1.Occurrence of Rhizopus Soft Rot on Peach (Prunus persica var. vulgaris) Caused by Rhizopus nigricans in Korea.
Jin Hyeuk KWON ; Soo Woong KANG ; Chang Seuk PARK
Mycobiology 2000;28(4):177-179
A soft rot of fruits caused by Rhizopus nigricans occurred on peach (Prunus persica var. vulgaris ) in The Chinju City Agricultural Products Wholesale Marke during in summer season of 2000. The disease infection usually started from wounding after harvest fruits, and then moved to outside. At first, the lesions started with water soaked and rapidly softened and diseased area gradually expanded. In severely infected film house, the rate of infected fruits reached 65.2%. Numerous sporangiospores were produced on the diseased fruits. Most of the sporangiospores were appeared to be readily dispersed in the air. The mycelia grew surface of fruits and produced stolons. Colonies on potato dextrose agar at 25~30degrees C white cottony at first becoming heavily speckled by the presence of sporangia and the browinish black at maturity, spreading rapidly by means of stolons fired at various points to the substrate by rhizoids. Sporangia were 85.3~243.5x53.4~219.2microm in size and were globose or sub-globose with. somewhat flattened base. The color of sporangia was white at first and then turned black with many spores, and never over-hanging. Sporangiophores were 8.9~36.6microm in width, smooth-walled, non-septate, light brown, simple, long, arising in groups of 3~5 from stolons opposite rhizoids. Sporangiospores was 9.7~24.8x5.9~15.8microm, irregular, round, oval, elongate, angular, and browinish-black streaked. Columella was 70.2x149.7microm. brownish gray, and umberella-shaped when dehisced. The causal organism was identified as. Rhizopus nigricans Lind on the basis of the morphiogical characteristics of the fungus. Rhizopus soft rot on peach (Prunus persica ) caused by the fungi has not been reported in Korea. This is the first report of rhizopus soft rot on peach caused by Rhizopus nigricans in Korea.
Agar
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Fires
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Fruit
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Fungi
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Glucose
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Gyeongsangnam-do
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Korea*
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Prunus persica*
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Rhizopus*
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Seasons
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Solanum tuberosum
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Sporangia
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Spores
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Water
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Wounds and Injuries
2.Occurrence of Sword bean Scab Caused by Cladosporium cucumerinum in Korea.
Jin Hyeuk KWON ; Soo Woong KANG ; Chang Seuk PARK
Mycobiology 2000;28(1):54-56
A black scab disease occurred on sword bean (Canavalia gladiata) in plastic film houses around Chinju area during the spring season of 1999. The disease started from flower bud, then moved to flower stalk, pod, petiole, cirrus, stem and leaves. The lesions started with small dark brown spots then were gradually expanded. Severely infected plants reached 37.4% of whole plant covered with scab. Numerous conidia were produced on the diseased flower disk, pod, floral axis, stem and leaves. Most of the conidia were appeared to be readily dispersed in the air, but the mycelia were not suggested causing of sooty mold by ectoparasitism. A fungus was isolated from the diseased stem, and inoculated to healthy plants to satisfy the Koch's postulates and proved the fungus was the causal agent of the disease. The isolated fungus grew on potato dextrose agar, forming greenish black to pale brown colonies. Conidia were ellipsoidal, fusiform or subspherical, mostly one-celled but occasionally septated. The conidia were 3.9~34.1x2.7~5.1microm in size and formed in long branched chains on the erected conidiophores which were pale olivaceous brown and variable in length between 7.2~210.7microm in size. Ramoconidia were 7.6~29.2x3.2~14.4microm in size. The fungus was identified as Cladosporium cucumerinum based on the above morphological characteristics. The optimum temperature for mycelial growth and conidial formation was about 15 to 25degrees C. Cladosporium scab of sword bean caused by the fungi has not been reported in Korea previously.
Agar
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Axis, Cervical Vertebra
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Cladosporium*
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Flowers
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Fungi
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Glucose
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Gyeongsangnam-do
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Korea*
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Plants
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Plastics
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Seasons
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Solanum tuberosum
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Spores, Fungal
3.Stem Rot of Garlic (Allium sativum) Caused by Sclerotium rolfsii.
Mycobiology 2010;38(2):156-158
Stem rot disease was found in garlic (Allium sativum L.) cultivated from 2008 to 2010 in the vegetable gardens of some farmers in Geumsan-myon, Jinju City, Gyeongnam province in Korea. The initial symptoms of the disease were typical water-soaked spots, which progressed to rotting, wilting, blighting, and eventually death. White mycelial mats had spread over the lesions near the soil line, and sclerotia had formed over the mycelial mats on the stem. The sclerotia were globoid in shape, 1~3 mm in size, and tan to brown in color. The optimum temperature for growth and sclerotia formation on potato dextrose agar (PDA) medium was 30degrees C. The diameter of the hyphae ranged from approximately 4 to 8 microm. Typical clamp connection structures were observed in the hyphae of the fungus, which was grown on PDA medium for 4 days. On the basis of the mycological characteristics and pathogenicity of the fungus on the host plants, the causal agent was identified as Sclerotium rolfsii Saccardo. This is the first report of stem rot disease in garlic caused by S. rolfsii in Korea.
