• The Plant Pathology Journal
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• 제31권2호
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• pp.115-122
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• 2015

Anthracnose, caused by Colletotrichum gloeosporioides (C. gloeosporioides; Teleomorph: Glomerella cingulata), is the most destructive disease that affects sweet persimmon production worldwide. However, the biology, ecology, and genetic variations of C. gloeosporioides remain largely unknown. Therefore, in this study, the development of fungicide resistance and genetic diversity among an anthracnose pathogen population with different geographical origins and the exposure of this population to different cultivation strategies were investigated. A total of 150 pathogen isolates were tested in fungicide sensitivity assays. Five of the tested fungicides suppressed mycelial pathogen growth effectively. However, there were significant differences in the sensitivities exhibited by the pathogen isolates examined. Interestingly, the isolates obtained from practical management orchards versus organic cultivation orchards showed no differences in sensitivity to the same fungicide. PCR-restriction fragment length polymorphism (RFLP) analyses were performed to detect internal transcribed spacer regions and the ${\beta}$-tubulin and glutamine synthetase genes of the pathogens examined. Both the glutamine synthetase and ${\beta}$-tubulin genes contained a complex set of polymorphisms. Based on these results, the pathogens isolated from organic cultivation orchards were found to have more diversity than the isolates obtained from the practical management orchards.

• The Plant Pathology Journal
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• 제33권2호
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• pp.118-124
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• 2017

Bell pepper is an economically important crop worldwide; however, production is restricted by a number of fungal diseases that cause significant yield loss. Chemical control is the most common approach adopted by growers to manage a number of these diseases. Monitoring for the development to resistance to fungicides in pathogenic fungal populations is central to devising integrated pest management strategies. Two fungal species, Fusarium incarnatum-equiseti species complex (FIESC) and Colletotrichum truncatum are important pathogens of bell pepper in Trinidad. This study was carried out to determine the sensitivity of 71 isolates belonging to these two fungal species to fungicides with different modes of action based on in vitro bioassays. There was no significant difference in log effective concentration required to achieve 50% colony growth inhibition ($LogEC_{50}$) values when field location and fungicide were considered for each species separately based on ANOVA analyses. However, the $LogEC_{50}$ value for the Aranguez-Antracol locationfungicide combination was almost twice the value for the Maloney/Macoya-Antracol location-fungicide combination regardless of fungal species. $LogEC_{50}$ values for Benomyl fungicide was also higher for C. truncatum isolates than for FIESC isolates and for any other fungicide. Cropping practices in these locations may explain the fungicide sensitivity data obtained.

• 한국식물병리학회지
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• 제10권4호
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• pp.297-304
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• 1994

This study was carried out to develop bioassay for detection of pesticide residues in agricultural products by using the soil microbial isolates sensitive to pesticides. One hundred bacterial isolates and eighty five fungal isolates were obtained from soil and their sensitivity to 10 ppm of several pesticides was examined in vitro. Five bacterial isolates and three fungal isolates were found sensitive to organochloride fungicide and two fungal isolates sensitive to organocopper fungicide. Among these isolates, B46, B93 and F67 were tested to find out the difference in sensitivity according to the methods of fungicide treatment. All of the isolates were found sensitive to 10 ppm of organochloride fungicides mixed directly in PDA. But they were found insensitive to the fungicide mixed in PDA after filtering through membrane filter. In case of organocopper fungicide, the isolates were found sensitive only when it was treated in PDA. And their sensitivity showed difference among various kinds of organochloride fungicides. B46 and B93 were employed to check the possibility as the agent for detection of the pesticidal residues in twenty eight agricultural products including rice. It was found that all samples had not residues because the samples did not inhibit the growth of isolates. When organochloride fungicides were applied to the above products, it was possible to detect the residues in fruits and vegetables at the concentration of 10 ppm, but not in starch-rich grains. B46 and B93 were identified as Bacillus sp. according to their bacterial characteristics in culture.

• 농약과학회지
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• 제4권2호
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• pp.1-10
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• 2000

국내 살균제 저항성 연구는 아직 초보적 수준으로 대부분의 연구가 실내에서의 살균제 저항성 균주의 검출보고에 국한하고 있다. 향후 살균제 저항성연구는 포장에서 대상 병원균 집단의 살균제에 대한 감수성 분포를 근거로 하여 그 살균제에 대한 저항성을 판별하는 기준 농도를 설정한 후 병원균주의 저항성 여부가 판정되어야 한다. 국내의 대부분의 연구가 이점을 간과하고 있기 때문에 연구자간에 저항성 기준에 차이가 있어 병원균 집단의 약제에 대한 감수성 변화를 추적하거나 해석하는데 많은 문제점이 있었다. 실내시험에서 검출된 살균제 저항성은 포장에서 감수성 및 저항성 균을 대상으로 방제효과를 조사한 후 그 저항성을 실증할 수 있어야 한다. 살균제 저항성은 실제로 농가포장에서의 약재 방제효율의 저하와 연관되어야 비로서 실용적인 의미를 갖기 때문이다. 저항성 균주에 대한 기생적 적응력의 조사는 병원균집단내의 저항성 균주들의 생존력이나 안정성을 검정하기 위하여 반드시 필요하다. 또한 살균제 저항성에 대한 장.단기적 대책을 강구하기 위하여 병원균 집단의 특정 살균제에 대한 감수성의 변화가 그 살균제를 사용하고 있거나 사용한 적이 없는 포장에서 주의 깊게 조사되어야만 한다. 이러한 연구들은 국내 살균제 저항성 문제를 해결하기 위한 기본적인 정보를 제공한다는 면에서 매우 시급한 연구과제가 되고 있다.

