• Research in Plant Disease
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• v.12 no.2
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• pp.119-121
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• 2006

Anthracnose of pomegranate (Punica granatum) caused by Colletotrichum acutatum was observed in the exhibition field at Hamyang-gun, Gyeongsangnam-do Agricultural Research and Extension Services, and in farmer's orchard at Gaheo-myon, Hapcheon-gun, Gyeongnam province, Korea. The pathogen generally attacks on the fruits and induces dark lesion and rotting. The infected fruits were mostly dropped or mummified. The color of colonies of the pathogenic fungus grown on potato dextrose agar was pinkish gray. Conidia were fusiform in shape and was $8{\sim}16{\times}3{\sim}4{\mu}m$ in size. Appressoria were pale to dark brown in color, clavate in shape and was $8{\sim}12{\times}4{\sim}6{\mu}m$ in size. Optimum temperature for mycelial growth was $25^{\circ}C$. Pathogenicity of the causal organism was proved according to Koch's postulate. On the basis of mycological characteristics and pathogenicity test on fruit, the fungus was identified as Colletotrichum acutatum. This is the first report on the anthracnose of pomegranate caused by C. acutatum in Korea.

• Research in Plant Disease
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• v.10 no.4
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• pp.272-278
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• 2004

The disease development of Anthracnose of sweet persimmon in relation to release of conida of Colletotrichum gloeosporioides were observed in a farmer's field located in Jinju from 1998 to 2002. The conidia started to release from early April and reached maximum in June to late July. The amount of conidia production reduced drastically from early August. The number of conidia trapped was closely related to amount of precipitation at the same period and number of new infections on the emerging branches and young fruits in orchard. The conidia released during the April was not effected to disease occurrence of persimmon tree but the spores produced from inoculum source after early May significantly important to the infection of the pathogen on emerging branch and this infection was directly related to infections on young fruits. Consequently the early infections on the branches brought severe occurrence of Anthracnose in the orchard. Most of the infected fruits were dropped in unripe state. The earlier infection caused the earlier fruit drop. The rate of fruit drop was reached up to 84.1% in August when the disease was occurred severely. Anthracnose of sweet persimmon also occurred in market shelf and storage warehouse. The anthracnose fruits are presumed to be infected while in orchard. Because the symptom formed on the fruit was too tiny to eliminate, the infected fruits were involved in storage boxes and anthracnose gradually developed in storage condition. The rate of diseased fruit observed in Jinju area were 1.2 to 1.6%.

• Korean Journal of Environmental Agriculture
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• v.36 no.4
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• pp.299-305
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• 2017

BACKGROUND: Although the filamentous fungal pathogen Colletotrichum species causing anthracnose disease on various fruits including peach, apple, persimmon and grape, there is no report on Japanese plum in Korea. METHODS AND RESULTS: In 2016, diseased fruits showing typical anthracnose symptoms of Japanese plum were collected in market and ochards. Diseased tissue was cut off and disinfected subsequently with 70% ethanol for 1 min, and in 1% sodium hypochloride solution for 1 min, followed by three washes with sterile distilled water. The disinfected tissues were placed onto potato dextrose agar (PDA), and incubated at $25^{\circ}C$ in the dark for 5 to 7 days. For single-spore isolation, conidia were scraped off the plate using a loop, and suspended with 10 mL sterile distilled water. One hundred microliter of the conidial suspension was spread on PDA plates and incubated at $25^{\circ}C$. Finally, one germinated conidium was transferred onto PDA plates. Morphological and cultural characteries of colonies and spores of isolated Colletotrichum were observed after 7 to 10 days incubation on PDA. Molecular identification of isolates were analyzed by comparing rDNA-ITS gene sequences with NCBI GeneBank. CONCLUSION: Of eleven isolates of Colletotrichum isolated from anthracnose diseased Japanese plum fruits, six were identified as C. acutatum, and five as C. gloeosporioides based on diagnostic characteristics such as colony growth rate, shape and size of conidia, and rDNA-ITS sequences. This is the first report of Colletotrichum causing the anthracnose on Japanese plum in Korea.

• The Plant Pathology Journal
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• v.37 no.2
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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.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.185-188
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• 2010

This study was undertaken to isolate and to identify a fungal pathogen Monilinia sp. KV-27 associated with apple anthracnose. Rotted Fuji apples were used for the isolation of the fungus. The infected tissues were sterilized with 70% ethanol, washed with sterilized distilled water and were transferred to 50 ml containing potato dextrose broth (PDB) flasks. The peripheral hyphae of the fungal colony which developed from the infected tissues were isolated on to potato dextrose agar (PDA). On PDA plates the fungus grew well at $25^{\circ}C$ and occupied more than half of a 9 cm petri dish within 5 days. The fungal cultures on PDA were used for morphological observation and identification of the fungus. Conidiophores were produced on the gray to whitish sporodochial structures scattered on PDA plates. These conidiophores gave rise to chains of conidia, which were branched and easily detached in water. These structures were dark brown to black and consisted of hyphal masses. Conidia produced on PDA plates were hyline or light colored, lemon shaped or ellipsoidal ($10-13{\times}8.5-11{\mu}m$) in size.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.442-446
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• 2009

