• The Korean Journal of Mycology
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• v.31 no.1
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• pp.50-52
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• 2003

The powdery mildew of Phlox (Phlox paniculata) extensively occurred in the experimental farm of Cheongam-myon, Hadong-gun, Gyeongnam province in 2002. Both sides of the leaves and stems were covered with the white fungal spores and mycelia, and then the leaves became brown to dark brown in color, eventually died. The conidiophores on the lesion were observed. Conidia were cylindric in shape, colorless, $25.3{\sim}49.4{\times}12.3{\sim}17.2{\mu}m$ in size and borne singly on conidiophore. Fibrosin bodies were not observed. Conidiophores were straight with 2-4 cylindric cells, and $65.7{\sim}124.8{\mu}m$ in size. Appressoria were lobed. Cleistothecia were not formed. This is the first report on powdery mildew of Phlox caused by Oidium sp. in Korea.

• Mycobiology
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• v.30 no.1
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• pp.31-36
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• 2002

Soil bacteria were screened for the ability to control cucumber anthracnose caused by Colletotrichum orbiculare through induced systemic resistance(ISR). Sixty-four bacterial strains having in vitro antifungal activity were used for selecting ISR-inducing strains in cucumber. Cucumber seeds(cv. Baeknokdadagi) were sown in potting mixtures incorporated with the soil bacteria, at a rate of ca. $10^8$ cells per gram of the mixture. Two week-old plants were then transplanted into the steam-sterilized soil. Three leaf-stage plants were inoculated with a conidial suspension($5{\times}10^5$ conidia/ml) of C. orbiculare. Diseased leaf area(%) and number of lesions per $cm^2$ leaf were evaluated on third leaves of the plants, $5{\sim}6$ days after inoculation. Among 64 strains tested, nine strains, GC-B19, GC-B35, GK-B18, MM-B22, PK-B14, RC-B41, RC-B64, RC-B65, and RC-B77 significantly(P=0.05) reduced anthracnose disease compared to the untreated control. In contrast, some bacterial strains promoted susceptibility of cucumber to the disease. From the repeated experiments using the nine bacterial strains, GC-B19, MM-B22, PK-B14, and RC-B65 significantly(P=0.05) reduced both diseased leaf area(%) and number of lesions per $cm^2$ leaf in at lease one experiment. These strains with control efficacy of $37{\sim}80%$ were determined to be effective ISR-inducing strains.

• The Korean Journal of Mycology
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• v.10 no.2
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• pp.89-92
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• 1982

The seeds of 20 barley cultivars were tested for aflatoxin contamination and susceptibility to infection by an aflatoxin-producing mold. When the samples were tested as they arrived, no aflatoxin was detected on any of them. When their moisture was raised to 25% and they were kept as $25^{\circ}C$ for 2 weeks, all expect 2 cultivars showed aflatoxin contamination. Aflatoxins $B_2$ and $G_2$ were not detected in this incubation period. After wetting (25% moisture) the samples, inoculating them with Aspergillus parasiticus conidia and storing them at $25^{\circ}C$ for 2 weeks, all cultivars were found heavily contaminated with aflatoxin, those with seedcoats more so than those without seedcoats.

• Mycobiology
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• v.41 no.4
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• pp.221-224
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• 2013

Aphids are one of the most destructive pests in crop production such as pepper, cucumber, and eggplants. The importance of entomopathogenic fungi as alternative pest control agents is increasing. Conidia of entomopathogenic fungi are influenced by environmental conditions, such as temperature and relative humidity, and cause slow and fluctuating mortality. These factors have prevented wider application and use of biocontrol agents. For investigation of means of mitigation of such problems, we conducted bioassays with 47 fungal culture filtrates in order to evaluate the potential of secondary metabolites produced by entomopathogenic fungi for use in aphid control. Among 47 culture filtrates cultured potato dextrose broth, filtrate of Beauveria bassiana Bb08 showed the highest mortality (78%) against green peach aphid three days after treatments. Filtrate of Bb08 cultured in Adamek's medium showed higher toxicity as 100% to third instar nymphs of the aphid compared with seven other filtrates cultured in different broths amended with colloidal chitin or oil. The culture filtrates and fungal cultures from media amended with colloidal chitin or oil had lower control efficacies than filtrates without these additives in three different media. These results indicate that the fungal culture fluid or culture filtrate of B. bassiana Bb08 cultured in Adamek's medium has potential for development as a mycopesticide for aphid control.

• Korean journal of applied entomology
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• v.14 no.4 s.25
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• pp.205-208
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• 1975

Effect of light and temperature on the sporulation and mycelial growth by 4 strains of Mycosphaerella fragariae was examined. The light source was day light fluorescent lamps with an intensity of 2000 Lux at the colony surface. The treatment were constant light, alternating light(10hr) and darness (14h.) and constant darkness af $15^{\circ}C,\; 22^{\circ}C\; and\; 30^{\circ}C$ 1. Of the 4 strains tested, alternating light and darkness at $22^{\circ}C\;and\;15^{\circ}C$ gave the greatest sroducedtion, constant light in intermediate, constant darkness in minimum, but darkness at $30^{\circ}C$ produced abundant conidia over that obtained in the other two treatment. Differences in number of sporulation due to light, strains and the interaction of these two were all statistically significant. 2. There were not on significant differences in amount of mycelial growth due to light, but amount of mycelial growth of$S_3$ strain were the nest abundant among the 4 strains.

