Occurrence of Sooty Blotch and Flyspeck Disease on Sweet Persimmon in Korea

Sooty blotch and flyspeck (SBFS), a disease caused by a complex of fungi, results in substantial economic losses for commercial growers of sweet persimmon (Diospyros kaki L.) in Korea. However, many species causing SBFS in Korea have not been identified and sources of inoculum are uncertain. Based on mycological characteristics, pathogenicity, and molecular data, the causal fungi were identified as Dissoconium sp. and Zygophiala wisconsinensis. This is the first report of SBFS of sweet persimmon in Korea.

Soft Rot of Rhizopus oryzae as a Postharvest Pathogen of Banana Fruit in Korea

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 30degrees C. Sporangia were globose and 30~200 microm. Sporangiophores were usually straight, 8~20 microm, and rhizoids usually in groups of 3~5. Columella were globose to sub-globose and 90~110 microm. Sporangiospores were sub-globose or oval and 4~10 microm. 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.

Spot Anthracnose Disease Caused by Colletotrichum gloeosporioides on Tulip Tree in Korea

The tulip tree (Liriodendron chinense) has been widely cultivated in Korea as a street or garden tree for its large flowers, which have a superficial resemblance to tulips. Occurrence of anthracnose disease on the leaves of tulip trees growing on the campus of Gyeongsang National University, Jinju, Korea, has been observed. Based on mycological characteristics, pathogenicity, and internal transcribed spacer sequence, the causal fungus was identified as Colletotrichum gloeosporioides. This is the first report on anthracnose disease caused by C. gloeosporioides on tulip trees in Korea.

Occurrence of Sclerotium Rot in Allium tuberosum Caused by Sclerotium rolfsii in Korea

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 30degrees C. The diameter of the hypae ranged from 4 to 8 microm. 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.

First Report of Rhizopus oryzae as a Postharvest Pathogen of Apple in Korea

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.

First Report of Botrytis cinerea as a Postharvest Pathogen of Blueberry in Korea

Gray mold of blueberry caused by Botrytis sp. is reported for the first time in Korea. A detailed description of the fungus is given, along with its rDNA internal transcribed spacer sequence. The fungus was identified as Botrytis cinerea based on mycological characteristics and molecular data.

First Report of Stem Rot on Asiatic Dayflower (Commelina communis L.) Caused by Sclerotium rolfsii in Korea

Stem rot was found for the first time on the Asiatic dayflower plant (Commelina communis L.) in Korea. A detailed description of this Korean specimen is given, along with its rDNA internal transcribed spacer sequence. The fungus was identified as Sclerotium rolfsii Saccardo based on mycological characteristics and molecular data.

Stem Rot of Garlic (Allium sativum) Caused by Sclerotium rolfsii

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.

Soft Rot on Cucumis melo var. makuwa Caused by Rhizopus oryzae

Rhizopus oryzae is reported for the first time on Cucumis melo L. var. makuwa Makino. A detailed description of this Korean specimen is given, along with its rDNA internal transcribed spacer sequence. On the basis of mycological characteristics and molecular data, the fungus was identified as R. oryzae Went & Prinsen Geerligs.

Occurrence of Fruit Rot of Melon Caused by Sclerotium rolfsii in Korea

In 2007 to 2008, a fruit rot of Melon (Cucumis melo L.) caused by Sclerotium rolfsii occurred sporadically in a farmer's vinyl house in Jinju City. The symptoms started with watersoaking lesion and progressed into the rotting of the surface of fruit. White mycelial mats appeared on the lesion at the surface of the fruit and a number of sclerotia formed on the fruit near the soil line. The sclerotia were globoid in shape, 1~3 mm in size, and white to brown in color. The hyphal width was measured 3 to 8 microm. The optimum temperature for mycelial growth and sclerotia formation was 30 on PDA. Typical clamp connections were observed in hyphae of grown for 4 days on PDA. On the basis of symptoms, mycological characteristics and pathogenicity to the host plant, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report of the fruit rot of Melon caused by S. rolfsii in Korea.

Rhizopus Soft Rot on Pear (Pyrus serotina) Caused by Rhizopus stolonifer in Korea

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.

Soft Rot of Eggplant (Solanum melongena) Caused by Choanephora cucurbitarum in Korea

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.

