• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.705-718
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• 2014

This study was performed to evaluate the suppressive effects of organic fungicides made using environment-friendly materials on leaf spot disease and anthracnose that infect ginseng. Anthracnose (Colletotrichum gloeosporioides) and leaf spot disease (Alternaria panax) are principal diseases that decrease the yield of ginseng by defoliation before root enlargement. Fermented eggs and oyster shells, water extract of green tea and ethanol extract of red ginseng dregs were significantly effective in suppressing leaf spot disease. Fermented crab and shrimp shells and fermented motherwort were also effective in suppressing the recurrence of ginseng anthracnose. The preventive effects of these environment-friendly materials were definitely superior to the therapeutic effects. Therefore, these materials could be used as alternatives to chemical pesticides, which can not be applied in organic ginseng cultivation field. These organic fungicides need to be applied before the incidence of ginseng anthracnose in order to maximize their suppressive effects.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.127-133
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• 2012

Inhibition effects on spore germination and mycelia growth for pepper anthracnose fungi (Collectricum acutatum) were investigated in vitro using eco-friendly agricultural materials as well as ecofriendly pesticides. The inhibition effect on mycelia growth of anthracnose fungi is the highest when the anthracnose mycelia were treated with a pesticide (commercial name: Koreayeok) that contains a mixture of Bacillus subtilis and Panibacillus polymyxa, resulting in 100% inhibition of the mycelia growth. Meanwhile, the range of 20~40% inhibition effects on the growth of anthracnose mycelia was observed with other commercial agricultural materials. The significant inhibition effects on spore formation of anthracnose fungus were shown in vitro with two water dispersible pesticides containing sulfur [BTB (100%) and SulfurStar (95.1%)], Koreayeok (95.0%), Borstar (99.0%) containing Bordeaux mixture, and Jihabudea-KM containing Psedomonas spp. (96.1%), respectively. Taken from these in vitro results of inhibiting of the spore germination and mycelia growth together, Koreayeok is the most effective on control of pepper anthracnose disease in vitro. In addition, two water dispersible pesticides containing sulfur (BTB and SulfurStar) and Borstar (99.0%) containing Bordeaux mixture are also significantly applicable to prevent pepper plants from anthracnose disease in vitro. It remains to be determined whether the selected eco-friendly agricultural materials in effective control of anthracnose in vitro can be used to control pepper anthracnose in field.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.134-139
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• 2012

Inhibition effects on spore germination and mycelia growth for gray mold (Botrytis cinerea) were investigated in vitro using environment-friendly agricultural materials as well as environment-friendly pesticides. The inhibition effect on mycelia growth of gray mold is the highest when the gray mold mycelia were treated with a pesticide (commercial name: Koreayeok, Jihabudea KM, Sootingtan, Sootingstar) that contains a mixture of Bacillus subtilis, resulting in 100% inhibition of the mycelia growth. Meanwhile, the range of less than 20% inhibition effects on the growth of gray mold mycelia was observed with other commercial agricultural materials. The significant inhibition effects on spore germination of gray mold fungus were shown in vitro with two water dispersible pesticides containing sulfur [BTB (97.7%) and SulfurStar (92.3%)], respectively. These in vitro results of inhibiting of the spore germination and mycelia growth together cannot found. It remains to be determined whether the selected environment-friendly agricultural materials in effective control of gray mold in vitro can be used to control gray mold in field.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.112-113
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• 2021

Phosphate based inhibitor is playing a decisive role in inhibiting the corrosion of steel rebar in chloride condition. We have used different amount of ammonium phosphate monobasic (APMB) as corrosion inhibitor in mortar with different amount of chloride ions. The compressive strength, flexural strength, open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization resistance (PPR), scanning electron microscopy (SEM) and Raman spectroscopy were performed to access the effect of inhibitor on corrosion resistance. As the amount of inhibitor is increased, the compressive strength increased. The electrochemical results show that as the amount of inhibitor and chloride ions are increased, the total impedance and corrosion resistance of steel rebar increased attributed to the formation of the stable oxide films onto the steel rebar surface. It is suggested that APMB can work in high concentration of chloride ions present in concrete where phosphate ion helps in formation of stable and protective phosphate based oxide film.

• Korean Journal of Organic Agriculture
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• v.26 no.4
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• pp.649-660
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• 2018

To control the pepper anthracnose caused by Colletotrichum acutatum, antifungal bacterium strains which was selected among bacterium from natural soil, was tested the antimicrobial activity against various pathogens and its control efficacy on anthracnose disease in the fields. We confirmed that antagonistic activity of CAB13001 strain to pathogens such as Sclerotinia cepivorum, Sclerotinia sclerotium and Botrytis cinerea including Colletotrichum acutatum was remarkable superior with the dual culture method in the artificial medium. In vitro bioassay using the green pepper fruit, CAB13001 strain suppressed the lesion development of Anthracnose disease, and its control value compared to the untreated one was 82.4% on pepper fruit in field test. These results suggested that CAB13001 strain could be a very useful biological control agents to anthracnose disease caused by air born plant pathogens of pepper. By the way, analysis of nucleotide sequence of the gene 16S rDNA, antagonistic bacterium CAB13001 strain used in this study was identified as Burkholderia lata.

