• Korean journal of applied entomology
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• v.19 no.4 s.45
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• pp.228-233
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• 1980

The infection rate of soybean black root rot disease caused by Calonectria crotalariae was about $14\%$. The isolated fungi from the infected soybean roots and stems were Calonectria crotalariae, Fusarium solani, F. roseum, Phomopsis sojae, Pythium aphanidermatum, Rhizoctonia solani and Macrophomina sp. Among them, C. crotalariae was the most virulent pathogen under the laboratory conditions. Mycelial growth and microsclerotial formation were good on PSA containing 1000cc of water, 100g of potato and 20g of sugar. Mycelial growth, sporulation and microsclerotial formation were good on sterilized root. Perithecial formation was better in the dark condition than in the light. Survival of macroconidia was not available between $0\~25\%$ soil water content. Microsclerotia and mycelium in infected plant debris were survived for 4 months at to $8\%\;50\%$ soil water content. The plant height, when inoculated with $1.2\%$ inoculum density, reached approximately half of uninoculated plants. Disease severity was much higher at nonsterilized soil than completely sterilized soil. It was determined that the host range of this pathogen includes soybean, peanut, green bean and red bean.

• Korean Journal of Medicinal Crop Science
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• v.14 no.4
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• pp.202-205
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• 2006

Ginseng is major medicinal plant in Korea. Because of its long cultivation period the yield losses of 5 years of ginseng is 50% due to various diseases. The objective of this study is to select potential biocontrol agents. As the result of research so far achieved to contribute to rational prevention of ginseag plant disease for the stable cultivation of ginseng, three bacterial strains, Streptomyces lauretii strain B8180, Bacillus subtilis strain 8856, and Burkholderia cepacia strain 7944 were isolated from oak leaf compost. The strains showed antagonistic activities against five ginseng pathogenic fungi (Cylindrocarpon destructans, Rhizoctonia solani, Phytophthora cactorum, Botrytis cinerea, Fusarium solani f. sp. panacis) and control effects on Phytophthora blight.

• Mycobiology
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• v.33 no.4
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• pp.206-209
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• 2005

Narceine methyl ester and narceine are potent alkaloids which were isolated from Corydalis longipes were found effective in vitro at very low concentration, i.e., $100{\sim}500\;ppm$ against spore germination of some test plant pathogenic fungi (Alternaria solani, A. tagetica, Cercospora abelmoschi, Curvularia maculans, Erysiphe cichoracearum, E. pisi, Fusarium udum, Helminthosporium oryzae, H. penniseti, Ustilago cynodontis). Among the test, phytopathogens the spores of F. udum, C. maculans and H. penniseti were highly sensitive at 200 ppm. However, spores of E. pisi, A. solani and A. tagetica were less sensitive at low concentration followed by other test fungi. Most of the fungi showed zero or nearly zero percent spore germination at 400 and 500 ppm.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.606-611
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• 1998

An antagonistic bacterium, Pseudomonas flurorescens MC07 inhibited the mycelial growth of Rhizoctonia solani, Pythium ultimum, Fusarium oxysporum, and Phytophthora capsici in on potato dextrose agan (PDA) and other media. The strain MC07 conlonizes various plant roots and possesses antifungal activity. To determine the role of antifungal activity of the bacterium in disease suppression, a mutant Okm3-4 which lost its activity was isolated after screening 2,500 colonies generated by Omegon-Km insertions. The mutant Okm3-4 showed diminished growth inhibition of R. solani, P. ultimum, F. oxysporum, and Ph. capsici in vitro and had reduced suppressive effects on sesame damping.-off compared to the parental strain. In soils, accumulation of the pathogens by continuous cropping, 90% of sesame plants were killed by natural infection of damping-off whereas, only 29% of plants grown from seeds treated with MC07 were killed. On the other hand, 85% of plants died when sesame seeds were treated with the Okm3-4 cells. This indicated that antifungal activity of MC07 in vitro is directly responsible for the suppression of damping-off disease. Emergence rates of sesame seeds in pots containing diseased soil were 33%. However, MC07 treatments on seeds significantly improved emergence rates, which has similar effects of Benomyl treatment. The mutant Okm3-4 exhibited 53% of emergence rate. This indicated that antifungal activity of MC07 also affects the emergence rate of sesame seeds.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.484-490
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• 1998

