• Korean Journal of Microbiology
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• v.35 no.3
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• pp.173-179
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• 1999

As a result of PCR-RFLP, the isolates used in this study were classified into five groups. Isolates 1 and 3 were included in AG-5 with 97% genetic similarity. Isolates 12 and 13 were included in AG-1 wilh 100% genetic similarily. Isolates 10 and AG-2-2 showed 97% similarity Isolates 7, 8, 11. 13, and 15 were included in AG-1. When isolates of 4, 5, 7 and 8 were restricted with Hae I. there was a single 700 bp fragment matched with AG-1. A 517 bp restriction fragment of isolate 9 was matched with AG-2-1. Based on the result of southem hybridization of genomic DNAs, all isolates restricted with Msp I showed more variable restriction differences than those restricted with Hae Ill. Isolates AG-2-1 and 9 showed 200 bp restriction fragment, and isolates 3 and AG-1 showed 1 kb restriction fragments.

• Korean Journal Plant Pathology
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• v.1 no.1
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• pp.72-78
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• 1985

The effects of temperature. pH, carbon and nitrogen sources on the growth of Rhizoctonia solani were studied by using five hyphal anastomosis groups(four cultural types, 7 isolates) of the fungus. The ranges of optimum temperature were $20^{\circ}C$ in the AG 2-1, AG 2-2 and AG 4, and $25^{\circ}C$ in the AG 1-IA, AG 1-IB, AG 3, AG 5. The optimum pH for the mycelial growth was 6-7 in the fungus. Glucose in the AG 1-lA, AG 1-IB, AG 2-2, AG 3 and AG 5, sucrose in the AG 2-1 and fructose in the AG 4 were the most effective for the mycelial growth, but glycerine, cellulose and lactose were not effectively utilized as nutrients. $Ca(NO_3)_2$ in the AG 1-IA, AG 1-IB and AG 4, asparagine in the AG 2-1, $KNO_3$ in the AG 2-2 and $NaNO_3$ in the AG 5 were the best nitrogen sources for the mycelial growth, but $NH_4NO_3$ was not easily utilized by the fungus. Nitrate and organic nitrogens for the fungal growth were utilized better than ammonium nitrogen.

• The Korean Journal of Mycology
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• v.51 no.2
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• pp.141-146
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• 2023

Stem rot symptoms were observed in Gondre (Cirsium setidens) plants growing in a vinyl greenhouse in Taebaek, Korea during a disease survey in June 2022. The plants presented with dark brown to black rot on the stems at or above the soil line. Severely diseased plants displayed wilt and blight. Disease incidence among these plants ranged from 1 to 5%. Three isolates of Rhizoctonia sp. were obtained from the stem lesions of diseased plants. All isolates were identified as Rhizoctonia solani AG-2-2(IV) based on the morphological and cultural characteristics, results of the anastomosis test, and phylogenetic analysis. The pathogenicity of the isolates to Gondre plants was confirmed using an artificial inoculation test. The lesions induced by the inoculation test were similar to those observed in the investigated vinyl greenhouse. Here, we report a case of R. solani AG-2-2(IV) causing stem rot in Gondre.

• Korean Journal Plant Pathology
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• v.11 no.3
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• pp.278-281
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• 1995

An isolate of Rhizoctonia solani AG 2-2(IV) from zoysiagrass was examined on development of its teleomorph by the modified soil-on-agar culture method. The most effective growth medium for sporulation was Czapek's 1/2 agar medium added with yeast extract and peptone. The characters of teleomorph of R. solani AG 2-2 (IV) are as follows. Hymenia developed on soil surface after the development of vegetative hyphae. Basidia were barrel-shaped, short clavate or obovate and were 11.4~17.9$\times$7.1~11.4 ${\mu}{\textrm}{m}$ (mean : 15.1$\times$9.0 ${\mu}{\textrm}{m}$) in size. Sterigmata were horn-shaped and slightly bent to the inner side and 4.3~18.6 ${\mu}{\textrm}{m}$ (mean : 10.3 ${\mu}{\textrm}{m}$) in size. Two to four sterigmata developed on each basidium. Basidiospores were obovate, ellipsoid to oblong-ellipsoid, hyaline, smooth, thin walled, with an apiculus, and 3.6~10.4$\times$2.9~5.7 ${\mu}{\textrm}{m}$ (mean : 7.8$\times$4.4 ${\mu}{\textrm}{m}$) in size.

