• 한국환경농학회지
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• 제16권3호
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• pp.212-215
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• 1997

Metalaxyl과 streptomycin sulfate(SM) 내성 획득여부를 알아보기위해 감자역병균의 모균주와 단일 포자낭에서 얻은 $F_1$세대에 대한 반응을 조사하였다. 모균주 KM10, U6, CDB6은 metalaxyl에 내성을 보였으며, F827, DNC303, DN107 균주는 SM에 내성을 나타냈다. 약제에 노출시킨 단일 포자낭에서 얻은 $F_1$세대는 모균주보다 생육이 양호하였다. 특히, F817, CDB6, JD1의 $F_1$세대는 metalaxyl 처리배지에서 대조구보다 51%이상 신장하였고, KM10, U6, JD1의 $F_1$세대는 모균주보다 SM처리에서 51%이상 신장하였다. 이것들은 본 실험의 표준에 의하면 내성을 획득하였다. 또 모균주와 $F_1$세대간에는 약제저항성에 정의 상간관계가 있었다. Metalaxyl의 경우 SM의 경우보다 준내성 이상을 보인 모균주로부터 얻은 $F_1$세대의 내성획득 정도가 더 큰 경향을 보였다.

• 한국식물병리학회지
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• 제10권2호
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• pp.92-98
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• 1994

Phytophthora infestans populations collected from various geographical locations of Korea in 1991 and 1993 were analyzed for mating types and responses to metalaxyl. Both A1 and A2 mating type isolates were detected in 1991. The majority of the isolates were A2 mating type, but no A1 mating type was detected in 1993. About 40% of the isolates collected in 1991 were resistant to metalaxyl, and the distribution of metalaxyl-resistant isolates of P. infestans was strongly associated with their geographic origins in Korea. Metalaxyl-resistant isolates with EC50 values > 50$\mu\textrm{g}$/ml were collected from the northern provinces of Kangwon, Kyungbuk, and Chonbuk, but not from the southern provinces of Kyungnam, Chonnam, and Jeju in 1991. The drastic increase in the degree of quantitative resistance to metalaxyl was detected among the isolates from the southern provinces during 1991~1993. More than 50% of the isolates collected from the southern provinces of Kyungnam and Chonnam in 1993 had EC50 values >50$\mu\textrm{g}$/ml. The province of Kangwon had isolates with the greatest resistance to metalaxyl. this alpine areas might be the origin of metalaxyl-resistant isolates of P. infestans in Korea. The A2 genotype with metalaxyl resistance appears to be displacing the A1 genotype which is presently the predominant genotype in Korea.

• 한국균학회지
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• 제52권2호
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• pp.73-96
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• 2024

Root and stem rot caused by Phytophthora palmivora is one of the most serious diseases affecting durian production in Thailand where metalaxyl, an effective fungicide against oomycetes, has been used extensively for a long period to control this disease. Although field isolates of P. palmivora resistant to metalaxyl exist in Thailand, a molecular basis for P. palmivora has not yet been elucidated regarding metalaxyl resistance. The current study tested whether P. palmivora RPA1 (the DNA-directed RNA polymerase I subunit gene), a homolog gene of RPA190 associated with metalaxyl resistance in some isolates of Phytophthora infestans, had a role in the resistance mechanism toward metalaxyl. In total, 40 durian-derived isolates of P. palmivora were assessed for metalaxyl sensitivity using a mycelial growth inhibition assay. The effective concentrations for 50% mycelial growth inhibition values for all isolates tested were in the range 0.01-872.88 mg/L. The isolates were clustered into three groups: sensitive (n=23), moderately resistant (n=11), and resistant (n=6) groups. No polymorphism was revealed based on multiple alignment analysis of the amino acid sequences translated from the corresponding DNA sequences in the region of RPA1 of the metalaxyl-sensitive (n=5), moderately resistant (n=2), and resistant isolates (n=6). Furthermore, investigation of the RPA1 expression among these representative isolates (n=3, each group) indicated that RPA1 expression may not be involved in the regulation of P. palmivora resistance to metalaxyl. Based on this line of evidence, there was no detected relationship regarding metalaxyl resistance and P. palmivora RPA1.

