• 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.

• Asian Journal of Turfgrass Science
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• v.8 no.1
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• pp.47-52
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• 1994

Attempts were made to investigate the antagonistic activity of soil borne microorganisms Pseudomonas spp. and Trichoderma spp. against to the pathogens of turf diseases Rhizoctionia solani spp. and Pythiom spp. in vitro by a dual culture bioassay. Inhibition zone between the edge of the my-celium and the margin of each antagonistic bacteria, Pocudontonas, on potato dextrose agar was measured 3 days after incubation at 28˚C. Psudomonas spp. showed relatively high inhibition of mycelium growth of R. solani AG-i and Pythium spp. which cause brown patch and pythium blight, respectively. Antagonistic fungi Trichodenma spp. also showed effective inhibition against mycelium growth of both pathogens, more proper methods of measuring the inhibition effects were required because of fast growth of Trichodenna hypae. Brown patch and pythium blight both, re-quire most higher rate of fungicide use to control in golf curses in Korea. Application of antagon-istic microorganisms are useful as biological resources an approach to sole environmental contamination.

• Journal of Ginseng Research
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• v.13 no.1
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• pp.114-118
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• 1989

Tolclofos-methyl applied as seed dipping at 1,000 ppm for 3 hrs before sowing and soil drenching at the rate of 300 g ai./10 a in the middle of April protected emerging seedlings of Panax ginseng from damping-off caused by Rhiiutonia solani(AG2-1) in Yangjik Soil artificially infested with the pathogen. Germination rates with tolclofos-methyl, pencycuron, and control were 53.7%, 45.8%, and 7.5%, respectively, while the rate of the seeds at non-infested soil was 62.6%. The effectiveness of Tolclofos-methyl against the pathogen in the soil lasted upto 32 days in vitro. However, the transpiratio of ginseng seedlings increased greatly with chemical treatment, showing 0.02, 0.12, and 0.24 m1/cm2 leaf area/day at 0, 1,2, and 4 ppm a.i. of the fungicide, respectively.

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.176-181
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• 2010

Brown patch (Rhizoctonia solani AG1-1), dollar spot (Sclerotinia homoeocarpa), pythium blight (Pythium spp.), anthracnose (Colletotrichum graminicola), yellow patch (Rhizoctonia cerealis) and Zoysia patch (Rhizoctonia solani AG2-2) are the major turfgrasses diseases in Korea. In this study, 23 medicinal plant extracts were tested for antifungal activities against turfgrass pathogenic fungi. In paper disk diffusion method, 12 medicinal plant extracts, including Sophora flavescens, showed antifungal activity. Also, in the test of antifungal activity on media contained the extracts of S. flavescens, Curcuma longa, Rheum undulatum, Coptis chinensis and Asiasarum sieboldi showed above 80% inhibitory effects on the mycelial growth in 110 mg/10 ml concentration of the extracts. S. flavescens, in particularly, showed antifungal activity against the six turfgrass pathogenic fungi. The inhibition rate of S. homoeocarpa was 100% in 10 mg/10 ml, 5 mg/10 ml and 2 mg/10 ml concentrations of C. longa extract. In case of Pythium spp., the extracts of S. flavescens, R. undulatum and C. chinensis showed 100 % inhibition rate on the test media.

• 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.

• Asian Journal of Turfgrass Science
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• v.21 no.2
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• pp.113-126
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• 2007

Mineral nutrients and population dynamics of soil microbes in the root zones of zoysiagrass infected by Rhizoctonia solani AG2-2 and that of healthy plants were sampled from ten golf courses using a cup cutter(diameter $10\;cm\;{\times}\;8\;cm$ deep). Analysis of variance(ANOVA) showed significant differences in content of $NO_3$-N(P = 0.05), $NH_4$-N(P = 0.1), and K(P = 0.1) between infected and healthy samples. The content of $NO_3$-N in the soils of large patch was 9.49 mg/kg and that in soil of healthγ plants was 7.02 mg/kg. However, the content of $NH_4$-N in the soil of large patch was 12.02 mg/kg whereas 14.40 mg/kg for the soil under the healthy plants. The content of K in the soil of large patch was lower than that of soil of healthy plants. There was few numbers of Pseudomonas colonies In the soils of large patch compared to that of healthy plants. These results indicated that the content of $NO_3$-N, NH4-N, and K and the microbial population dynamics in root zones correlated to occurrence of large patch.

