• Weed & Turfgrass Science
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• v.2 no.4
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• pp.387-394
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• 2013

The Rhizoctonia blight causing by Rhizoctonia spp. is an important disease of turfgrass, requiring fungicide application to maintain acceptable conditions for turfgrass good qualities in the golf course. The experiment was conducted to determine the mean 50% effective concentration inhibiting mycelial growth ($EC_{50}$) value of to flutolanil, pyraclostrobine and hexaconazole to Rhizoctonia solani AG-1 IB, Rhizoctonia cerealis and Rhizoctonia solani AG2-2IV isolated from Gyeongbuk province of Korea in vitro. Five discriminatory concentrations of each fungicide were used to detect in vitro sensitivity. The mean of $EC_{50}$ values to three systemic fungicides was the lowest isolate of R. solani AG-1 IB. However, the sensitivity of fungicides to Rhizoctonia solani AG2-2IV were higher mean $EC_{50}$ value of 0.026 ${\mu}g\;a.i.\;ml^{-1}$ of pyraclostrobine and 0.044 ${\mu}g\;a.i.\;ml^{-1}$ of flutolanil. R. cerealis was the lowest sensitivity to hexaconazole which was an average $EC_{50}$ value of 0.022 ${\mu}g\;a.i.\;ml^{-1}$. Inhibition of mycelial growth rate (%) by three combine fungicides using the $EC_{50}$ value of each fungicide was the highest R. solani AG2-2IV. Results of this study were may confirmed in vitro response fungicide of three Rhizoctonia species for control of Rhizoctonia blight in the field.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.172-178
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• 2018

The sterilization rates were investigated to develop effective pretreatment methods of garlic and ginger using antimicrobial agents and blanching. Antibacterial components in chopped garlic and ginger, such as allicin, ginger, and shogaol, exhibited an antibacterial effect that reduced bacteria by a factor of $10^1(CFU/g)$. The total number of bacteria in garlic and ginger was decreased by $10^1(CFU/g)$ after individually soaking in 1% (w/w) citric acid, calcium oxide and 200 ppm sodium hypochlorite solution for 1 h, respectively. When chopped garlic and ginger were immersed in 1% (w/w) calcium oxide solution for 1 h, the bactericidal effect was increased by $10^4-fold$. Total cells with thermoduric bacteria exhibited a $10^3-10^4-fold$ reduction after heating for 30-40 s at $90-95^{\circ}C$. The combination of soaking in 200 ppm sodium hypochlorite solution and blanching at $95^{\circ}C$, 40 s showed $10^1-fold$ decrease in total number of cells compared to blanching in whole ginger.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.356-362
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• 2000

Yakju(rice wine) was sterilized with high-voltage square-wave pulses of $1\;{\mu}s$ duration at various electric field strengths and frequencies on a serial multiple electrode pulsed electric field(PEF) treatment system consisted of 7 electrodes connected in series. The initial microbial counts of Yakju were $1.88{\times}10^3{\sim}2.13{\times}10^4$ CFU/mL for total aerobes, $1.55{\times}10^3{\sim}2.85{\times}10^4$ CFU/mL for lactic acid bacteria and $1.72{\times}10^3{\sim}2.39{\times}10^4$ CFU/mL for yeasts. The sterilization of microorganisms in Yakju was a first order reaction and the sterilization effect increased as the field strength and the frequency increased. The $D_{Hz}-value$ and the $D_{PEF}-value$ decreased with the electric field strength. Yeast showed lower $D_{PEF}-value$ than bacteria. Lactic acid bacteria showed lower $D_{PEF}-value$ than general aerobic bacteria under the electric field strength below 30 kV/cm, but higher ones under that above 40 kV/cm. The $Z_{PEF}-value$ of general aerobic bacteria, lactic acid bacteria and yeast in Yakju were 39.4, 49.3 and 47.6 kV/cm, respectively. The PEF sterilization resulted in less changes in color and sensory properties than heat sterilization, and the PEF treated Yakju showed superior quality to the heat treated one. The commercial sterilization of Yakju was accomplished with 2-cycle treatment on the tested serial PEF treatment system.

• Research in Plant Disease
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• v.29 no.2
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• pp.145-157
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• 2023

Apple grower in the Cheongsong region, Korea has reported the increased loss of apple yield due to severe bitter rot incidence. We noticed that this indience is because the Colletotrichum population has developed resistance to commonly used fungicides. We isolated 39 Colletotrichum isolates from 13 orchards in Cheongsong, and all the isolated Colletotrichum species were identified as C. siamense or C. fructicola. These 39 strains were tested for mycelial growth and conidial germination against 12 fungicides. trifloxystrobin (30-55% in recommended concentrations) was shown lower inhibitory effect on mycelial growth. However, the inhibition of conidial germination was shown higher than mycelial growth (62-100%). Kresoxim-methyl was shown lower inhibitory effect on mycelial growth (29-55%). conidial germination inhibitory effect was shown 51% to 96%. dithianon was shown diversity response to inhibition of mycelial growth (43-100%). Tebuconazole was shown high inhibitory effect on mycelial growth (84-100%) and conidial germination inhibitory effect was shown to be 64 to 100%. metconazole has been found to display with high inhibitory effect on mycelial growth (79-100%) and conidial germination (70-80%). fluazinam was shown to possess high inhibitory effect on mycelial growth (87-100%) and conidial germination (94-100%). This study provides basic information for the effective management of apple bitter rot.

