• The Korean Journal of Mycology
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• v.40 no.4
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• pp.266-270
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• 2012

Stem canker and tuber rot symptoms were observed on yam grown in Andong and Jinju, Korea in 2011. A total of 20 isolates of Rhizoctonia and allied fungi were obtained from the symptomatic plants. Among the isolates, 8 isolates were identified as Rhizoctonia solani and 12 isolates as Ceratobasidium sp. based on rDNA-internal transcribed spacer (ITS) sequence similarity. In the cluster analysis of rDNA-ITS sequences, 7 isolates of R. solani belonged to AG 2-2IIIB and remaining one to AG 1-1A. In addition, among the 12 isolates of Ceratobasidium sp., 7 isolates belonged to AG-Fa, three isolates to AG-A and the other two isolates to AG-Fb and AG-O, respectively. Pathogenicity tests showed that all the R. solani AG 2-2IIIB isolates are pathogenic on stem and tuber of yam but R. solani AG 1-1A and all the Ceratobasidium isolates are non-pathogenic. The results indicate that R. solani AG 2-2IIIB is an important pathogen causing stem canker and tuber rot on yams grown in the study areas. This is the first report of R. solani AG 2-2IIIB causing stem canker and tuber rot of yam in Korea.

• The Korean Journal of Mycology
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• v.49 no.3
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• pp.413-416
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• 2021

In July 2019, damping-off symptoms of young Fischer's ragwort (Ligularia fischeri) plants were observed in four vinyl greenhouses of a farmer located in Taebaek, Gangwon Province, Korea. This disease occurred in 20-30% of plants in the vinyl greenhouses investigated. Nine isolates of Rhizoctonia sp. were obtained from the diseased plants. All the isolates were identified as Rhizoctonia solani AG-2-2 (IIIB), based on morphological, cultural characteristics, and anastomosis test. Three isolates were used for artificial inoculation test on Fischer's ragwort. Pathogenicity of these isolates was confirmed on the plants with the inoculation tests. Damping-off symptoms observed on the inoculated plants were similar to those observed in the diseased plants in the vinyl greenhouses. This is the first report of R. solani AG-2-2 (IIIB) being the causative agent in damping-off in Fischer's ragwort.

• The Korean Journal of Mycology
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• v.23 no.3 s.74
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• pp.257-265
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• 1995

Morphological characteristics and pathogenicity of Rhizoctonia species causing blight diseases of turfgrasses were studied. The species were identified as Rhizoctonia cerealis Van der Hoeven, R. oryzae Ryker et Gooch, and R. solani $K{\ddot{u}hn}$ based on their morphological and cultural characteristics. Isolates of R. solani were assigned to anastomosis groups (AG) with cultural type 1 (1A), 2-2 (IIIB), and 2-2 (IV). R. cerealis, R. oryzae and R. solani induced sheath rot and foliar blight symptoms on creeping bentgrass (Agrostis palustris) and zoysiagrass (Zoysia japonica). Inoculation tests showed that disease severity with isolates of R. cerealis and R. oryzae were more serious to creeping bentgrass than zoysiagrass. AG 1(1A) isolates of R. solani were strongly pathogenic on creeping bentgrass, but moderate to zoysiagrass. AG 2-2 (III) isolates were moderately pathogenic to zoysiagrass, but weakly to creeping bentgrass. AG 2-2 (IV) isolates from zoysiagrass were moderately pathogenic to zoysiagrass, but weakly to creeping bentgrass.

• Research in Plant Disease
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• v.29 no.4
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• pp.377-383
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• 2023

In 2020 and 2021, we surveyed diseases of three-leaf ladybell (Adenophora triphylla) plants grown in fields at two locations in Korea. During the disease surveys, severe leaf rot symptoms were observed on the young plants in Hongseong, and stem rot symptoms on the adult plants in Cheolwon. The incidence of leaf rot was 5-60%, and that of stem rot 1-10%. We obtained 6 fungal isolates each from the leaf rot lesions and the stem rot lesions. All the isolates were morphologically identified as Rhizoctonia solani. Anastomosis test and investigation of cultural features of the fungal isolates revealed that the isolates from the leaf rot lesions corresponded to R. solani AG-1(IB), and those from the stem rot lesions to R. solani AG-2-2(IIIB). Two isolates each of R. solani AG-1(IB) and AG-2-2(IIIB) were used for DNA sequence analysis and pathogenicity test to three-leaf ladybell plants through artificial inoculation. The anastomosis groups and cultural types of the R. solani isolates were confirmed by the sequence analysis. The pathogenicity tests revealed that the isolates of R. solani AG-1(IB) caused only leaf rot symptoms on the inoculated plants, and those of R. solani AG-2-2(IIIB) leaf rot and stem rot symptoms. The induced symptoms were similar to those observed in the fields investigated. Leaf and stem rot of three-leaf ladybell caused by the two anastomosis groups and cultural types of R. solani is first reported in this study.

