• Title, Summary, Keyword: fungicides

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Fungicide selections for control of chili pepper stem rot caused by Sclerotium rolfsii using an agar dilution method

  • Lee, Soo Min;Min, Jiyoung;Kim, Heung Tae
    • Korean Journal of Agricultural Science
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    • v.44 no.3
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    • pp.339-347
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    • 2017
  • Sclerotium rolfsii causing southern blight on numerous vegetable and fruit crops was isolated from stems of chili peppers showing wilting symptoms. The pathogen was identified by morphological observation and DNA sequencing analysis of ITS region. To select an effective fungicide for control of southern blight, we investigated the inhibition efficacy of thirty fungicides included in nine groups of fungicides with different mechanisms of action. A fungal growth inhibition assay was conducted through an agar dilution method by using mycelial discs and sclerotia of the pathogen as inoculum, respectively. When mycelial discs were used as an inoculum, several fungicides showed good inhibitory activity against the mycelial growth of S. rolfsii 12-6. All DMI fungicides tested had a good inhibition except for prochloraz which had low inhibitory effect. All strobilurin fungicides tested except for kresoxim-methyl and all SDHI fungicides tested except for boscalid and fluopyram, had a good inhibition. Also, fludioxonil, a protective fungicide and fluazinam had a good inhibitory effect. Interestingly, when sclerotia were used as an inoculum, inhibition efficacy was increased for fluopyram, a SDHI fungicide, and for some protective fungicides such as propineb, chlorothalonil, dithianon, and folpet. All the fungicides selected in this study should be tested in the field for their control activities against stem rot for practical use in chili pepper cultivation.

Selection of Effective Fungicides Against Xylogone sphaerospora, a Fungal Pathogen of Cultivated Mushroom, Ganoderma lucidum (영지 노랑병 방제에 효과적인 살균제의 선발)

  • 최경자;이종규;우성희;조광연
    • Korean Journal Plant Pathology
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    • v.14 no.5
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    • pp.491-495
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    • 1998
  • A fungal disease of the cultivated mushroom, Ganoderma lucidum, caused by Xylogone sphaerospora was epidemic throughout all cultivation areas in Korea which caused a lot of yield losses in the mushroom production. For controlling the disease, the screening of effective fungicides against the pathogenic fungus were conducted. Thirty seven commercially available fungicides were tested for their inhibitory activities on potato dextrose agar media supplemented with these fungicides at various concentrations. Twenty one fungicides significantly inhibited mycelial growth of the pathogen, Xylogone sphaerospora, but 16 fungicides had no inhibitory effect. Among these 21 fungicides, 17 fungicides also inhibited mycelial growth of Ganoderma lucidum as well, but imazalil, procymidone, triforine, and vinclozolin had no inhibitory effects. However, vinclozolin showed no inhibitory effect on mycelial growth of the mushroom even at the concentration of 50 $\mu\textrm{g}$/ml vinclozolin solution for 2 hours, and then the pathogen was inoculated. After two month-cultivation of the mushroom, over 90% of logs treated with vinclozolin without pathogen inoculation produced fruiting bodies. However, fruiting bodies were not produced form the logs inoculated with the pathogen, but not treated with vinclozolin. Fifty seven percent of logs. which were pre-treated with vinclozolin and then inoculated with the pathogen produced fruiting bodies. Based on the results, vinclozolin is effective for the control of yellow disease of the Ganoderma lucidum caused by Xylogone sphaerospora.

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After-infection Activity of Protective Fungicides against Apple White Rot

  • Lee, Dong-Hyuk;Kim, Dae-Hee;Woo, Hyun;Uhm, Jae-Youl
    • The Plant Pathology Journal
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    • v.23 no.3
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    • pp.166-173
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    • 2007
  • In a trial to select suitable fungicides for developing a spray program that can control apple white rot effectively, after-infection activities in some protective fungicides were detected. Six fungicides, mancozeb, propineb, benomyl, folpet, azoxystrobin and iminoctadine-triacetate, which had been extensively used in apple orchards, were sprayed on 12-year-old apple trees (cv. Fuji) at 15-day intervals from late May to late July. Disease incidences and infection frequencies of the fruit bagged just before and soon after each spray were examined. When the infection frequency or disease incidence of the fruit bagged after each spraying of fungicide was significantly lower than those of the fruit bagged before spraying, the fungicides appeared to confer after-infection activity. The six fungicides showed diverse activities on white rot: folpet showed after-infection activity on disease development, iminoctadine-triacetate showed after-infection activity on infection, azoxystrobin showed after-infection activity on disease development and infection, and mancozeb, propineb and benomyl showed no distinct activity. The activity of a fungicide became much higher when it was sprayed alternately with other fungicide rather than successive spraying of the same fungicide. Analysis of the properties of these protective fungicides could lead to the development of a highly effective spray program against white rot.

