• Research in Plant Disease
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• v.10 no.2
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• pp.126-129
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• 2004

In July of 2002, leaf spot disease was found on kudzu (Pueraria lobata) leaves in Jeonbuk province. A small leaf spot was appeared on leaves as a typical symptom and the spot was then surrounded by chlorotic halo. The lesions were expended and coalesced and the infected leaves became yellow leaf and later fall out. A causal fungal pathogen was isolated and the colony of the pathogen was light gray green to dark green on PDA. The pathogen produced mostly the single conidium but rarely long chain of 3 to 8 conidia. The conidia were dark brown in color, long ellipsoid or oval and 20-60 ${\times}$ 10-25 ${\mu}{\textrm}{m}$ in size. Their septa were 4-8 transverse and 1-2 longitudinal or oblique. The pathogen was, therefore, identified as Alternaria tenuissima based on cultural and morphological characteristics. This is the first report on the leaf spot of kudzu caused by A. tenuissima in Korea.

• The Korean Journal of Mycology
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• v.16 no.2
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• pp.64-69
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• 1988

Isoates with changed pathogenicity were selected among iprodione-resistant Alternaria mali to investigate any relationship between their pectolytie enzyme activity and pathogenicity. In artificial medium, strongly pathogenic isolates $S_1$, and $R_3$ showed higher enzyme activity than weakly pathogenic isolate $R_8$.Activity of endo-polymethylgalacturonase and end-o-polygalacturonase was more than 3 times. But activity of pectin methylesterase and pectin Iyase by isolaste $S_1$ was higher than those by $R_3$ and $R_8$ isolates. In apple medium dialyzed against distilled water, activity of enzyme by each isolate was increased but growth of each isolate was reduced. When iprodione was added to the medium, enzyme activity and growth of isolate $S_1$, were reduced but strongly pathogenic isolate .$R_3$ among iprodione-resistant ones showed increased enzyme activity except for exo-polygalacturonase in dialyzed apple medium.

• Research in Plant Disease
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• v.8 no.2
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• pp.117-119
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• 2002

Leaf spot disease was found on broad bean (vicia faba) in several farmer's fields located in Changseon-myon, Namhae-gun, Gyeongnam province, Korea. The typical symptoms of the disease were appeared on leaves, stems and pods. The infection rates of the disease in the surveyed area were ranged from 8.4 to 46.8％. Colonies formed on PDA were developed aerial hyphae with grayish white, which later turned olive-green to black. Conidia were dark brown in color, long ellipsoid to elongated ovoid, obclavate and 23.7~61.3$\times$7.2~16.8 ${\mu}{\textrm}{m}$ in size. Septa were 4~10 transvers, 1~2 longitudinal or oblique. Conidiophores were solitary or fascicles and 18~113$\times$3~6 ${\mu}{\textrm}{m}$ in size. The optimum temperature for growth of the fungus was about 3$0^{\circ}C$. This is the first report on the leaf spot of broad bean caused by Alternaria tenuissima in Korea.

• Research in Plant Disease
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• v.24 no.4
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• pp.292-301
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• 2018

Alternaria leaf spot disease has been a concern during a tomato production in greenhouse. In vitro antifungal activities of vapours of four plant essential oils, cinnamon oil, fennel oil, origanum oil and thyme oil, were investigated during in vitro conidial germination and mycelial growth of Alternaria alternata causing the tomato leaf spots to find eco-friendly alternatives for chemical fungicides. The four plant essential oils showed different antifungal activities against in vitro conidial germination of A. alternata in dose-dependent manners, and cinnamon oil vapour was most effective to suppress the conidial germination. The four plant essential oils showed similar antifungal activities against the in vitro mycelial growth of A. alternata in dose-dependent manners, but low doses of thyme oil vapour slightly increased in vitro mycelial growth of A. alternata. Necrotic lesions on the A. alternata-inoculated tomato leaves were reduced differently depending on kinds and concentrations of plant essential oils. Delayed conidial germination and germ-tube elongation of A. alternata were found on the tomato leaves treated with cinnamon oil and origanum oil vapours at 6 hpi. These results suggest that volatiles from cinnamon oil and origanum oil can be provided as alternatives to manage Alternaria leaf spot during the tomato production eco-friendly.

