• The Plant Pathology Journal
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• 제20권4호
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• pp.235-239
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• 2004

Phytophthora rot on sword bean, Canavalia gladiata, which has not been reported yet in Korea, occurred in some fields of Jinju in 2003. The disease develops on the basal stem of the plant, but is also often observed on leaves and pods. Rot lesions begin with small dark brown spots and as these are water-soaked, they enlarge rapidly. The magnitude of at the field reached 40%. Abundant sporangia of Phytophthora were formed on the surface of diseased pods and were mummied later. The causal fungus was identified as P. nicotianae with the following mycological characteristics: Sporangium-readily formed in water, papillate, noncaducous, ovoid to spherical, 24-58 (L) ${\times}$ 22-35 (W) in size; Oogonium-spherical, smooth walled, and 22-30; Oospore- aplerotic, spherical, and 18-24; Antheridium- amphigynous, unicellula, and spherical; Chlamydospore- abundant, spherical, and 25-35; Sexuality- heterothallic, and A1 or A2; Optimum growth temperature- about 28$^{\circ}C.$ The fungus showed strong pathogenicity to sword bean. Symptoms similar to those observed in the fields appeared 2 days and 4 days after inoculation with and without wound on pods. This is the first report of Phytophthora rot of sword bean in Korea.

• The Plant Pathology Journal
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• 제25권2호
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• pp.121-127
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• 2009

Since July 2005, survey of chestnut ink disease was carried out in chestnut stands located at southern parts of Korea. Dead chestnut trees showing inky ooze on necrotic trunks were found in two different locations. In order to isolate and identify the causal fungus, infected tissues and soil samples around dead or dying trees were collected and placed on Phytophthora-selective medium. Rhododendron and chestnut tree leaves were used as a bait to isolate the fungus from soil samples by attracting zoospores in soil suspensions. On V-8 culture medium, the isolates produced homothallic oogonia with protuberances ($34.0-46.2{\times}21.9-26.7{\mu}m$) abundantly, but did not produced sporangia. Mass production of sporangia was possible by immersing agar plugs with actively growing mycelium in the creek water at $18^{\circ}C$ for 3 days. Sporangia were papillate, and ovoid to obpyriform ($17.0-38.9{\times}14.6-29.2{\mu}m$) in shape. Comparison of the ITS sequences revealed that the isolates had 100% identity to the P. katsurae isolates from Japan and New Zealand and 99.6% identity to other P. katsurae isolates. All of the examined isolates from Korea were completely identical to each other in ITS sequence. Numerous sporangia were formed in filtered as well as unfiltered creek water, but no sporangia formed in sterilized distilled water. Light induced sporangia formation, but has no influence on oospore formation. Amendments of ${\beta}$-sitosterol in culture media have no significant effect on mycelial growth but significantly stimulate oospore and sporangia formation.

• 식물병연구
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• 제11권1호
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• pp.72-76
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• 2005

2002년에서 2003년까지 경상남도 사천시 와룡산 기슭의 서향 재배포장에서 Phytophthora nicotianae에 의한 서향 역병이 발생하였다. 병징은 잎이 황화되면서 떨어지고 줄기 및 지제부워가 암갈색의 수침상으로 갈변되어 썩으면서 시들어 말라 죽는다. PDA 배지 상에서 균총은 전형적인 장미꽃 또는 거미집 형태를 나타내었고 균사생육은 느렸다. 유주자낭은 구형 또는 난형이며 많은 양의 후막포자를 형성하였으며, 크기는 23~$56{\times}21$~$34\mu\textrm{m}$ 이었다. 유성생식형은 자웅이주이며, 후막포자는 구형이며 크기는 16~$32\mu\textrm{m}$이었다. 난포자는 비충만형으로 크기는 18~$26\mu\textrm{m}$ 이다. 장정기는 저착이며 구형이었다. 균사 생육적온은 25~$30^{\circ}C$ 였다.