• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.2
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• pp.201-205
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• 2004

During the routine survey, the mortality of mulberry seedlings was noticed due to damping-off disease. The disease recognized by rotting of emerged seedlings near the soil line (just below the soil level) resulting in collapse of the seedlings. Two fungi were isolated from affected samples and identified as Alternaria alternata (Fr.) Keissler and Fusarium solani (Mart.) Sacc. Both the fungi were found to be responsible in causing pre and post emergence damping-off of seedlings in mulberry. For management of the disease, an experiment was conducted using fungicides. These fungicides were applied as seed treatment; soil drenching and foliar spray alone and in combination. Among the different treatments, integration of seed treatment and soil application of Dithane M-45 (Mancozeb 75% WP) + Bavistin (Carbendazim 50% WP) followed by foliar spray of these fungicides (after 35 days of sowing) resulted in better survivability of seedlings (93.3 %) on $90^th$ day and controlled the pre and post emergence damping off by 100 and 89.5%, respectively over the check.

• Research in Plant Disease
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• v.27 no.1
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• pp.45-47
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• 2021

Damping-off symptoms were frequently observed on young plants of coastal hogfennel (Peucedanum japonicum) grown in a farmer's vinyl greenhouse located in Goseong, Gangwon Province, Korea during a disease survey in June 2019. Incidence of the diseased plants was 50-70% in the vinyl greenhouse investigated during the disease survey. Eight isolates of Rhizoctonia sp. were obtained from the diseased plants. All the isolates were identified as Rhizoctonia solani AG-4 based on the morphological characteristics and anastomosis test. Three isolates of R. solani AG-4 were tested for pathogenicity on coastal hogfennel by artificial inoculation. All the tested isolates induced damping-off symptoms on the inoculated plants. The symptoms were similar to those observed in the farmer's vinyl greenhouse investigated. This is the first report of R. solani AG-4 causing damping-off in coastal hogfennel.

• The Korean Journal of Mycology
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• v.48 no.3
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• pp.325-328
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• 2020

Damping-off symptoms were frequently observed on young plants of edible amaranth (Amaranthus mangostanus) grown in vinyl greenhouses by farmers located in Goyang and Yangpyeong in Korea during disease surveys carried out in 2019 and 2020. The incidence of the disease was 1-20%. A total of eight isolates of Rhizoctonia sp. were obtained from the stems of the diseased plants. All the isolates were identified as Rhizoctonia solani AG-4, based on the morphological characteristics and anastomosis test. Three isolates of R. solani AG-4 were tested for pathogenicity on edible amaranth by artificial inoculation. All the tested isolates of R. solani AG-4 induced damping-off symptoms on the inoculated plants; these symptoms were similar to those observed on the vinyl greenhouse plants surveyed. This is the first report of R. solani AG-4 causing damping-off in edible amaranth.

• Research in Plant Disease
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• v.28 no.4
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• pp.245-247
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• 2022

In August 2021, we surveyed diseases of wild vegetables grown in Taebaek, Gangwon Province, Korea. During the disease survey, we observed severe damping-off symptoms in young edible aster (Aster scaber) plants in a vinyl greenhouse investigated. The incidence of the disease in the plants ranged from 5% to 20%. Diseased plants of edible aster were collected from the vinyl greenhouse, and fungi were isolated from petiole lesions of the diseased plants. Rhizoctonia sp. was consistently isolated from the petiole lesions. We examined morphological characteristics and anastomosis groups of nine Rhizoctonia sp. isolates obtained from the petiole lesions. The examination results revealed that all the isolates corresponded to Rhizoctonia solani AG-4 based on the morphological characteristics and anastomosis test. Three isolates of R. solani AG-4 were tested for their pathogenicity on edible aster plants by artificial inoculation. Inoculation tests showed that the tested isolates caused damping-off symptoms on the inoculated plants. The induced symptoms were similar to those observed in the vinyl greenhouse investigated. Damping-off of edible aster caused by R. solani AG-4 is first reported in this study.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.606-611
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• 1998

