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

• Korean journal of applied entomology
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• v.26 no.3 s.72
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• pp.171-178
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• 1987

Pathogenic isolates of Alternaria mali produced host-specific toxin(AM-toxin) in liquid culture. The toxin was also released by germinating spores of the fungus. The physiological event of apple leaves induced by germinating spores was an increased loss of electrolytes from susceptible leaves. This reaction was evident soon after spore inoculation, indicating that the leakage was caused by AM-toxin from germinating spores. Typical symptoms were developed only in susceptible leaves of apple within 48hr after inoculation with pathogenic spores. Similar symptoms occurred on susceptible leaves when non-pathogenic isolates plus AM-toxin were used.

• The Korean Journal of Mycology
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• v.12 no.2
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• pp.75-77
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• 1984

An undescribed Cercospora leaf spot of pepper grown in a greenhouse was observed at Jinju area in 1983. The symptom of this disease showed frog eyes spot on lower leaves of pepper. Leaves and petiole of pepper plant inoculated with spore suspension of this pathogen app­eared leaf spot after 2 weeks and exhibited cicular, brown frog eyes spot. This fungus was grown slowly on PDA and produce condia on infected leaves. The occurrence of this disease was responsi­ble for factors with high temperature and humidity conditions in the ill-ventilated greenhouse. This causal fungus was identified as Cercospora capsici Heald et. Wolf from the shape and length of the conidiophores, the length of the condia, and pathogenic behaviors.

• Journal of the Korean earth science society
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• v.29 no.6
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• pp.466-473
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• 2008

This study deals with the morphological characteristics and structure of organ fossils of Neocalamites carrerei such as rhizomes, aerial leafy stems, and cones collected in situ from the Amisan Formation of Nampo Group. Judging from the size of some extant Equisetum and paleoclimate of Daedong flora, it is considered that the size of Neocalamites carrerei was probably very large. The cone of Neocalamites takahashii (Kon'no) is closely associated with the leaves of Neocalamites carrerei. It indicates that two organ fossils mentioned above probably belong to the same species. Comparing with very abundant occurrence of aerial leafy stems and rhizomes in the Amisan Formation, cones are very rare. This fact implies that Neocalamites reproduce not only by spore reproduction, but also by asexual reproduction. Neocalamites largely differ in the leaf form and size from Equisetum.

• Korean journal of applied entomology
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• v.23 no.1 s.58
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• pp.61-67
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• 1984

Conidial germination of Septoria glycines Hemmi, brown spot fungus of soybean, was studied by slide germination test. Poor conidial germination of S. glycines was observed on sterile distilled water, but potato dextrose agar(PDA) and distilled water floated with soybean leaf disc furnished a satisfactory medium for conidial germination. Exogenous supply of carbon source was essential for conidial germination, while phosphorous and potassium were not evident as that for carbon. Soluble starch was the most suitable as a carbon source for conidial germination and followed by D-glucose, D-galactose and lactose in that order. Maximum germination was attained in the $5\times10^{-2}mol$. concentration of glucose. Germination was decreased with increment of conidial concentration and was almost completely suppressed in the density of 10,000 conidia per $mm^2$. It suggested existing a self-inhibitor(s). Non-washed conidia germinated more than washed conidia and this was obvious when the conidia density was over $2\times10^3$ conidia per $mm^2$ on the dry agar block.

• The Korean Journal of Mycology
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• v.25 no.1 s.80
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• pp.30-34
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• 1997

Glomerella cingulata (conidial state: Colletotrichum gloeosporioides) was identified as the causal organism of anthracnose of citrus on the basis of morphological characteristics of the conidial state of the fungus isolated from infected leaves of Satsuma mandarin and its ascigerous state isolated from diseased twigs. The pathogen infected the leaves of Satsuma mandarin, citron and Natsu daidai only by wound inoculation. The optimum temperature range for mycelial growth and sporulation of conidia of the strain was $25{\sim}30^{\circ}C$, respectively. The characteristics of anthracnose strain of Satsuma mandarin such as growth rate and color of colony, shape and size of conidia, and appressoria were similar to those of FGG strain. However, the strain isolated from infected leaves and twigs of Satsuma mandarin was different from FGG strain to cause postharvest anthracnose of citrus, because some of morphological and pathological characteristics of the strain isolated did not correspond to those of FGG strain.

