• Weed & Turfgrass Science
• /
• v.2 no.3
• /
• pp.306-311
• /
• 2013

Pythium blight occurred by Pythium aphanidermatum on chewing fescue cv. "Jamestowm II" from early June, 2010 and 2011 at the test field in Daegu University in Gyeongbuk Province, Korea. Disease symptoms on the turfgrass were leaf blights dying from the leaf tip and root rot, which appeared patches of brown to dark brown color or gray brown color in the field. The pathogens (40-1 isolate) of Pythium blight was isolated from the diseased leaf and crown tissue and cultured on potato-dextrose agar (PDA) for identification. Lobulate sporangia were inflated, complex structures, and filamentous sporangia were usually indistinguishable from vegetative hyphae. Sequences of ribosomal RNA gene of the fungus were homologous with similarity of 100% to those of P. aphanidermatum isolates in GenBank database. Pathogenicity was also confirmed on the chewing fescue, creeping betgrass and Kentucky bluegrass by Koch's postulates. This is the first report of Pythium blight on chewing fescue caused by P. aphanidermatum in Korea.

• Research in Plant Disease
• /
• v.13 no.1
• /
• pp.20-23
• /
• 2007

We investigated the first symptom emerging date of rice bacterial leaf blight disease during four years from 2002 to 2005. The disease occurrence date was earlier 20$\sim$30 days in 2005 than that of 2002. The damage in different rice growth stage by the bacterial disease on rice yield and grain quality in southern part of Korea was examined. The disease decreased rice yield following by increased infection rates. Slight loss in rice yield and brown head rice rate were observed at below 10% level of infected leaf area, while over 25% infected leaf area caused the significant decrease in rice yield and brown head rice rate. More than 50% of the infected leaf area rate caused 29% yield reduction in case of infection at panicle formation stage and 18% of brown head rice rate. Cooked rice quality was also affected in the diseased rice by damage in palatability score and viscosity.

• Mycobiology
• /
• v.47 no.4
• /
• pp.408-414
• /
• 2019

Crinum asiaticum and Hymenocallis littoralis, commonly known as spider lilies are bulbous perennial and herbaceous plants that widely planted in Malaysia as ornamental. During 2015-2016, symptom of leaf blight was noticed on the hosts from several locations in Penang. The symptom appeared as irregular brown to reddish lesions surrounded by yellow halos. As the disease progressed, the infected leaves became blighted, dried, and fell off with the presence of black microsclerotia and pycnidia on the lesions parts. The present study was conducted to investigate the causal pathogen of leaf blight on C. asiaticum and H. littoralis. Based on morphological characteristics and DNA sequences of internal transcribed spacer (ITS) region and translation elongation factor 1-alpha (TEF1-α) gene, the causal pathogen was identified as Macrophomina phaseolina. Phylogenetic analysis of combined dataset of ITS and TEF1-α grouped the isolates studied with other isolates of M. phaseolina from GenBank. The grouping of the isolates was supported by 96% bootstrap value. Pathogenicity test proved the role of the fungus in causing leaf blight on both hosts.

• Weed & Turfgrass Science
• /
• v.5 no.2
• /
• pp.101-104
• /
• 2016

Curvularia leaf blight of creeping bentgrass (Agrostis stolonifera) putting green by caused Curvularia trifolii was observed in Hapcheon, Korea. In July to September 2014, curvularia leaf blight developed on leaf blades of creeping bentgrass as small water-soaked lesions that subsequently turned into dark-colored, necrotic spots. The spots were expanded and became gray, grayish-brown, or light brown, circular to oblong lesions with purple to dark brown borders that often were surrounded by a yellow halo. The necrotic lesions coalesced, became irregular in shape and caused tip or complete blighting of the leaves. Blighted leaf blades appeared grayish-white to tan. The fungus was identified by morphological characters and 16S rDNA sequencing as C. trifolii. Conidia of the pathogen were short, with predominantly 3-septa, straight or often curved, with end cells frequently paler than intermediate cells. Size of the 3-septate conidia in culture are $26{\sim}28{\times}11{\sim}12{\mu}m$. Pathogenicity of the fungus was proved by artificial inoculation on the host. This is the first report of C. trifolii causing leaf blight on creeping bentgrass in Korea.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1990.05a
• /
• pp.48-49
• /
• 1990

• Journal of agriculture & life science
• /
• v.50 no.4
• /
• pp.249-253
• /
• 2016

Aster glehni Franchet et Schmidt is a compositae plant and has been known as a native specie in Ulleung Island, Korea. It is officially recognized as a regional specialty that grows only in this region. In 2014, brown and dark spots were observed on aster leaves in a forest research field, Jinju, Korea. A causal agent was isolated from the disease symptomatic leaves and identified as fungus Alternaria solani. Fungal morphological characteristics and molecular identification with internal transcribed spacer sequences were synchronized as A. solani. The isolated fungi reproduced the same disease symptoms when the fungus was artificially inoculated on healthy aster leaves. This is the first report that A. solani caused leaf blight disease in Aster glehni in Korea.