Soft Rot of Tomato Caused by Mucor racemosus in Korea

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 32~54 microm in size and globose in shape. Sporangiophores were 8~14 microm in width. Sporangiospores were 5~12 x 4~8 microm in size, ellipsoidal to subglobose in shape. Columella was 27~42 microm in size, obovoid, ellipsoidal, cylindrical-ellipsoidal, slightly pyriform in shape. Chlamydospores were numerous in sporangiophores and barrelshaped when young, subglobose in old cultures. Optimum growth temperature was about 25degrees 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.

Stem Rot of Tawny Daylily (Hemerocallis fulva) Caused by Sclerotium rolfsii in Korea

In July 2002, a destructive stem rot of tawny daylily(Hemerocallis fulva) was occurred sporadically in exhibition farm of Gyeongsangnam-do Agricultural Research and Extension Services located in Hamyang-gun, 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 were formed on the old lesions and near the soil surface. The optimum temperature for mycelial growth and scierotial formations was 30degrees C on PDA. The mycelial width ranged 4.2~10.4microm and the color was white, usually many narrow mycelial strand grew in the aerial mycelium and formed clamp connection. The shape of sclerotia was spherical and 1.0~3.2 mm in diameter. The fungus was isolated repeatedly from the infected tissues and confirmed its pathogenicity to Hemerocallis fulva and identified as Sclerotium rolfsii. This is the first report on the stem rot of H. fulva caused by S. rolfsii in Korea.

Fruit Soft Rot of Sweet Persimmon Caused by Mucor piriformis in Korea

A fruit soft rot caused by Mucor piriformis occurred on sweet persimmon storages in Jinju, Changwon and Gimhae, Gyeongnam province, Korea, 2003. The disease infection usually started from wounding after cracking of fruits. At first, the lesions started with water soaked and rapidly softened and diseased lesion gradually expanded. Colonies on potato dextrose agar at 20degrees C were whitish to olivaceous-buff Sporangia were globose, black and 96~153microm in size. Sporangiophores were 26~42microm in width. Sporangiospores were ellipsoid and 5.8~10.6x4.3~7.6microm in size. Columella was obovoid, cylindrical-ellipsoidal, pyriform, subglobose and 80~125microm in size. Optimal temperature for mycelial growth was 20degrees C on PDA. The causal organism was identified as M. piriformis. This is the first report of fruit soft rot on sweet persimmon caused by M. piriformis in Korea.

Leaf Spot of Cotton Rose Caused by Corynespora cassiicola in Korea

A leaf spot of cotton rose (Hibiscus mutabilis) occurred severely in the flower beds of cotton rose around Uiryeong-gun, Gyeongnam Province in Korea. The causal fungus was identified as Corynespora cassiicola on the basis of cultural and morphological characteristics of the fungus. The fungus grew well on potato dextrose agar and the colony color was gray to brown. Conidia were solitary or catenate, obclavate to cylindrical in shape, and pale olivaceous brown or brown in color. They had 420 pseudosepta, and measured 35.2~173.6 x 8.8~19.9 microm. Conidia germinated as a bipolar type. Conidiophores were pale to mid brown in color, and measured 74.2~275.6 x 3.8~10.8 microm. Optimal temperature for mycelial growth was 30degrees C. The fungal isolate grown on PDA showed strong pathogenicity to cotton rose plant. This is the first report on the corynespora leaf spot of cotton rose (Hibiscus mutabilis) caused by Corynespora cassiicola in Korea.

Stem Rot of Tomato Caused by Sclerotium rolfsii in Korea

A destructive stem rot of tomato (Lycopersicon esculentum) occurred sporadically some farmers' fields in Jinju City, Gyeongnam province in Korea. The infected plants also showed stem, crown rot or whole plant blight. White mycelium spread over stems of infected plants and formed sclerotia on the old lesions nearby soil surface. The fungus showed maximum mycelial growth around 30degrees C. The fungus formed white colony on PDA, usually with many narrow mycelial strands in the aerial mycelium and the width were 4.0~9.8 microm. The typical clamp connections were formed on the mycelium. Numerous sclerotia was formed on PDA at 30degrees C. The shape of sclerotia was globoid and 1.0~3.0 mm in size. The fungus was isolated repeatedly from the infected tissues and the pathogenicity was confirmed to tomato and identified as Sclerotium rolfsii. This is the first report on the stem rot of tomato caused by S. rolfsii in Korea.

Stem Rot of Tatarian Aster (Aster tataricus) Caused by Sclerotium rolfsii in Korea

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.

Occurrence of Stem Rot of Wild Aster (Aster koraiensis) Caused by Sclerotium rolfsii in Korea

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.

Occurrence of Strawberry Scab Caused by Cladosporium herbarum in Korea

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.