provide protection for three weeks, which, we believe, is not only cost-effective, but also environment-friendly. Powdery mildew fungus was affected by COY treatment quickly which is recognizable in three days. Net photosynthesis and evapotranspiration was remarkably reduced by powdery mildew infection compared to healthy leaves, suggesting that prevention and early protection is the most critical strategy for peak paprika fruit yield. Moreover, COY treatment did not adversely affect the photosynthesis and evapotranspiration of foliages.

• Korean Journal of Organic Agriculture
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• v.15 no.4
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• pp.437-452
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• 2007

From the experiments on the effect of chitosan and wood vinegar, which are environment-friendly materials, on the growth of eggplant and leaf lettuce, the following results were obtained. 1. The effect of chitosan and wood vinegar treatment on the growth of eggplant 1) There was no difference in soil component elements before and after treatment with chitosan and wood vinegar. The total number of microorganisms tended to increase after treatment with chitosan and wood vinegar, while the number of bacteria increased among microorganisms. However, there was no consistent tendency in the number of Acinomycetes, fungi, and trichodema between treatments. 2) The growth and the yield of eggplant increased compared with the control plot in both the chitosan-treated plot and the wood vinegar-treated plot. However, there was no significant difference between the treatments. The yield of eggplant per 10a increased in chitosan- and wood vinegar-treated plots compared with the controlled plot. There was no significant difference in treatments, however, the plot treated with 800 times-diluted solution showed a higher growth. 2. The effect of chitosan and wood vinegar treatment on the growth of leaf lettuce 1) There was no difference in soil component elements before and after treatment with chitosan and wood vinegar. The number of bacteria increased among microorganisms. However, there was no consistent tendency in the number of Acinomycetes, fungi, and trichodema between treatments. 2) The growth of leaf lettuce in both chitosan-treated plot and wood vinegar-treated plot increased compared with the control plot, however, there was no significant difference between the treatments. On the whole, the plot treated with greater concentration showed a higher growth.

• Korean Journal of Environmental Agriculture
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• v.39 no.3
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• pp.222-227
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• 2020

BACKGROUND: Among the biomass conversion techniques of livestock manure, composting process is a method of decomposing organic matter through microorganisms, and converting it into fertilizer in soil. The aerobic composting process is capable of treating cow manure in large quantities, and produces greenhouse gas as CO₂ and N₂O, although it has economical benefit. By using the activated rice hull biochar, which is a porous material, it was intended to mitigate the greenhouse gas emissions, and to produce the compost of which quality was high. Objective of this experiment was to estimate CO₂ and N₂O emissions through composting process of cow manure with different cooperated biochar contents. METHODS AND RESULTS: The treatments of activated rice hull biochar were set at 0%, 5%, 10% and 15%, respectively, during composting cow manure. The CO₂ emission in the control was 534.7 L kg^-1, but was 385.5 L kg^-1 at 15% activated rice hull biochar. Reduction efficiency of CO₂ emission was estimated to be 28%. N₂O emission was 0.28 L kg^-1 in the control, but was 0.03 L min^-1 at 15% of activated rice hull biochar, estimating about 89% reduction efficiency. CONCLUSION: Greenhouse gas emissions during the composting process of cow manure can be reduced by mixing with 15% of activated rice hull biochar for eco-friendly compost production.

• Clean Technology
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• v.23 no.2
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• pp.133-139
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• 2017

Bio-based plastics containing the biomass content higher than 25 wt% have been considered as environment-friendly materials due to their effects on the reduction in the $CO_2$ emission and petroleum consumption as well as biodegradability after use. In this study, poly vinyl chloride, plant-derived plasticizers, by adding a biodegradable catalyst was observed a change in the biodegradability and physical properties. To produce the oxidative decomposition transparent bio film, which is broken down in the initial percent elongation and physical properties such as tensile strength, it was to test the safety of the product as a food packaging material. Poly vinyl chloride, primary plasticizer, secondary plasticizer, anti fogging agent, the combined stabilizer were mixed in a high speed mixer, then extruded using an extrusion molding machine, after cooling, winding, to produce a oxidative decomposition transparent bio film and the control film, with a thickness of $12{\mu}m$ through winder role. Mechanical properties tensile strength, elongation, and the maximum load elongation and biodegradation test. Transparent bio film produced by biodegradation catalyst is compared with the control film. Tensile strength and elongation of films were found to be no significant difference. Further, as a result of the biodegradation test for 45 days based on the ASTM D6954-04 method, biodegrability of film is 61.4%.