• Korean journal of applied entomology
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• v.22 no.4 s.57
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• pp.277-282
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• 1983

Number and percentage of diseased area of leaf blast lesions formed on different leaf location were mostly distributed from the flag leaf(n-1) to the 3rd leaf from the top(n-3) in Tongil line rice varieties and on the 2nd leaf from the top(n-2) in Japonica type rice varieties. Especially leaf lesions of Nopung which was more susceptible to leaf blast among Ton1 line rice varieties were mostly distributed on flag leaf. Relation between the degree of lesion distribution and level of fertilizer was more clear with an increase of fertilizer quantity. Leaf blast lesions of rice varieties were generally distributed from the flag leaf to the with leaf from the top but mainly those at flag leaf and the 2nd leaf from the top were found to be most responsible for inoculum source of panicle blast after booting stage. Increase of the conidia formation was resulted from fluctuation of temperature$(24^{\circ}C\~16^{\circ}C)$ in low temperature range after booting stage and many inoculum sources were supplied on panicles until the end of September without impeding dispersal from leaf blast lesions as an inoculum source of panicle blast.

• Korean journal of applied entomology
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• v.5_6
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• pp.65-69
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• 1968

The effect of respiratory inhibition was investigated by treating conidia or mycelium of Cochliobolus miyabeanus with phenylmercuric 8-oxyquinolinate (PMQ) or. phenylmercuric acetate (PMA) in terms of $O_2$ up take ul/mg dry weight of cells. The results obtained are as follows: 1. In inhibition of mycelial growth, PMQ gave somewhat less effective than PMA, hut there was no remarkable difference between them, and the two indicated strong inhibitory effect on mycelial growth at the range from 0.01 to 1.0 ppm. 2. In inhibition of conidial respiration, PMA gave somewhat stronger than PMQ except at 0.1ppm, but there was no notable difference between them, and it seemed that there was no inhibitory effect at 0.01ppm. 3. PMQ was stronger than PMA in inhibition of mycelial respiration as compared with the cibudail respiration, ration, and the difference between them was about $10\%$. 4. According to the above results, the inhibitory effect of spore germimation by PMQ was the same as to PMA or somewhat lower than that of PMA. The inhibitiry effect of PMQ on mycelial growth was lower than that of PMA.

• Journal of Sericultural and Entomological Science
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• v.46 no.1
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• pp.18-22
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• 2004

For the purpose of accumulating the research outcomes on Cordyceps and retrieving them efficiently, this study was carried out to identify and standardize the key factors in cultivating Paecilomyces tenuipes and classifying characteristics of Cordyceps. The key factors in cultivating Paecilomyces tenuipes are divided into three major sections according to its stage: silkworm rearing period, cultivation period, and preservation period. Silkworm rearing and cultivation sections are divided into three sub-sections: temperature, humidity, and duration. There are other factors including rearing tools, equipment etc. The key factors in classifying characteristics of Cordyceps are divided into 14 items, 41 divisions on the basis of its general features and its taxonomic features. 14 items contain general article, host, perithecium, conidia, etc. 41 divisions are partitioned by its size and color. The classification system of Kobayasi (1940) or of Shimizu (1994) was adopted for the key factors of Cordyceps species and their anarmorphs.

• The Korean Journal of Mycology
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• v.34 no.1
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• pp.59-61
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• 2006

Gray mold caused by Botrytis cinerea on Agastache rugosa was occurred at a field of Jinju from 2003 to 2005. The disease symptoms started with water-soaked lesions in the leaves and stem, then these infected lesions became withered, discolored, rotten and died eventually. The fungal pathogen was isolated from the lesions. The fungal conidia were one-celled and mostly ellipsoid or ovoid in shape and light gray in color and $4{\sim}20{\times}4{\sim}13\;{\mu}m$ in size. The fungal conidiophores were $14{\sim}28\;{\mu}m$ in width. The Pathogen formed sclerotia abundantly on PDA. The optimum temperature for mycelial growth and sclerotia formation was $20^{\circ}C$. Pathogenicity of the causal organism was proved according to Koch's postulates. On the basis of symptom, mycological characteristics and pathogenicity test, the fungus was identified as Botrytis cinerea. This is the first report on gray mold of Agastache rugosa caused by B. cinerea in Korea.

• Mycobiology
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• v.43 no.3
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• pp.354-359
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• 2015

Blossom blight in strawberry was first observed in a green house in Nonsan, Damyang, and Geochang areas of Korea, between early January to April of 2012. Disease symptoms started as a grey fungus formed on the stigma, which led to the blossom blight and eventually to black rot and necrosis of the entire flower. We isolated the fungi purely from the infected pistils and maintained them on potato dextrose agar (PDA) slants. To test Koch's postulates, we inoculated the fungi and found that all of the isolates caused disease symptoms in the flower of strawberry cultivars (Seolhyang, Maehyang, and Kumhyang). The isolates on PDA had a velvet-like appearance, and their color ranged between olivaceous-brown and smoky-grey to olive and almost black. The intercalary conidia of the isolates were elliptical to limoniform, with sizes ranging from $5.0{\sim}10.5{\times}2.5{\sim}3.0{\mu}m$ to $4.0{\sim}7.5{\times}2.0{\sim}3.0{\mu}m$, respectively. The secondary ramoconidia of these isolates were 0- or 1-septate, with sizes ranging betweem $10.0{\sim}15.0{\times}2.5{\sim}3.7{\mu}m$ and $8.7{\sim}11.2{\times}2.5{\sim}3.2{\mu}m$, respectively. A combined sequence analysis of the internal transcribed spacer regions, partial actin (ACT), and translation elongation factor 1-alpha (TEF) genes revealed that the strawberry isolates belonged to two groups of authentic strains, Cladosporium cladosporioides and C. tenuissimum. Based on these results, we identified the pathogens causing blossom blight in strawberries in Korea as being C. cladosporioides and C. tenuissimum.