Agar
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Allyl Compounds
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Fungi
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Garlic
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Glucose
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Humans
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Hyphae
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Korea
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Soil
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Solanum tuberosum
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Sulfides
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Triacetoneamine-N-Oxyl
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Vegetables
4.Occurrence of Strawberry Scab Caused by Cladosporium herbarum in Korea.
Jin Hyeuk KWON ; Soo Woong KANG ; Jeong Soo KIM ; Chang Seuk PARK
Mycobiology 2001;29(2):110-112
A black scab was observed on strawberry(Fragaria ananassa) in plastic film houses around Jinju area during the winter of 2000. The disease started from leaves then moved to calyx and runner. At the beginning, the infected area started with small dark brown spots then gradually expanded. The pathogenic fungus was purely isolated from the diseased leaves, calyx and runner. The fungus was inoculated to test Koch's postulates and proved to be the causal agent of the disease. The isolated fungus grew readily on potato dextrose agar, forming dark green to dark gray colonies. The optimum temperature for mycelial growth was about 25degrees C. The diameter of growing hyphae was 3.8~5.6 microm. Conidia were ellipsoidal, ovoid or subspherical, mostly one-celled but occasionally septate. The size of conidia were 4.1~11.7x3.8~5.3 1-cell, 9.3~18.8x4.0~7.4 microm 2-cell and formed in long branched chains on the erected conidiophores which were dark brown and variable in length between 28.8~236.2x3.0~6.2 microm in size. The fungus was identified as Cladosporium herbarum on the basis of its morphological characteristics. The black scab disease of strawberry caused by C. herbarum has not been reported in Korea previously.
Agar
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Cladosporium*
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Fragaria*
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Fungi
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Glucose
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Gyeongsangnam-do
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Hyphae
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Korea*
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Plastics
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Solanum tuberosum
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Spores, Fungal
5.Occurrence of Stem Rot of Wild Aster (Aster koraiensis) Caused by Sclerotium rolfsii in Korea.
Jin Hyeuk KWON ; Soo Woong KANG ; Shun Shan SHEN ; Chang Seuk PARK
Mycobiology 2001;29(1):58-60
A destructive stem rot of wild aster (Aster koraiensis) occurred sporadically some farmers' fields in Guman-myon, Kosong-gun, Kyongsangnam-do in 2000. One of the most severely infected field in Kosong showed 28.6 percent of infection rate. The fungus also caused stem or crown rot and systemic wilt or blight of the plants. White mycelium spread over stems and petioles of infected plants and sclerotia formed on the old lesions and near the soil surface. The fungus showed maximum mycelial growth around 30degrees C and did not grow under 5degrees C and over 45degrees C and mycelial width were 4.3~10.2 microm. Colony was white, usually many narrow mycelial stand in the aerial mycelium and formed clamp connection. Numerous sclerotia were formed on PDA at 30degrees C. The shape sclerotia were globoid and 0.8~3.0x0.9~3.4 mm in size. The fungus was isolated repeatedly from the infected tissues and confirmed its pathogenecity to wild aster and identified as Sclerotium rolfsii. This is the first report on the stem rot of wild aster caused by S. rolfsii in Korea.
Crowns
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Fungi
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Gyeongsangnam-do
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Korea*
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Mycelium
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Soil
6.Occurrence of Powdery Mildew on Safflower Caused by Sphaerotheca fuliginea in Korea.
Jin Hyeuk KWON ; Soo Woong KANG ; Heung Su LEE ; Chang Seuk PARK
Mycobiology 2000;28(1):51-53
The powdery mildew of safflower (Carthamus tinctorius L.) extensively occurred at 1999 at the experimental farm of Kyongsangnam-do Agricultural Research and Extension Services. Both sides of the leaves and the older stems were covered with the fungus, and then the leaves and stems turned yellow. The conidia, conidiophores and perithecia were observed on the leaf lesion. Perithecia were ellipsoidal, 80-117microm in diameter. Asci were subglobose and 84~99x59~73microm in size. Ascospore were ellipsoidal to ovoid, and 15~34x11~23microm in size. Conidia were ellipsoid to barrel-shaped, 25~37x11~22microm in size and formed in long chains. The causal organism was identified as Sphaerotheca fuliginea. This is the first report on powdery mildew of safflower caused by Sphaerotheca fuliginea in Korea.