• The Plant Pathology Journal
• /
• v.24 no.2
• /
• pp.125-130
• /
• 2008

Various kinds of leaf spots and blights were found in kiwifruit (Actinidia deliciosa) orchards on 2006 in Korea. Disease incidences were quite variable between open-field and rain-proof shelter. Rate of diseased leaves was recorded as about 70% at open-field orchards in late season but use of rain-proof vinyl shelters alleviated the disease incidences by 20%. Angular leaf spots appeared at early infection stage on June and several other symptoms were also recognized as the disease developed afterward. On September, brown leaf blights were the most frequent, followed by grayish brown ring spots, silvering gray leaf blights, zonate leaf blights, dark brown ring spots and angular leaf spots at open-field orchards. Four fungal species were frequently isolated from the disease symptoms. Phomopsis sp. was the most predominant fungus associated with the leaf spot and blight symptoms on kiwifruit, followed by Glomerella cingulata, Alternaria alternata and Pestalo-tiopsis sp. Phomopsis sp. was commonly isolated from angular leaf spots, silvering gray leaf blights, and zonate brown leaf blights. G. cingulata, A. alternata and Pestalotiopsis sp. were isolated from grayish brown ring spots (anthracnose), brown ring spots and zonate dark brown leaf blights. Typical symptoms appeared on the wounded and unwounded leaves, which were inoculated by each of Phomopsis sp., G. cingulata, and Pestalotiopsis sp., but A. alternata caused symptoms only on the wounded leaves.

• The Korean Journal of Mycology
• /
• v.32 no.2
• /
• pp.130-133
• /
• 2004

Leaf blight and fruit rot of sweet persimmon (cv. Fuyu) caused by Pestalotia diospyri were observed during the growing season and postharvest such as storage and transport, respectively. Typical symptoms on leaves developed with small brown spots and were later reddish brown colors. In the storage fruit, the white mycelial mats formed between fruit and calyx. The pathogenic fungus was isolated from infected fruits and cultured on potato dextrose agar (PDA). Colony color of the fungus was white at first on PDA. Conidia were ovoid or fusiform, 5 cells, middle 3 cells were olive, upper and lower 2 cells were colorless, and their size were $16{\sim}22\;{\times}\;6{\sim}8\;{\mu}m$. They had were $2{\sim}3$ appendage at basal cell and size $9{\sim}18\;{\mu}m$. Based on the cultural and mycological characteristics and pathogenicity test on host plants and fruits, the fungus was identified as Pestalotia diospyri Syd.&P. Syd. This is the first report on the leaf blight and fruit rot of sweet persimmon caused by Pestalotia diospyri in Korea.

• Korean Journal Plant Pathology
• /
• v.13 no.1
• /
• pp.22-29
• /
• 1997

Etiological and ecopathological studi88888es on the leaf blight of kiwifruit (Chinese gooseberry), a disease newly found in 1993 in Korea, were carried out in this experiment. The leaf blight symptom was prevalent in the southern area of Chonnam Province where kiwifruits were widely cultivated. The disease occurred from July to fall, causing early defoliation of kiwifruit vines. Small brownish circular or irregular lesions appeared initially on the leaves, starting from the marginal leaf areas, and enlarged. Afterwards small grayish black granules (acervuli) were formed on the lesions. The color of old lesions changed to grayish brown or grayish white. The causal fungus was identified as Pestalotiopsis menezesiana (Bress. & Torr.) Bissett according to its morphological characters and pathogenicity (pathogenic to Chinese gooseberry and grapevine, but not to other hosts of Pestalotiopsis spp.such as tea, apple, persimmon, and chestnut). As P. longiseta and P. neglecta were reported recently in Japan as pathogens causing similar blight symptoms in kiwifruit, P. menezesiana is a new leaf blight pathogen in kiwifruit. Development of the disease was stimulated by wounding, prevailing wind, and drought. The causal fungus was proven to be overwintered in the diseased leaves on the ground surface.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• v.18 no.1
• /
• pp.174-176
• /
• 2005