• Research in Plant Disease
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• v.17 no.3
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• pp.405-409
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• 2011

Azolla Lam. is a small aquatic fern with deeply bilobed leaves, which are consisted of a thick greenish, with chlorophyll, upper (dorsal) lobe and a thinner, translucent lower (ventral) lobe, without chlorophyll, submerged in the water. Azolla blight was observed at a lotus pond. Mycological characteristics of the fungus associated with Azolla blight was immediately determined as Rhizoctonia sp. by the thickness and branching of hypha at right angles at the point toward the distal end of septa, with branching hypha is constricted. The fungus produced brown mycelia and dark brown sclerotia on PDA. The optimum temperature for mycelial growth and sclerotia formation were $25^{\circ}C$ and $30^{\circ}C$, respectively. The optimum temperature for fungal infection was $30^{\circ}C$, when spray inoculated. Phylogenetic analysis of rDNA-ITS revealed that the fungus was identified as Rhizoctonia solani (AG-1 IA) closest to one causing rice sheath blight disease. This is the first report on the blight disease of Azolla caused by R. solani in Korea.

• The Korean Journal of Mycology
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• v.32 no.2
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• pp.105-111
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• 2004

The changes of microflora and chemical characteristics during fermentation process of cotton waste for oyster mushroom cultivation were investigated with 5 l bench-scale reactors placed in an incubator at different temperatures ($40,\;50\;and\;60^{\circ}C$). Cotton waste was wetted to 70% moisture, and air flow rates to the substrate were 50, 100 and 300 cc/min. In processing of composting, the mesophilic bacterial population decreased sharply but thermophilic bacterial population increased. In case of fungi, both mesophilic and thermophilic population decreased. The daily $CO_2$ evolution showed little difference in all treatments, while $NH_3$ dropped sharply after 3 days. The desirable composting temperature and air flow based on the mycelial growth of oyster mushroom were $50^{\circ}C$ and 100 cc/min, respectively.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.74-81
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• 1984

The experiments were conducted to study the distribution of wilt of strawberry caused by Fusarium in Korea, the characters of the causal fnngus and its control. The results obtained are summarized as follows. 1. Wilt of strawberry has been found in Gimhae and Samrangjin, Gyeongnam province a few years ago. This disease has been spreading year after year, and observed on farms in most of the strawberry-growing areas in Korea. 2. The fungus was isolated frequently from the crowns and petioles of diseased straw berry plants, and the fungus belonging to Fusariun oxysporum in terms of the morphological characteristics of macroconidia, microconidia, chlamydospore and conidiophore on V-8 Agar. 3. The macroconidia formation of the fungus varied remarkably with the Isolates and kinds of medium tested. However. all isolates abundantly produced macroconidia on V-8 Agar. 4. The cross-inoculation tests with several forma specialis of F. oxysporum to cucumber, tomato, watermelon, luffa, cabbage, melon and strawberry were carried out. The isolates from strawberry viz. Kodama's F. oxysporum f. sp. fragariae and S-1 of the authors were pathogenic to only strawberry. The fungus was also similar in morphology and symptoms to Kodama's and Winks' isolate of F. oxysporum f. sp. fragariae. Therefore, the fungus is identified as Fusarium oxysporum Schl. f. sp. fragariae Winks & Williams. 5. The most effective fungicides were Benomyl and Homai for inhibiting sporulation and mycelial growth of the fungus. 6 The cultivar Kurumae 35, Himiko, Senga gigana and Daehak I were resistant, whereas Hokowase, Instiate Z4, Juspa, Puget beauty and Marshall were susceptible to the fungus with artificial inoculation.

• The Korean Journal of Mycology
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• v.39 no.1
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• pp.39-43
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• 2011

A new cultivar "Dan Bi" of Pleurotus eryngii was developed by the method of mono-mono crossing between monokaryotic strains derived from KNR2312 and KNR2596. The parental strains, KNR2312 and KNR2596, are characterized by the property of high quality and a small number of primordia formation, respectively. The optimum temperature of mycelial growth was 25 and that of fruiting body development was $15{\sim}16^{\circ}C$. The period of harvesting including primordia formation was 0.7~1.3 days later than that of control strain Knneutari No. 3 in the culling cultivation. The color of pileus and stipe surface was neutral-brown and pure white, respectively. The shape of pileus was dome and has a scale like as cobweb. The yield was $93{\pm}9.7$ g per 850 cc of plastic bottle. Analysis of the genetic characteristics of the new commercial variety "Dan Bi" showed a different profile as that of the control strain, Knneutari No. 3, when RAPD (Random Amplified Polymorphic DNA) primer #8005 was used. This new variety "Dan Bi" of Pleurotus eryngii is characterized by a small number of primordia formation after scratching.

