• 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.

• 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.

• 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.

• The Plant Pathology Journal
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• v.37 no.4
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• pp.329-338
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• 2021

Alternaria leaf blight is one of the most common diseases in watermelon worldwide. In Korea, however, the Alternaria species causing the watermelon leaf blight have not been investigated thoroughly. A total of 16 Alternaria isolates was recovered from diseased watermelon leaves with leaf blight symptoms, which were collected from 14 fields in Korea. Analysis of internal transcribed spacer (ITS) region, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and RNA polymerase II second largest subunit (RPB2) were not competent to differentiate the Alternaria isolates. On the contrary, analysis of amplicon size of the histone H3 (HIS3) gene successfully differentiated the isolates into three Alternaria subgroups, and further sequence analysis of them identified three Alternaria spp. Alternaria tenuissima, A. gaisen, and A. alternata. Representative Alternaria isolates from three species induced dark brown leaf spot lesions on detached watermelon leaves, indicating that A. tenuissima, A. gaisen, and A. alternata are all causal agents of Alternaria leaf blight. Our results indicate that the Alternaria species associated watermelon leaf blight in Korea is more complex than reported previously. This is the first report regarding the population structure of Alternaria species causing watermelon leaf blight in Korea.

• Mycobiology
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• v.44 no.3
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• pp.187-190
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• 2016

In July 2015, diseased leaves of black chokeberry (Aronia melanocarpa) were observed in Danyang and Gochang, Korea. The symptoms appeared as circular or irregular brown leaf spots, from which Alternaria tenuissima was isolated. The isolates were cultured on potato dextrose agar, and their morphological characteristics were observed under a light microscope. The colonies were whitish to ash colored. The pathogenicity test on healthy black chokeberry leaves produced circular brown spots, in line with the original symptoms. Molecular analyses of the ITS, GPD, RPB2, and TEF genes were conducted to confirm the identity of the pathogen. The phylogeny of the multi-gene sequences indicated that the causal agent was A. tenuissima. This study is the first report of A. tenuissima leaf spot on black chokeberry (A. melanocarpa).

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.1
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• pp.1-5
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• 2010

The studies have been conducted to control the soil borne fungal pathogens viz, Fusarium solani (Mart) Sacc. and Alternaria tenuissima the incitants of root rot and die-back diseases on mulberry stem cuttings planted in the mulberry nurseries and also in established mulberry gardens ten plant extracts with 10% concentration except Lantana camara (undiluted) were tested through poisoned food technique and four biofungicides were also screened by dual culture method under in vitro conditions. Plant extract of Prosopis juliflora showed the maximum inhibition on the mycelial growth (81.2% over A. tenuissima and 80.0% over F. solani) and followed by L. camara (66.7% over A. tenuissima and 68.9% over F. solani). Among the antagonists Pseudomonas fluorescens and Trichoderma viride showed maximum inhibition on the mycelial growth of both pathogenic fungi. The promising plant extracts (P. juliflora and L. camara) and antagonists (P. fluorescens and T. viride) were tested against both the pathogenic fungi under in vivo conditions along with the existing popular chemical Mancozeb. All the tested plant products and bio-fungicides showed inhibitory effect on both fungi. But the maximum survival percentage of mulberry cuttings was recorded in the treatment with T. viride (95% against F. solani and 90% against A. tenuisssima) followed by P. fluorescens (90% against both fungi) and T. harzianum (80% against F. solani and 85% against A. tenuisssima). Incase of the treatments with plant extracts and chemical fungicide the P. juliflora (60% against F. solani and 55% against A. tenuisssima) showed higher survival percentage and followed by L. camara (55% against F. solani and 50% against A. tenuisssima) and Mancozeb (55% against both fungi). In case of control only 10% of survival was recorded in F. solani inoculated cuttings and 15% survival in A. tenuissima inoculated cuttings.

• Mycobiology
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• v.43 no.2
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• pp.93-106
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• 2015

Alternaria species are common saprophytes or pathogens of a wide range of plants pre- and post-harvest. This review considers the relative importance of Alternaria species, their ecology, competitiveness, production of mycotoxins and the prevalence of the predominant mycotoxins in different food products. The available toxicity data on these toxins and the potential future impacts of Alternaria species and their toxicity in food products pre- and post-harvest are discussed. The growth of Alternaria species is influenced by interacting abiotic factors, especially water activity ($a_w$), temperature and pH. The boundary conditions which allow growth and toxin production have been identified in relation to different matrices including cereal grain, sorghum, cottonseed, tomato, and soya beans. The competitiveness of Alternaria species is related to their water stress tolerance, hydrolytic enzyme production and ability to produce mycotoxins. The relationship between A. tenuissima and other phyllosphere fungi has been examined and the relative competitiveness determined using both an Index of Dominance ($I_D$) and the Niche Overlap Index (NOI) based on carbon-utilisation patterns. The toxicology of some of the Alternaria mycotoxins have been studied; however, some data are still lacking. The isolation of Alternaria toxins in different food products including processed products is reviewed. The future implications of Alternaria colonization/infection and the role of their mycotoxins in food production chains pre- and post-harvest are discussed.