Chemical Control of Brown Leaf Blight in Alisma plantago Double Cropping after Early Rice

  • Shin, Jong-Sup;Kwon, Byung-Sun;Park, Hee-Jin
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.46 no.5
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    • pp.348-351
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    • 2001
  • This study was conducted to evaluate the control effect of fungicides on control of brown leaf blight, growth characteristics, and dry root yield in the cultivation of Alisma plantago after early maturing rice cropping. All fungicides treated had no effect on the growth and flowering rate of Alisma plantago. The major fungicides were mancozeb Wp, 75%, chlorothalonil Wp, 75%, dithianon Wp, 43%, difenoconazole Wp, 10%, benomyl Wp, 50%, and propineb Wp, 70%. Dry root of yield were increased largely with chlorothalonil Wp, 75%(33 g/20), fungicide than the other fungicides and control. All fungicides had no injury with standard dosage. On the other hand all fungicides had slight injury in the double dosage level for the Alisma plantago.

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Chemical Control of Gray Blight of Tea in Korea

  • Shin, Gil-Ho;Hur, Jae-Seoun;Koh, Young-Jin
    • The Plant Pathology Journal
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    • v.16 no.3
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    • pp.162-165
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    • 2000
  • Screening of effective fungicides, determination of effective fungicide application time and investigation of the emergence of resistant isolates to fungicides were conducted to establish effective chemical control strategy of gray blight of tea (Camellia sinensis) in Korea. Systemic fungicides, such as bitertanol, were effective for controlling gray blight when the fungicides were sprayed within 3 days after cutting tea leaves for harvest. Sprayed immediately after cutting, contact fungicides such as chlorothalonil were also effective, but control efficacy rapidly decreased with lengthening of the intervals between cutting and spraying. Korean isolates of P. longiseta and P. theae were still sensitive to bitertanol or fluazinam. However, the isolates highly insensitive to copper hydroxide or thiophanate-methyl have already emerged in Korea. Therefore, careful attention should be paid to use of fungicides and spraying programs for the effective control of gray blight of tea in Korea.

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Effects of Organophosphorus Fungicides on Cutinase Activity and Infection of Apple by Glomerella cingulata (사과 탄저병균 Glomerella cingulata에 의한 감염과 Cutinase의 활성에 미치는 유기인계 살균제의 효과)

  • 김기홍;이창은
    • Korean Journal Plant Pathology
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    • v.10 no.2
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    • pp.119-122
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    • 1994
  • Effects of organophosphorus fungicides on cutinase activity from Glomerella cingulata causing apple anthracnose and infection of apple were investigated. Diisoprophylfluorophosphate (DFP) inhibited the enzyme activity indicating that catalysis involves an active serine. In inhibition of the enzyme activity by organophosphorus fungicides, I50 (molar concentration of fungicide at which the enzyme activity is inhibited 50%) of Hinosan and Kitazin P were 26.3 $\mu$M and 427.7 $\mu$M, respectively. At concentration of 10-3 M DFP and organophosphorus fungicides, the infection of G. cingulata was inhibited to 5% in comparison with 15% infection at the unwounded healthy control, but increased to 30% when added with 1 mg/ml of cutinase. Mycelial growth was 36 mm in colony diameter on the medium added with 10-4M of hinosan in comparison with 90 mm of the untreated control, but was 90 mm on the medium added with 10-4M of kitazin P showing lower inhibition than hinosan. The spore germination was more than 60% at all the concentrations of both fungicides.