• 농약과학회지
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• 제12권3호
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• pp.270-276
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• 2008

전국 고추재배 포장에서 2005년부터 2007년까지 3년간 분리한 151개의 고추 역병균을 가지고 연도별 metalaxyl에 대한 감수성 정도를 조사하였다. 그 결과 Phytophthora capsici에 대한 metalaxyl의 평균 $EC_{50}$ 값은 역병균을 채집한 3년 동안 2005, 2006, 2007년의 균주들이 1.454, 0.830, $0.323{\mu}g\;mL^{-1}$로 그 값이 감소하고 있었으며, 2007년에 채집한 균주에서는 저항성 병원균을 전혀 분리하지 못하였다. Metalaxyl에 저항성인 고추 역병균이 mandiproramid와 dimethomorph에 대해서 교차 저항성을 보이는 지를 조사한 결과, metalaxyl과 다른 두 약제 mandipropamid와 diinethomorph의 사이에는 전혀 상관관계가 없었다. 또한 metalaxyl에 대한 저항성은, 역병균의 균사 생장 속도와 고추에 대한 병원성과도 상관관계가 없었다.

• The Plant Pathology Journal
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• 제19권3호
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• pp.143-147
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• 2003

Sensitivity of Phytophthora infestans isolates to fungicides metalaxyl and ethaboxam in Korea was examined with 260 isolates for 3 years (9 isolates in 2000,93 isolates in 2001, and 158 isolates in 2002). Both Al and A2 mating types were found from the isolates collected for 3 years. Al mating type was dominant in the population with 8 isolates (88.9%) in 2000, 84 isolates (89.4%) in 2001, and 138 isolates (87.3%) in 2002. Only some isolates from diseased tomatoes in Buyergun and diseased potatoes in Pyeongchanggun were of the A2 mating type. As for metalaxyl sensitivity, 77.0% of the isolates were moderately resistant with 8 isolates (88.9%) in 2000, 73 isolates (77.7%) in 2001, and 120 isolates (75.9%) in 2002. Meanwhile, those found resistant were 1 isolate (11.1%) in 2000, 16 isolates (17.0%) in 2001, and 33 isolates (20.9%) in 2002. Only 5 isolates (3.2%) were sensitive to metalaxyl in 2002. There was no significant difference in the sensitivity among years. As for ethaboxam, no isolate was able to grow at 5.0 $\mu\textrm{g}$ /ml, and only four isolates (1.5 %) grew at 1.0 $\mu\textrm{g}$ /ml with heavy retardation compared with the untreated control. Based on these 3-year results, the minimum inhibitory concentration (MIC) of ethaboxam to p. infestans was determined to be 0.2-1.0 $\mu\textrm{g}$ /ml. Results indicate that resistance development by p. infestans to ethaboxam is not likely to occur in the natural condition. furthermore, there was no indication of cross resistance between metalaxyl and ethaboxam because all the isolates, regardless of classification for their sensitivity to metalaxyl, were not able to grow at 5.0 $\mu\textrm{g}$ /ml of ethaboxam.

• 식물병연구
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• 제9권4호
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• pp.224-228
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• 2003

우리 나라 농가에서 담배역병 방제약제로 사용되고 있는 Metalaxyl의 약제 저항성균 발생억제 및 방제를 위한 대체 약제를 선발하기 위하여 시중에서 판매되고 있는 역병방제용 약제 중 Dimethomorph를 비롯한 5종의 약제를 구입하여 시험하였다. 실내 시험에서는 Propamocarb hydrochloride는 Metalaxyl과 유사한 반응을 보여 서로 교차저항성이 있는 것으로 조사되었으며 Oxadixyl + Mancozeb, Dimethomorph + Mancozeb 등이 실내시험 및 포장시험 결과 약효가 우수하여 Metalaxyl 대체약제로 선발되었다.

• 농약과학회지
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• 제11권4호
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• pp.305-312
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• 2007