• Korean Journal of Plant Resources
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• v.30 no.4
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• pp.343-351
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• 2017

Plant extracts were screened for antifungal activity against major plant pathogens, Botrytis sp., Collectotrichum sp., Alternaria sp. and Cylindrocarpon sp. using 96-well microdilution method. Among the 662 methanol extracts from 401 plant species, 36 extracts showed complete inhibition of spore germination against at least one of four pathogenic fungi. Extracts of Morus alba twig and Sophora flavescens root showed minimum inhibition concentration (MIC) at $1,250{\mu}g/ml$ against Botrytis sp.. Extracts of Chloranthus japonicus root showed MIC at $1,250{\mu}g/ml$ against Collectotrichum sp.. Extracts of Glycyrrhiza uralensis aerial part, Inula helenium root and Menispermum dauricum root showed MIC between 625 and $1,250{\mu}g/ml$ against Alternaria sp.. G. uralensis aerial part and I. helenium root showed MIC at $1,250{\mu}g/ml$ against Cylindrocarpon sp.. Specifically, the extracts of Agrimonia pilosa root, Angelica tenuissima root, Asarum sieboldii root, Campsis grandifolia leaf and twig, Cnidium officinale root, Dictamnus dasycarpus root, G. uralensis aerial part, I. helenium root and M. alba twig completely inhibited spore germination at lower than $5,000{\mu}g/ml$ against all of four pathogenic fungi. Two methanol extracts from G. uralensis aerial part and M. alba twig may used as a candidate to develop into effective disease management materials in plant cultivation.

• Mycobiology
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• v.28 no.4
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• pp.185-189
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• 2000

The antifungal activity of methanolic extracts of Centella asiatica and Andrographis paniculata leaves was observed against fourteen fungi, viz., Alternaria alternata, A. brassicae, A. brassicicola, A. solani, A. tenuissima, Cercospora blumae, Curvularia lunata, C. penniseti, and Drechslera monoceras, D. oryzae, D. turitica, Fusarium albizziae and F. udum. Different concentrations of the methanolic extract (1000, 2000, 3000, 5000, 7000, 10000ppm) were used. The effect of mixed leaf extract (1500 ppm of C. asiatica + 1500 ppm of A. paniculata) and its 1:2 ad 1:4 dilutions were also studied. The individual extracts of both the plants showed significant inhibitory effect on spore germination of all the fungi tested. F. udum, F. albizzae, D. oryzae, D. turtica, and D. monoceras were particularly sensitive to these extracts. In general, the extract of C. asiatica showed a higher inhibitory effect in all concentrations against all the fungi as compared to A. paniculata, except for A. brassicae A. solani, D. oryzae, D. penniseti and Curvularia sp. The inhibitory effect of extracts increased when they were used in combination with or without dilutions against A. brassicicola, A. solani A. brassicae, A. alternata, A. tenussima, C. blumae, C. lunata, C. penniseti and Curvularia species. Higher efficacy of active ingredient of these extracts under field condition is envisaged against plant pathogens.

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.221-228
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• 2018

BACKGROUND: Spoilage fungi can reduce the shelf life of fresh fruits and cause economic losses by lowering quality. Especially, mulberry fruits have high sensitivity to fungal attack due to their high water content (> 70%) and soft texture. In addition, the surface of these fruits is prone to damage during harvesting and postharvest handling. However, any study on postharvest spoilage fungi in mulberry fruit has not been reported in Korea. This study aimed to examine the spoilage fungi occurring in mulberry fruits during storage after harvest. METHODS AND RESULTS: In this study, we isolated postharvest spoilage fungi from mulberry fruits stored in refrigerator (fresh fruits) and deep-freezer (frozen fruits) and identified them. In the phylogenetic analysis based on comparisons of the ITS rDNA sequences, the 18 spoilage fungi isolated from mulberry fruits and the 25 reference sequences were largely divided into seven groups that were subsequently verified by high bootstrap analysis of 73 to 100. Alternaria spp. including A. alternate and A. tenuissima, were the most frequently isolated fungi among the spoilage isolates: its occurrence was the highest among the 18 isolates (38.9%). CONCLUSION: The findings of this study will be helpful for increasing the shelf life of mulberry fruits through the application of appropriate control measures against infection by spoilage fungi during storage.