• 한국유기농업학회지
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• 제23권1호
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• pp.133-148
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• 2015

Although several adverse effects have been increased in recent years, synthetic agro-chemicals have been widely used to control diseases on paprika. This research was conducted to isolate and to characterize the antagonistic microorganism to control major paprika diseases, gray mold rot, fruit and stem rot, phytophthora blight, sclerotium rot, and wilt disease. Analysis of the fatty acid and analysis of the 16S rDNA gene sequence revealed that YKJ2 isolated in this research belongs to a group of Burkholderia cepacia. Specially, 16S rDNA gene sequence of YKJ2 showed 99% of sequence similarity with B. cepacia. Observation through the optical microscope revealed that YKJ2 was effective on suppression of the spore germination and the hyphal growth of pathogens. YKJ2 treatment on pathogens induced marked morphological changes like hyphal swelling and degradation of cell wall. In the case of phytophthora blight, the zoosporangium formation was restrained. On the basis of the results of this study, we propose that an antagonistic microorganism, B. cepacia, found in this study naming as "B. cepacia strain YKJ2" and has great potential as one of biological control agents against major diseases of paprika.

• 농약과학회지
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• 제3권2호
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• pp.86-89
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• 1999

일련의 methanesulfonamide(Ia-Ig)와 phenylhydrazone(IIa-IIh) 유도체를 합성하고 식물성 병원균인 잿빛 곰팡이병균(BC: Botrytis cinerea), 고추 역병균(PC: Phytophthora capsici) 및 문고병균(RS: Rhizoctonia solani)에 대한 살균활성을 한천 희석법으로 측정하였다. 살균활성은 (I)보다 (II)가 다소 큰 영향을 미쳤으며 (I)과 (II) 모두 PC=BC>RS의 순서로 살균활성을 나타내었다. 다루어진 화합물 중에서 3-chlorophenyl 치환체, IIg가 PC균에 대하여 가장 강한 활성 ($pI_{50}=3.96$)을 보였다. 또한, parameter focusing을 통하여 검토된 살균활성에 미치는 요인들로는 Ovality, 극성 및 logP상수 등이었다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1994년도 Proceedings of International Symposium on BIOLOGICAL CONTROL OF PLANT DISEASES Korean Society of Plant Pathology
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• pp.50-61
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• 1994

Biological control of important fungal diseases such as Phytophthora blight of red pepper, gary mold rot of vegetables, and powdery mildew of many crops was attempted using an antagonistic bacterium, Bacillus sp. AC-1 in greenhouses and fields. The antagonistic bacterium isolated from the rhizosphere soils of healthy red pepper plant was very effective in the inhibition of mycelial growth of plant pathogenic fungi in vitro including Phytophthora capsici, Rhizoctonia solani, Pyricularia oryzae, Botrytis cinerea, Valsa mali, Fusarium oxysporum, Pythium ultimum, Alternari mali, Helminthosporium oryzae, and Colletotrichum gloeosporioides. Culture filtrate of antagonistic Bacillus sp. AC-1 applied to pot soils infested with Phytophthora capsici suppressed the disease occurrence better than metalaxyl application did until 37 days after treatment in greenhouse tests. Treatments of the bacterial suspension on red pepper plants also reduced the incidence of Phytophthora blight in greenhouse tests. In farmers' commercial production fields, however, the controlling efficacy of the antagonistic bacteria was variable depending on field locations. Gray mold rot of chinese chives and lettuce caused by Botrytis cinerea was also controlled effectively in field tests by the application of Bacillus sp. AC-1 with control values of 79.7% and 72.8%, respectively. Spraying of the bacterial suspension inhibited development of powdery mildew of many crops such as cucumber, tobacco, melon, and rose effectively in greenhouse and field tests. The control efficacy of the bacterial suspension was almost same as that of Fenarimol used as a chemical standard. Further experiments for developing a commercial product from the antagonistic bacteria and for elucidating antagonistic mechanism against plant pathogenic fungi are in progress.

