• 한국약용작물학회지
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• 제27권6호
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• pp.404-411
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• 2019

Background: In September 2017, wilting and rhizome rot symptoms were observed on Atractylodes macrocephala Koidz. in Jecheon-si and Eumseong-gun. This study was carried out to isolate hitherto unidentified pathogenic fungi from A. macrocephala and to test the pathogenicity of isolated fungi against Atractylodes spp. genus such as A. macrocephala, A. japonica, and their interspecific hybrids. Methods and Results: The diseased plants were washed with running tap water, and the boundary between the healthy area and the diseased area was cut while the pathogens were isolated by growing cultures from the diseased areas on Phytophthora semi-selective medium. The internal transcribed spacer (ITS) region of the isolates was used in this study for identification. Test plants were cultivated in the glasshouse at 20℃ - 30℃ for 4 months and then used for pathogenicity test. The pots with plants inoculated with mycelial plugs and zoospores were placed at 25℃ for 48 h in a dew chamber where relative humidity was above 95%, and then moved into the glasshouse at 20℃ - 30℃. The presence or absence of pathogenicity of the strains was determined by evaluating the symptom of plant wilting. The inoculation test was performed in three replicates with a non-treated control. Conclusions: On the basis of results of ITS sequence analysis, the strains isolated from the diseased plants was identified as Phytophthora sansomeana. Biological assay using test plants confirmed the pathogenicity of P. sansomeana against Atractylodes macrocephala. This is the first report of rhizome rot in A. macrocephala caused by P. sansomeana.

• 식물병연구
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• 제26권2호
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• pp.88-94
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• 2020

Recently, the severe dieback of apple trees resulting from soil-borne diseases has occurred in South Korea. The casual agents of dieback were surveyed on 74 apple orchards that had been damaged nationwide in 2016-2019. The number of apple orchards affected alone by Phytophthora rot, violet root rot, and white root rot was 31, 34, and 3, respectively. Also, the total number of mixed infection orchards was 6. Out of 9,112 apple trees affected by dieback, the trees damaged by Phytophthora rot, violet root rot, and white root rot were 3,332, 3,831, and 44, respectively. Moreover, the total number of mixed infection apple trees was 1,905. The provinces mainly affected were Gyeongnam, Gyeongbuk, Chungbuk, and Jeonbuk. The survey on these infected apple orchards will be available to form management strategy for the dieback that had been increased by soil-borne fungal pathogens.

• The Plant Pathology Journal
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• 제17권3호
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• pp.184-188
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• 2001

Phytophthora-induced diseases on citrus in Jeju island have been considered of minor importance because of the use as root stock of trifoliate orange, which is immune to Phytophthora. However, brown rot on fruit, which severely occurred in 1998 and 1999, has become a great threat to citrus production in the island. About one-half of the surveyed orchards were infected in 1998 and 4 out of 19 infected fields showed over 20% fruit infection rate. The disease was less severe in 1999, with an estimated infected area and total fruit reduction of 3,155 ha and 15,300 tons, respectively. Typical gummosis was also occasionally observed on cv. Shiranugi, which is mostly cultivated under plastic film houses. Two types of Phytophthora were consistently isolated from various plant parts, identified as P. citrophthora and P. nicotianae. The former was isolated from the aerial parts of the fruit, young leaf, and shoot in the fields. Meanwhile, the latter was only isolated from the basal stem showing gummosis in plastic film houses.

• 식물병연구
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• 제8권1호
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• pp.41-44
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• 2002

＇97∼＇98년에 경북지역의 대구와 경산, 군위, 영천, 청도등 대추과원에서 과실에 역병이 발생되었다. 병징은 과실이 적갈색의 반점이 생기며 심하면 미이라가 되고, 말라서 조기낙과되며 엽병과 신초에도 마름증상을 나타내기도 했다. 이병과에서 2종의 역병균이 검출되었는데 총 18개 역병균중 6균주는 P. nicotiamae로 동정되었고, 나머지 12균주는 P. palmivora로 동정되었다. P. nicotianae는 유두돌기가 뚜렷하고 비탈락성인 구형 혹은 난형의 유주자낭과 다량의 후막포자를 형성하였으며 유성생식형은 자웅이주로 A1 mating type이 조사되었다. P. palmivora는 유주자낭이 유두돌기가 뚜렷하고 탈락성이며 장타원형 혹은 난형, 구형 등이었고, 다량의 후막포자를 형성하였으며 유성생식형은 자웅이주로 A1 mating type이 조사되었다. 2종의 역병균 모두 대추와 배에 강한 병원성을 나타내었으나. 사과에는 병원성이 없었다. P. nicotiamae 와 P. palmivora에 의한 대추 역병은 국내에서 최초로 보고되는 것이다.

