• 한국식물병리학회지
• /
• 제10권3호
• /
• pp.222-227
• /
• 1994

Effects of field applications of benomyl on Phomopsis seed decay of early soybeans were investigated at Suwon in 1992 and 1993. Pod and immature seed infections were markedly suppressed by benomyl application at the R6 stage whereas the spray at the R7 stage was not as effective as the spray at R6. When compared with unsprayed plots, benomyl spray at R6 resulted in decrease in Phomopsis seed infection by 37.1% and 73.9%, and increased in frequency of seed germination by 1.8% and 8.0% in 1992 and 1993, respectively. The results indicated that only one spray at early R6 could effectively reduce seed infection by Phomopsis spp.and could be adopted in a disease management program for commercial production of healthy soybean seeds.

• The Plant Pathology Journal
• /
• 제24권2호
• /
• pp.125-130
• /
• 2008

Various kinds of leaf spots and blights were found in kiwifruit (Actinidia deliciosa) orchards on 2006 in Korea. Disease incidences were quite variable between open-field and rain-proof shelter. Rate of diseased leaves was recorded as about 70% at open-field orchards in late season but use of rain-proof vinyl shelters alleviated the disease incidences by 20%. Angular leaf spots appeared at early infection stage on June and several other symptoms were also recognized as the disease developed afterward. On September, brown leaf blights were the most frequent, followed by grayish brown ring spots, silvering gray leaf blights, zonate leaf blights, dark brown ring spots and angular leaf spots at open-field orchards. Four fungal species were frequently isolated from the disease symptoms. Phomopsis sp. was the most predominant fungus associated with the leaf spot and blight symptoms on kiwifruit, followed by Glomerella cingulata, Alternaria alternata and Pestalo-tiopsis sp. Phomopsis sp. was commonly isolated from angular leaf spots, silvering gray leaf blights, and zonate brown leaf blights. G. cingulata, A. alternata and Pestalotiopsis sp. were isolated from grayish brown ring spots (anthracnose), brown ring spots and zonate dark brown leaf blights. Typical symptoms appeared on the wounded and unwounded leaves, which were inoculated by each of Phomopsis sp., G. cingulata, and Pestalotiopsis sp., but A. alternata caused symptoms only on the wounded leaves.

• 한국작물학회지
• /
• 제42권3호
• /
• pp.299-305
• /
• 1997

풋콩에서 문제시되는 미이라병의 꼬투리 리병 및 종실감염을 줄이기 위해 포장에서 베노밀을 생육 시기별로 처리한 결과는 다음과 같다. 1. 베노밀 처리에 따라 미이라병반이 없는 풋콩의 건전 꼬투리비율은 R5기 1회처리와 R4＋R5기 2회처리에서 가장 높았다. 2. 건전 꼬투리비율은 주경보다 분지에서, 그리고 상위부가 하위부보다 높았다. 3. 종실의 미이라리병입율은 베노밀 처리에 따라 감소되었고, R6기 1회처리와 R4.＋R6기 2회처리에서 낮았다. 4. 베노밀 처리에 다라 건전 꼬투리 및 종실비율이 높아져서 건전 꼬투리수량은 34∼76％ 그리고 종실수량은 51∼98％ 증수하였다.

• The Plant Pathology Journal
• /
• 제19권5호
• /
• pp.231-234
• /
• 2003

Brown rot symptoms severely occurred on fruits of apricot and mume grown in Changnyeong, Suwon and Yeongi in Korea during a disease survey in June 2002. A total of 32 isolates of Phomopsis sp. was obtained from the fruit rot symptoms. All isolates were identified as Phomopsis vexans based on their morphological and cultural characteristics. Four isolates of the fungus were tested for pathogenicity to fruits of apricot and mume by artificial inoculation. All isolates induced brown rot symptoms on the fruits of apricot and mume by wound inoculation. Unwounded inoculation also induced symptoms on mume fruits but not on apricot fruits. The symptoms on the fruits induced by artificial inoculation were similar to those observed in the orchard. The pathogenicity tests revealed that mume was more susceptible to the pathogen than apricot. This is the first report of brown rot of apricot and mume caused by P. vexans.