Microorganisms associated with seed-rhizome rot of gingers preserved in three underground storage caves were identified with respect to rot types. Rot patterns were grouped into 4 different types : yellow soft rot, brown rot, localized ring rot, and water-soaked rot. Water-soaked rot was highest in frequency with 40% and ring rot the least with 14%. Causal pathogens differed with rot type, yellow soft rot by Erwinia carotovora and Pseudomonas aeruginosa, brown rot by Fusarium solani and Pseudomonas aeruginosa, localized ring rot by F. solani, and water-soaked rot by Pythium spinosum and P. ultimum. Pythium myriotylum, the causal pathogen of ginger rhizome rot which occurs severely in fields was rarely detected from storage seed-rhizomes suggesting its minor involvement with storage rot. Pathogenic Pythium isolates were frequently obtained from both rhizome surface and inner tissues of rotten rhizomes. Detection frequency of Pythium isolates in inner tissues decreased as increasing distance from rhizome surface. In wound-inoculation tests, above pathogens caused a varying degree of rot on healthy rhizomes at 15$^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$ with increasing severity at higher temperatures.

• Journal of Applied Biological Chemistry
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• v.42 no.3
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• pp.146-150
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• 1999

As a part of the integrated disease system in greenhouse, an antifungal fungus(AF1) was isolated from greenhouse soil. It exhibited strong inhibitory activites against Pythium ultimum, Phytophtora capsici, Rhizoctonia solani, Botrytis cinerea, and Fusarium oxysporum based on dual culture on 1/5 strength of potato dextrose agar between antagonistic fungus and several plant pathogens. The antagonistic fungus was identified as Chaetomium cochliodes, based on morphological characteristics; the body of the perithecium bears straight or slightly wavy, unbranched hairs, whilst the apex bears a group of spirally coiled hairs. To investigate antagonistic principles, antifungal compound was extracted and fractionated by different solvent systems. An antifungal compound was isolated as pure crystal from is culture filtrate using organic solvent extraction and column chromatography, followed by preparative thin layer chromatography. The chemical structure of the purified antifungal compound was identified as chaetoglobosin A based on the data obtained form $^1H-NMR$, $^{13}C-NMR$, DEPT 90, 135, $^1H-^1H$ COSY, $^1H-^{13}C$ COSY and EI/MS. $ED_{50}$ values of the chaetoglobosin A against P. ultimum, P. capsici, R. solani, B. cinerea and F. oxysporum were 1.98, 4.01, 4.16, 2.67 and 35.14 ppm, respectively.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1001-1010
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• 2005

Bacillus megaterium KL39, an antibiotic-producing plant growth promoting rhizobacterium (PGPR), was selected from soil. The antifungal antibiotic, denoted KL39, was purified from culture filtrate by column chromatography using Dion HP-20, Silica gel, Sephadex LH-20, and prep-HPLC. Thin layer chromatography, employing the solvent system of ethanol:ammonia:water=8:1:1, showed the $R_{f}$. value of 0.32. The antibiotic KL39 showed a negative reaction with ninhydrin solution, positive with iodine vapor, and also positive with Ehrlich reagent. It was soluble in methanol, ethanol, butanol, and acetonitrile, but insoluble in chloroform, toluene, hexane, ethyl ether, or acetone. Its UV spectrum had the maximum absorption at 208 nm. Amino acid composition, FAB-mass, $^{1}H-NMR,\;^{13}C-NMR$, and atomic analyses showed that the antibiotic KL39 (MW=1,071) has a structure very similar to iturin E. The antibiotic KL39 has a broad antifungal spectrum against a variety of plant pathogenic fungi including Rhizoctonia solani, Pyricularia oryzae, Monilinia froeticola, Botrytis cinenea, Altenaria kikuchiana, Fusarium oxysporum, and F. solani. An MIC value of $10\;{\mu}g/ml$ was determined for Phytophthora capsici. Macromolecular incorporation studies with P. capsici using radioactive [$^{3}H-adenine$] as the precursor, indicated that the antibiotic KL39 strongly inhibits the DNA biosynthesis of the fungal cell. Microscopic observation of the antifungal action showed abnormal hyphal swelling of P. capsici. The purified antibiotic KL39 was very effective for the biocontrol of in vivo Phytophthora-blight disease of pepper.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.165-170
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• 2006