• Mycobiology
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• 제45권2호
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• pp.101-104
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• 2017

We identified two genes related to fungicide resistance in Fusarium fujikuroi through random mutagenesis. Targeted gene deletions showed that survival factor 1 deletion resulted in higher sensitivity to fungicides, while deletion of the gene encoding F-box/WD-repeat protein increased resistance, suggesting that the genes affect fungicide resistance in different ways.

• Journal of Biosystems Engineering
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• 제31권6호
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• pp.535-540
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• 2006

For a biosensor development, an enzyme-linked immunosorbent assay (ELISA) of the fungicide iprovalicarb was developed by minimizing the processing time. The time for whole incubation process was reduced from 135 minutes to 15 minutes. The concentration of antibody was varied to improve sensitivity. The total processing time was reduced from 2.5 hours to 20 minutes, the final sensitivity ($IC_{50}$ value) of 7.93 ng/mL and the lowest detection limit of 0.045 ng/mL were obtained. This ELISA was applied to potatoes and onions, and the recoveries were in the range of 98.85 $\sim$ 101.20% and 87.97 $\sim$ 102.70%, respectively. Accordingly, this method can be used as basis for a biosensor for rapid monitoring of iprovalicarb residues in crops.

• The Plant Pathology Journal
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• 제25권4호
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• pp.317-321
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• 2009

Sensitivity to the new carboxylic acid amide fungicide, mandipropamid, of Phytophthora capsici causing pepper Phytophthora blight was determined on 187 isolates collected in Korea over 3 years, from 2005 to 2007. All isolates were sensitive to mandipropamid, with $EC_{30}$ values for growth of mycelia ranging from 0.001 to $0.037\;{\mu}g/ml$. Among the isolates, 147 (79.0%) isolates were sensitive to metalaxyl, whereas others were resistant to this fungicide. Mandipropamid had the same effect on mycelium growth of both metalaxyl-sensitive and metalaxyl-resistant isolates, indicating an absence of cross-resistance between these two fungicides. Comparison of the sensitivities of P. capsici isolates showed a positive correlation between sensitivity to mandipropamid and dimethomorph ($r^2$=0.8533). The results of this study indicate that there is no evidence for development of resistance to mandipropamid in this population of P. capsici isolates collected in Korea.

• The Plant Pathology Journal
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• 제33권6호
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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.

• The Plant Pathology Journal
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• 제32권6호
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• pp.570-574
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• 2016

Botrytis cinerea is a necrotrophic pathogen causing a major problem in the export and post-harvest of strawberries. Inappropriate use of fungicides leads to resistance among fungal pathogens. Therefore, it is necessary to evaluate the sensitivity of B. cinerea to various classes of fungicide and to determine the effectiveness of different concentrations of commonly used fungicides. We thus evaluated the effectiveness of six classes of fungicide in inhibiting the growth and development of this pathogen, namely, fludioxonil, iprodione, pyrimethanil, tebuconazole, fenpyrazamine, and boscalid. Fludioxonil was the most effective ($EC_{50}$ < $0.1{\mu}g/ml$), and pyrimethanil was the least effective ($EC_{50}=50{\mu}g/ml$), at inhibiting the mycelial growth of B. cinerea. Fenpyrazamine and pyrimethanil showed relatively low effectiveness in inhibiting the germination and conidial production of B. cinerea. Our results are useful for the management of B. cinerea and as a basis for monitoring the sensitivity of B. cinerea strains to fungicides.

• 식물병연구
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• 제27권4호
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• pp.164-171
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• 2021

2020년 8월에 전라북도 순창군 소재 25개 고추 재배지에서 채집한 탄저병 감염 과실로부터 377개 탄저병균주를 분리한 후 지역별로 선발된 62개 균주를 대상으로 국내에 등록된 11개의 고추 탄저병 살균제에 대한 균사생장억제율을 조사하여 각각의 살균제에 대한 감수성 정도를 조사하였다. 살균제에 대한 탄저병균의 살균제 감수성 실험 결과 fluazinam, prochloraz manganese, benomyl에서는 저항성 균주가 관찰되지 않았으나 이외의 약제에서는 최소 3개의 지역에서 저항성 균주가 출현하였으며, dithianon은 모든 지역의 모든 균주가 저항성이었다. 이를 통해 일부 지역에서 살균제의 지속적인 처리로 인하여 균주집단 내 살균제 내성이 발현되었음을 확인할 수 있었다. 지역별로는 순창읍과 팔덕면에서 7개 농약에 대한 저항성 균주가 출현하였고, 금과면, 복흥면, 쌍치면, 유등면, 풍산면에서 6개 농약에 대한 저항성 균주가 출현하였음을 확인하였다. 약제 등록시기와 저항성 균주의 출현에는 유의미한 상관관계가 없었다.