• Title/Summary/Keyword: Alternaria

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Effect of Apple Leaf Hair Density on the Occurrence and Infection of Alternaria Leaf Spot Caused by Alternaria mali Roberts (모용(毛茸)이 사과나무 반점낙엽병(斑點落葉病) 발생(發生)과 병원균(病原菌)의 감염(感染)에 미치는 영향(影響))

  • Yoon, J.T.;Lee, J.T.
    • Korean journal of applied entomology
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    • v.26 no.4 s.73
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    • pp.245-249
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    • 1987
  • In the 82 apple varieties tested, the distribution of varieties grouped on the damage degree to Alternaria leaf spot were 15 varieties(l8.3%), which damaged above 50%, and 51 varieties(62.2%) damaged below 5%. Susceptible varieties to Alternaria leaf spot were Raritan, Indo, Winesap and Starkrimson, moderately resistant varieties Sekaiichi and Starking, and resistant Jonathan, Tsugaru, Molliies, Jonagold, Gala etc. The leaf hair density on the backside of leaf were rarer inresistant varieties than susceptible one. In inoculation test, penetration and infection of Alternaria mali were easier on the backside than surface of apple leaf at the same varity, and infection rate with Alternaria mali were higher at removal treatment than non-removal one of leaf hairs, so we can guess that leaf hair are related to resistance of variety to Alternaria mali.

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Effect of Calcium on the Apple Varieties Resistance to Alternaria Leaf Spot and Mycelial Growth of Alternaria mali Roberts (Ca물질(物質)이 사과나무 반점낙엽병(斑點落葉病) 발생(發生) 및 병원균(病原菌)의 균사생육(菌絲生育)에 미치는 영향(影響))

  • Yoon, J.T.;Lee, J.T.
    • Korean journal of applied entomology
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    • v.26 no.4 s.73
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    • pp.239-244
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    • 1987
  • This studies was carried out to find the effect of inorganic matters of Apple Leaves on the occurrence of Alternaria leaf spot and calicium compounds on mycelial growth of Alternaria mali. Diseased leaf rate of Alternaria leaf spot of susceptible apple varieties was 84.8%, moderate resistant 8.1% and resistant 0.3% respectively and in No. of lesion per leaf, the tendency was same. CaO contents of apple leaves was contained much in the resistant varieties than susceptible one. It was estimated that calcium is one of factors on resistance to apple leaf spot by the results of relations among CaO contents and diseased leaf rate from July to August and No. of lesion per leaf was correlated significantly as r=-0.551, r=-0.585, -0.485 but in T-N, $P_2O_5,\;K_2O,\;MgO,\;Na_2O$, there was no difference among varieties. Then, growth of Alternaria mali was possible in the media of which pH ranged up to $11{\sim}13$, and calcium has effect of inhibition on growth of Alternaria mali.

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Alternaria Leaf Spot Caused by Alternaria mali on Black Chokeberry in Korea (Alternaria mali에 의한 아로니아 점무늬낙엽병)

  • Hahm, Soo-Sang;Kwon, Mi-Kyung;Kim, Byung-Ryun;Han, Kwang-Seop;Nam, Yun-Gyu
    • Research in Plant Disease
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    • v.22 no.1
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    • pp.50-54
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    • 2016
  • In early June 2014, leaf spot symptoms were observed on black chokeberry (Aronia melanocarpa) in Yesan-gun and Geumsan-gun, Chungcheongnam-do in Korea. The initial symptoms on leave surfaces were brown small-circular spots with a yellow halo lesion, and gradually the small spots were fused, all of infected leaves dropped eventually. A fungus were isolated from the initial lesion, and cultured on potato dextrose agar. Colony color on upper surface of plate varied from olive gray to charcoal gray. Size of conidia mostly extend to $19-50{\times}5-9{\mu}m$ in nature and $20-59{\times}8-13{\mu}m$ in culture, with 3-8 transverse septa and usually no longitudinal septum or only 1 longitudinal septum in 1-3 of the transverse compartments, and also have a short or long beak. Pathogenicity was investigated using wounded or unwounded black chokeberry and apple leaves. After 7 days of inoculation, leaf spots were similar to the symptoms naturally occurred in the field. On the basis of mycological characteristics, pathogenicity, and ITS rDNA sequence analysis, this fungus was identified as Alternaria mali. This is the first report of Alternaria leaf spot on black chokeberry caused by A. mali in Korea.

