• Title/Summary/Keyword: Helminthosporium leaf spot disease

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Environmental Factor Analysis of Helminthosporium-Leaf-Spot-Disease Occurrence in Rice (벼 깨씨무늬병 발생의 환경요인 분석)

  • Won Jong-Gun;Seo Young-Jin;Choi Jang-Soo;Kim Seung-Han;Kim Jong-Soo;Yoon Jae-Tak
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.51 no.3
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    • pp.199-203
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    • 2006
  • In the late growth stage of rice plant, the growth declines even though they grow well in early growth stage. This phenomenon is called autumn declining and it often accompanies the infection of Helminthosporium leaf spot disease. This study was carried out to identify the related environmental factors and to establish the integrated control system of Helminthosporium Leaf Spot Disease in rice. The total area of infected paddy field by Helminthosporium leaf spot was 470 ha in 2000 and 1,004 ha in 2001, which occupied about 1% of the total paddy area in Gyeongbuk province, Korea. The ill-drained sandy paddy occupied 50% of the total area of infected paddy fields and followed by sandy paddy (28%). Comparing the content of soil elements between infected and normal paddy, it was clarified that the organic matter content of normal was higher than that of infected paddy and the contents of inorganic elements such as Mn, Fe, Zn and available $SiO_2$ were also higher in normal paddy. The results of comparing the inorganic elements between infected and normal rice plants also showed the same results. The contents of inorganic elements such as MgO, $SiO_2$, Fe, Mn were higher in normal rice plants. Especially highly significant difference of $SiO_2$ content on both soil and rice plants was noticeable.

수도호마엽고병이병(水稻胡麻葉枯病罹病)과 수도건전엽중(水稻健全葉中)의 무기성분(無機成分)에 관(關)하여

  • Park, Yeong-Dae;Kim, Yeong-Seop;Kim, Mu-Gyeom
    • Applied Biological Chemistry
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    • v.5
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    • pp.49-51
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    • 1964
  • Results obtained from Leaves and soils may be summarized as follow; It was found that the rice plant which grown under the deficiency of silica, manganese and magnesium become very susceptible to Helminthosporium leaf spot, as compared with that grown under normal condition. While no close correlation was found in nitrogen, phosporus and potassium between the health and disease. On the other hand, reducible manganese content of normal paddy soils is also 13.2 times as high as that of diseased paddy soils (Akioch soil) Considering from the results, it seems to have certain relationship between resistance to Helminthosporium and unbalance of inorganic elements in rice blade.

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Occurrence of Diseases and Insects in Organic Sweet Corn Seed Production Area (유기농 찰옥수수종자 생산지의 병해충 발생 소장)

  • Kim, Jeong-Soon;Goh, Byeong-Dae;Gwag, Jae-Gyun;Lee, Myung-Chul;Kim, Chang-Yung;Kim, Chung-Kon;Shim, Chang-Ki
    • Korean Journal of Organic Agriculture
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    • v.18 no.1
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    • pp.93-104
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    • 2010
  • This study was conducted screening of the population densities of fungal pathogens and insect and observed the disease symptoms on the organic sweet corn seed producing field from 2008 to 2009. The dissemination spores, Alternaria sp., Cladosporium sp., Helminthosporium sp., Pyricularia sp., Collectotrichum sp., and Bipolaris sp., were detected and the three fungal spores from the front were observed for whole growth stage. Seed and seedling diseases were shown as the rotted seed and damping-off seedling caused by Penicillium sp. and Rhizoctonia sp.. The larva of Black cutworm cut down the root crown of seedlings. The damaged plants were ranged from 14% to 16%. On the Oriental corn borer, the population densities and the percentage of damaged plants were showed a low difference between two sweet corn varieties. The population densities of Oriental corn borer were scored as from 3.5 to 20.5 in 2008 and from 0.5 to 6 in 2009. Also the percentage of damaged plants were significantly increased until harvesting stage and was recorded from 7.5% to 21% in 2008 and from 1% to 46% in 2009. On the Corn leaf blight, the percentage of diseased plant were scored from 7% to 34% in 2008. The first occurrence of date was after June 18, and the percentage of diseased plant was continuously increased after August 21 and the values of diseased plants was ranged from 56% to 69% in 2009. On common smut, the percentage of diseased plant was recorded from 5% to 15% in 2008, and the first occurrence date were delayed as 17 days (July 17) and were showed less than 8% of diseased plants in 2009. Corn Southern Leaf spot was scored as average 11% at early stage and showed high score as 62% at September 19 in 2008. In 2009, the first occurrence date were advanced about 20 days (after June 8), and continuously increased up to 86% in 2009.