• The Plant Pathology Journal
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• 제22권1호
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• pp.94-96
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• 2006

In a search for plant extracts with potent in vivo antifungal activity against various plant pathogenic fungi, the methanol extract of the Curcuma longa rhizomes effectively controlled the development of rice blast catised by Magnaporthe grisea and tomato late blight caused by Phytophthora infestans. Three curcuminoids such as curcumin, demethoxycurcumin, and bisdemethoxycurcumin were purified from the methanol extract of C. longa rhizomes as antifungal principles. Among the three curcuminoids, demethoxycurcumin was the most active to both rice blast and tomato late blight, followed in order by curcumin and bisdemethoxycurcumin. However, they all exhibited no or little in vivo antifungal activity against other fungal pathogens causing rice sheath blight (Corticium sasaki), tomato gray mold (Botrytis cinerea), wheat leaf rust (Puccinia recondita), or barley powdery mildew (Blumeria graminis f. sp. hordel).

• 식물병연구
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• 제15권2호
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• pp.88-93
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• 2009

고추 유묘의 신초가 말라죽고 잎에 수침상점무의 증상으로부터 병원균을 분리하여 균총의 색깔과 형태, 포자의 모양과 크기를 관찰한 결과 균총의 색깔은 처음에는 핑크색 띄나 차츰 회색으로 변하였고, 분생포자는 방추형으로 크기가 $8.1-17.0{\times}2.0-3.8{\mu}m$이며 생장최적온도 $25-27^{\circ}C$이다. 종 특이적 프라이머를 이용하여 고추 유묘에서 분리한 균을 동정한 결과 C. acutatum에 특이적인 프라이머인 CaINT에서만 496 bp의 증폭산물을 얻었다. 이들 결과를 바탕으로 유묘에서 분리한 균은 Collectotrichum acutatum으로 동정하였다. 고추 유묘에서 분리한 균주를 고추묘 생육단계별로 병원성 검정한 결과 유묘 뿐 아니라 식물체 전 생육기에 잎 탄저병 증상을 나타내었으며 또한 고추 열매에서도 강한 병원성을 나타내었다.

• Mycobiology
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• 제31권3호
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• pp.179-182
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• 2003

A total of 187 endophytic fungi were isolated from 11 plant species, which were collected from 11 locations in Korea. Their antifungal activities were screened in vivo by antifungal bioassays after they were cultured in potato dextrose broth and rice solid media. Antifungal activity against plant pathogenic fungi such as Magnaporthe grisea(rice blast), Corticium sasaki(rice sheath blight), Botrytis cinerea(tomato gray mold), Phytophthora infestans(tomato late blight), Puccinia recondita(wheat leaf rust), and Blumeria graminis f. sp. hordei(barley powdery mildew) was determined in vivo by observing the inhibition of plant disease development. Twenty(11.7%) endophytic fungi fermentation broths were able to control, by more than 90%, at least one of the six plant diseases tested. Among 187 liquid broths, the F0010 strain isolated from Abies holophylla had the most potent disease control activity; it showed control values of more than 90% against five plant diseases, except for tomato late blight. On the other hand, fourteen(7.5%) solid culture extracts exhibited potent disease control values of more than 90% against one of six plant diseases. The screening results of this study strongly suggested that metabolites of plant endophytic fungi could be good potential sources for screening programs of bioactive natural products.

• The Plant Pathology Journal
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• 제37권2호
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• pp.137-151
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• 2021

The present study describes the bacterial blight of walnut, caused by Xanthomonas arboricola pv. juglandis (Xaj) in the northern Gyeongbuk province, Korea. Disease symptoms that appear very similar to anthracnose symptoms were observed in walnut trees in June 2016. Pathogens were isolated from disease infected leaves, fruits, shoots, bud, flower bud of walnut, and cultured onto yeast dextrose carbonate agar plates. Isolated bacteria with bacterial blight symptoms were characterized for their nutrient utilization profiles using Biolog GN2 and Vitek 2. In addition, isolates were subjected to physiological, biochemical, and morphological characterizations. Furthermore, isolates were identified using 16S rDNA sequence analysis, and multi-locus sequence analysis using atpD, dnaK, efp, and rpoD. To confirm pathogenicity, leaves, fruits, and stems of 3-year-old walnut plants were inoculated with bacterial pathogen suspensions as a foliar spray. One week after inoculation, the gray spots on leaves and yellow halos around the spots were developed. Fruits and stems showed browning symptoms. The pathogen Xaj was re-isolated from all symptomatic tissues to fulfill Koch's postulates, while symptoms were not appeared on control plants. On the other hand, the symptoms were very similar to the symptoms of anthracnose caused by Colletotrichum gloeosporioides. When walnut plants were inoculated with combined pathogens of Xaj and C. gloeosporioides, disease symptoms were greater in comparison with when inoculated alone. Xaj population size was more in the month of April than March due to their dormancy in March, and sensitive to antibiotics such as oxytetracycline and streptomycin, while resistant to copper sulfate.