Carthamus tinctorius*
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Fungi
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Gyeongsangnam-do
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Korea*
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Spores, Fungal
7.Soft Rot of Eggplant (Solanum melongena) Caused by Choanephora cucurbitarum in Korea.
Jin Hyeuk KWON ; Hyeong Jin JEE
Mycobiology 2005;33(3):163-165
In April 2002 and 2003, soft rot on fruit of eggplant (Solanum melongena) caused by Choanephora cucurbitarum was observed in the experimental fields at Gyeongnam Agricultural Research and Extension Services in Korea. The disease began with water-soaking and dark-green lesions, and then the infected tissues were rapidly rotten. Sporangium was subglobose in shape and sized 40~130 microm. Monosporous sporangiola were elliptic, fusiform or ovoid, brown in color, and measured as 12~20 x 6~14 microm. Sporangiospores having three or more appendages were elliptic, fusiform or ovoid in shape, dark brown or brown in color, and sized 14~20 x 7~16 microm. The fungus grew well on potato dextrose agar between 15 and 40degrees C and its optimum growth temperature was 30degrees C. Based on morphological characteristics, the causal fungus of the fruit soft rot of eggplant was identified as C. cucurbitarum. This is the first report on the soft rot of S. melongena caused by C. cucurbitarum in Korea.
Agar
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Fruit
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Fungi
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Glucose
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Korea*
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Solanum melongena*
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Solanum tuberosum
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Sporangia
8.Rhizopus Soft Rot on Pear (Pyrus serotina) Caused by Rhizopus stolonifer in Korea.
Jin Hyeuk KWON ; Chan Jung LEE
Mycobiology 2006;34(3):151-153
Rhizopus soft rot caused by Rhizopus stolonifer occurred on pears (Pyrus serotina) in the Jinju City Agricultural Products Wholesale Market in Korea from 2004 to 2005. The infection usually started from wounds due to cracking at harvest time. The lesions started as water-soaked, rapidly softened, then gradually expanded. The mycelia grew vigorously on the surface of the fruits and formed stolons. Colonies on potato dextrose agar at 25degrees C were white cottony to brownish black. Sporangia were globose, black and 90~120 microm in size. Sporangiophores were light brown and 480~2600 x 12~18 microm in size. Sporangiospores were globose to oval, brownish, streaked, and 8~14 x 6~10 microm in size. Columella were light brownish gray, hemispherical and 70~80 microm in size. On the basis of these symptoms, mycological characteristics and pathogenicity tests on host plants, the fungus was identified as Rhizopus stolonifer (Ehrenb.) Vuill. This is the first report of rhizopus soft rot on pear (P. serotina) caused by R. stolonifer in Korea.
Agar
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Fruit
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Fungi
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Glucose
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Gyeongsangnam-do
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Korea*
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Pyrus*
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Rhizopus*
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Solanum tuberosum
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Sporangia
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Virulence
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Wounds and Injuries
9.First Report of Rhizopus oryzae as a Postharvest Pathogen of Apple in Korea.
Jin Hyeuk KWON ; Jinwoo KIM ; Won Il KIM
Mycobiology 2011;39(2):140-142
Soft rot in apple caused by Rhizopus oryzae was found for the first time in Korea. A detailed description of the specimen is given along with its internal transcribed spacer rDNA sequence. The fungus was identified as Rhizopus oryzae based on the mycological characteristics, molecular data, and pathogenicity testing.
DNA, Ribosomal
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Fungi
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Korea
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Oryza
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Rhizopus
10.Stem Rot of Tatarian Aster (Aster tataricus) Caused by Sclerotium rolfsii in Korea.
Jin Hyeuk KWON ; Chang Seuk PARK
Mycobiology 2002;30(2):102-104
In July 2001, a destructive stem rot of tatarian aster (Aster tataricus) was occurred sporadically in exhibition farm of Gyeongsangnam-do Agricultural Research and Extension Services, in Hamyang, Korea. The fungus also caused collar and crown rot and systemic wilt or blight of whole plant. White mycelium spread over stems and petioles of infected plants and sclerotia formed on the old lesions and near the soil surface. The fungus showed maximum mycelial growth was obtained around 30degrees C but did not grow below 5degrees C or above 45degrees C. The mycelial width ranges 4.2~10.4 microm. and the color is white, usually many narrow mycelial stand grow in the aerial mycelium and formed clamp connection. Numerous sclerotia were formed in artificial media like PDA at 30degrees C. The shape of sclerotia were sphere and 1.0~3.2microm in diameter. The fungus was isolated repeatedly from the infected tissues and confirmed its pathogenecity to aster and identified as Sclerotium rolfsii. This is the first report that Sclerotium rolfsii causes stem rot of tatarian aster in Korea.
Crowns
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Fungi
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Gyeongsangnam-do
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Korea*
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Mycelium
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Plants
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Soil