• Journal of Microbiology and Biotechnology
• /
• 제20권3호
• /
• pp.494-500
• /
• 2010

Bacterial blight, an important and potentially destructive bacterial disease in rice, is caused by Xanthomonas oryzae. Recently, this organism has developed resistance to available antibiotics, prompting scientists to find a suitable alternative. This study focused on secondary metabolites of Phomopsis longicolla to target X. oryzae. Five bioactive compounds were isolated by activity-guided fractionation from ethyl acetate extracts of mycelia and were identified by LC/MS and NMR spectroscopy as dicerandrol A, dicerandrol B, dicerandrol C, deacetylphomoxanthone B, and fusaristatin A. This is the first time fusaristatin A has been isolated from Phomopsis sp. Deacetylphomoxanthone B showed a higher antibacterial effect against X. oryzae KACC 10331 than the positive control (2,4-diacetyphloroglucinol). Dicerandrol A also showed high antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and yeast (Candida albicans). In addition, high production yields of these compounds were obtained at the stationary and death phases.

• Journal of Microbiology and Biotechnology
• /
• 제23권2호
• /
• pp.177-183
• /
• 2013

Bacterial blight, an important and potentially destructive bacterial disease in rice caused by Xanthomonas oryzae pv. oryzae (Xoo), has recently developed resistance to the available antibiotics. In this study, mass spectrometry (MS)-based metabolite profiling and multivariate analysis were employed to investigate the correlation between timedependent metabolite changes and antimicrobial activities against Xoo over the course of Phomopsis longicolla S1B4 fermentation. Metabolites were clearly differentiated based on fermentation time into phase 1 (days 4-8) and phase 2 (days 10-20) in the principal component analysis (PCA) plot. The multivariate statistical analysis showed that the metabolites contributing significantly for phases 1 and 2 were deacetylphomoxanthone B, monodeacetylphomoxanthone B, fusaristatin A, and dicerandrols A, B, and C as identified by liquid chromatography-mass spectrometry (LC-MS), and dimethylglycine, isobutyric acid, pyruvic acid, ribofuranose, galactofuranose, fructose, arabinose, hexitol, myristic acid, and propylstearic acid were identified by gas chromatography-mass spectrometry (GC-MS)-based metabolite profiling. The most significantly different secondary metabolites, especially deacetylphomoxanthone B, monodeacetylphomoxanthone B, and dicerandrol A, B and C, were positively correlated with antibacterial activity against Xoo during fermentation.

• 한국작물학회지
• /
• 제41권2호
• /
• pp.178-187
• /
• 1996

풋콩 조생품종들인 오꾸하라와세, 미카와시마, 화엄풋콩 및 석량풋콩의 4품종을 고냉지인 철원과 평창 및 평야지인 수원과 대구의 4개 지역에 1992년 5월15일과 6월15일 2회 파종하여 수확종실의 병해정도와 품종에 따라 6~7개월의 저온 저장후(5$\pm$1$^{\circ}C$) 발아율을 검토하였던 바, 그 결과를 요약하면 다음과 같다. 1. 종실의 병감염은 미이라병 나병률이 가장 높았고, 다음으로 갈반병이었으며 갈반병 나병이 가장 낮았다. 2. 종실의 미이라병, 갈반병 및 자반병 나병을 포함한 총 병해립율은 평창지역이 가장 낮았고, 6월15일 파종이 5월I5일 파종보다 낮은 경향을 보였다. 3. 종실의 미이라병 나병립율은 고냉지인 평창과 철원이 평야지인 수원과 대구보다 낮았고, 6월 15일 파종이 5월I5일 파종보다, 성숙기수확이 성숙후10일 수확보다 낮았다. 4. 종실의 저장후 발아율은 고냉지인 평창과 철원이 90% 이상으로 높아 평야지인 수원과 대구보다 높았으며 6월15일의 만파가 5월15일 파종보다 높았다. 5. 풋콩종실의 미이라병 나병이 낮고, 발아율이 높은 양질종자를 생산키 위해서는 국내 고냉지에서 6월15일의 만파가 유리하였다.