• Research in Plant Disease
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• v.26 no.1
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• pp.29-37
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• 2020

Stem blight symptom of soybean was severely developed in 2016 in Hwaseong and Yeoncheon. During the seedling period, the damping-off of seedlings and the brown or black spots of cotyledons were observed. After August, the leaves began to be yellowed, and partially browned areas on leaves began to develop. After September, microsclerotia began to form even on the surface of the stems that had exhibited water-soaking symptom. After mid-October of the harvest season, the epidermis of the stem was peeled off, resulting in the formation of a large number of microsclerotia in the cortex. The pathogens isolated from these symptoms were the best in mycelial growth at 32-35℃, and the formation of microsclerotia was the most at 20-28℃. The pathogen was identified as Macrophomina phaseolina through the morphological characteristics of the pathogen and the sequencing of the internal transcribed spacer region gene. In addition, when inoculated with a soybean stem using toothpicks cultured with the pathogen, the same symptoms as seen on the soybean field occurred. When the pathogen was re-isolated at the lesion site, the same pathogen was isolated and identified as Macrophomina phaseolina. Based on the results, the disease is reported as soybean charcoal rot.

• Korean Journal of Breeding Science
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• v.42 no.6
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• pp.711-716
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• 2010

'Sanggang', a new cultivar of Agrocybe aegerita, was bred with mating between monokaryotic strains isolated from 'GMAG45109' and 'GMAG45107' in Mushroom Research Station, Gyonggi Province A.R.E.S. in 2009. The optimum temperature for the mycelial growth of 'Sanggang' was 26 to 28$^{\circ}C$ on PDA(potato dextrose agar) medium. The optimum temperature for the primordia formation and fruiting body development of 'Sanggang', was 18 to 20$^{\circ}C$. In the bottle cultivation of 'Sanggang', the period of spawn running was around 38 days at 22 to 23$^{\circ}C$ and the period from scratching of inoculum to harvest was 12 days. These characteristics of 'Sanggang' were not different from those of 'Mihwang' (control). 'Sanggang' had brown-colored pileus, whereas 'Mihwang' had yellowish brown-colored one. In bottle cultivation, 'Sanggang' hada little smaller but stronger stipe and pilus than 'Mihwang', and 'Sanggang', as well as 'Mihwang', had upright stipe. And 'Sanggang' was shown to have lower veil opening ratio than that of 'Mihwang' at harvest time.The yield of fruiting bodies of 'Sanggang' was 134 g/850ml bottle, which was similar to that of 'Mihwang'. Resistance of'Sanggang' against Trichoderma spp., as well as 'Mihwang', was weak. Freshness of 'Sanggang' was maintained for 13 days under storage temperature 4$^{\circ}C$, while that of 'Mihwang' was maintained for 10 days.

• Research in Plant Disease
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• v.16 no.3
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• pp.316-319
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• 2010

The gray mold disease occurred on tuberous roots of yacon in storage facilities in Gangneung, Korea, in March 2010. Symptoms typically appeared as in the form of dark brown discoloration on the surface of tuberous roots and water-soaked brown lesions in cross sections of the affected portions. A total of five isolates of Botrytis sp. were obtained from the symptomatic portions. All isolates on potato-dextrose agar (PDA) produced abundant conidia which were pale brown, one-celled, mostly ellipsoid or ovoid in shape and $8.2{\sim}14.8{\times}6.5{\sim}9.9\;{\mu}m$ in size. Large numbers of round to irregular, smooth, black, hard sclerotia were produced on PDA over time. The optimal temperature for mycelial growth and sclerotia formation of the fungal isolates was $20^{\circ}C$. On the basis of morphological and cultural characteristics, all the fungal isolates were identified as Botrytis cinerea. Pathogenicity test on host plants showed that the fungus could infect not only tuberous roots but also leaves and petioles of yacon. This is the first report on gray mold of yacon (Smallanthus sonchifolius) caused by Botrytis cinerea in Korea.

