• The Plant Pathology Journal
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• v.21 no.4
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• pp.406-408
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• 2005

Web blight symptoms were frequently observed on soybean plants grown in a farmer's fields located in Jincheon in Korea during a disease survey in August, 2005. Incidence of the disease was $5-20\%$ infected plants in two of four soybean fields investigated. A total of 31 isolates of Rhizoctonia sp. were obtained from leaves, leaf petioles, and pods of diseased soybean plants. The isolates were identified as Rhizoctonia solani AG-l(IA) by anastomosis test and based on the morphological and cultural characteristics. Three isolates of R. solani AG-l(IA) were tested for pathogenicity to five cultivars of soybean by artificial inoculation. All the isolates induced blight symptoms on the leaves of soybean and formed sclerotia on the lesions, which were similar to those observed in the field. The pathogenicity tests revealed that all the soybean cultivars tested were susceptible to the pathogen. There was no difference in the pathogenicity among the isolates. The present study first reveals that R. solani AG-l(IA) causes web blight of soybean in Korea.

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.7-12
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• 1994

Incidence of radish disease caused by Rhizoctonia solani ranged from 1 to 30% in fields located at Hwaseong, Naju and Yeoncheon in Korea during the growing seasons in 1989, 1990 ad 1993. A total of 133 isolates of R. solani was obtained from the diseased seedlings, leaves and roots of radish collected. The fungus was most commonly isolated from the roots. Among 133 isolates of R. solani, 56 isolates were classified as anastomosis group AG-1 by anastomosis test, 37 isolates as AG-2-1, and 40 isolates as AG-4. Among the isolates of AG-1, 26 isolates were grouped as cultural type IA, and the others as cultural type IB. Cultural types IA and IB of AG-1, were isolated from the leaves, AG-2-1 from the roots, and AG-4 from the seedlings, leaves and roots. Pathogenicity tests revealed that the AG-1(IA) isolates were highly virulent on leaves of radish, but avirulent on the seedlings, petioles and roots. The AG-1(IB) isolates were highly virulent on the leaves, but mildly virulent on the seedlings and avirulent or mildly virulent on the petioles and roots. The AG-2-1, isolates were mildly virulent on the leaves and seedlings and mildly or highly virulent on the petioles and roots. The AG-4 isolates were highly virulent on the seedlings and mildly or highly virulent on the leaves, petioles and roots.

• Research in Plant Disease
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• v.28 no.1
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• pp.51-53
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• 2022

In January 2021, unusual outbreak of shoot rot symptoms was observed in young spikenard (Aralia cordata) plants growing in vinyl greenhouses located in Chuncheon and Yanggu, Gangwon Province, Korea. The symptoms initially appeared on young shoots of the plants at or above the soil surface level. Later, the infected shoots wholly rotted and blighted. The incidence of diseased plants in the vinyl greenhouses investigated ranged from 5% to 30%. Eight isolates of Rhizoctonia sp. were obtained from shoot lesions of the diseased plants. All the isolates were identified as Rhizoctonia solani AG-2-1 based on the morphological characteristics and anastomosis test. Three isolates of R. solani AG-2-1 were tested for pathogenicity on young shoots of spikenard plants using artificial inoculation. All the tested isolates induced shoot rot symptoms on the inoculated plants. The symptoms were similar to those observed in spikenard plants from the vinyl greenhouses investigated. This is the first report of R. solani AG-2-1 causing shoot rot in spikenard.

• The Korean Journal of Mycology
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• v.20 no.1
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• pp.44-50
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• 1992

The protoplast formation of Rhizoctonia solani in the fast growing anastomosis groups (AGs) 1 and 4, the intermediate AG-2 and AG-5, and the slow AG-3 yielded the most, moderate and the least in that order, respectively. Sclerotia formation varied with AGs. A high yield of protoplasts from AGs was obtained with a combined lytic enzyme system containing cellulase 'Onozuka' R-10, macerozyme R-10 and ${\beta}-glucuronidase$. When 3g (fresh weight) of 30 hr old mycelia was incubated for 3 hr at $32^{\circ}C$ with the enzyme mixture in 0.6 M mannitol, maximum protoplasts were obtained in the five AGs. A protoplast fusion between sclerotia forming AG-1 inactivated with heat and non-forming AG-5 was induced by polyethylene glycol and ${Ca}^{2+}$. Seven fusants obtained were based on characteristics of colony and sclerotium formation on culture plates. The fusants were confirmed by isozyme patterns of esterase and killing reaction between AG-1 and a fusant F1501.

• Korean journal of applied entomology
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• v.10 no.1
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• pp.7-12
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• 1971

1. The number of Rhizoctonia solani, Pythium debaryanum, Fusarium and Trichoderma was detected by the modification of Boosails special plating method when ginseng seed bed was drenched with Captan, Difolatan, Zineb, Maneb and PCNB at weekly intervals. Pythium debaryanum Hesse was described for the first time on Panax ginseng in Korea. 2. The number of Rhizoctonia solani and Pythium debaryanum was decreased gradually as the geason Progressed, whereas that of Fusarium and rrichcderma was increased. 3, The number of Rhixoctonia solani was greatly reduced by PCNB, and soils treated with other fungicides generally showed less Rhizoctonie solani than in the control. The number of Pythium debaryanum was significantly reduced by Zineb, Maneb, followed by Captan and Difolatan. None of the fungicids reduced the number of Fusarium colonies in the fourth week. Effects of the chemicals on Trichoderma were not statistically significant. 4. More fresh weight of the seedling roots was obtained using Difolatan, Maneb and PCNB. Phytotoxicity was noted with Maneb, Zineb and Captan after the third treatment.