• 식물병연구
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• 제7권1호
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• pp.8-10
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• 2001

1998년 경기도 고양시의 분화용 칼랑코에(Kalanchoe sp.)재배농가에서 줄기 하부가 검게 썩으며 급격히 시드는 증상으로부터 병원균을 분리.동정한 결과 Phytophthora nicotianae로 동정되었다. 병원균의 형태적 특성은 뚜렷한 유두돌기를 가진 유주자낭을 형성하였고, 원형~rPfis형이며 크기는 20~48$\times$24~64$\mu\textrm{m}$였고, 구형의 후막포자를 다량 형성하였다. 배양적 특성은 V8 juice agar와 corn-meal agar에서는 풍부한 균사를 형성하였으며, PDA에서는 전형적인 거미집 형태로 자라는 특성을 보였다. 생육온도범위는 최저 1$0^{\circ}C$, 최고 37$^{\circ}C$, 최적온도는 3$0^{\circ}C$였다. \\\"Florus\\\"를 비롯한 14개 칼랑코에 주요 재배품종에 대한 병원성검정을 실시한 결과 품종에 따라 저항성의 차이가 있었다.의 차이가 있었다.

• The Plant Pathology Journal
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• 제20권1호
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• pp.63-66
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• 2004

Ginseng (Panax ginseng) is one of the most widely cultivated medicinal herbs in Korea. However, yield losses reached up to 30-60％ due to various diseases during 3 or 5 years of ginseng cultivation in the country. Therefore, successful production of ginseng roots depends primarily on the control of diseases. The objective of this study was to select potential biocontrol agents from rhizobacteria isolated from various plant internal root tissues for the control of multiple ginseng diseases as an alternative to fungicides. Among 106 Bacillus strains, two promising biocontrol agents, Bacillus pumilus strain B1141 and Paenibacillus lentimobus strain B1146, were selected by screening against root rot of ginseng caused by Cylindrocarpon destructans in a greenhouse. Pre-inoculation of selected isolates to seed or l-year-old root of ginseng resulted in stimulation of shoot and/or root growth of seedlings, and successfully controlled root rot caused by C. destructans (P<0.05). Furthermore, drenching of cell suspension of the selected isolates on seedling-growing pots reduced the incidence of Phytophthora blight after the seedlings were challenged with zoospores of Phytophthora cactorum (P<0.05). P. lentimorbus strain B1146 showed antifungal activity against various soil-borne pathogens in vitro, while B. pumilus strain B1141 did not show any. Results of this study suggest that some rhizobacteria can induce resistance against various plant diseases on ginseng.

• The Plant Pathology Journal
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• 제35권3호
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• pp.219-233
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• 2019

Soybean cultivars susceptible to Phytophthora root and stem rot are vulnerable to seed rot and damping-off of seedlings and young plants following an infection by Phytophthora sojae. In this study, the disease responses of Japanese soybean cultivars including currently grown main cultivars during the early growth stages were investigated following infections by multiple P. sojae isolates from Japanese fields. The extent of the resistance to 17 P. sojae isolates after inoculations at 14, 21, and 28 days after seeding varied significantly among 18 Japanese and two US soybean cultivars. Moreover, the disease responses of each cultivar differed significantly depending on the P. sojae isolate and the plant age at inoculation. Additionally, the treatment of 'Nattosyo-ryu' seeds with three fungicidal agrochemicals provided significant protection from P. sojae when plants were inoculated at 14-28 days after seeding. These results indicate that none of the Japanese soybean cultivars are completely resistant to all tested P. sojae isolates during the first month after sowing. However, the severity of the disease was limited when plants were inoculated during the later growth stages. Furthermore, the protective effects of the tested agrochemicals were maintained for at least 28 days after the seed treatment. Japanese soybean cultivars susceptible to Phytophthora root and stem rot that are grown under environmental conditions favorable for P. sojae infections require the implementation of certain practices, such as seed treatments with appropriate agrochemicals, to ensure they are protected from P. sojae during the early part of the soybean growing season.