• Korean Journal of Breeding Science
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• v.42 no.3
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• pp.288-293
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• 2010

'Cham', a new cultivar of Agrocybe aegerita, was bred by crossing between monokaryotic strains isolated from GMAG45021 and 'Beodeulsongi1ho' in Mushroom Research Station, Gyonggi Province A.R.E.S. in 2007. The optimum temperature for the mycelial growth of 'Cham' was 26 to $28^{\circ}C$ on PDA medium, whereas that of 'Beodeulsongi1ho'(control) was 24 to $26^{\circ}C$. The optimum temperature for the primordial formation and fruiting body development of 'Cham', as well as 'Beodeulsongi1ho', was 18 to $20^{\circ}C$. In the bottle cultivation, the spawn run period of 'Cham' at 22 to $23^{\circ}C$ was around 38 days and the period from scratching of inoculum to harvest was 12 days. These characteristics of 'Cham' were not different from those of 'Beodeulsongi1ho'. However, 'Cham' had more dark brown-colored, and thicker and stronger pileus, and longer and thicker stipe compared to that of 'Beodeulsongilho'. Freshness of 'Cham' was maintained for 10 days at the storage temperature of $4^{\circ}C$, while that of 'Beodeulsongi1ho' was maintained for 8 days. Moreover, the yield of fruiting bodies of 'Cham' was $141g/850m{\ell}$ bottle, which was similar to that of 'Beodeulsongi1ho'. Both 'Cham' and 'Beodeulsongilho' have lower resistivity against Trichoderma virens and Trichoderma harzianum.

• Research in Plant Disease
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• v.21 no.1
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• pp.36-39
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• 2015

In June 2012 and 2013, a destructive stem rot symptoms of Ligularia fischeri occurred sporadically in Hoengseong-gun and Pyeongchang-gun Gangwon-do, Korea. The typical symptom included water-soaking on the main stem, rotting, wilting and blighting, which eventually leads to death of the plant. White mycelial mats were spread over lesions and brown sclerotia were formed on stems and near soil surface. The sclerotia were white to brown, spherical or irregular, 1-3 mm in size on potato dextrose agar (PDA), The optimum temperature range of hyphal growth was $25-30^{\circ}C$ and the hyphal diameter was $4-10{\mu}m$. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. The resulting sequence of 695 bp was deposited in GenBank. A BLAST search revealed that sequences of the this isolates showed >99% identity with those of Sclerotium rolfsii. On the basis of the morphological characteristics and phylogenetic analyses of molecular markers ITS rDNA, the fungi were identified as S. rolfsii. A pathogenicity test was carried out to fulfill Koch's postulates. To our knowledge, this is the first report of S. rolfsii on Ligularia fischeri in Korea.

• Journal of Life Science
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• v.14 no.5
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• pp.761-769
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• 2004

This study was investigated the occurrence of sclerotinia rot caused by Sclerotinia sclerotiorum at the major perilla cultivating area, Gangdong-dong, Gangseo-gu, Busan in 1998. The incidence of this disease ranged from 8.1 to 28.3% at Gangdong-dong area during the growing seasons. Symptoms of the disease initially appeared damping-off of infected stems and soft-rot on the leaves of perilla. Under the relatively high humidity, abundant white mycelia of the pathogen formed on the lesion developed into black sclerotia later and the infected leaves were finally fell down. Sixteen isolates, Sl-S16, isolated from diseased lesions showing typical symptoms, and pathogenicity was tested using mycerlial disks. Among them, S2 isolate showing the most strong pathogenicity was selected and identified as Sclerotinia sclerotiorum on the basis of morphological and cultural characteristics. For biological control, an antagonistic bacteria, N4 isolate which effectively inhibited not only mycelial growth of S2 isolate but also suppress sclerotinia rot on the pot assay, was selected and identified as Bacillus megaterium according to Bergey's manual and API system., Wettable powder type, N4 formulation using B. megaterium N4 isolate was developed and estimated its control effect on perilla crops in a plastic house. As a results, N4 formulation which applied before 3 days inoculation of pathogen was effectually controlled Sclerotinia rot as the control value of 98.0%, was more effective than chemical fungicide, benomyl showing the control value of 78.0%. This is the first report of wettable powder formulation as a biocontrol agent using B. megaterium N4 against Sclerotinia rot caused by S. sclerotiorum on perilla.