• Korean Journal Plant Pathology
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• v.14 no.3
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• pp.260-267
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• 1998

This study was undertaken to find a new formulation of soil amendment, and selection of antogonists and to effectively control brown and large patch of turfgrasses caused by Rhizoctoniz solani AG1-1 and AG 2-2. Fourteen inorgainc chemicals (1%, w/w) were added individually in vitro, and some chemicals showed suppressiveness to R. solani. Alum suppressed effectively mycelial growth of R. solani in the range of 17 to 77% as compared with control. The four chemicals such as Al2(SO4)3, alum, CaO, and NH4NO3 were finally selected. Out of three organic compounds, composted pine bark (CPB) showed prominent suppressive effect as compared with milled alfalfa and pine leaves. After inoculation of R. solani isolates AG-1 and AG2-2 on the turf seedlings, water soaked lesions and blight symptoms were developed on the whole seedlings. According to inhibition zone method, mycelial growth of the fungus were greatly suppressed by culture filterates of the antagonists, Gliocladium virens (Gl1-) and Pseudomonas sp. (P713). CPB soil amendment mixed with antagonists (1% w/w) controlled not only brown and large patch of turfgrasses, but also promote the good growth of the seedlings. In addition, the controlling effect was maintained more than 30 days. Especially, the controlling effect of two antagonists was similar to Cㅖㅠ soil amendment with the antagonists and also stimulated a favorable growth of the seedlings. Therefore, its is expected that continuous control of Rhizoctonia blight of turfgrasses can be obtained in field by subsequent applications of the antagonists.

• Journal of Microbiology and Biotechnology
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• v.21 no.4
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• pp.379-386
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• 2011

The objective of this work was to investigate the ability of the plant growth-promoting rhizobacterium Pseudomonas aureofaciens 63-28 to induce plant defense systems, including defense-related enzyme levels and expression of defense-related isoenzymes, and isoflavone production, leading to improved resistance to the phytopathogen Rhizoctonia solani AG-4 in soybean seedlings. Seven-day-old soybean seedlings were inoculated with P. aureofaciens 63-28, R. solani AG-4, or P. aureofaciens 63-28 plus R. solani AG-4 (P+R), or not inoculated (control). After 7 days of incubation, roots treated with R. solani AG-4 had obvious damping-off symptoms, but P+R-treated soybean plants had less disease development, indicating suppression of R. solani AG-4 in soybean seedlings. Superoxide dismutase (SOD) and catalase (CAT) activities of R. solani AG-4-treated roots increased by 24.6% and 54.0%, respectively, compared with control roots. Ascorbate peroxidase (APX) and phenylalanine ammonia lyase (PAL) activities of R. solani AG-4-treated roots were increased by 75.1% and 23.6%, respectively. Polyphenol oxidase (PPO) activity in soybean roots challenged with P. aureofaciens 63-28 and P+R increased by 25.0% and 11.6%, respectively. Mn-SOD (S1 band on gel) and Fe-SOD (S2) were strongly induced in P+R-treated roots, whereas one CAT (C1) and one APX (A3) were strongly induced in R. solani AG-4- treated roots. The total isoflavone concentration in P+Rtreated shoots was 27.2% greater than the control treatment. The isoflavone yield of R. solani AG-4-treated shoots was 60.9% less than the control.