This study was undertaken to isolate and to identify a fungal pathogen Colletotrichum sp. KV-21 associated with apple anthracnose. Rotted Gala apples were used for the isolation of the fungus. The infected tissues were sterilized with 70% ethanol, washed with sterilized distilled water and were transferred to 50 ml containing potato broth (PDB) flasks. The peripheral hyphae of the fungal colony which developed from the infected tissues were isolated on to potato dextrose agar (PDA). On PDA plates the fungus grew well at $25^{\circ}C$ and occupied more than half of a 9 cm petri dish within 5 days. The fungal cultures on PDA were used for morphological observation and identification of the fungus. Conidiophores were produced on the gray to whitish sporodochial structures scattered on PDA plates which gave rise to conidiogenous cells. The structures of the conidia produced on PDA plates were subcylindrical to obovoid, fusoid, tapered and 4 to $6\;{\mu}m$ in size.

• Mycobiology
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• v.29 no.1
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• pp.48-53
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• 2001

Plants have the ability to acquire an enhanced level of resistance to pathogen attack after being exposed to specific biotic stimuli. To obtain plant growth-promoting rhizobacteria inducing resistance against cucumber anthracnose by Colletotrichum orbiculare, more than 800 strains of rhizobacteria were screened in the greenhouse. Among these strains, Bacillus amyloliquefaciens solate EXTN-1 showed significant disease control efficacy on the plants. Induction of pathogenesis-related(PR-la) gene expression by EXTN-1 was assessed using tobacco plants transformed with PR-1a::$\beta$-glucuronidase(GUS) construct. GUS activities of tobacco treated with EXTN-1 and salicylic acid-treated transgenic tobacco were significantly higher than those of tobacco plants with other treatments. Gene expression analyses indicated that EXTN-1 induces the accumulation of defense-related genes of tobacco. The results showed that some defense genes are expressed by the treatment with EXTN-1 suggesting the similar resistance mechanism by salicylic acid.

• The Plant Pathology Journal
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• v.37 no.3
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• pp.307-314
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• 2021

Pepper (Capsicum annuum L.) is an important agricultural crop worldwide. Recently, Colletotrichum scovillei, a member of the C. acutatum species complex, was reported to be the dominant pathogen causing pepper anthracnose disease in South Korea. In the present study, we isolated bacterial strains from rhizosphere soil in a pepper field in Gangwon Province, Korea, and assessed their antifungal ability against C. scovillei strain KC05. Among these strains, a strain named BS1 significantly inhibited mycelial growth, appressorium formation, and disease development of C. scovillei. By combined sequence analysis using 16S rRNA and partial gyrA sequences, strain BS1 was identified as Bacillus velezensis, a member of the B. subtilis species complex. BS1 produced hydrolytic enzymes (cellulase and protease) and iron-chelating siderophores. It also promoted chili pepper (cv. Nockwang) seedling growth compared with untreated plants. The study concluded that B. velezensis BS1 has good potential as a biocontrol agent of anthracnose disease in chili pepper caused by C. scovillei.

• Mycobiology
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• v.46 no.2
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• pp.85-91
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• 2018

Endophytic fungi strains (n = 81) were isolated from the leaves, barks, and fruits of Camellia oleifera from Hunan province (China) to delineate their species composition and potential as biological control agents of C. oleifera anthracnose. The fungi were identified by morphological and phylogenetic analyses. Fungal colonization rates of the leaves, barks, and fruits were 58.02, 27.16, and 14.81%, respectively. The isolates were identified as 14 genera, belonging to two subdivisions, Deuteromycotina and Ascomycotina; 87.65% of all isolates belonged to Deuteromycotina. The dominant species, occurring with a high relative frequency, were Pestalotiopsis sp. (14.81%), Penicillium sp. (14.81%), and Fusarium sp. (12.35%). The Simpson's and Shannon's diversity indices revealed the highest species diversity in the leaves, followed by the barks and fruits. The similarity index for the leaves versus barks comparison was the highest, indicating that the number of endophytic fungal species shared by the leaves and barks was higher than barks and fruits or leaves and fruits. Based on the results of dual culture experiments, only five strains exhibited antifungal activity against C. oleifera anthracnose pathogen, with isolate ty-64 (Oidium sp.) generating the broadest inhibition zones. Our results indicate that the endophytes associated with C. oleifera could be employed as natural agents controlling C. oleifera anthracnose.

• Research in Plant Disease
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• v.22 no.2
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• pp.127-131
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• 2016

During the year 2014, black locust (Robinia pseudoacacia L.) had been observed with dark brown spots on the leaves at Andong, Cheongsong, Mungyeong in Korea. Symptoms initially appeared as small, black lesions on the leaves, and sometimes, the leaves become yellow and ultimately leads to fall off the leaves. The pathogenic fungus grown in potato dextrose agar was white or sometime gray with mycelia in tufts and from which numerous conidia were produced. The conidia were straight and fusiform in shape and measured $8.3-17.2{\times}2.5-4.1{\mu}m$. Internal transcribed spacer (ITS) rRNA sequence analysis for sequence similarity of the ITS region revealed 100% identity with nucleotide sequences for Colletotrichum acutatum. The morphological characteristics, pathogenicity and molecular data have been confirmed that the symptomatic pathogen was C. acutatum. This is the first report of anthracnose caused by C. acutatum on black locust in Korea.