Brown Ring Spot on Leaves of Kiwifruit Caused by Alternaria alternata (Alternaria alternata에 의한 참다래 갈색둥근무늬병)

  • Jeong, In-Ho;Kim, Gyung-Hee;Lim, Myoung-Taek;Hur, Jae-Seoun;Shin, Jong-Sup;Koh, Young-Jin
    • Research in Plant Disease
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    • v.14 no.1
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    • pp.68-70
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    • 2008
  • Brown leaf spots on leaves of kiwifruit(Actinidia deliciosa) were observed at farmers' orchards in Suncheon and Goheung, Jeonnam Province, Korea in June, 2006. They developed to form dark brown ring spots and severely infected leaves resulted in defoliation during the growing season of kiwifruit. Alternaria sp. was isolated from the diseased leaves repeatedly and was identified as Alternaria alternata on the basis of its mycological characteristics on potato dextrose agar and its pathogenicity was confirmed by wound inoculation on healthy leaves of kiwifruit. A. alternata formed gray to dark sooty gray colony and produced numerous conidia on potato dextrose agar. The conidia, commonly in long chains of 5 or more produced on conidiophores, have $3{\sim}5$ transverse and $1{\sim}2$ longitudinal septa and mostly ovoid or obclavate in shape and were pale brown golden brown in color. The condia were $16.5{\sim}42.1{\times}6.7{\sim}19.5\;{\mu}m$ in size and conidiophores were $8.6{\sim}112.7\;{\mu}m$ in length. This is the first report on the brown ring spot on leaves of kiwifruit caused by A. alternata in Korea.

Studies on the Pear Abnormal Leaf Spot Disease - 2. Identification of Causal Agent - (배나무잎 이상반점증상에 관한 연구 - 2. 원인구명 -)

  • 남기웅;김충회
    • Korean Journal Plant Pathology
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    • v.11 no.3
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    • pp.210-216
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    • 1995
  • Alternaria spp.were predominantly isolated from the abnormal leaf spot lesions of pear cultivars Niitaka and Nijiiseiki. Alternaria isolates from the cultivar Niitaka were not pathogenic to both cultivars, but the isolates from the cultivar Nijiiseiki developed typical lesions of black leaf spots and were identified as A. kikuchiana. However, no typical abnormal leaf spot lesions were produced by the Alternaria isolates. Foliar spray of twelve different agrochemicals including lime sulfur, either alone or in combinations, with 7 times applications from April to July failed to reduced the disease development. Application of 17 different pesticides including fungicides, insecticides and herbicides currently used in pear orchards did not cause leaf injury similar to the abnormal leaf spot. Simulated acid rain of as low as pH 3.0 did not incite any leaf lesions alike the abnormal spot lesions. Mineral contents in the leaves of both cultivars did not differ significantly between the healthy leaves and those with abnormal leaf spots. When cuttings of pear tree were obtained in February from newly emerged twigs of the healthy or the diseased trees of Niitaka and planted in sand in the greenhouse, only those from the diseased trees developed typical leaf lesions of the abnormal spot. These results indicate that abnormal leaf spots are caused by unknown systemic agents in pear trees, rather than by Alternaria spp., chemical injury or acid rain.

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Detection of Alternaria spp. in Carrot Seeds and Effect of the Fungi on Seed Germination and Seedling Growth of Carrot

  • Kim, Wan-Gyu;MatHur, Suaresh-Behari
    • The Plant Pathology Journal
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    • v.22 no.1
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    • pp.11-15
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    • 2006
  • Five seed samples of carrot were tested to detect Alternaria spp. by blotter method. A. alternata and A. radicina were detected from all the seed samples as high as $25.8-70.5\%$ and $37.5-63.5\%$, respectively. A. dauci was detected from four seed samples as low as $0.5-7.5\%$. The three Alternaria spp. were detected from the pericarp and the seed coat and endosperm of the carrot seeds but not from the embryo by component plating test. A. alternata and A. radicina were much more detected from the pericarp than the seed coat and endosperm. A. dauci was detected from the pericarp and the seed coat and endosperm at similar rate. The seed sample which was most severely infected with A. radicina showed the lowest rate of germination in the test on top of paper (TP). In the TP test, differences in total infection rate of A. radicina and A. dauci of the seed samples were very closely correlated with those in incidence of seedling rot on the seed samples. However, there was no correlation between infection rate of A. alternata and rate of germination or seedling rot of the seed samples. Soil test for seedling growth revealed that there was no correlation between differences in total infection rate of A. radicina and A. dauci and those in rate of normal seedlings of the seed samples.