• Journal of Family Resource Management and Policy Review
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• v.21 no.4
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• pp.1-15
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• 2017

The purpose of this study was to identify the effect of satisfaction with the marriage support policy on marriage intention among unmarried employed men and women. The study subjects included 300 unmarried working men and women aged over 30 years residing in the Seoul metropolitan area. First, according to the analysis of the subjects' overall tendency towards satisfaction with the marriage support policy and towards marriage intention, the marriage support policy gained the highest level of support in relation to housing for newlywed couples, which scored 3.29 (sd=.93), followed by improvements in corporate and family culture for the purposes of work-family compatibility at 3.24 (sd=.95), wedding loans at 3.18 (sd=1.01), and the paid leave system for marriage preparation at 3.12 (sd=.88). These variables scored slightly higher than the median 3 points. Conversely, satisfaction with the availability of marriage-related information and the provision of opportunities for dating scored 2.65 (sd=.88) and 2.78 (sd=.80), respectively, both of which were slightly lower than the median of 3. The overall mean score for satisfaction with the marriage support policy was 3.03 (sd=.95), which was slightly higher than the median of 3. In regards to marriage intention, the score was 3.32 (sd=1.15) points out of a perfect score of 5, which was slightly higher than the median. This indicated a slightly higher level in terms of the subjects' intention to marry. Second, a hierarchical regression analysis was performed to identify the effect of satisfaction with the marriage support policy on marriage intention among unmarried employed adults. Sociodemographic variables were entered as control variables in the regression at the first stage, and variables relating to satisfaction in a family-friendly social environment were entered at the second stage. When gender, age, educational level, monthly income, period of employment, working hours, and type of employment were inserted in the first stage of regression as control variables, gender, monthly income, period of employment, and type of employment were found to have a significant effect on marriage intention. Marriage intention was found to be greater in unmarried men with higher monthly incomes and longer periods spent working, and in unmarried working men and women engaged in tenured employment work. When variables relating to satisfaction with the marriage support policy were inserted in the second stage of regression, gender, monthly income, type of employment, and satisfaction with direct marriage support had significant effects on marriage intention. It was found that marriage intention was greater in unmarried men whose monthly income was higher, whose employment type was tenured work, and who showed greater satisfaction with direct marriage support.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.40-47
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• 2009

Heavy reliance on organosynthetic chemical methods to control agricultural pest tends to deteriorate and lower fertility of soil. We studied annual occurrence of earthworm in environment-friendly agroecosystem and attempted to determine the degree of soil contamination. Candidate bioindicators of earthworm in agroecosystem were selected through analysis of earthworm diversities. Depending on the degree of pesticide use, the fields were devided into conventional, less-pesticide, pesticide free, and organic fields. A nearby field not in agricultural use was chosen as a control. This study was carried out in the greenhouses (lettuce and grape) in 2006 and in orchards (apple, pear, peach, citrus and grape) in 2007. Earthworm was collected from 50 $\times$ 50 $\times$ 10 cm$^3$ of respective soil. We found 11 species from 5 genera and 3 families, and 12 species from 4 genera and 3 families in the greenhouses and in orchards, respectively. The contents of organic matter in soil in the greenhouses were variable but quite less so in orchards. Amynthas heteropodus occurred most frequently in both sites suggesting that it could be adopted as a bioindicator in agroecosystem in Korea.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.335-343
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• 2006

Five strains of Korean entomopathogenic nematodes(EPN), steinernematids and heterorhabditids(Steinernama carpocapsae GSN1, Steinernema sp. GSNUS-10, Steinernama sp. GSNUS-14, Heterorhabditis bacteriophora Hamyang, Heterorhabditis sp. GSNUH-1) were evaluated and tried in petri dish, pot, and vegetable greenhouses for environmentally friendly control of beet armyworm, Spodoptera exigua. $LC_{50}$ values of five EPN strains against beet armyworm was different depending on nematode strain and beet armyworm instar. $LC_{50}$ value of Steinernema carpocapse GSN1(GSN1) was 3.8-5.1 infective juveniles(Ijs) in 2nd to 4th instars of beet armyworm. Pathogenicity of five EPN strains against beet armyworm different in nematode strain, concentration, application times, and vegetable species in pot and greenhouse. Steinernema spp. was more effective than Heterorhabditis spp. against beet armyworm. Two or three times of applications of EPN were found to be effective regardless of nematode strain and concentration in pot and greenhouse. ENP showed different reactions on vegetable species. Efficacy of EPN was higher on Chinese cabbage than that on cabbage and kale. GSN1 was one of the most effective nematodes and 100,000 infective juveniles per $m^2$(720,000 Ijs/$7.2m^2=1{\times}10^9$Ijs/ha) resulted in higher mortality in greenhouse.