An antagonistic bacterium, Pseudomonas flurorescens MC07 inhibited the mycelial growth of Rhizoctonia solani, Pythium ultimum, Fusarium oxysporum, and Phytophthora capsici in on potato dextrose agan (PDA) and other media. The strain MC07 conlonizes various plant roots and possesses antifungal activity. To determine the role of antifungal activity of the bacterium in disease suppression, a mutant Okm3-4 which lost its activity was isolated after screening 2,500 colonies generated by Omegon-Km insertions. The mutant Okm3-4 showed diminished growth inhibition of R. solani, P. ultimum, F. oxysporum, and Ph. capsici in vitro and had reduced suppressive effects on sesame damping.-off compared to the parental strain. In soils, accumulation of the pathogens by continuous cropping, 90% of sesame plants were killed by natural infection of damping-off whereas, only 29% of plants grown from seeds treated with MC07 were killed. On the other hand, 85% of plants died when sesame seeds were treated with the Okm3-4 cells. This indicated that antifungal activity of MC07 in vitro is directly responsible for the suppression of damping-off disease. Emergence rates of sesame seeds in pots containing diseased soil were 33%. However, MC07 treatments on seeds significantly improved emergence rates, which has similar effects of Benomyl treatment. The mutant Okm3-4 exhibited 53% of emergence rate. This indicated that antifungal activity of MC07 also affects the emergence rate of sesame seeds.

• The Korean Journal of Mycology
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• v.44 no.3
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• pp.193-195
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• 2016

Korean ginseng (Panax ginseng) possesses various biological and pharmacological properties. Damping-off is a critical disease on ginseng seedlings, which is caused by the fungal pathogens Rhizoctonia solani and Pythium sp.. This disease is generally controlled by the application of fungicides, but also biological control is an efficient and environmentally friendly way to prevent ginseng damping-off. In a previous study, we screened soil-borne bacteria with potential applications as biological control agents for ginseng damping-off and selected the bacterial strain Streptomyces sp. A3265, producing antifungal substances guanidylfungin and methylguanidylfungin. In this study, we investigated control efficacy of Streptomyces sp. A3265 against ginseng damping-off in the field. As a result, the incidence of damping-off was significantly reduced when soaking ginseng seeds in the culture broth of Streptomyces sp. A3265.

• Research in Plant Disease
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• v.24 no.4
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• pp.353-358
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• 2018

An effective bioformulation of mixtures of chitin-degrading bacteria has been used successfully to control plant diseases and nematodes. In this study, the bioformulation approach was assessed to control damping-off disease of ginseng. In pot experiments with soils infested with dapming-off pathogens of ginseng, root-drenchings of Chrobacterium sp. C-61, Lysobacterium enzymogenes C-3, and mixture of two bacterial strains grown in chitin minimal medium were signficantly increased emergence of seeds and reduced damping-off disease incidence of seedlings. Efficacy of the bioformulated product depended on the dose and timing of application. In two-year-old ginseng field, the high control efficacies were achieved by soil drenching of two times with an undiluted product or three times with a 10-fold diluted product. In a To-jik nursery (self soil nursery), biocontrol efficacy of the undiluted product against damping-off disease were similar to that of a seed dressing with fungicide, Tolclofos-methyl WP. These results suggest that the bioformulated product containing Chromobacterium sp. C-61 and L. enzymogenes C-3 could be an effective approach to control of ginseng damping-off disease.

• 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.48 no.4
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• pp.519-521
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• 2020

Damping-off symptoms were frequently observed on young plants of Indian lettuce (Lactuca indica) grown in a farmer's vinyl greenhouse located in Goseong, Gangwon province of Korea during a disease survey in June 2019. The incidence of diseased plants in the vinyl greenhouse investigated was 30-50%. Four isolates of Rhizoctonia sp. were obtained from the diseased plants and identified as Rhizoctonia solani AG-4 based on the morphological characteristics and anastomosis test. Three isolates of R. solani AG-4 were tested for pathogenicity on Indian lettuce by artificial inoculation. All the tested isolates induced damping-off symptoms on the inoculated plants. The symptoms were similar to those observed in plants from the farmer's vinyl greenhouse investigated. This is the first report of R. solani AG-4 causing damping-off in Indian lettuce.

• The Korean Journal of Mycology
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• v.49 no.2
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• pp.249-251
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• 2021

Damping-off symptoms were frequently observed in young deltoid synurus (Synurus deltoides) plants grown in a farmer's vinyl greenhouse located in Hwacheon, Gangwon Province, Korea, during a disease survey in July 2019. The incidence of diseased plants in the vinyl greenhouse investigated was 5-30%. Five isolates of Rhizoctonia sp. were obtained from the diseased plants and identified as Rhizoctonia solani AG-1 (IB), based on morphological and cultural characteristics and anastomosis test results. Three isolates of R. solani AG-1 (IB) were tested for pathogenicity on deltoid synurus using artificial inoculation. All the tested isolates induced damping-off symptoms in the inoculated plants. The symptoms were similar to those observed in plants from the farmer's vinyl greenhouse. To our best knowledge, this is the first report of R. solani AG-1 (IB) causing damping-off in deltoid synurus.