• Journal of Ginseng Research
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• v.14 no.3
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• pp.432-436
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• 1990

Incidence of damping-off callsed by Rhizoctonia solani was 0.6-10.9% at "Yangjik" seedbed in Pocheon, Korea. The seedbeds where the lengths of etiolated stems (underground portion) of ginseng seedlings were 0.78-1.25 cm showed 0.8-3.2% of the disease, while 6.9-10.9% disease incidence was observed at the seedbeds with the longer etiolated stem (1.89-2.26 cm). The pathogen produced a typical girdle symptom on the etiolated portion of ginseng stems close to the soil surface. The deeper the seeds were sown, the more the disease occurred in pot soil inoculated with the pathogen, AG 2-1, showing 18.4, 27.4 and 32.9% of damping-off at the seeding depth of 1, 2 and 4 cm, respectively. Cuticle layers of colored stems (over ground portion) were well - developed to be 42.8, 58.0, and 55.0 um in thickness compared to the etiolated stems with 8.5, 15.0 and 8.0um for seedling, 2 year-old, and 3 year-old ginsengs, respectively, when the disease occurred. In the seedling and 2 year-old ginseng, the colored stems were more rigid than the etiolated. There was however, no difference in rigidness of the stem of the 3 year-old ginseng where the disease is not severe as in seedlings and 2 year-old ginseng plants.ng plants.

• Research in Plant Disease
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• v.17 no.3
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• pp.405-409
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• 2011

Azolla Lam. is a small aquatic fern with deeply bilobed leaves, which are consisted of a thick greenish, with chlorophyll, upper (dorsal) lobe and a thinner, translucent lower (ventral) lobe, without chlorophyll, submerged in the water. Azolla blight was observed at a lotus pond. Mycological characteristics of the fungus associated with Azolla blight was immediately determined as Rhizoctonia sp. by the thickness and branching of hypha at right angles at the point toward the distal end of septa, with branching hypha is constricted. The fungus produced brown mycelia and dark brown sclerotia on PDA. The optimum temperature for mycelial growth and sclerotia formation were $25^{\circ}C$ and $30^{\circ}C$, respectively. The optimum temperature for fungal infection was $30^{\circ}C$, when spray inoculated. Phylogenetic analysis of rDNA-ITS revealed that the fungus was identified as Rhizoctonia solani (AG-1 IA) closest to one causing rice sheath blight disease. This is the first report on the blight disease of Azolla caused by R. solani in Korea.

• Asian Journal of Turfgrass Science
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• v.19 no.2
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• pp.73-83
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• 2005

This study was carried out to investigate control efficacy of fungicides mixed with pyroligneous acid on Large patch caused by Rhizoctonia solani AG2-2. R. solani AG2-2 was not inhibited by concentration of 500 times and 1,000 times diluents of pyroligneous acid. It is thought that R. solani AG2-2 was not inhibited by Pyroligneous acid alone. Pencycuron and tebuconazol mixed with pyroligneous acid had a good effect in prevention of R. solani AG2-2 in zoysiagrass. Concurrently, it was observed that those were reduced $50\%$ of usage of fungicides. 500 times and 1,000 times diluents of pyroligneous acid treated group had a significantly effect compared to control turf in the leaf length, leaf width and dry weight. In conclusion, usage of fungicides could be reduced about $50\%$ by a fungicides mixed with pyroligneous acid for protection of R. solani AG2-2. Therefore, It is thought that fungicides mixed with pyroligneous acids can be reduced an economic load and also an environmental pollution such as a tolerance to pathogenic bacteria and a destruction of an ecological system of soil microbes according to use fungicides.

• Weed & Turfgrass Science
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• v.2 no.1
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• pp.70-75
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• 2013

Seven medicinal plant extracts were tested for antifungal activities against six species of the major turfgrass pathogenic fungi (Colletotrichum graminicola, Pythium spp., Rhizoctonia cerealis, Rhizoctonia solani AG1-1, Rhizoctonia solani AG2-2, and Sclerotinia homoeocarpa) using paper disk diffusion method. Three medicinal plant extracts, including Pinus densiflora showed antifungal activities. In suppression of mycelium growth test, on medium adding P. densiflora extract showed that inhibition rate of mycelium growth were above 80% in 10 mg/10 ml concentration of the extract. The inhibition rate of Pythium spp. was 100% and C. graminicola was 84.3% in 10 mg/10 ml concentrations of P. densiflora extract, respectively. In particularly, the inhibition rate of Pythium spp. was 89.5% in 2 mg/10 ml concentrations of P. densiflora extract. As a result, P. densiflora extract showed high antifungal activity to Pythium spp. and C. graminicola of the turfgrass pathogen in in vitro test.