• The Plant Pathology Journal
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• 제36권3호
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• pp.218-230
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• 2020

Net blotch of barley caused by Pyrenophora teres (Died.) Drechsler, is one of the most destructive diseases on barley in Algeria. It occurs in two forms: P. teres f. teres and P. teres f. maculata. A total of 212 isolates, obtained from 58 fields sampled in several barley growing areas, were assessed for fungicide sensitivity by target gene analysis. F129L and G137R mitochondrial cytochrome b substitution associated with quinone outside inhibitors (QoIs) resistance, and succinate dehydrogenase inhibitors (SDHIs) related mutations (B-H277, C-N75S, C-G79R, C-H134R, and C-S135R), were analyzed by pyrosequencing. In vitro sensitivity of 45 isolates, towards six fungicides belonging to three chemical groups (QoI, demethylase inhibitor, and SDHI) was tested by microtiter technique. Additionally, sensitivity towards three fungicides (azoxystrobin, fluxapyroxad, and epoxiconazole) was assessed in planta under glasshouse conditions. All tested isolates were QoI-sensitive and SDHI-sensitive, no mutation that confers resistance was identified. EC₅₀ values showed that pyraclostrobin and azoxystrobin are the most efficient fungicides in vitro, whereas fluxapyroxad displayed the best disease inhibition in planta (81% inhibition at 1/9 of the full dose). The EC₅₀ values recorded for each form of net blotch showed no significant difference in efficiency of QoI treatments and propiconazole on each form. However, in the case of fluxapyroxad, epoxiconazole and tebuconazole treatments, analysis showed significant differences in their efficiency. To our knowledge, this study is the first investigation related to mutations associated to QoI and SDHI fungicide resistance in Algerian P. teres population, as well as it is the first evaluation of the sensitivity of P. teres population towards these six fungicides.

• 한국환경농학회지
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• 제40권2호
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• pp.127-133
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• 2021

BACKGROUND: Dithiocarbamte fungicides have been used in crop cultivation for diseases protection and treatment. And cultivated agricultrual products were used as feedstuff, and residual pesticides are likely to be absorbed and transferred to livestock. But the maximum residue limits (MRLs) were not established for dithiocarbate fungicides in livestock products, and thus an analysis method was developed and validated for dithiocarbamate fungicides to establish MRLs. METHODS AND RESULTS: Samples were prepared using CS₂ trap method and detected with UV/VIS spectrophotometer. Calibration line (0.1 ~ 10 ㎍/mL) was linear with r² > 0.99. For validation, the recovery tests were carried out at three fortification levels (MLOQ, 10 MLOQ and 50 MLOQ) from livestock samples (egg, milk, beef, pork, and chicken). The results for mancozeb, propineb, and thiram ranged between 76.8 to 109.6%, 79.4 to 108.8%, and 80.2 to 107.8%, respectively and % RSD (relative standard deviation) values were below 9.5%. Furthermore, inter-laboratory analysis was performed to validate the method. CONCLUSION: All values were corresponded with the criteria ranges requested by both the CODEX (CAC/GL 40-1993, 2003) and MFDS guidelines (2016). This might be used as an official analytical method for determination of dithiocarbamate fungicides at established MRLs and monitoring.

• The Plant Pathology Journal
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• 제39권4호
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• pp.351-360
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• 2023

Citrus melanose, caused by Diaporthe citri, has been one of the serious diseases, and chemical fungicides were used for protection in many citrus orchards of Jeju Island. Establishing a disinfectant resistance management system and reducing pesticide usage would be important for contributing to safe agricultural production. In this study, monitoring of chemical resistance was performed with 40 representative D. citri isolates from many citrus orchards in Jeju Island. Four different fungicides, kresoxim-methyl, benomyl, fluazinam, and prochloraz manganese, with seven different concentrations were tested in vitro by growing the mycelium of the fungal isolates on the artificial medium potato dextrose agar. Among the 40 fungal isolates, 12 isolates were investigated as resistant to kresoxim-methyl which could not inhibit the mycelium growth to more than 50%. Especially isolate NEL21-2 was also resistant against benomyl, whose hyphae grew well even on the highest chemical concentration. However, any chemical resistance of fungal isolates was found against neither fluazinam nor prochloraz manganese. On the other hand, in vivo bio-testing of some resistant isolates was performed against both kresoxim-methyl and benomyl on young citrus leaves. Typical melanose symptoms developed on the citrus leaves pre-treated with both agrochemicals after inoculation with the resistant isolates. However, no or less symptoms were observed when the susceptible isolates were inoculated. Based on these results, it was suggested that some resistant isolates of D. citri occurred against both systemic fungicides, which may be valuable to build a strategy for protecting citrus disease.

