• Research in Plant Disease
• /
• v.8 no.1
• /
• pp.50-54
• /
• 2002

A total of 55 Colletotrichum isolates from strawberry plants with anthracnose symptoms(crown rot) were inhibited in mycelial growth on potato-dextrose agar(PDA) amended with fungicides in variable degrees depending on the chemicals used, especially showing no growth on PDA with 1 mg/m/tricyclazole. However, in the detached leaf test by treating chemicals before or after inoculation of Colletotrichum sp., tricyclazole was little effective in controlling symptom development; instead azoxystrobin, which had low in vitro inhibition of mycelial growth, inhibited strongly the symptom development. Some chemicals were tested for the control of strawberry crown rot in greenhouse using three methods, sprays soil drenching and plant dipping. No or little control effect were made by chemical spray and soil drenching, but plant dipping in chemical solution, especially azoxystrobin: reduced crown rot development by about 50% in the greenhouse suggesting that the azoxystrobin treatment may be an effective control method of the crown rot of strawberry. No differences in the control efficacy were noted according to the dipping time and chemical concentration of azoxystrobin not less than 10 min and 250 mg/m/, respectively.

• The Korean Journal of Mycology
• /
• v.50 no.3
• /
• pp.235-241
• /
• 2022

Anthracnose crown rot (ACR) has been observed in greenhouses during the nursery and harvest seasons in Gangwon Province, Korea. Infected plants showed black leaf spot, dark sunken pink conidial masses on petioles, wilting, and eventually death. Five isolates were obtained from the lesions of strawberry plants and were identified as a Colletotrichum gloeosporioides species complex based on their cultural and morphological characteristics. Multilocus sequence analysis of actin, calmodulin, chitin synthase, glyceraldehyde-3-phophate dehydrogenase genes, and internal transcribed spacer rDNA regions showed that the isolates formed a monophyletic group with the type strain of C. siamense. Pathogenicity tests were performed on the isolate, and Koch's postulates were performed to verify the relationship between Colletotrichum sp. and the strawberry plant variety Seolhyang. The isolate was pathogenic to strawberry plants, which exhibited typical ACR symptoms. Based on morphological characteristics, pathogenicity, and DNA sequence analyses, the fungus isolated in Korea was identified as C. siamense. This is first time C. siamense has been confirmed in ever-bearing strawberry varieties in Korea.

• Korean Journal Plant Pathology
• /
• v.11 no.1
• /
• pp.30-38
• /
• 1995

Anthracnose fungi associated with soybean (Glycine max), small red bean (Vigna angularis), and green bean (Phaseolus radiatus var. aurea) were compared with respect to cultural characteristics, morphological aspects, and pathogenicity. From the legumes, four different species of Colletotrichum were identified based on their morphological characters : C. truncatum, C. destructivum, C. trifolii and C. gloeosporioides. Colonies of Colletotrichum spp.on culture media varied in colour and growth habits depending upon the media and isolates. In general, formation of conidia, setae, and perithecia on water agar leaf medium was better than that on potato dextrose agar medium under near ultraviolet light. In cross inoculation tests, isolates of C. truncatum, c. destructivum, C. trifolii and C. gloeosporioides could infect soybean, small red bean, and green bean at different growth stages. There were some differences in pathogenicity or susceptibility depending on crops tested. C. truncatum was the most virulent and major pathogenic species among the four species.

• Korean Journal of Medicinal Crop Science
• /
• v.18 no.4
• /
• pp.244-247
• /
• 2010

It's crucial to control Alternaria blight and Anthracnose emerging mostly on ginseng leaves during the rainy season to increase the organic ginseng products. The purpose of this study is to investigate the efficay of lime-brodeaux spray on the ginseng leaves and evaluate the growth and yield of the ginseng, and the contents of ginsenoside and 70% ethanol extracts from 3-year-old ginseng variety, Cheonpoong. Lime-bordeaux sprayings were conducted in the ratio of 6-6 in June, 8-8 from July to September every 15 days. After June 10, the spraying have no effects on the growth leaf and stem, and there was no significant increase in chlorophyll contents. The ratio of intact leaf and root were distinctly increased because Alternaria blight and Anthracnose were decreased by spraying lime-bordeaux mixture. Root weight per plant and root yield were increased by 15%, and 62% in 3-year old ginseng, respectively, because the ratio of intact leaf and root were higher by using lime-bordeaux mixture. Furthermore, spraying of lime-bordeaux mixture is prone to increase the ratio of rusty root in ginseng. Spraying of lime-bordeaux mixture decreased both of the contents of ginsenoside and 70% ethanol extract by 13.7%, and 15.2% in 3-year-old ginseng, respectively.

