• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.4
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• pp.368-372
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• 1999

The practicality of utilizing chitosan as a natural antimicrobial compound to reduce soybean sprout rot was tested. Domestic and imported soybean seeds were soaked for 6 hours in solutions containing different levels of chitosan and acetic acid (glacial), and cultured at $25^{\circ}C$ for 6 days. In case of domestic seeds, soaking with 1,000ppm chitosan increased germination percentage, hypocotyl thickness, total length, and fresh weight of sprouts by 4%, 5%, 2%, and 1%, respectively. The total sprout yield was increased by chitosan in a concentration-dependent manner in that 1,000ppm chitosan resulted in 8% increment of total yield (7.47kg sprouts/kg seed). Chitosan significantly reduced sprout rot percentage to 7.0% compared to control (13.8%), and consequently enhanced marketable sprout yield by 39%. Compared to domestic seeds, the imported soybean seeds exhibited very low germination percentage regardless of chitosan treatments. Chitosan, nevertheless, consistently induced yield increment and rot decrement in imported soybean sprouts. Although 100ppm acetic acid was effective in reducing sprout rot percentage down to 11.8%, its yield-increasing effects were not as prominent as chitosan. In conclusion, soaking soybean seeds with chitosan seems to be a practical method to enhance the efficiency of soybean sprout production.

• Research in Plant Disease
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• v.10 no.4
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• pp.268-271
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• 2004

Occurrence and soil fumigation effect on black root rot of peony was investigated. Peony was severely infected to black root rot caused by Cylindrocarpon destructans in continuous cropping field, but in first cropping field was less infected. To control black root rot, soil improvement, soil fumigation and the root dipping in chemicals were trialed in peony continuous cropping field. Black root rot was not decreased by soil improvement, but incidence of black root rot of peony cultivated in continuous croping field of peony was decreased by soil fumigation with Dazomet GR. and dipping of peony root in chemicals.

• The Plant Pathology Journal
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• v.22 no.1
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• pp.16-20
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• 2006

Four leguminous crops grown in greenhouses and fields in Korea were surveyed from 2000 through 2002. Sclerotinia rot most severely occurred up to $60\%$ in Phaseolus vulgaris grown in greenhouses but occurred as low as $0-0.5\%$ in that grown in fields. Incidence of the disease in Pisum sativum grown in greenhouses ranged $1-5\%$, and that in Vicia Java and Vigna sinensis grown in fields was $0.8\%$ and $2\%$, respectively. Symptoms of Sclerotinia rot commonly developed on stems and pods of the crops. A total of 59 isolates of Sclerotinia species were obtained from diseased stems and pods of the crops. All of the isolates were identified as Sclerotinia sclerotiorum based on their morphological characteristics. Eight isolates of the fungus were tested for their pathogenicity to four host crops by artificial inoculation. All of the isolates induced rot symptoms on stems of the host crops tested, which were similar to those observed in the fields. The pathogenicity tests revealed that there was no significant difference in the susceptibility to the isolates among the leguminous crops tested This is the first formal report that S. sclerotiorum causes the Sclerotinia' rot of the four leguminous crops in Korea.

• Research in Plant Disease
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• v.10 no.1
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• pp.8-12
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• 2004

The diseased ginseng plants, their trunks fall down anil roots rot, were observed in ginseng cultivation field at Bongwha, Kyungbuk. Inoculation of the bacterium isolated from root rot lesion induced a range of symptoms on leaves, trunks and roots; The bacterium caused wilting with chlorosis and black discoloration on leaves, empty of inside trunks and rot on roots. The bacterium was identified as Serritia liquefaciens based on the morphologcal and physiological characteristics. This is the first report in Korea on roots rot of ginseng occurred by S. liquefaciens.

• The Plant Pathology Journal
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• v.19 no.5
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• pp.231-234
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• 2003

Brown rot symptoms severely occurred on fruits of apricot and mume grown in Changnyeong, Suwon and Yeongi in Korea during a disease survey in June 2002. A total of 32 isolates of Phomopsis sp. was obtained from the fruit rot symptoms. All isolates were identified as Phomopsis vexans based on their morphological and cultural characteristics. Four isolates of the fungus were tested for pathogenicity to fruits of apricot and mume by artificial inoculation. All isolates induced brown rot symptoms on the fruits of apricot and mume by wound inoculation. Unwounded inoculation also induced symptoms on mume fruits but not on apricot fruits. The symptoms on the fruits induced by artificial inoculation were similar to those observed in the orchard. The pathogenicity tests revealed that mume was more susceptible to the pathogen than apricot. This is the first report of brown rot of apricot and mume caused by P. vexans.