• The Plant Pathology Journal
• /
• 제31권3호
• /
• pp.290-298
• /
• 2015

Starting in 2012, severe diebacks usually accompanied by abundant gum exudation have occurred on yuzu trees in Goheung-gun, Jeonnam Province, where severely affected trees were occasionally killed. On-farm surveys were conducted at 30 randomly-selected orchards located at Pungyang-myeon, Goheung-gun, and the resulting disease incidences were 18.5% and 39.6% for dieback and gumming symptoms, respectively. Black spots on branches and leaves also appeared on infected trees showing a typical dieback symptom. Morphological and molecular identifications of the isolated fungal organisms from lesions on the symptomatic leaves and branches revealed that they are identical to Phomopsis citri, known to cause gummosis. In order to find the reason for this sudden epidemic, we investigated the weather conditions that are exclusively distinct from previous years, hypothesizing that certain weather extremes might have caused the severe induction of pre-existing disease for yuzu. There were two extreme temperature drops beyond the yuzu's cold hardiness limit right after an abnormally-warm-temperature-rise during the winter of 2011-12, which could cause severe frost damage resulting in mechanical injuries and physiological weakness to the affected trees. Furthermore, there was an increased frequency of strong wind events, seven times in 2012 compared to only a few times in the previous years, that could also lead to extensive injuries on branches. In conclusion, we estimated that the possible damages by severe frost and frequent strong wind events during 2012 could cause the yuzu trees to be vulnerable to subsequent fungal infection by providing physical entries and increasing plant susceptibility to infections.

• The Plant Pathology Journal
• /
• 제33권3호
• /
• pp.238-248
• /
• 2017

Pokkah Boeng is a serious disease of sugarcane, which can lead to devastating yield losses in crop-producing regions, including southern China. However, there is still uncertainty about the causal agent of the disease. Our aim was to isolate and characterize the pathogen through morphological, physiological, and molecular analyses. We isolated sugarcane-colonizing fungi in Fujian, China. Isolated fungi were first assessed for their cell wall degrading enzyme capabilities, and five isolates were identified for further analysis. Internal transcribed spacer sequencing revealed that these five strains are Fusarium, Alternaria, Phoma, Phomopsis, and Epicoccum. The Fusarium isolate was further identified as F. verticillioides after Calmodulin and EF-$1{\alpha}$ gene sequencing and microscopic morphology study. Pathogenicity assay confirmed that F. verticillioides was directly responsible for disease on sugarcane. Co-inoculation of F. verticillioides with other isolated fungi did not lead to a significant difference in disease severity, refuting the idea that other cellulolytic fungi can increase disease severity as an endophyte. This is the first report characterizing pathogenic F. verticillioides on sugarcane in southern China.

• The Plant Pathology Journal
• /
• 제28권1호
• /
• pp.55-59
• /
• 2012

Northern stem canker caused by $Diaporthe$ $phaseolorum$ var. $caulivora$ ($Dpc$) has become a serious disease in soybean. The objectives of this study were to survey the existence of $Dpc$ on soybean in Korea, and to examine the potential pathogenicity of $Dpc$ in seed decay. One such isolate, SSLP-4, isolated from a field-grown plant of the Korean soybean cultivar Danbaekkong, was identified as $Dpc$, based on its morphological and molecular characteristics by sequences of internal transcribed spacer (ITS), translation elongation factor (TEF) 1-${\alpha}$ and ${\beta}$-tubulin regions, as well as pathogenic analyses. Moreover, morphological and molecular analyses revealed that isolate SSLP-4 was nearly identical to $Dpc$ strains from the United States. Pathogenicity tests on hypocotyls of soybean seedlings and detached leaves resulted in typical symptoms of soybean northern stem canker and inoculation on plants at R5-R7 stage caused seed decay. All results suggest that the $Dpc$ strain SSLP-4 can cause both stem canker and seed decay on soybean. Thus, the SSLP-4 isolate has the potential to contribute greatly to understanding of host plant resistance mechanisms, both at vegetative and reproductive growth stages in soybean.