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Chemical Control of Sclerotinia rot in Rapeseed Double Cropping after Rice

  • Sun Kwon-Byung;Lim June-Taeg;Jung Dong-Soo;Shin Jong-Sup
    • Korean Journal of Plant Resources
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    • v.19 no.3
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    • pp.392-396
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    • 2006
  • This study was conducted to evaluate the control effect of fungicides of sclerotinia rot control, growth characteristics, and seed yield in the cultivation of rapeseed. All fungicides treated had no effect on the growth of rapeseed. The major fungicides were mancozeb 75% WP, chlorothalonil 75% WP, dithianon 43% WP. difenoconazole 10% WP, benomyl 50% WP, and propineb 70% WP. Dry seed yield and control were increased largely with chlorothalonil 75% WP ($33g/12{\ell}$), fungicide than the other fungicides Sclerotinia rot. All fungicides had no injury with standard dosage. On the other hand all fungicides had slight injury in the double dosage level for the rapeseed.

Selecting of Useful Chemicals Reducing of Leaf Blight on Job's Tears (Coix lachry-ma-jobi L. Var.)

  • Kwon, Byung-Sun
    • Plant Resources
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    • v.8 no.2
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    • pp.161-166
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    • 2005
  • This study was conducted evaluate the control effect of fungicides on control of Leaf blight, growth characteristics, and dry yield in the cultivation of Job's tears. All fungicides treated had no effect on the growth of Job's tears. The major fungicides were mancozeb Wp, $75\%$, chlorothalonil Wp, $75\%$, dithianon Wp, $43\%$, difenoconazole Wp, $10\%$, benomyl Wp, $50\%$, and propineb Wp, $70\%$. Dry seed yield were increased largely with chlorothalonil Wp, $75\%\;(33g/20\ell)$, fungicide than the other fungicides and control. All fungicides had no injury with standard dosage. On the other hand all fungicides had slight injury in the double dosage level for the Job's tears.

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Triazole Fungicides Sensitivity of Sclerotinia homoeocarpa in Korean Golf Courses

  • Lee, Ji Won;Choi, Jihye;Kim, Jin-Won
    • The Plant Pathology Journal
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    • v.33 no.6
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    • pp.589-596
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    • 2017
  • Chemical management of dollar spot in turf may lead to the development of Sclerotinia homoeocarpa populations with reduced fungicide sensitivity. The objective of this study was to investigate resistance of S. homoeocarpa isolates to triazole fungicides and to test cross-resistance among three triazole fungicides. A total of 66 isolates of S. homoeocarpa were collected from 15 golf courses across Korea, and tested via in vitro sensitivity assay against hexaconazole, propiconazole and tebuconazole. $EC_{50}$ values of the isolates to these fungicides were distributed in the range of $0.001-1.1\;a.\;i.\;{\mu}g\;ml^{-1}$. Based on the $EC_{50}$ values, twelve representative strains were selected as sensitive isolates including control and insensitive isolates with respect to each fungicide. At a concentration of $0.1\;a.\;i.\;{\mu}g\;ml^{-1}$ for all fungicides, the selected strains were distinguished as sensitive or resistant isolates with the mycelial growth inhibition rate of 50% as the criterion. The $EC_{50}$ values of resistant strains exposed to hexaconazole, propiconazole and tebuconazole were 20-50 times, 50-70 times, and 77 times greater, respectively, than that of the control strains. Two isolates of S. homoeocarpa S0-41 and Sh14-2-1 showed sensitivity toward all the fungicides used, while two other isolates Sh7-5-1 and Sh2-1-1 showed resistance to all fungicides. Each isolate showed similar resistance to the three types of triazole fungicides, whereby cross-resistance of isolates was confirmed in the present study; all three triazole fungicide combinations displayed significant correlation coefficients equivalent to or greater than 0.8.

Synergistic Interactions Between Chitinase ChiCW and Fungicides Against Plant Fungal Pathogens

  • Huang, Chien-Jui;Chen, Chao-Ying
    • Journal of Microbiology and Biotechnology
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    • v.18 no.4
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    • pp.784-787
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    • 2008
  • Antifungal activity of ChiCW and synergistic interactions between ChiCW with fungicides were investigated. Conidial germinations of phytopathogenic fungi, Alternaria brassicicola, Botrytis elliptica, and Colletotrichum gloeosporioides, were inhibited by ChiCW but A. longipes was not. In addition, ChiCW showed synergistic effect with fungicides Switch (cyprodinil+fludioxonil) and tebuconazole to inhibit fungal conidial germinations. The level of synergism of ChiCW with tebuconazole was higher than that with Switch. The results indicate that ChiCW may exhibit a higher level of synergism with fungicides that have a primary effect upon membranes.