• Research in Plant Disease
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• v.19 no.1
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• pp.55-59
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• 2013

The purpose of this experiment was to investigate the development of new spot disease on the leaf and stem of rosemary (Rosmarinus officinalis) in commercial greenhouses at Jeonju and Namwon in Korea. Incidence of target spot on rosemary was higher at the end of the rainy season with high humidity. Those symptoms were black ring spots (3-5 mm in diameter) and withering on green leaves and stems. Conidiophores and conidia were formed on the infected tissue in moist chamber and conidia were shown as the cylindrical and oval types in chain, ranged from 55 to $275{\mu}m$ in length, and 7 to $14{\mu}m$ in width. Conidia with eight to ten pseudosepta were formed on the conidiapore. The optimum growth temperature of isolates was $30^{\circ}C$ on the PDA medium under the dark condition. In the pathogenesis test, the target spot and withering symptoms were appeared on the leaves and stems 3 days after inoculation showing similar symptoms compared to those of in nature. The same fungus was re-isolated from infected lesion, indicating that Corynespora cassiicola caused leaf target spot and twig blight on rosemary. The rDNA ITS nucleotide sequences of the pure cultured isolate from the diseased area on rosemary showed 100% similarity to the sequences of C. cassiicola available in the GenBank database (JQ595296, JQ595297, FJ852715 and AY238606). Therefore, we report that the target spot of leaves and stems in rosemary was caused by C. cassiicola.

• The Korean Journal of Mycology
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• v.46 no.1
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• pp.58-68
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• 2018

Sunn hemp (Crotalaria juncea) is used as a nitrogen-fixing green manure in Korea to improve soil quality, reduce soil erosion, and suppress weeds and nematodes. In 2014, wilting sunn hemp plants were observed in green manure-cultivated fields in Wanju, Korea. Leaves of the infected plants began yellowing, starting with the lower leaves, eventually leading to their death. Moreover, a number of dark perithecia were observed on the wilting stems. Six isolates were obtained from these perithecia by single spore isolation. Based on their morphological characteristics, the isolates were identified as Fusarium udum (teleomorph: Gibberella indica). Macroconidia were slightly curved with almost hooked apical cell, and microconidia were formed on false heads by monophialides. Chlamydospores were produced abundantly in the hyphae, either singly or in clusters. To confirm the identification, multilocus sequence analysis was conducted using translation elongation factor 1 alpha (TEF), calmodulin (CAL), and histone 3 (HIS3). The sequences of TEF, CAL, and HIS3 showed 94.4~96.2%, 99.7%, and 99.6~99.8% similarity to the reference sequences of F. udum in NCBI GenBank, respectively. Pathogenicity was tested on sunn hemp and two soybean cultivars using the inoculation method of soil drenching with spore suspension. The wilting symptoms were observed only in sunn hemp and one cultivar of soybean (cv. Teagwang) after 14~21 days of inoculation. This is the first report of wilt disease in sunn hemp caused by Fusarium udum in Korea.

• Korean journal of applied entomology
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• v.12 no.1
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• pp.23-27
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• 1973

In an effort to find effective inoculation method of Fusarium nivale, this experiment was conducted. The results obtained are summarized as follows: (1) Distilled water-spore suspension of this fungus was inoculated on rice seedling and the result showed that negligible disease symptoms were observed when the inoculated plants were placed in a moist chamber for one day, whereas considerable symptoms were indicated when kept for two days. (2) After giving physical wounds by wind or wooden stick to the rice seedling, distilled water-spore suspenion was sprayed on them and considerable diseased spots were formed. (3) Sufficient disease occurrence was due to the addition of $1\%$ rice leaf extract, glucose, polypeptone, and yeast extract solution to the spore suspension. (4) In distilled water, spore germination was poor, while in nutrient added solution good germination rate as well as anastomosis was found. (5) A new rice variety Tong-il turned out to be more susceptible to Fusarium nivale than Pung-kwang.

• Research in Plant Disease
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• v.21 no.4
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• pp.337-340
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• 2015

During July to November 2014, severe rust infection was consistently found on Peucedanum japonicum growing farm in Yeosu, Korea. The rust was observed mainly on lower leaf surfaces. Symptoms of typical plants included yellow-orange rust pustules were observed on the petiole and leaf surface with small yellowish to chlorotic lesions on the upper surface. No symptom was observed on flowers. Uredinia were occurred amphigenous on leaf surface, and occasionally caulicolous, scattered or loosely aggregate, rounded to oblong, 0.4 to 4 mm in diameter, covered by epidermis, then naked, surrounded by ruptured epidermis, pulverulent, and brown. Urediniospores were ovate-ellipsoid, ellipsoid or subglobose, light brown, 20 to $45{\times}15$ to $35{\mu}m$, walls 2 to $4{\mu}m$ thick. The resulting sequences were deposited in GenBank with accession No. KT778808, KT778809, and KT778810, respectively. Since this was the first accession of 28S sequence Puccinia jogashimensis, there was no exact match in GenBank nucleotide database. On the basis of the morphological characteristics and phylogenetic analyses of 28S rDNA, the fungus was identified as P. jogashimensis. To our knowledge, this is the first confirmed report on the occurrence of P. jogashimensis on P. japonicum in Korea.