• Research in Plant Disease
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• v.20 no.2
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• pp.126-128
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• 2014

This study was carried out to assay the disease incidence degree of Sclerotium rot caused by Sclerotium rolfsii in sixteen most popular commercial cultivars of sweet potato (Ipomoea batatas) in Republic of Korea. The degree of disease incidence was evaluated on pot experiments. In pot experiments using artificial inoculation, the Sclerotium rolfsii caused a stem rot on seedling of sweet potato plants and causes a crown rot on lower stems near or at the soil line at favorable environmental conditions. White mycelial mats and sclerotia were formed at the infection sites. Plants severely infected were fell over or died because lower stems near soil surface were rotten. The degree of disease incidence was varied according to cultivars. Two cultivars, Bio-mi and Deayumi, were very resistant, while five cultivars, Shinjami, Shingeonmi, Hongmi, Yeonjami, and Shinhung-3 were highly susceptible.

• Research in Plant Disease
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• v.9 no.1
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• pp.25-27
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• 2003

In 2002, a stem rot disease was found on Pansy (Viola tricolor) in several road-side flower beds in Jinju City, Gyeongnam province, Korea. The typical symptoms of the disease were stem rot, crown rot, wilt or blight. Upper parts of the infected stems were mostly blighted. White mycelial mats were spread over lesions and the sclerotia were farmed on the stems near soil line. The sclerotia was globoid or irregular in shape, 1.3~4.2 mm in size, and brown in color, The optimum temperature for fungal growth was about 3$0^{\circ}C$. The typical clamp connections were found in the hyphae of the fungus grown on PDA, and hyphal diameter was 3.9~10.4 ${\mu}{\textrm}{m}$. On the basis of mycological characteristics and pathogenecity test on host plants, the fungus was identified as Sclerotium rolfsii. This is the first report on the stem rot of Viola tricolor caused by Sclerotium rolfsii in Korea.

• The Korean Journal of Mycology
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• v.29 no.2
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• pp.131-133
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• 2001

A destructive collar rot disease was found on broad bean (Vicia faba) in several farmer's field located in Changseon-myon, Namhae-gun, Gyeongsangnam-do in 2001. The typical symptoms of the disease were stem rot, crown rot, wilt or blight. Upper parts of the infected stems were mostly blighted and white mycelial mats were spread over lesions and the sclerotia were formed on the stems near soil line. The infection rates of the disease in the surveyed area were ranged from 28.6 to 42.8%. The sclerotia of the fungus readily formed in artificial media such as PDA at $30^{\circ}C$ and its shape was globoid or irregular and size was $1.0{\sim}3.7{\times}1.0{\sim}2.8\;mm\;(av.\;1.0{\sim}2.3\;mm)$ and was brown or dark brown in color. The optimum temperature for growth of the fungus was about $30^{\circ}C$. The typical clamp connections were found in the hypha of the fungus grown on PDA. On the basis of mycological characteristics and pathogenecity test on host plants, the fungus was identified as Sclerotium rolfsii. This is the first report on the collar rot of broad bean caused by Sclerotium rolfsii in Korea.

• Mycobiology
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• v.33 no.4
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• pp.240-242
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• 2005

A soft rot of fruits caused by Mucor racemosus occurred on cherry tomato collected in Agricultural Products Wholesale Market in Jinju, Korea. The disease infection usually occurred wounded areas after cracking of fruits. At first, the lesions started with water soaked and rapidly softened and diseased lesion gradually expanded. Colonies were white to brownish to gray in color. Sporangia were $32{\sim}54\;{\mu}m$ in size and globose in shape. Sporangiophores were $8{\sim}14\;{\mu}m$ in width. Sporangiospores were $5{\sim}12\;{\times}\;4{\sim}8\;{\mu}m$ in size, ellipsoidal to subglobose in shape. Columella was $27{\sim}42\;{\mu}m$ in size, obovoid, ellipsoidal, cylindrical-ellipsoidal, slightly pyriform in shape. Chlamydospores were numerous in sporangiophores and barrel-shaped when young, subglobose in old cultures. Optimum growth temperature was about $25^{\circ}C$. The fungus was identified as M. racemosus Fres.. This is the first report of soft rot on cherry tomato caused by M. racemosus in Korea.

• Mycobiology
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• v.40 no.3
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• pp.214-216
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• 2012

Soft rot on banana fruit caused by Rhizopus oryzae was identified for the first time in Korea. Colonies were white to light brown and formed numerous sporangiospores. Optimum temperature for mycelial growth was $30^{\circ}C$. Sporangia were globose and $30{\sim}200{\mu}m$. Sporangiophores were usually straight, $8{\sim}20{\mu}m$, and rhizoids usually in groups of 3~5. Columella were globose to sub-globose and $90{\sim}110{\mu}m$. Sporangiospores were sub-globose or oval and $4{\sim}10{\mu}m$. Based on its mycological characteristics, molecular analysis, and pathogenicity to host plants, this fungus was identified as Rhizopus oryzae Went & Prisen Geerligs. This is the first report of soft rot on banana caused by Rhizopus oryzae in Korea.