Occurrence of Leaf Spot Disease Caused by Alternaria crassa (Sacc.) Rands on Jimson Weed and Potential Additional Host Plants in Algeria

  • Bessadat, Nabahat;Hamon, Bruno;Bataille-Simoneau, Nelly;Chateau, Corentin;Mabrouk, Kihal;Simoneau, Philippe
    • The Plant Pathology Journal
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    • v.36 no.2
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    • pp.179-184
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    • 2020
  • A leaf spot pathogen Alternaria sp. was recovered from jimson weed, tomato, parsley, and coriander collected during surveys of blight diseases on Solanaceae and Apiaceae in Algeria. This species produced large conidial body generating long apical beaks that tapered gradually from a wide base to a narrow tip and short conidiophores originating directly from the agar surface. This species exhibited morphological traits similar to that reported for Alternaria crassa. The identification of seven strains from different hosts was confirmed by sequence analyses at the glyceraldehyde-3-phosphate dehydrogenase, RNA polymerase second largest subunit, and translation elongation factor 1-alpha loci. Further the pathogen was evaluated on jimson weed, coriander, parsley, and tomato plants, and this fungus was able to cause necrotic lesions on all inoculated plants. A. crassa is reported for the first time as a new species of the Algerian mycoflora and as a new potential pathogen for cultivated hosts.

Altering Conidial Dispersal of Alternaria solani by Modifying Microclimate in Tomato Crop Canopy

  • Jambhulkar, Prashant Prakash;Jambhulkar, Nitiprasad;Meghwal, Madanlal;Ameta, Gauri Shankar
    • The Plant Pathology Journal
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    • v.32 no.6
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    • pp.508-518
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    • 2016
  • Early blight of tomato caused by Alternaria solani, is responsible for severe yield losses in tomato. The conidia survive on soil surface and old dry lower leaves of the plant and spread when suitable climatic conditions are available. Macroclimatic study reveals that highest inoculum concentration of Alternaria spores appeared in May 2012 to 2013 and lowest concentration during January 2012 to 2013. High night temperature positively correlated and significantly (P < 0.01) involved in conidial spore dispersal and low relative humidity (RH) displayed significant (P < 0.05) but negative correlation with conidial dispersal. The objective of the study was to modify microclimatic conditions of tomato crop canopy which may hamper conidial dispersal and reduce disease severity. We evaluated effect of marigold intercropping and plastic mulching singly and in consortia on A. solani conidial density, tomato leaf damage and microclimatic parameters as compar to tomato alone (T). Tomato-marigold intercropping-plastic mulching treatment (T + M + P) showed 35-39% reduction in disease intensity as compared to tomato alone. When intercropped with tomato, marigold served as barrier to conidial movement and plastic mulching prevented evapotranspiration and reduced the canopy RH that resulted in less germination of A. solani spores. Marigold intercropping and plastic mulching served successfully as physical barrier against conidial dissemination to diminish significantly the tomato foliar damage produced by A. solani.

Detection of Seed Born Fungi from the Imported Seed and Effect of Fungicide for Them (수입종자에서의 병원균분리와 약제처리효과)

  • Um Kyung Ho;Sung Jae Mo;Jo Wan Kee;Yu Ki-Yull
    • Korean journal of applied entomology
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    • v.22 no.4 s.57
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    • pp.307-313
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    • 1983
  • Twenty-five species of fungi were deleted and identified from 27 kinds of the intercepted seeds from 5 countries. Eight species of fungi including Fusariun moniliforme were detected from the imported calabash seed (Lagenaria siceraria). These seeds were the most contaminated among the intercepted reeds tested. Six kinds of seeds including larch(Larix kaemferi) were disinfected with Vitathiram, Benlate-T and Captan. Rhynchosporium was detected from seeds treated with Vitathiram whereas Alternaria spp. were detected from seeds treated with Benlate T or Captan. Six genera of fungi were detected from the untreated seeds. In the case of germination, it seem that seed disinfectants do not have any damage on germination of seed.

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