• 농약과학회지
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• 제9권4호
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• pp.429-436
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• 2005

오이에 균핵병을 일으키는 Sclerotinia sclerotiorum은 $25^{\circ}C$에서 균사의 생육이 가장 왕성하였으며, 병원성 실험을 위해 오이 열매를 이용한 실내 검정 실험의 경우 동일한 온도에서 병원성이 가장 강한 것으로 나타났다. 분리한 모든 Sclerotinia sclerotiorum 균주는 오이 절편 접종법과 상처 접종법을 사용한 실내 검정에서 모두 강한 병원성을 나타냈지만, 오이 절편 접종법의 경우는 상처 접종법과는 다르게, 균주와 환경, 처리한 살균제 간에 차이를 볼 수 없을 정도로 병원성이 강하여 실내 검정법으로는 적합하지 못하였다. 오이 절편접종법과 상처접종법을 사용하여 dichlofluanid와 carbendazim과 diethofencarb의 혼합제의 병 발생 억제 효과를 조사한 결과, 오이 절편접종법에서는 500과 $3.0{\mu}g/mL$의 처리구에서 14.3과 42.8%의 낮은 효과를 보였지만, 상처 접종법에서는 동일한 농도에서 100와 92.5%의 우수한 발병 억제 효과를 보였다. 두 살균제는 포장에서도 우수한 효과를 보였는데, $100{\mu}g/mL$의 혼합제와 $825{\mu}g/mL$의 dichlofluanid는 병 발생 억제 효과가 각각 91.1과 82.9%이었다. 충남 연기 지역의 오이 시설 재배지에서 분리한 37개의 S. sclerotioum 균주는 7가지의 살균제에 대한 저항성 모니터링을 실시하여 균주들의 평균 EC50값을 구하였는데, fenhexamid는 $0.13{\mu}g/mL$, 병원균의 세포막에서 과산화반응을 일으켜 병원균을 사멸시키는 것으로 알려진 procymidon과 iprodione은 0.18과 $0.24{\mu}g/mL$, Tubulin 단백질의 중합 반응을 억제하는 것으로 보고된 carbendazim과 carbendazim과 diethofencarb의 혼합제는 0.13과 $0.05{\mu}g/mL$, 보호용 살균제로 알려진 iminoctadine과 dichlofluanid는 평균 $EC_{50}$ 값이 1.94와 $8.95{\mu}g/mL$이었다. 특별히 dichlofluanid의 경우는 $EC_{50}$값의 범위가 0.001에서 $21.54{\mu}g/mL$ 사이의 넓은 범위에 분포하였지만, 포장에서의 사용 농도가 $1,650{\mu}g/mL$인 것을 감안한다면 저항성균의 출현은 확인하지 못하였다. 충북의 연기 지역에서는 7가지 살균제에 대하여 저항성을 뚜렷하게 나타내는 균핵병균은 발견하지 못하였다.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1703-1706
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• 2012

Rice blast is the most serious disease of rice due to its harmfulness and its world wide distribution. $Magnaporthe$ $grisea$ is the cause of rice blast disease and destroys rice enough to feed several tens of millions of people each year. Fungicides are commonly used to control rice blast. But $M.$ $grisea$ acquires resistance to chemical treatments by genetic mutations. 2-Phenylimino-1,3-thiazolines were proposed as a novel class of fungicides against $M.$ $grisea$ in the previous study. To develop compounds with a higher biological activity, a new series of 2-phenylimino-1,3-thiazolines was synthesized and its fungicidal activity was determined against $M.$ $grisea$. The QSAR analysis was carried out on a series of 2-phenylimino-1,3-thiazolines. The QSAR results showed the dependence of fungicidal activity on the structural and physicochemical features of 2-phenylimino-1,3-thiazolines. Our results could be used as guidelines for the study of the mode of action and further design of optimal fungicides.