• Mycobiology
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• v.39 no.3
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• pp.230-232
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• 2011

In this study, we characterized sporadically occurring sclerotium rot caused by Sclerotium rolfsii in Chinese chive (Allium tuberosum Roth.) in farm fields in Sacheon, Korea. The initial symptom of the disease was water-soaked, which progressed to rotting, wilting, blighting, and eventually death. Further, mycelial mats spread over the lesions near the soil line, and sclerotia formed on the scaly stem and leaves. The sclerotia were globoid, 1~3 mm, and white to brown. The optimum temperature for growth and sclerotia formation on potato dextrose agar (PDA) was $30^{\circ}C$. The diameter of the hypae ranged from 4 to 8 ${\mu}m$. Clamp connection was observed on PDA medium after 5 days of incubation. Based on the mycological characteristics, internal transcribed spacer sequence analysis, and pathogenicity test, the causal agent was identified as Sclerotium rolfsii Saccardo. This is the first report of sclerotium rot in Chinese chive caused by S. rolfsii in Korea.

• Korean Journal of Environmental Agriculture
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• v.15 no.2
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• pp.207-216
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• 1996

Simulated acid rain(SAR) treatment caused a lethal effect on the newly germinated seedlings of Capsicum annum cv. Komyung even though the germination rate of the seeds was stimulated by the treatment of SAR. Young germinated seedlings were much more sensitive to SAR than the already-grown seedlings. The typical symptom caused by SAR was white spot or lesion on the leaf and appeared readily and severely at the low pH of SAR. Generally, Phytophthora rot was severer in SAR treatments than in control. However, the disease was less severe in lower pH of the SAR treatment than in higher pH. Pathogen inoculation following the SAR treatment increased the disease. The severest Phytophthora rot was observed in the SAR treatment of pH 4.0 or 4.5 regardless of the inoculation time.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.354-356
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• 2001

In August 2001, pod rot of cowpea caused by Choanephora cucurbitarum was found in the experimental fields of the Gyeongsangnam-do Agricultural Research and Extension Services, Korea. Initial symptoms of the disease were the appearance of water-soaked, dark-green lesions and followed by rapid rotting of the infected tissues. As the disease progressed, whitish mycelia and monosporous sporangiophore with monosporous sporangiola were produced on the lesions. The fungus produced white to pale yellowish brown mycelia with scattered monosporous sporangiophore and monosporous sporangia containing sporangiospores on potato dextrose agar (PDA). Monosporous sporangiophore was long, slender and branched at the apex, with each branch bearing a sporangiospore. Sporangium was subglobose in shape and 42.6-112.6 ㎛ in size. Monosporous sporangiola were elliptic, fusiform or ovoid, brown in color, and 9.8-23.4$\times$7.2-12.8 ㎛ in size. Sporangiospores were elliptic, fusiform or ovoid in shape, dark brown or brown in color, 12.9-24.6$\times$8.6-15.4 ㎛ in size, and had three or more appendages. Zygospores were black and 43.6-72.4 ㎛ in size. The fungus grew on PDA at 15-40$\^{C}$, and optimum temperature was 30$\^{C}$. This is the first report on pod rot of cowpea caused by C. cucurbitarum in Korea.

• Research in Plant Disease
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• v.8 no.2
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• pp.113-116
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• 2002

A sclerotinia rot of Leonurus sibiricus caused by Sclerotinia sclerotio겨m occurred severely in farmer's fields at Seosang-myon, Hamyang-gun, Gyeongnam Province, Korea in 2001. The typical symptoms of the disease were that leaves, stems or collar of the infected plants at first became darker green and then watery soft rotted, and white fluffy mycelia formed on the lesion developed into black sclerotia later, Sclerotia on the plant and PDA medium were globose to cylindrical or irregular in shape, and 0.8~10.3$\times$0.8~6.4 m in size. Aphothecia with numerous asci were cup-shape, and 0.6~1.2 cm in diameter, Asci with 8 spores were cylindrical, and 87~246$\times$4.6~21.6 $\mu\textrm{m}$ in size. Ascospores of one cell were hyaline, ellipsoid to ovoid in shape, and 10.2~14.6$\times$4.7~7.2 $\mu\textrm{m}$ in size. The range of temperature for mycelial growth was from 5 to 3$0^{\circ}C$, and the optimum was $25^{\circ}C$. This is the first report on the sclerotinia rot of L. sibiricus caused by Sclerotinia sclerotioum in Korea.

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.86-91
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• 1995

Isolation and pathogenicity of Fusarium spp. from mulberry shoot rot and severity of diseases which were known as bacterial blight were examined on four mulberry varieties in Suwon, Kongju and Chuncheon, A symptom of mulberry shoot rot was initiated long brown spot on young leaves and shoots. It was developed into dark brown spot and produced white mycelia and spores on the diseased symptoms. A symptom of bacterial blight showed leaf rolling and water soaking spot and produced bacterial ooze on leaf and shoot However later stage of upper two types of symptom was hardly distinguished. Severities of shoot rot and bacterial blight were 7.5% and 4.4% in Suwon, respectively. Isolation of Fusarium spp. on shoot rot symptoms was highter than that on bacterial blight symptoms, but isolation of Pseudomonas spp. was higher on bacterial blight symptoms. Trends of pathogenicity of Fusarium spp. and Pseudomonas spp. were similar to inoculation works, and isolations of pathogenic Fusarium spp. from center of symptom was higher than that from 30cm of symptom of all samples in three cultivation areas. Disease severities of shoot rot on variety of Kaeryangppong were 13.9%, 15.9% and 17.2% in Suwon, Kongju and Chuncheon, respectively. However variety of Cheongolppong was highly resistant to shoot rot disease in three cultivation areas.