• Proceedings of the Turfgrass Society of Korea Conference
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• 2011.02a
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• pp.35-35
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• 2011

A large patch disease caused by Rhizoctonia solani AG2-2(IV) is a serious problem in turfgrass sites including golf courses and sports fields in Korea. The objectives of this study were to isolate some antagonistic microorganisms and to explain some involving mechanisms. Initially single colonies which were formed from the filtrates of various soil samples were obtained from LB culture and then co-cultured with R.solani AG2-2(IV) on PDA plate to explore some antagonistic microbes against for large patch fungus, Rhizoctonia solani AG2-2(IV). Out of total 82 antagonistic isolates which commonly had inhibition effect on Rhizoctonia solani AG2-2(IV) mycelial growth, one candidate (YPIN22) showed the most antifungal effect, which was confirmed by the longest distance from the edge of bacterial colony to the mycelial edge of the Rhizoctonia solani AG2-2(IV) in the dual culture. A succeeding investigation was to test any potential effect of the isolate on growth inhibition of 5 other turfgrass pathogens including R. solani solani AG2-2(IIIB), P. ultimum, C. caudatum, C. lunata, and F.oxysporum. Preliminary result indicated that the new isolate YPIN22 was also found to have antagonistic potential on the growth inhibition of those turfgrass pathogenic fungi, which was explained by inhibition zones ranging from 8 to 22mm. A further explanation of some characteristics of the isolate YPIN22 will be discussed in detail.

• Korean Journal Plant Pathology
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• v.12 no.1
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• pp.21-32
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• 1996

Rhizoctonia solani 균주들의 각 균사융합군 및 배형별 72종의 기주작물에 대한 병원성을 접종실험에 의해 조사하였다. 33종의 작물에서 단독으로 분리된 균사융합군 및 배양형은 그 기주작물에 병원성이 강하였으며, 8종의 작물에서 단독으로 분리된 것들은 병원성이 약하거나 강하였고, 6조의 작물에서 단독으로 분리도니 것들은 병원성이 약하거나 없었다. 26종의 작물에서 같이 분리된 균사융합군 및 배양형은 그 기주작물에 대한 병원성이 대부분 다르거나 간혹 비슷했다. AG-1(IA)는 1종을 제외한 기주작물에 잎마름병 혹은 잎썩음병과 잎집무늬마름병을 일으켰다. AG-1(IB)는 19종의 기주작물에 잘록병과 잎마름병 혹은 잎썩음병을 일으켰으나, 9종의 기주작물에는 병징을 약하게 유발시키거나 혹은 유발시키지 못했다. AG-1(IC)는 2종의 유채속작물에 잘록병과 밑둥썩음병 혹은 잎썩음병을 일으켰다. AG-2-1은 1종을 제외한 기주작물에 잘록병, 밑둥썩음병, 관부썩음병, 눈마름벼, 뿌리썩음병, 잎마름병을 일으켰다. AG-202(IIIB)는 기주작물에 뿌리 및 줄기썩음병, 잎마름병, 잘록병, 잎자루썩음병을 일으켰다. AG-2-2(IV)는 기주작물에 잘록병, 관부썩음병, 줄기썩음병, 라이족토니아마름병을 일으켰다. AG-3은 감자에 검은무늬썩음병을 일으켰다. AG-4는 42종의 기주작물에 여러 가지 병을 일으켰으나, 3종의 기주작물에는 잘록병, 눈마름병, 잎집무늬마름병을 일으켰으나, 9종의 기주작물에는 병징을 약하게 유발시키거나 혹은 유발시키지 못했다.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.309-324
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• 1994