The antifungal activity of crude methanolic extract and fractions from Yucca smalliana Fern. leaves, roots and flowers were investigated in vitro against a panel of plant pathogenic fungi. The minimal inhibitory concentration(MIC) was determined by an agar dilution method. Preliminary liquid culture and agar plate assays showed that the growth of Fu sarium oxysporum, Phytophthora capsici, Rhizoctonia solani and Botrytis cinerea were inhibited by Y. smalliana extracts. The extracts from flowers and leaves showed antifungal activity of 64.0% and 34.0% against F. oxysporum, 66.0% and 62.0% against P. capsici, and 27.0% and 41.0% against B. cinerea, respectively. The methanolic extract from Y. smallina leaves in distilled water was fractionated using solvents of increasing polarity: hexane, ethyl acetate and butanol. These fractions had a broad spectrum of antifungal activity, found to reside entirely in the butanol and aqueous fraction. The aqueous fraction showed inhibition rate of 60.0, 67.8, 84.6 and 58.3% against F. oxysporum, R. solani, C. gloeosporioides, and B. cinerea, respectively, and the butganol fracgtion showed 36.0, 46.0, 66.1 and 58.3%, respectively. Phenolics(e.g. flavonoids, steroids and terpenoids) were observed in the thin layer profile of the different fractions. Leave extract showed a prominent antioxidant activity totally scavenging the free radical of DPPH at a concentration of 1 mg/ml.

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.161-164
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• 2010

Dollar spot, caused by Sclerotinia homoeocarpa F.T. Bennett, is the most economically important turfgrass disease on golf courses in North America due to its persistent nature. Fungicides, plant growth regulators, and other products were evaluated for preventative control of dollar spot and the secondary effects on brown patch and Pythium in a mixed stand of creeping bentgrass and annual bluegrass golf course putting green. Most fungicides provided excellent control of dollar spot throughout the trial but Rhapsody alone did not provide adequate control. Civitas applied alone and tank-mixed with Banner MAXX(R) and Daconil Ultrex(R) provided acceptable control throughout the study. No phytotoxicity was observed on any of the treatments applied but a darker green color and reduction in turfgrass growth was observed in a treatment with plant growth regulator, Trimmit. Treatments that contained Civitas and the Civitas Harmonizer also exhibited green pigmentation.

• Food Science and Preservation
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• v.10 no.2
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• pp.224-229
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• 2003

This study was carried out to isolate of antagonistic bacterium to Allium cepa L. pathogens. A total of 250 strains were isolated from A. cepa L. roots. The isolates were screened for antagonism to A. cepa L. pathogens and the isolated strain No. YJ-4 was selected among these bacteria. It was identified as Bacillus ehimensis based on morphological and physiological characteristics according to the Bergey's mannual of systematic bacteriology, Sherlock system of Microbial ID Int and 165 rDNA sequences methods. Bacillus ehimensis YJ-4 showed broad spectrum of antibacterial and antifungal activities against plant pathogens as Alternaria porri, Botrytis cinerea, Erwinia carotovora subsp. carotovora Fusarium of oxysporium, penicillium sp., Pseudomonas sp., Rhizoctonia solani, Sclerotium cepivotum, Septoria sp., Stemphylium botryosum. Speially B. ehimensis YJ-4 showed high antifungal activity on growth against F. oxysporium, the causal agent of onion Fusarium wilt.