• Korean Journal Plant Pathology
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• v.11 no.4
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• pp.318-323
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• 1995

The effect of AF-toxin I produced by the strawberry pathotype of Alternaria alternata on the protein synthesis of susceptible strawberry protoplasts was examined by using the radiolabeled amino acids. The incorporation of the radiolabeled amino acids into newly synthesized proteins in the strawberry protoplasts was stimulated by the toxin treatment at relatively low concentrations (2.2$\times$10-11 to 2.2$\times$10-9 M), but not at higher concentrations (2.2$\times$10-8 to 2.2$\times$10-6 M). An one-dimensional SDS-polyacrylamide gel electrophoresis revealed no detectable differences in the proteins synthesized in both the toxintreated and untreated protoplasts. The susceptible strawberry protoplasts were treated with AF-toxin I and stained with Fluostain I to detect the extracellular polysaccharides. The toxin treatment induced the accumulation of extracellular polysccharides in a dose-dependent manner. These results indicate a transient activation of cellular metabolism in the susceptible cells by the toxin exposure.

• Journal of Microbiology
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• v.40 no.4
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• pp.289-294
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• 2002

The fungal strain SW-3 having antimicrobial activity was isolated from soil of crucified plants in Pocheon, Kyungki-Do, Korea. Strain SW-3 was identified as Alternaria brassicicola by its morphological characteristics, and confirmed by the analysis of the 18S gene and ITS regions of rDNA. The fungus showed a similarity of 99% with Alternaria brassicicola in the 18S rDNA sequence analysis. A. brassicicola has been reported to produce an antitumor compound, called depudecin. We found that strain SW-3 produced antimicrobial metabolites, in addition to depudecin, during sporulation under different growth conditions. The metabolite of the isolated fungus was found to have strong antifungal activity against Microsporium canis and Trichophyton rubrum, and antibacterial activity against Staphylococcus aureus and Pseudomonas aerogenes. The amount and kind of metabolites produced by the isolate were affected by growth conditions such as nutrients and growth periods.

• Research in Plant Disease
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• v.21 no.4
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• pp.330-333
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• 2015

In June 2013, we collected leaf spot disease samples of Datura metel from Gangneung, Gangwon Province, Korea. The symptoms observed were small circular to oval dark brown spots with irregular in shape or remained circular with concentric rings. We isolated the pathogen from infected leaves and cultured the fungus on potato dextrose agar. We examined the fungus morphologically and confirmed its pathogenicity according to Koch's postulates. The results of morphological examinations, pathogenicity tests, and the rDNA sequences of the internal transcribed spacer regions (ITS1 and ITS4), glycerol-3-phosphate dehydrogenase (G3PDH) and the RNA polymerase II second largest subunit (RPB2) gene sequence revealed that the causal agent was Alternaria tenuissima. To the best of our knowledge, this is the first report of leaf spot of D. metel caused by A. tenuissima in Korea as well as worldwide.

• Mycobiology
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• v.38 no.4
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• pp.316-320
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• 2010

Leaf spot and blight disease was observed on two-year-old seedlings of Dendropanax morbifera (Korean name: Hwangchil tree) during July of 2008 in Jindo Island, Korea. Symptoms included yellow-brown to dark brown irregularly enlarged spots frequently located along the veins of leaves. The lesions were often surrounded by chlorotic haloes. Severe leaf blight and subsequent defoliation occurred when conditions favored disease outbreak. The causal organism of the disease was identified as Alternaria panax based on morphological characteristics and sequence analysis of the internal transcribed spacer region of rDNA. A. panax isolates induced leaf spots and blight symptoms not only on D. morbifera but also on the other members of Araliaceae tested. This is the first report of foliar blight caused by A. panax on D. morbifera.

• Mycobiology
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• v.41 no.3
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• pp.167-169
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• 2013

Black spot of sweet persimmon, caused by Alternaria alternata, occurred in an orchard in Gyeongnam province, Korea in 2012. The symptom was appearance of 0.5 to 4 cm black spots on the surface of fruit. The pathogen was isolated from flesh of disease lesions. The causal agent was identified as A. alternata by morphological characteristics and sequencers of the internal transcribed spacer (ITS) 1 and ITS4 regions of rRNA. Artificial inoculation of the pathogen resulted in development of disease symptoms and the re-isolated pathogen showed characteristics of A. alternata.

• Mycobiology
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• v.42 no.4
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• pp.405-408
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• 2014

Leaf spot disease was observed in sesame (Sesamum indicum L.) during 2009 and 2010 in Korea. The pathogen was identified as Alternaria simsimi based on morphological and cultural characteristics. The morphological identification was well supported by phylogenetic analysis of the ribosomal DNA-internal transcribed spacer region. A. simsimi isolates caused spot symptoms on leaves and stems of sesame plants 2 wk after artificial inoculation, which were similar to those observed in the field. This is the first record of leaf spot disease in Korea caused by A. simsimi.