A total of 2,276 isolates of Rhizoctonia solani obtained from diseased crops of 68 species was classified into anastomosis groups AG-1, AG-2-1, AG-2-2, AG-3, AG-4 and AG-5 by anastomosis test. Among the isolates, 1,091 isolates were identified as AG-1, 326 isolates as AG-2-1, 191 isolates as AG-2-2, 71 isolates as AG-3, 505 isolates as AG-4, and 92 isolates as AG-5. Among the isolates of AG-1, 791 isolates were grouped as cultural type IA, 280 isolates as cultural type IB, and the others as cultural type IC. Among the isolates of AG-2-2, 112 isolates were grouped as cultural type IIIB, and the others as cultural type IV. Cultural types IA, IB and IC of AG-1 were isolated from 7, 26 and 2 species of crops, respectively. AG-2-1 was isolated from 10 species of crops. Cultural types IIIB and IV of AG-2-2 were isolated from 7 and 3 species of crops, respectively. AG-3 was only isolated from Solanum tuberosum. AG-4 was isolated from 43 species of crops, and AG-5 from 13 species of crops. A single anastomosis group was isolated from each of 45 species of crops, but two or more than two anastomosis groups were isolated from each of the other crops. Cultural appearance of the isolates belonging to an anastomosis group or a cultural type was mostly distinct from that belonging to others, although cultural appearances of some anastomosis groups or cultural types were similar to one another. Optimum temperature for mycelial growth of AG-1, AG-2-2, AG-4 and AG-5 ranged from 26 to $30^{\circ}C$, and that of AG-2-1 and AG-3 from 22 to $26^{\circ}C$. Minimum temperature for mycelial growth of AG-2-1 was the lowest as $2{\sim}3^{\circ}C$, that of AG-1(IA) and AG-4 was the highest as $10{\sim}11^{\circ}C$, and that of the others ranged from 5 to $10^{\circ}C$. Maximum temperature for mycelial growth of AG-2-2(IIIB) was the highest as $36{\sim}37^{\circ}C$, that of AG-2-1 was the lowest as $29{\sim}30^{\circ}C$, and that of the others ranged from 31 to $36^{\circ}C$. When the mycelial growth rates at $26^{\circ}C$ were compared, AG-1(IC) grew most rapidly, followed by AG-1(IA) and AG-1(IB), and AG-2-1 grew most slowly.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.879-886
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• 2014

This study was conducted to test in vitro the antagonistic effect of composted liquid manure (CLM) against soil-borne turfgrass pathogenic fungi, Rhizoctonia solani AG-2-2 (IIIB) (brown patch), R. solani AG-2-2 (IV) (large patch), and Sclerotinia homoeocarpa (dollar spot) for environmentally friendly turfgrass management. CLMs were collected from 9 livestock excretion treatment facilities around the country including Gunwi (GW), Hapcheon (HC), Hoengseong (HS), Icheon (IC), Iksan (IS), Muan (MA), Nonsan (NS), and Yeoju (YJ). CLMs of IC, GW, and IS showed s ignificant (p < 0.05) mycelium growth inhibition that was 17.8%, 20.4%, and 48.0% against R. solani AG-2-2 (IIIB), R. solani AG-2-2 (IV), and S. homoeocarpa, respectively. A t otal of 110 bacterial isolates were obtained from the CLMs that showed antagonistic effects. Among them, 5, 4, and 10 microbe isolates showed promising antifungal activity against mycelium growth of R. solani AG-2-2 (IIIB), R. solani AG-2-2 (IV), and S. homoeocarpa, respectively. The bacterial isolates ICIIIB60, GWIV70, and ISSH20 effectively inhibited the mycelial growth of three soil-borne turfgrass pathogens. Selected bacterial isolates were identified as Alcaligenes sp., Bacillus licheniformis Ab2, and B. subtilis C7-3 through 16s rDNA gene sequence analysis. Among 5 fungicides, the most compatible fungicide with ICIIIB60, GWIV70, and ISSH20 was tebuconazol, toclofos-methyl and toclofos-methyl, respectively. These findings suggested that CLMs could be effectively used not only as organic liquid fertilizer sources but also as biological control agents for soil-borne turfgrass diseases such as brown patch, large patch, and dollar spot.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.48-51
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• 2011

This study was performed to functional improvement by fermenting of SCB (Slurry Composting and Biofiltering) liquid fertilizer. After screening of cellulose decomposing test using microorganisms originated from composts produced with turf grass clipping, five kinds of Cellulose Decomposing Microorganisms (CDMs) were selected. The optimum medium for CDMs culture was Tryptic soy broth. The optimum fermenting time of CDMs in SCB liquid fertilizer was 36 hour. In addition, CDMs showed antimicrobial activity in vitro. Sclerotinia homoeocarpa, Rhizoctonia solani AG2-2(IV) and Pythium spp. were inhibited by CDMs, but Rhizoctonia solani AG2-2(IIIB) in vitro uneffected by CDMs we isolated.