• Asian Journal of Turfgrass Science
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• v.13 no.3
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• pp.131-138
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• 1999

A synergistic effect of biocontrol agent and chemicals on control of the large patch on turfgrass caused by Rhizoctonia solani AG2-2 was evaluated. Chemicals; mepronil, toclofos-methyl and iprodione inhibited 90∼100% mycelial growth of R. solani AG1 and AG2-2 in vitro. While on the other, the chemicals inhibited only 0∼5%, 18∼46% and 30∼67% of mycelial growth of the antagonists, respectively. In field application, toclofos-methyl was the best to suppress the disease in single application, however, the combination of mepronil and T. viride 41D showed highest disease control effect among combinations of antagonists and chemicals. Effect of the combination of mepronil and T. viride 41D was similar to that of toclofos-methyl and T. viride 41D stage of disease development, but became higher in six week late. Results indicated that the combined application of selected antagonistic agent and chemical increased control efficasy of turgrass large patch.

• Asian Journal of Turfgrass Science
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• v.6 no.2
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• pp.89-98
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• 1992

Cultural characteristics and pathogenicity on the isolates of Rhizoctonia oryzae, R. oryzae-sativae and anastomosis group of R. solani and evaluation of selected fungicides on brown patch disease of creeping bentgrass and large patch disease of zoysia grass were studied comparatively. From effect of temperature on the rate of mycelia growth, the result indicated that the temperature groups were separated into four types : isolates of R. oryzae and R. oryzae-sativae had an optimum temperature of $30~35^{\circ}C$. Anastomosis groups of R. solani were separated into three temperature types as followings : high temperature type had an optimum temperature from 25 to $30^{\circ}C$, moderate type had grown from 20 to $25^{\circ}C$ for optimum and low temperature type had an optimum temperature of $20^{\circ}C$ but at $35^{\circ}C$ did not grow. Inoculation tests showed that AG-1( I A), AG-1( I B), bentgrass isolate of R. solani and R. oryzae were strongly pathogenic on creeping bentgrass, followed by AG-2-1, AG-4, AG-5 and AG-2-2 isolates of R. solani moderately to weakly. Zoysia grass isolate of R. solani and R. oryzae were strongly pathogenic on zoysia grass but AG-1( I B) and AG-5 isolates of R. solani showed moderately pathogenic. Capro(iprodione oxine-copper) and mytan(myclobutanil) were extremely effective against brown patch disease of creeping bentgrass and large patch disease of zoysia grass followed by thiopan (thiopanate-methyl) and pencycuron for brown patch disease and tolos(tolclofos-methyl) and thiopan for large patch disease.

• 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.

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.54-60
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• 1994

Incidence of Rhizoctonia blight ranged from 22.2% to 100% in the golf courses at six geographical locations in Korea from 1989 to 1993. Rhizoctonia blight occurred more severly in southern area than in northern area. Fifty seven isolates of Rhizoctonia solani obtained from diseased parts of zoysiagrasses were grouped to AG2-2 by anastomosis test. Pathogenicity testes revealed that this pathogen was strongly pathogenic to Korean lawngrasses(Zoysia japonica, Z. matrella, Z. tenuifolia), but not pathogenic to creeping bentgrass(Agrostis palustris), bermuldagrass(Cynodon dactylon), Kentucky bluegrass(Poa pratensis), perennial ryegrass(Lolium prenne), and creeping red fescue(Festuca rubra subsp. rubra L.). The isolation frequency of R. solani AG2-2 fro sheaths of the infected plants was the highest by 91.67%, and that from stolons and roots was 11.13% and 5.63% respectively. The pathogen was not isolated from the leaves. Population density of R. solani in the lawn of large circular patch was highest on surface soils down to 1 cm deep with the value of 4.9$\times$104 (CFU/g soil), but below 1 cm population density decreased sharply down to 0.8~9.8$\times$103 (CFU/g soil). Horizontal distribution of propagules in turfgrass soil was higher in the margin than in center of patch, where the number of propagules was similar to these of healthy looking soils close to the margin of diseased patch. The meteorological factors influencing the outbreak of the disease were temperature, the number of rainy days and precipitation. Optimum temperature for disease development of Rhizoctonia blight in field was 20~22$^{\circ}C$, and that for hyphal growth of R. solani AG2-2 in vitro was 25~3$0^{\circ}C$. In Pusan area, Rhizoctonia blight first occurred in late April and rapidly developed in late June. The disease slightly decreased during July to August and developed again in late September in 1993. The monthly disease progress in Pusan area was similar to that in Kyeonggi province.