• 식물병연구
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• 제9권1호
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• pp.32-35
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• 2003

1999년 강원도 평창의 고랭지 감자 재배지에서 감자 홍색부패병이 발견된 이후 2001년과 2002년에는 전남 보성의 감자 재배지에서도 발생이 확인되었고 발병이 심한 지역에서는 약 5%정도의 이병율을 보였다. 병든 감자의 주요 병징은 괴경 외부가 연갈색으로 변색되어 부패증상이 나타나고 피목과 눈이 흑갈색으로 변화되어 건전 부위와 이병 부위가 쉽게 구분되었다. 또한 괴경 내부는 삶은 감자처럼 스폰지 형태로 변하고 냄새가 없었으며 괴경 절단면은 공기 중에 노출된지 30분 이후에 핑크색으로 변색되는 특징을 확인할 수 있었다. 균사는 배지에 따라 방사형, 장미꽃 또는 솜털 모양으로 특징적인 생육을 하였고, 균사생육온도는 5.0~3$0^{\circ}C$범위이고 최적온도는 $25^{\circ}C$였다. 유주자낭은 유두돌기 없이 선단 부위가 평편하고, 계란 또는 서양배 모양의 다양한 형태로 크기는 41.3~69.6$\times$26.8~47.4(평균 55.5$\times$37.1) $\mu\textrm{m}$이었다. 병원균은 동종생식에 의하여 유성생식기관을 형성하여 동일 배지에서 배양초기부터 엷은 황색의 난포자를 대량으로 생산하였고 장난기 형태는 구형으로 크기가 30$\times$46 $\mu\textrm{m}$이었고, 장정기는 저착성이고 형태가 신장된 타원형으로 크기가 13$\times$14 $\mu\textrm{m}$이었다. 이들 병원균의 배양적, 형태적 특성에 의거, Phytophthora erythroseptica에 의한 감자 홍색부패병으로 동정되어 국내에서 처음으로 보고한다.

• 한국응용곤충학회지
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• 제14권2호
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• pp.77-79
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• 1975

우리나라에서 Phytophthora capsici균에 의한 가지의 병해는 아직 그 발생이 보고되어 있지 않다. 근래 수원을 포함한 중부지방에 P. capsici균에 의한 피해과가 채집되어 기록병해인 P. parasitica균에 의한 솜털역병과 그 병징, 병원성 및 병원균의 형태등을 비교 검토하였다. 본 병은 9월 강우가 있은 후 발생이 심하였으며 처음 과면에 원형갈색의 병반이 나타나 점차 확대되면서 그 위에 짧은 균계와 분생자경이 밀생하고 유주자양이 풍부히 형성되어 솜털모양으로 공중균계가 길게 자라고 유주자양이 거의 형성되지 않는 솜털병역과는 구별되었다. 그리고 병원균의 형태 및 병원성에 있어서도 뚜렷한 차이를 볼 수 있었다. 따라서 본 병원균은 P. capsica임을 확인할 수 있었으며 미기록인 본병해에 대하여 가지갈색썩음병이라는 이름을 붙이기로 하였다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.103.2-104
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• 2003

Ginseng (Panax ginseng) is one of the most widely cultivated medicinal herbs in Korea. During 3 or 5 years cultivation of ginseng, yield losses can reach as high as 30-60％ due to numerous diseases in Korea. Among 106 Bacillus strains isolated from various plant internal roots, we selected three promising biocontrol agents by screening against root rot caused by Cylindrocarpon destructan in a greenhouse. Preinoculation of selected isolates to seed or one-year-old root resulted in stimulation of shoot and/or root growth of seedlings, and control of root rot in infested soils with Cylindronrpon destructans (P=0.05). Furthermore, drenching of selected isolates on seedling-growing pots reduced the incidence of Phytophthora blight when the seedlings were challenged with zoospores of Phytophthora cactorum (P=0.05). However, isolates B1141 and B1142 did not show any antifungal activity against various soilborne pathogens while B1146 did in vitro. Our results provide an insight that rhizobacteria can induce resistance against various plant diseases on ginseng even if any resistant breeds have been unknown on ginseng yet.