• Research in Plant Disease
• /
• v.15 no.2
• /
• pp.88-93
• /
• 2009

In 2008, leaf rot and blight on pepper seeding ("Dokya-chungchung") occurred in a pepper farm at Hwaseong-si, Gyeonggi-do, Korea. The typical symptom is water-soaking and dark brown leaf blight at edges and tips of leaves. The fungal colonies isolated from infected tissues were pinkish at first and turned gradually to gray. Conidia were fusiform, non-septum, and $8.1-17.0{\times}2.0-3.8{\mu}m$ in size. Several specific PCR primers derived from the sequence of the internal transcribed spacer (ITS) region of the rDNA, such as CaINT, CgINT and CcINT were used for the identification of the fungal pathogen. The C. acutatum-specific primer CaINT was amplified single fragment of 496 bp that discriminated C. acutatum from the other species. The pathogenicity test was performed on seedlings and fruits of red pepper. On the basis of the morphological, molecular characteristics and pathogenicity test, we identified as Colletotrichum acutatum. This is the first report on leaf rot and blight on pepper seedling caused by C. acutatum in Korea.

• Korean Journal of Medicinal Crop Science
• /
• v.23 no.4
• /
• pp.284-291
• /
• 2015

This study was performed to investigate the effects of enhanced light transmission on plant growth, photosynthetic ability, and disease tolerance to leaf blight, anthracnose in ginseng (Panax ginseng C. A. Meyer, Araliacease family) during the early growth stage (April to June). The photosynthetic ratio, stomatal conductance, and stem diameter of plants grown under a shade net with 15% light transmission rate showed an increasing trend compared to the control plants (5% light transmission rate) although the growth of the aerial parts were not influenced significantly. Plant height, stem length, and leaf length of treated plants were not significantly different from those of the control plants. Root parameters, such as root length, diameter, and weight of treated plants increased significantly compared to the control. Yield performance ($187.4kg{\cdot}10a^{-1}$) of treated plants was 55.5% higher than that of the control ($150.4kg{\cdot}10a^{-1}$). Additionally, disease severity scores of treated plants were lower than those of the control plants, revealing higher survival rates. To retain high yield potential and enhance the level of disease tolerance in ginseng, we suggest the increase of light transmission rate during the early growth stage.

• Korean Journal of Medicinal Crop Science
• /
• v.20 no.5
• /
• pp.339-344
• /
• 2012

This study was carried out to research microorganisms having the antifungal activity against ginseng Alternaria blight pathogen Alternaria panax and ginseng anthracnose pathogen Colletotrichum gloeosporioides. Eleven Bacillus strains. were isolated from Korean traditional soybean paste and Kimchi. Among the 11 isolates, DJ5, KC1, KC2 and KC4 showing antagonistic activity on the mycelial growth of A. panax and C. gloeosporioides in pairing culture were finally selected as the antagonistic microorganisms. Based on 16s rRNA sequence and phylogenetic tree analysis, they were identified as Bacillus spp.. The selected microorganisms were investigated antagonistic activity by measured leaf-segment colonization in pot test. When Bacillus sp. were injected after A. panax treatment, KC1, KC2 and KC4 showed similar effect to chemical pesticides treated control. To measure preventive effect of Bacillus sp, antagonistic microorganisms were injected and C. gloeosporioides was treated in pot. When measuring the effectiveness for the prevention of Anthracnose, All Bacillus spp. showed approximately 83~90 % degree of superior preventive effect. In general, The four Bacillus spp. isolated from Korean traditional fermented foods showed therapeutic effect of Alternaria blight and preventive effect of Anthracnose.

• The Korean Journal of Mycology
• /
• v.47 no.4
• /
• pp.393-406
• /
• 2019

In August 2017, anthracnose symptoms were observed on the petioles and leaf veins of Korean radish (Rhaphanus sativus) in Hongcheon, Jeongseon, and Pyeongchang of the Gangwon province, Korea. Many grayish to dark-brown spots of 1-2 mm in diameter, appeared on the lower surface and leaf veins of the radish leaves. The spots gradually enlarged and coalesced to form dark-brown irregular lesions. Ten Colletotrichum isolates were obtained from the affected tissues of the Korean radish. Out of them, eight isolates were identified as C. higginsianum and two isolates were identified as C. truncatum based on morphological characteristics and multi-locus molecular phylogenetic analysis using the internal transcribed spacers and intervening 5.8S rDNA (ITS), partial beta-tubulin gene (TUB2), partial actin gene (ACT), and partial chitin synthase-1 gene (CHS1). The pathogenicity test was carried out on wounded and unwounded Korean radish (cv. Siraegimu and Osarimu), and Chinese cabbage (cv. Chuno and Smart) by inoculating with a spore suspension. All isolates except one C. truncatum isolate developed typical symptoms on both wounded and unwounded Korean radish. In Chinese cabbage, only the plants inoculated with C. higginsianum isolates developed symptoms regardless of the wound. This is the first report of anthracnose caused by C. truncatum on Korean radish in Korea.

• The Plant Pathology Journal
• /
• v.24 no.2
• /
• 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.

• 한국약용작물학회:학술대회논문집
• /
• 2011.09a
• /
• pp.342-343
• /
• 2011