• The Korean Journal of Ecology
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• v.15 no.3
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• pp.281-285
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• 1992

Essential oils isolated from five angiospermic plants viz. citrus medica, trachyspermum amminepeta hindostana, amomum subulatum, and hyptis suaveolens have been tested against four fungiviz. aspergillus awamori, alternaria matini, aspergillus nidulans and penicillium sp. at 100ppm, 500 ppm, and 1, 000ppm. The oils of c. medica, n. hindostana and t. ammi were found to be effective in checking growth of fungi, while the hyptis and amomum oils were observed to be the worst effective. The antifungal poitency of some of the oils has been compared with synthetic fungicides viz. dithane m-45, ceresan and captan.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.119.2-120
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• 2003

Seed-borne fungal pathogens on rice seeds were investigated in order to evaluate their effect on rice grain quality. Rice seeds of two cultivars, Ilmibyeo and Daesanbyeo were collected from 27 areas of Korea and the fungal parasites on seeds were isolated by using a blotter method. Isolation frequency and number of species were varied from collection areas of seed samples. A total 13 species of fungi were identified from the seeds. Among them, Altemana alternata was the most frequent over the country. Bipoiaris oryzae most commonly from Gyeongbuk and Jeonbuk, Alternaria padwickii from Jeonbuk, and Nigrospora oryzae from Choongnam. However Bipolaris. oryzae, Alternaria padwickii, and Nigrospora oryzae were the most frequently isolated fungi from Gyeongbuk and Jeonbuk, and Chungnam, respectively. B. oryzae, A. alternata, A. padwickii, and N. oryzae were dominants on Ilmibyeo showing 10.3％, 10.2％, 5.2％, and 5.2％ infection rate, respectively. While, N. oryzae, A alternata, and Cladosporium sp. were most frequently isolated fungi from Deasanbyeo revealing 15.1％, 9.6％, and 7.5％ infection rate, respectively. These fungi inhabiting on hulls or endosperms of rice seed might be considered as potential factors decreasing rice grain quality. Further investigation of the fungi on grain rice quality are undergoing.

• Korean Journal Plant Pathology
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• v.14 no.3
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• pp.191-202
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• 1998

About 300 actinomycetes were isolated from two forest and one sea-shore soil and tested for inhibitory effects on mycelial growth of six plant pathogenic fungi Magnaporthe grisea, Alternaria mali, Colletotrichum gloeosporioides, Phytophthora capsici, Fusarium oxysporum f. sp. cucumerinum, and Rhizoctonia solani. Among 300 actinomycetes tested, only 16 actinomycetes showed the antifungal activity against the test fungi. Isolate NH 50 was selected for production and purification of antifungal antibiotic substances. Actinomycete isolate NH 50 displayed the broad antifungal spectra against 11 plant pathogenic fungi. To identify actinomycete isolate NH 50, cultural characteristics on various agar media, diaminopimelic acid type, and morphological characteristics by scanning electron microscopy were examined. As a result, actinomycete isolate NH 50 was classified as a rare actinomycete that had LL-DAP type and did not produce spores. After incubation of isolate NH 50 in yeast extract-malt extract-dextrose broth, antifungal compound NH-B1 that inhibited mycelial growth of some plant pathogenic fungi was purified from the methanol eluates of XAD-16 resins by a series of purification procedures, i.e., silica gel flash chromatography, C18 flash chromatography, Sephadex LH-20 column chromatography, silica gel medium pressure liquid chromatography (MPLC), C18 MPLC, and high pressure liquid chromatography (HPLC). UV spectrum and 1HNMR spectrum of antifungal compound NH-B1 dissolved in methanol were examined. The antibiotic NH-B1 showed the major peaks at 230 and 271.2nm. Based on the data of 1H-NMR spectrum, NH-B1 was confirmed to be an extremely complex polymer of sugars called polysaccharides. The antibiotic NH-B1 showed strong antifungal activity against Alternaria solani and Cercospora kikuchi, but weak activity against M. grisea.