• Research in Plant Disease
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• v.19 no.1
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• pp.49-54
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• 2013

Sclerotinia white rot disease was observed on 5 and 6-year-old ginseng (Panax ginseng) roots in Hongchun, Cheorwon, and Yanggu, Gangwon Province, Korea from 2006 to 2010. Symptoms included a brownish watery soft rot of the roots, and black sclerotia were often found on the rotten roots. The causal agent of the disease was identified as Sclerotinia nivalis based on cultural characteristics and sequence analyses of the internal transcribed spacer region of rDNA and ${\beta}$-tubulin gene with 100% sequence similarity. Pathogenicity tests were performed on 2-year-old ginseng roots with mycelium plugs without wounds. A watery soft rot of the roots and black sclerotia were observed 10 days after inoculation. These symptoms were identical to those observed on naturally infected roots. The same fungus was re-isolated from the lesions induced by artificial inoculation. This is the first report of sclerotinia white rot caused by S. nivalis on P. ginseng in Korea.

• Korean Journal Plant Pathology
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• v.12 no.1
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• pp.116-120
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• 1996

Water-soaked spots or lesions were observed on fruits or stems of melon plants at house-melon farms in Andong, Korea. The symptoms developed to soft rot of the fruits of wilting of the whole plants. The causal organism isolated from the water-soaked le-sions was identified as Erwinia carotovora subsp. carotovora based on the morphological and physiological characteristics. The causal bacterium was susceptible to not only two kinds of medical antibiotics but also two kinds of agrochemicals tested. Since the bacterial soft rot is a first described bacterial disease in melon in Korea, we propose to name the disease as "bacterial soft rot of melon".

• Structural Engineering and Mechanics
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• v.61 no.1
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• pp.15-29
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• 2017

The recently introduced index Ratio Of Torsion (ROT) quantifies the base shear amplification due to torsional effects on shear cantilever types of building structures. In this work, a theoretical proof based on the theory of elasticity is provided, depicting that the ratio of torsion (ROT) is independent of the forces acting on the structure, although its definition stems from the shear forces. This is a particular attribute of other design and evaluation criteria against torsion such as center of rigidity and center of strength. In the case of ROT, this evidence could be considered as inconsistent, as ROT is a function solely of the forces acting on structural members, nevertheless it is proven to be independent of them. As ROT is the amplification of the shear forces due to in-plan irregularities, this work depicts that this increase of internal shear forces rely only on the structural topology. Moreover, a numerical verification of this theoretical finding was accomplished, using linear statistics interpretation and nonlinear neural networks simulation for an adequate database of structures.

• Journal of Ginseng Research
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• v.17 no.1
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• pp.45-51
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• 1993

In 61 abolished ginseng fields examined in 1986, the average plant missing was 49.2%, root rusting, 34.4%, and root rot, 3.3%. Plant missing was not different among the ages of ginseng fields; however, rate of root rusting was high in 3- and 4-year-old ginseng fields, and rate of root rot was high in 5- and 6-year-old ginseng fields, suggesting that root rusting and root rot were relatively more important factors related to the abolishment of ginseng filed in younger and older ginseng fields in 1986, respectively. Out of 61 ginseng fields, 18 were infested with more than 509) alternaria blights, and out of 19 fields with root rot, 2 were caused by Sclerotinia sp., 5 by potato rot nematode, and the causal agents were not identified in 12 fields. With increase of the ridge height, root rusting was significantly decreased, and plant missing rate was significantly lower in fields with straw mulching than those without mulching. The physico-chemical characteristics of the fields with more than 50fi root rusting, the contents of $NO_3,\;P_2O_5$ and Ca were higher than those of good fields with less than 40% root rusting and plant missing. The population of Erwinia sp. was significantly corralled with plant missing.

• Mycobiology
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• v.32 no.4
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• pp.149-154
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• 2004

Toxin produced by Colletotrichum falcatum Went, the incitant of red rot of sugarcane was isolated, purified and assayed to determine host specificity and identify its chemical nature. The toxin was found to be not host specific as it inhibited germination of various seeds(gram, greengram, blackgram, pea, cowpea, rice and sugarcane) as well as different seedlings viz. tomato, coriander, pea and rice. The toxin consists of two distinct fraction-one fraction having $R_f$, value at 0.36 producing identical red rot lesion when inoculated at leaf midrib of sugarcane, and the other having $R_f$, value at 0.72 not showing any red rot lesion. Chromatogram of high performance liquid chromatography(HPLC) of the red rot lesion causing fraction showed a sharp peak at 1.62 min of retention time(RT), and spectral analysis indicated the presence of following chemical $CH_3$ - groups-C-H, C=O, C-N, $-CH_3,\;-CH_2$ -CH and molecular mass of the compound was 203. - ($M^+,\;C_{11}H_{11}N_2O_2$).