• 아시안잔디학회지
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• 제21권2호
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• pp.147-154
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• 2007

2004년 3월에 전라북도에 위치한 한 골프장의 켄터키 블루그래스와 퍼레니얼 라이그래스에 설부병이 발병되었다. 감염된 잔디잎들은 서로 엉켜저 매트화 되고, 흰색에서 회백색의 균사체들로 덮여있었다. 균핵들은 잔디의 엽신, 엽초 및 관부 위에 형성되어 있었다. 이병 잎으로부터 분리된 곰팡이는 직경이 1.4 mm 미만의 밝은 핑크에서 갈색의 불규칙한 모양의 균핵과 꺽쇠연결체, 흰색의 균사체 등을 형성하여 Typhula incarnata와 같은 특징을 보였다. 분리된 T. incarnata의 균사생육 적온은 $5{\sim}15^{\circ}C$이었다. 원인균의 ribosomal RNA IST1의 부분 염기서열은 GeneBank database에 등록된 T. incarnata의 부분 염기서열과 91%로의 상동성을 보여 T. incarnata로 동정되었다. 실내 약제방제 시험결과 14개 살균제 중 iprodione, tebuconazole, polyoxin D, flutolanil, hexaconazole, tolclofos-methyl, fosetyl-Al, mepronil, pencycuron+ tebuconazole 및 fenarimol 살균제들은 추천농도에서 완전하게 균생장을 억제하였다. 포장시험에서, 이들 살균제와 thifluzamide와 thiram과 같은 살균제들은 다소 방제효능의 정도 차이는 있지만 효과적으로 잔디 설부병을 방제하였다.

• Weed & Turfgrass Science
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• 제5권2호
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• pp.101-104
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• 2016

2014년 7월부터 9월까지 경상남도 합천 지역의 크리핑벤트그래스(Agrostis stolonifera) 퍼팅 그린에서 Curvularia trifolii에 의한 Curvularia 잎마름병이 관찰되었다. Curvularia 잎마름병은 크리핑벤트그래스 잎몸에서 수침상으로 시작되어 진한 괴사반점으로 변한 다음, 크기가 확대되어 회갈색 또는 밝은 갈색의 동그란 타원형 병반이 되었다. 반점의 둘레는 자주 분홍 또는 진한 갈색의 경계를 갖으며 둥그런 무리(halo)를 보였다. 괴사 반점들은 융합되어 불규칙한 모양이 되었고 잎끝 또는 잎 전체가 말랐다. 마른 잎몸은 회백색이나 황갈색을 나타냈다. 그 균은 균학적 특성과 16S rDNA 서열 분석에 의해 동정되었다. 병원균의 분생포자는 크기가 짧았고, 보통 3개의 격막을 가졌으며, 곧거나 자주 휘었는데 양끝 세포는 일반적으로 가운데 세포보다 투명하였다. 3개의 격막을 지닌 분생포자의 배지상 크기는 $26{\sim}28{\times}11{\sim}12{\mu}m$였다. 기주에 대한 균의 인공접종으로 병원성이 확인되었다. 본 논문은 C. trifolii가 크리핑벤트그래스에 Curvularia 잎마름병을 일으키는 우리나라 최초의 보고이다.

• 식물병연구
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• 제15권2호
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• pp.127-129
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• 2009

2008년부터 2009년까지 경상남도농업기술원 논포장에서 Botrytis cinerea에 의한 자운영 잿빛곰팡이병이 발생하였다. 병징은 잎과 잎자루, 줄기 부분이 수침상으로 물러지고 부패되어 병반부위에 잿빛색의 분생포자가 많이 형성하였다. 균총은 감자한천 배지에서 회갈색이며 균사생육과 균핵형성 적온은 $20^{\circ}C$였다. 분생포자는 무색이고 단포자이며 난형 또는 타원형으로 크기는 $7{\sim}16{\times}10{\mu}m$이었고, 분생포자경의 폭은 $14{\sim}28{\mu}m$였다. 병든 부위에서 병정과 분리한 병원균의 균학적 특징을 조사한 결과, Botrytis cinerea Persoon: Fries에 의한 자운영 잿빛곰팡이 병으로 동정되었다.