• Research in Plant Disease
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• v.17 no.2
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• pp.148-154
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• 2011

This study was conducted to control the seed borne pathogens (Alternaria spp.) of carrot and to examine the seed germination rate by using 13 environment friendly agricultural materials instead of conventional chemicals for organic cultivation. The growth inhibiting effects on pathogens showed the different responses according to each agricultural material and effective 7 materials against seed borne pathogens were selected. Among 7 materials, the carrot seeds sterilized with plant extracts, Tanger Stop and Land Saver were not germinated at all. The germination rate of seeds sterilized with other materials showed the similar levels with reference chemical (Benlate-T) and non-treated seeds. Infection rates of seeds sterilized with seaweed extract, Bellopper for controlling A. radicina and plant extract, Ssial-100 for A. dauci were similar or low infection rate compared with reference chemical. The germination rate and root length of seeds sterilized with Bellopper and Ssial-100 was similar or superior to those of chemical sterilized seeds. The optimal condition seemed to be a little bit different depending on the concentration of materials. As a result, the sterilization of carrot seeds by using the environment friendly materials could be effectively utilized as a technology to inhibit the infection of seed-borne pathogens.

• Journal of Applied Biological Chemistry
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• v.60 no.2
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• pp.173-178
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• 2017

This study was conducted to investigate the effect of pyroligneous acids on urea hydrolysis for the purpose of inhibiting ammonia volatilization during urea fertilizer application. Different types of synthetic urease inhibitors have been searched and developed, but their use is limited due to varying inhibition effects on soil urease, and environmental problems. In this study, the effect of pyroligneous acids, a natural substance, on urea hydrolysis in soil was evaluated by analyzing inhibition of urease activity. Pyroligneous acids inhibited plant urease and microbial urease activity, as well as soil urease with various urease complex. In addition, pyroligneous acids exhibited non-competitive urease inhibition effect through urease kinetics and inhibited urea hydrolysis in the soil. This study showed that pyroligneous acids treatment with urea fertilizer decreases the loss of urea fertilizer, improves the efficiency of nitrogen application on plant and reduces the amount of nitrogen fertilizers applied in soil.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.33-34
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• 2023

Corrosion of reinforcement steel is a major cause of deterioration in reinforced concrete (RC) structures. In order to protect these structures from corrosion, corrosion inhibitors are added to the concrete mix. In recent years, zwitterionic compounds have shown promising results as corrosion inhibitors in concrete due to their ability to form a protective layer on the surface of the reinforcement steel. The experimental study involves preparing concrete samples with different concentrations of adding the hybrid corrosion inhibitor at a high concentration of chloride ions. This study aims to determine the chloride threshold value and service life of hybrid corrosion inhibitors in reinforced concrete based on zwitterions. The samples are subjected to accelerated corrosion tests in a chloride environment to determine the threshold value and service life of the corrosion inhibitor. The effect of hybrid inhibitor on mechanical properties is guaranteed in allowable range. The chloride threshold concentration and service life of hybrid inhibitor containing samples perform greater than those of plain RC.

• The Korean Journal of Pesticide Science
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• v.15 no.3
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• pp.298-302
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• 2011

Bacterial wilt, caused by Ralstonia, solanacearum, is a very destructive disease to tomato plants (Solanum lycopersicum) in Korea. This study was undertaken to find out the growth inhibitory effect bactericides on bacterial wilt pathogen of streptomycin, oxytetracyclin streptomycin sulfate WP and significantly suppressed the growth of bacterial wilt pathogen. Copper hydroxide WP showed control value of 62.5%. Therefore, it is concluded that the bactericide used in this study showed strong inhibitory effect to tomato bacterial wilt and they can be recommend to control the disease. And also, Copper hydroxide WP may be effective for control of bacterial wilt of tomato in conventional culture, farming without agricultural and organic farming.

• Korean Journal of Organic Agriculture
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• v.28 no.2
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• pp.223-233
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• 2020

The aim of the present study was to investigate the suppressive effects of the bio-sulfur used by eco-friendly farms on the outbreak of citrus scab. To evaluate the inhibiting effect of bio-sulfur on citrus scab germ tube growth, the citrus scab pathogen Elsinoe fawcettiiwas cultured in PDB and agar media, and germ tube growth was observed after bio-sulfur treatment. At both 40 and 88 h after inoculation, germ tube formation was inhibited by 500-, 1000-, and 2000-fold diluted bio-sulfur, and at dilutions above 4000-fold, germ tube formation was observed, although growth was still inhibited, when compared to untreated cultures. Meanwhile, the occurrence of citrus scab on spring-flush leaves in the field was 40.3% in the untreated control and 5.3, 10.3, 12.3, 15.3, and 24.0% when treated with imibenconazole, 2-4 and 6-6 lime-Bordeaux mixtures, which are also used by eco-friendly farms, 500-fold diluted bio-sulfur, lime sulfur, and 1000-fold diluted bio-sulfur, respectively. The occurrence of citrus scab on citrus fruit was 79.3% in the untreated control and 4.0, 33.8, 42.0, 43.3, 44.8, and 78.0% when treated with imibenconazole, 2-4 lime-Bordeaux mixture, 6-6 lime-Bordeaux mixture, 500-fold diluted bio-sulfur, lime sulfur, and 1000-fold diluted bio-sulfur, respectively. Because citrus scab can infect citrus leaves as early as May, as the spring flush begins, preventative control should be implemented by mid- to late-April, thereby increase disease control and reducing both labor and farming costs.