• The Plant Pathology Journal
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• 제25권3호
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• pp.270-279
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• 2009

During the course of a study to develop a spraying program at 15-day spray intervals, two important findings were identified allowing for further reduction of spray frequency by increasing the spray interval. In evaluating the contribution of fungicides from a 15-day spray interval program, control of white rot, which is of prime importance in Korea, was not affected, in spite of the extended spray interval caused by omitting the fungicides during the season. In another experiment assessing the duration of the protective activities of several key fungicides used in the 15-day spray interval program, infection control was maintained for almost 30 days for some fungicide. Based on these two findings, a basic spraying program with a 25-day spray interval was developed. This program was modified for four successive years to improve the control efficacy against bitter rot and Marssonina blotch, which sometimes causes as much damage as white rot.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.117.1-117
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• 2003

Phytophthora blight, caused by P. capsici, is very important disease of pepper. Many fungicides to control of Phytophthora blight have been developed, but most of fungicides disappeared in short periods. Nowadays dimethomorph was known as one of the most effective to control of this disease. P. capsici isolates from pepper fields were collected and surveyed their growth in dimethomorph amended V8 medium in order to evaluate their fungicides resistance. The fungicide resistant isolates were not founded among them. Most of the sensitive isolates were inhibited perfectly in V8 medium amended with 10ppm dimethomorph. Mutants of P. capsici by dimethomorph, was grown very well in 250ppm. The difference of pathogenicity, colony morphology, drug response, RT-PCR results was identified between sensitive and resistance isolates. This study should be provided a basic information about the occurrence of dimethomorph resistant isolates and genetic changes in P. capsici population.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.91.1-91
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• 2003

Bakanae disease, caused by Gibberella fujikuroi (anamorph Fusarium moniliforme J. Sheldon), a typical seed-borne disease of rice occurs from nursery to paddy fields. Consequently, chemical seed disinfectants is the most efficient control method. Several seed treatment methods with various fungicides were attempted to inhibit disease. Spray and 24 hrs immersion of seeds using prochloraz emulsion reduced disease infection and the control value were 99.3 and 100％, respectively. In contrast, dressing to wet seeds thiophanate-methyl＋thiram wp and benomyl＋thiram wp reduced disease infection more effectively than 24 hrs immersion of seeds. However, dressing of carpropamid+imidacloprid＋fludioxonil wp to wet seeds did not reduced disease as well as wettable liquid of fludioxonil. The results suggest that the bakanae disease might be disinfected effectively by 24 hrs immersion of seeds in prochloraz emulsion and seed dressing of fungicides.

• 식물병연구
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• 제17권3호
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• pp.410-412
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• 2011

2000년대 후반부터 고흥지역의 비파나무(Eriobotrya japonica)와 제주지역의 홍가시나무(Photinia glabra)에 Entomosporium mespili에 의한 극심한 점무늬병이 발생하기 시작하였다. 따라서 방제효과가 높은 살균제를 선발하기 위하여 이 연구를 수행하였다. 효과를 검정한 3개의 농약 중 비파나무 점무늬병에는 propiconazole 처리가 방제가 64.1%로 가장 높게 나타났고, 홍가시나무 점무늬병에는 chlorothalonil 처리가 방제가 87.6%로 가장 높게 나타났다. Thiopanate-methyl 처리는 방제가가 비교적 낮게 나타났고, propiconazole은 홍가시나무에 약해를 나타내었다.

• The Plant Pathology Journal
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• 제24권4호
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• pp.439-446
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• 2008

A fungicidal spray program for effective control of three major apple diseases in Korea (white rot, bitter rot, and Marssonina blotch) was developed. This was based on our previous studies showing that application of ergosterol biosynthesis inhibitors (EBIs) in early or mid-August can eradicate white rot infection in fruit and that some protective fungicides show after-infection activity against white rot. The basic spray program focused on control of white rot, the main target disease, and the fungicides were sprayed at 15-day intervals from petal fall to late August using fungicides that show after-infection and EBI activity. The basic spray program was modified over 4 successive years to improve control efficacy against bitter rot and Marssonina blotch, which sometimes cause as much damage as white rot. Modifications to the regime were made every year by replacing one fungicide in the basic program at a specific spraying time. Substitution of only one fungicide in the spray program, even early in the growing season, greatly influenced the final disease incidence at harvest. Applying this principle, a moderately efficient spray program for cv. Fuji that increased the spray interval from 10 to 15 days and thus reduced the number of sprays required per crop season was developed.