• Microbiology and Biotechnology Letters
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• v.33 no.2
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• pp.112-116
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• 2005

Bacillus licheniformis KMU-3 shown a strong antifungal activity was isolated from Swedish forest soils. B. licheniformis KMU-3 produced a maximum level of antifungal substance under incubation aerobically at $24^{\circ}C$ for 24 hours in LB broth containing $1.0\%$ sodium acetate, $1.0\%$ ammonium sulfate at 180 rpm and initial pH adjusted to 8.0. Chloroform extraction of culture broth was confirmed inhibitory zone by plate assay and Rf value 0.49 substance by thin layer chromatography (TLC) represented high antifungal activity against Rhizoctonia solani AG-1. This substance also exhibited against Rhizoctonia solani AG-4, Colletotrichum orbiculare, Colletotrichum gloeosporioides, Cladosporium cucumerinum, Fusarium oxysporum, and Fusarium graminearum.

• The Korean Journal of Pesticide Science
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• v.9 no.1
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• pp.35-40
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• 2005

Damping-off of summer spinach caused by Rhizoctonia solani AG-4 has become a very important disease. For the control of summer spinach damping-off, antifungal activity of thirteen fungicides (pencycuron, trifloxystrobin, pyraclostrobin, azoxystrobin, kresoxim-methyl, validamycin, fluazinam, Benlate-T, flutolanil, cyazofamid, hexaconazole, tebuconazole, prochloraz) were evaluated in vitro and in vivo. Pencycuron, pyraclostrobin, validamycin, fluazinam, Benlate-T, hexaconazole, tebuconazole, and flutolanil significantly suppressed the mycelial growth of the pathogenic fungus. However, trifloxystrobin, azoxystrobia kresoxim-methyl, cyazofamid, and prochloraz did not represent good inhibition on the growth of R. solani. When applied by soil drenching (2,000 mg/L), pencycuron, pyraclostrobin, validamycin, fluazinam, Benlate-T, and flutolanil provided spinach survival ratios of 97.8%, 84.4%, 93.3%, 95.6%, 91.1%, and 86.7%, respectively. Also when treated in seed at 2,000 ing/L, pencycuron and pyraclostrobin displayed survival ratios of more than 85.1%.

• Research in Plant Disease
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• v.11 no.1
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• pp.77-79
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• 2005

Leaf blight of kudzu was found in Jeonbuk province in 2002. Water-soaked lesion appeared on leaves, and young stems and gray green blight sypmtom expanded from margin to main vine of leaves. As the disease became severe, blighted leaves and shoots turned dark brown and then collapsed. The causal pathgen showed initially white aerial mycelium and turned brown to gray. Mycelia were branched at 90o angles and multinucleate in one cell. It formed sclerotia on PDA. Slerotia were irregular, globose and 0.5~3.0 mm in diameter. The causal fungus of leaf blight was identified as Rhizoctonia solani Kuhn based on the cultural and morphological characteristics. This is the first report on leaf blight of kudzu caused by R. solani in Korea.

• The Plant Pathology Journal
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• v.17 no.4
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• pp.210-215
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• 2001

The phenotype of Rhizoctonia solani KR-13 was randomly segregated to both melanin-producing (M+) and non-producing (M-) types through successive cultures on PDA. M+type with dark melanin showed strong pathogenicity to rice and self-anastomosis. Meanwhile, M- type with white or less-melanized mycelia showed very weak pathogenicity and non-self-anastomosis. Melanin production of R. solani was affected by incubation temperature in both M+ and M- types, but not by light treatment. The application of tricyclazole, an inhibitor of fungal melanin biosynthesis, showed no controlling effect on R. solani causing rice sheath blight. Results of this study showed that melanization of mycelia of R. solani is an important pathogenicity factor in rice.

• The Plant Pathology Journal
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• v.15 no.1
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• pp.68-71
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• 1999

To illustrate the action mechanism of pencycuron on Rhizoctonia solani, two experiments were conducted including the comparison of amino acids of $\beta$-tubulin between R-C (sensitive isolate) and Rh-131 (non-sensitive isolate), and the inhibitory effect of pencycuron on tubulin assembly in vitro. Both $\beta$-tubulin genes of R-C and Rh-131 proved to have 1,582 nucleotides encoding a protein of 445 amino acids, showing 98% homology in amino acid sequences between them. It was found that codons at 103, 236, and 267 for lysine (AGG), valine (GTC) and isoleucine (ATT) in R-C were replaced by codons for methionine (ATG), isoleucine (ATT) and methionine (ATG) in Rh-131, respectively. No inhibitory effect of pencycuron on the tubulin assembly was observed. It suggests that pencycuron may have no direct inhibitory effects on the assembly of tubulin at least in vitro.