2005년과 2006년에 전국의 고추 재배지에서 분리한 역병균의 metalaxyl에 대한 약제 반응을 조사하였다. Metalaxyl에 대한 $EC_{50}$값을 가지고 저항성을 결정하였는데, $1.0\;{\mu}g\;mL^{-1}$ 이상인 경우를 저항성으로 규정하였다. 이 기준에 따르면 2005년에 분리한 역병균에서는 29.0%가, 2006년에는 21.8%가 저항성 균주로 밝혀졌다. 또한 2006년에 분리한 균주는 분리한 지역에 따라서 저항성 균주의 비율에 차이가 있었는데, 충남지역이 33.3%로 가장 높은 분리 빈도를 보였고, 충북과 경북이 26.3과 11.1%의 저항성 균주의 비율을 보였다. Metalaxyl에 대해서 감수성과 저항성인 균주들 중에서 각각 2균주씩을 선발하여, 각각 균주들에 대한 metalaxyl의 작용특성을 조사하였다. 감수성 균주인 P. capsici 06-37과 06-86은 $0.8\;{\mu}g\;mL^{-1}$의 metalaxyl 처리 구에서 균사생장이 98.1과 89.6%가 억제되었지만, 저항성 균주인 P. capsici 06-130과 06-155에 대한 균사생장 억제율은 48.7과 45.3%로 매우 낮았다. 하지만 metalaxyl은 선발한 4균주의 유주포자낭의 발아, 유주포자나출, 유주포자 발아 등에는 큰 효과를 나타내지 않았으며, 살균제에 대한 반응과는 관련이 없었다. 온실시험 결과, 감수성 균주인 06-37은 고추 유묘에서 전혀 병원성이 없었지만, 나머지 균주들은 뚜렷한 병원성을 보였다. $25\;{\mu}g\;mL^{-1}$의 metalaxyl을 토양 관주처리하고 병원균을 접종한 다음, 9일 후에 방제 효과를 조사하면, 감수성균인 06-86에 대해서는 100%의 방제 효과를 보여 주었지만, 저항성 균주인 06-130에 대해서는 20%의 효과를 보였고, 06-155에 대해서는 전혀 병 발생을 억제하지 못하였다.

• The Plant Pathology Journal
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• 제21권1호
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• pp.33-38
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• 2005

Changes of control efficacy of chemical to potato late blight caused by Phytophthora infestans in potato fields from 2001 to 2004 were examined. Control efficacy of metalaxyl was suddenly decreased from 100% in 2002 to 50% in 2004 and that of dimethomorph also was similar to those of metalaxyl. However, the control efficacy of ethaboxam no great change. Both A1 and A2 mating type isolates were isolated from 2001 to 2004 in several areas in Korea. The majority of the P. infestans isolates were A1 mating type. Total 939 isolates of P. infestans obtained from several areas in Korea from 2001 to 2004 were examined for changes of sensitivity to metalaxyl. Frequencies of metalaxyl resistance isolates were gradually increased from 17% in 2001 to 84.2% in 2004, but isolation frequencies of metalaxyl sensitive and intermediate resistant isolate were decreased. Cause of decreasing control efficacy of metalaxyl was thought by increase of resistance isolates in A1 mating type population according to increasing metalaxyl use. Most isolates were grown at 0.5 ${\mu}g/ml of dimethomorph and isolates grown at 1 ${\mu}g/ml of dimethomorph were approximately 10.2-22.9%. However, no isolate was able to grow at 5.0 ${\mu}g/ml. Based on these results, minimum inhibitory concentrations (MIC) of dimethomorph to P. infestans were determined to be 0.5-1.0 ${\mu}g/ml. Our results indicated that the reason decreasing control efficacy of dimethomorph was not caused by occurrence of resistant isolates. About 5% and 12.1% isolates among the total isolates collected in 2003 and 2004 were grown on V-8 juice rye agar containing 1.0 ${\mu}g/ml ethaboxam. The 2.1 and 25.4% isolates had MICs of 0.2-0.4 ${\mu}g/ml, and MIC values of 87.9% and 74.3% isolates were less than 0.2 ${\mu}g/ml concentrations of ethaboxam. Therefore, resistance development by P. infestans to ethaboxam is not likely to occur in the natural condition.

• 한국식물병리학회지
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• 제10권3호
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• pp.192-196
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• 1994

Two hundred and fourty-seven isolates of Phytophthora infestans obtained from infested potato leaves from the spring of 1991 to the fall of 1993 from potato fields in various regions of Korea were tested for their fungicides resistances. A total of 20.9% isolates were not suppressed at 50 ppm of metalaxyl in 1991, but isolates from 1993 were suppressed at 50 ppm of metalaxyl. Ten resistant isolates and 10 susceptible isolates to metalaxyl were selected and tested against oxadixyl, fosetyl-Al, and phosphorous acid. Effectiveness of these chemicals were no better than that of metalaxyl. Dimethomorph suppressed all isolates at 1 $\mu\textrm{g}$/ml suggesting that it might be a potential chemical to control Phytophthora infestans. Mating types of all isolates from diseased leaves in 1993 turned out to be A2 type.

• 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.