• The Korean Journal of Mycology
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• v.19 no.2
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• pp.109-119
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• 1991

The vertical distribution of the fungal population for the soil samples from two sites of producing and nonproducing of Tricholoma matsutake, song-yi mushroom, were examined at Yang­yang and Myung-joo, Gangweon province. By the dilution plate method, a total number of propagu­les of fungi per gram of soil was observed to be low at the song-yi producing sites but high at the song-yi nonproducing sites under the communities of Pinus densiflora. The tendency of the number of fungal propagules were decreased with the increasing vertical depth. In the incuhation method at $42^{\circ}C$, six genera and nineteen species of the fungi were isolated from two sites; Aspergillus fumigatus, Acremonium sp., Talaromyces stipitatus, Penicillium lilacinum, P. oxalicum and Westerdykella multispora. The most dominant species by this method was A. fumigatus. From heat treatment method at $70^{\circ}C$, seven genera and nineteen species were isolated; Aspergillus fumigatus, Alternaria alternata, Neurospora sitophila and Mucor sp.. In the ethanol treatment method, one genera and one species was isolated Mortierella sp.. From the three isolation methods, it was found that the total number of the soil fungi and the frequency of species appeared were the highest at the soil of upper layer whereas the lowest at the soils of lower layer in its vertical distribution.

• Journal of Korean Society of Forest Science
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• v.6 no.1
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• pp.19-23
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• 1967

The fungus which belongs to Alternaria has been isolated from "damping-off" infected seedlings of pitch pine (Pinus rigida Mill.) in the nursery (seed bed) of Chung Puk College, Cheong-Ju. The author has carried out this study regarding to (1) the effects of H-ion concentration on the growth of fungus, (2) the effects of temperature and humidity on the conidia germination, (3) the effects of temperature and humidity on the conidia formation. The summary of obtained in this experiments is as follows: 1. The suitable H-ion concentration for growth of isolated fungus is in the range of PH 4.0-9.5, the most suitable of it is PH 6.5-8.0. 2. The germination of the conidia is suppressed at below $0^{\circ}C$ or at $40^{\circ}C$ and above, the range of optimum temperature for the germination is $5^{\circ}C-35^{\circ}C$, the percentage of germination is highest at $20^{\circ}C$. And under relative humidities of 10% or below, the germination is suppressed, favorable relative humidities $85%{\cdots}100%$. 3. The formation of the conidia is suppressed at below $10^{\circ}C$ or at $34^{\circ}C$ and above, the favorable condition of the condia formation is as follows; Temperature; $22^{\circ}C-28^{\circ}C$ Relative humidity:85%-100%.

• Microbiology and Biotechnology Letters
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• v.30 no.2
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• pp.135-141
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• 2002

This study was carried out to isolate antagonistic bacterium against Sclerotium cepivorum causing Allium fistulosum white rot. Total of 146 strains were isolated from A. fistulosum roots. The isolates were screened for antagonism to S. cepivorum and the isolated strain No. AL-1 was selected among these bacteria. It was identified as Serratia plymuthica based on morphological and physiological characteristics according to the Bergey's mannual of systematic bacteriology and 16S rDNA sequences methods. Serratia plymuthica AL-1 showed broad spectrum of antifungal activities against plant pathogenic fungi Alternaria altrata, Colletotrichum gleosporioids, Phoma sp., Rhizoctonia solani, Sclerotinia sclerotiorum, Stemphylium solani, Fusarium oxysporium niveum but not inhibited Didymella bryoniae. When S. plymuthica AL-1 cultivated in the TSB medium containing 1％ colloidal chitin, the high molecular fraction (>10 kDa) have chitinase activity (3.2 units/ml) and the low molecular fraction (<10 kDa) have not chitinase activity. Oppositely, after heat treatment (80℃ for 30 min) of the cultivation supernatant, the high molecular fractions have not antifungal activity but the low molecular fractions have antifungal activity.

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.68-73
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• 1995

Extraction yields of Hizikia fusiforme and Aloe vera Linne by supercritical carbon dioxide($SC-CO_{2}$) with and without ethanol as a cosolvent, and antimicrobial activities of the extracts against Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae and Alternaria sp. were determined. Both yield and solubility of the extracts from Hizikia fusiforme and Aloe vera Linne by $SC-CO_{2}$ with ethanol were two times greater than those by only $SC-CO_{2}$. All of the extracts demonstrated antimicrobial activities in the decreasing order of bacteria, yeast and fungus. The extracts by $SC-CO_{2}$ with ethanol showed almost the same degree of microbial growth inhibition as those by only $SC-CO_{2}$. Based upon these data, it was speculated that the components soluble in nonpolar solvent might be more responsible for the antimicrobial activity.