• The Korean Journal of Pesticide Science
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• v.14 no.1
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• pp.30-36
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• 2010

This study was conducted to investigate the characteristics of conversion and residue for two EBDCs fungicides (mancozeb and metiram) and their metabolite, ethylenethiourea (ETU) under laboratory conditions. The sampling on the pesticides was done at 0, 1, 2, 5, 7, 9, 12, 15, 19, 22 and 26 days. The amounts of their residues and ETU were analyzed with an HPLC-DAD. The average recoveries were $86.9{\pm}4.3\;and\;90.2{\pm}8.0%$ for mancozeb, $85.2{\pm}2.4\;and\;98.6{\pm}1.6%$ for metiram, and $64.1{\pm}3.4\;and\;80.0{\pm}4.6%$ for ETU. The half-lives of mancozeb and metiram were 7.5 and 27.8 day, respectively. The conversion rates of mancozeb and metiram to ETU ranged from 4.7 to 67.2% and from 7.5 to 34.6%, respectively. These results may be different under the real environmental conditions. Therefore, following many studies are recommended to make the criteria for applying the use and safety for mancozeb and metiram.

• Journal of Applied Biological Chemistry
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• v.52 no.3
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• pp.126-132
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• 2009

In order to elucidate the relationship between the rainfastness of fungicides and their water solubilities, the fungicide residues on the leaf surface of hot pepper was assessed and compared after the drop-wise applications of fungicide solutions on leaf surface followed by artificial raining. As the raining was progressed after application of aqueous acetone solution of fungicides, the residue levels of fungicides were drop rapid at the early stage of raining, but the decreasing rates of residue level were slowed down thereafter. The initial rainfastness was reversely proportional to the water solubilities of the fungicides. Whole amount of dimethomorph residue, which water solubility is 18 mg/L, was washed off by 2.5 mm of raining. Although WP formulations of fungicides showed remarkable decreases of rainfastness compared to the aqueous acetone formulations, the fungicides having low water solubility showed better rainfastness. Chlorothalonil and mepanipyrim suspension concentrates was better in rainfastness than their WP formulation, and the rainfastness of mepanipyrim suspension was reversely proportional to the median diameter of suspension particles in the range of 1 to 4 ${\mu}m$. In brief, the rainfastness of 5 fungicides tested on the pepper leaf was, in the early stage of raining, closely related to water solubility. But, as the raining is progressed, the effect of the unknown factor, which is related with the particle size of fungicides, becomes serious.

• The Hankook-Saengyark Bo
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• no.260
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• pp.5-5
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• 2004

'황기 다년재배 비료 안쓰면 유리'(4년근 생존율 33$\%$로 높아지고 수량 늘어) - 도열병 워크숍 7월13$\~$14일 - 천적에 피해 안주는 농약 선발(농과원, 저독성 살충제$\cdot$살균제 밝혀 - '장뇌 품질기준$\cdot$규격 제정등 시급'(산양산삼 학술대회서 제기)

• Korean Journal of Food Science and Technology
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• v.52 no.1
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• pp.109-112
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• 2020

To evaluate the safety of bacteriophages for application of sanitizer, endotoxin content and cell cytotoxicity of two Escherichia coli and four Staphylococcus aureus phages were determined. Endotoxin ratio was determined by the Limulus amebocyte lysate (LAL) assay as a test for representative biological endotoxin content. The average endotoxin average content of the 9 log PFU/mL lysate was 18.6 EU/mL and that of the 10 log PFU/mL lysate was 5.9 EU/mL, suggesting that the phage lysate was not suitable for clinical applications, but suitable for food pathogen control applications. To confirm the cell cytotoxicity of the phage lysates, MTT assay was performed using Raw 264.7 cells treated with 9 log PFU/mL phages. Results of the assay indicated that the phage lysates did not significantly decrease the cell viability (p>0.05). These results indicated that bacteriophages would be suitable as a food safety sanitizer.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.6
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• pp.520-528
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• 1992

In order to establish the standard conditions for thermal sterilization of foods, a microcomputer based $F_o-value$ measuring system was developed upon the basis of the time-temperature profile in food. $F_o-value$ was calculated simultaneously from the time-temperature profile, and described as integrated lethality during the whole sterilization process. The accuracy of system was evaluated by the analysis of thermal diffusivity of the model solid food, Alaska pollack surimi. The $F_o-value$ could be measured precisely under the different sterilizing conditions as the varied time and temperature. The practical thermal diffusivities from various sterilizing conditions agreed well to the values predicted by some experimental equations suggested in the literatures. The differences were within the range of $\pm12\%$.

• Journal of Life Science
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• v.34 no.7
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• pp.500-508
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• 2024

Recently, there has been increasing interest in enhancing the indoor air quality, particularly in response to the growing utilization of public facilities. The focus of this study was on assessing the efficacy and safety of an air sterilizer equipped with electrolytic salt catalysts. To that end, we evaluated the antimicrobial activity of the vapor spraying from the air sterilizer and its cytotoxicity in condensed form on human cell lines (HaCaT, BEAS-2B, and THP-1). Against the test organisms, which comprised five bacterial strains (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium) and one fungal strain (Candida albicans), the air sterilizer exhibited relatively high antimicrobial activities ranging from 10.89 to 73.98% following 1 and 3 hr of vapor spraying, which were notably time-dependent. Importantly, cytotoxicity assessments on human cells indicated no significant harmful effect even at a 1.0% concentration. Comprehensive safety evaluations included morphological observations, gene expression (Bcl-2, Bax) tests, and FACS analysis of intracellular ROS levels. Consistent with previous cytotoxicity findings, these estimates demonstrated no significant changes, highlighting the air sterilizer's safety and antimicrobial activities. In a simulated 20-hr operation within an indoor environment, the air sterilizer not only showed an 89.4% removal of total bacteria but also a 100.0% removal of Escherichia sp. and fungi. This research outlines the potential of the developed electrolytic salt catalyst air sterilizer to effectively remove indoor microbial pollutants without compromising human safety, underscoring the solution that it offers for improving indoor air quality.