• The Korean Journal of Mycology
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• v.37 no.1
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• pp.96-103
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• 2009

For the control of pathogenic microorganisms, Bacillus spp. were isolated from diseased pepper fruits in Korea. Among them, Bacillus sp. IUB158-03 showed high inhibitory effect on mycelial growth and spore germination of C. gloeosporioides and Botrytis cinerea. The strain was identified as B. amyloliquefaciens IUB158-03 based on its physiological, biochemical characteristics and Microlog analysis. The highest level of antifungal substances by B. amyloliquefaciens IUB158-03 were obtained when the bacterium was cultured in medium containing 2% soluble starch, 3% yeast extract, 0.5% tryptone, 0.5% $NH_4H_2PO_4$, and 1% NaCl (pH 6.0) at $25^{\circ}C$ for 72 hrs. The antifungal substances were purified by butanol extraction, silica gel column chromatography, preparative thin layer chromatography, and high performance liquid chromatography. The purified antifungal substance was confirmed $R_f$ 0.27 by TLC. This substance exhibited antifungal activity against Fusarium solani, Rhizoctonia solani, Botrytis cineria, Alternata alternaria of plant pathogenic fungi and Trichophyton mentagrophytes, Epidermophyton floccosum, Cryptococcus neoformans of human pathogenic fungi.

• The Plant Pathology Journal
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• v.15 no.3
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• pp.152-157
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• 1999

An antibiotic compound was isolated from the culture of an antagonist against Fusarium oxysporum f. sp. sesami, Bacillus polymyxa strain KB-8, and tested for the control of Fusarium wilt of sesame in greenhouse conditions. Optimum conditions for culturing the antagonist to obtain the maximum antibiotic activity were determined using different culture media, initial medium acidity, and incubation periods for which yeast -malt extract agar with the initial acidity of pH 5 and over 13 days culture were best. Antibiotic substances extracted by methanol had 2 main fractions, KB-8A and KB-8B, in thin layer chromatography (OLC) with Rf values of 0.35 and 0.67 in a solvent system of chloroform : methanol = 7 : 3. The fraction KB-8A wa purified further by XAD-2, silica gel and Sephadex LH-20 column chromatography, and crystalization. Its minimum inhibitory concentrations (MICs) were $12.8\mu\textrm{g}$/ml for F. oxysporum and Alternaria mali, $6.4\mu\textrm{g}$/ml for Colletotrichum gloeosporioides and Rhizoctonia solani, and $3.2\mu\textrm{g}$/ml for Phytophthora capsici. Soil drenching of antibiotic KB-8A in the concentrations of $13.0\mu\textrm{g}$/ml and $26.0\mu\textrm{g}$/ml effectively inhibited the Fusarium wilt of sesame in a greenhouse test, which appeared to be comparable to the fungicide benlate of $6.5\mu\textrm{g}$ a. i./ml.

• Korean journal of applied entomology
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• v.18 no.3 s.40
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• pp.119-126
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• 1979

From the sample seeds of rice cultivar Palkoeng with the brown spot symptom, Helminthosporium oryzae was detected in $86\~92\%$ of hulls including empty glumes, lemma, palea, and rachilla in five to seven days of incubation. When the seeds were dehulled, the percentage detection decreased to $74\~83\%$ of pericarps. The fungus sporulated on whole surface of the seed and was detected within about ten cell layers deep of endosperm but not detected in embryo. Fusarium moniliforme was found in embryo as well as pericarp and endosperm. The frequency of F. roseum, Trichoconis padwickii, Curvularia spp., Atternaria tenuis, Cladosporium cladosporoides and Phoma sp. was less than three percent of hulls and pericarps. In seven days of incubation, $60\~87\%$ of the germinating seeds showed the symptom of H. oryzae while $13\~40\%$ were apparently healthy. This fungus in hilum of infected rice transmitted through pericarp to plumule shoot and radicle of the germinating seed.