• Research in Plant Disease
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• v.23 no.2
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• pp.202-205
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• 2017

Pink rot appeared in greenhouse-grown sunflower (Helianthus annuus L.) in Jeonju, Korea. The symptoms appeared as brown discoloration of sunflower head and progressed into stem in advanced stage. In order to investigate the causal organism of this disease, we isolated a fungus from the infected seeds and maintained the isolated fungal culture on potato dextrose agar medium. Conidiophores were simple or branched, 62.5 to $123.1{\mu}m$ long. Conidia were produced in basipetal chains, ellipsoidal to pyriform with oblique and prominent truncate basal scars, two-celled, hyaline and measured $10.2-21.4{\times}7.5-12.6{\mu}m$. The fungus was inoculated to a new sunflower plant and showed the typical blight on the leaves. Study of morphological characters, pathogenicity tests and sequence analysis revealed that the isolated fungus is confirmed to be Trichothecium roseum. To our knowledge, this is the first report of pink rot on sunflower caused by T. roseum in Korea.

• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.265-271
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• 1999

The direct seeding of seeds or the pellets of three native tree species (Pinus densiflora, Parthenocissus tricuspidata and Rhus chinensis) was tried on the rock cut-slope revegetation bed established by construction of mechanical excavation or erosion break with artificially enriched soil medium. The seed $pellet(1{\sim}2\;cubic\;cm)$ made by coating seeds(treated with proper previous pregermination treatments) with the mixture of peatmoss, clay, chemical absorbant(3.5:1.0:0.2, v/v) showed about twice better percent germination than the control seeds. The percent germination and the survival rate of the germinated seedlings were higher in the spring direct seeding than the summer or the fall. The soil medium containing the compost showed extremely low percent $germination(0{\sim}3%)$ which presumably attributed to the compost inducing damping-off disease. The survival rates were affected mainly by shading of natural herbaceous vegetation invading from outside to the revegetation bed. The planting of two year old container seedlings of P. densiflora and P. tricuspidata on August 2, 1998 was successful indicating that it could be an alternative revegetation method in case the summer direct seeding is unfavorable.

• The Korean Journal of Mycology
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• v.35 no.2
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• pp.115-120
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• 2007

Powdery mildew caused by Podosphaera fusca is one of the most important diseases in leafy lettuce (Lactuca sativa L.). Since the disease has been a threat to safe cultivation of leafy lettuce, its control methods have to develop to produce good quality of lettuce for farmer and consumer. Occurrence of lettuce powdery mildew is increasing more and more due to continuous cultivation of lettuce all through the year, non-removal of diseased plant parts of lettuce, spray of inadequate fungicides by mistaken acknowledge of lettuce powdery mildew for lettuce downy mildew, etc. The control effect of five fungicides against lettuce powdery mildew was examined in a plastic greenhouse located in Suwon. When fungicides were sprayed three times at 10 days-intervals in the early stage of occurrence of powdery mildew, the incidence of powdery mildew in the plants treated with kresoxim-methy SC, azoxystrobin SC, Ampelomyces quisqualis AQ94013 WP, Paenibacillus polymyxa AC-1 SC and Bacillus subtilis Y 1336 WP was 0.7%, 0.7%, 26.0%, 36.7% and 42.0%, respectively, whereas the incidence of non-treated control was 55.3% on eight days after final application. Phytotoxicity of five fungicides tested was not observed in lettuce seedling plants.

• Food Science and Preservation
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• v.11 no.4
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• pp.485-490
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• 2004

Crude corn oil (CCO) was obtained through the expression-extraction process from corn germ. The CCOs of final process at $90^{\circ}C,\;70^{\circ}C\;and\;50^{\circ}C$ were stored in outdoor storage tanks. From the samples, refined CCO (RCCO) were prepared with $0\%,\;10\%\;and\;20\%$ excessive of phosphoric acid, caustic solution and acidic clay were used in degumming-alkali refining-bleaching process. RCCOs were stored at room temperature in dark places. The color change was not effected by the amount of phosphoric acid, caustic solution and acidic clay, but temperature of process affects the color change. Finally, the prevention for color reversion of RCCO could be obtained by lowering the temperature of final process and optimal temperature of RCCO in summer was found about less than $50^{\circ}C$.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.90-95
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• 1986

A comparative study of chemical characteristics, efficacy and relative merits of extruded and coated granules, containing fungicide and insecticide, was conducted under laboratory and field conditions. Probenzole (3-allyloxy-1,2-benzisothiazole 1,1-dioxide) and carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methyl carbamate) were chosen as toxicants for rice blast(Pyricularia oryzae) and brown planthopper (Nilaparvata lugens) control, respectively. Stability of active ingredients in coated granule was superior to the extruded one under accelerated temperature. Active ingredient dissolution of coated one into distilled water showed slow release pattern. Pesticide residues in rice (Oryzae sativa, Chucheongbyeo) shoot applied with extruded one at the dosage of 3kg/10a retained higher levels than those with coated one on two days after application, while the residue levels were a reversed tendency on eight days after application. Efficacy on rice blast exhibited minute differences between the granules, on the other hand efficacy on brown planthopper by coated one was of higher rank than that by extruded one. Production cost of the combined pesticide granule by coating method could be cut down by 6% as compared to extrusion method.

• The Korean Journal of Pesticide Science
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• v.7 no.2
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• pp.149-154
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• 2003

Potato blackleg disease caused by Erwinia carotovora subsp. atroseptica has been a serious problem in Korea. It was previously reported that four mixtures [streptomycin (9.3 ppm) + copper oxide (171.6 ppm)/copper hydroxide (146.3 ppm), streptomycin sulfate (7.0 ppm)+copper oxide (171.6ppm)/copper hydroxide (146.3 ppm)] were effective for the control of E. carotovora subsp. atroseptica. in in vitro test. Using those four mixtures and two antibiotics [streptomycin (81.4 ppm) and streptomycin sulfate (61.3 ppm)], the effectiveness of control for E. carotovora subsp. atroseptica. was conducted in the field. Two antibiotics showed over 60% of control efficacy under different soil conditions, while mixtures of two antibiotics with copper compounds did not show any control effects on the infected seed potato. Two mixtures [streptomycin (27.9 ppm)+copper hydroxide (438.9 ppm), streptomycin sulfate (21.0 ppm) + copper oxide (514.8 ppm)] were effective in the control of potato blackleg disease on the infected potato plants under different climate conditions.

• Korean journal of applied entomology
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• v.21 no.2 s.51
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• pp.61-67
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• 1982

The strawberry cultivar Hokowase showing rapid wilting and death around harvest time was first found in the fold at Woongcheon, Chungnam province in 1974. The fungus, Fusarium oxysporum was isolated frequently from the crown, petiole and root of strawberry plants collected from Woongcheon and was pathogenic to Hokowase. The fungus abundantly produced micro-and macro-conidia and chiamydospore on PSA. The size of micro conidia, macro conidia and Chlamydospores was $5.0\~13.0\times2.5\~3.0,\;12.8\~62.5\times2.5\times50\mu\;and\;7.5\~13.8\times5.5\~12.5\mu$, respectively. Mycelial growth of the fungus was best between $25\~30^{\circ}C$ on PSA. The disease at Woongcheon occurred from the end of March and incidence of the disease increased from the beginning of May reaching $40.2\%$ of diseased Plants at the 1st part of June. In laboratory and field evaluation tests with twelve fungicides, Difolatan, Benlate T and Tospin M showed some control effects against the disease although they did not show ignificant differences in effects compared with that of the non-treatment. The cultivar Yachiyo, Daehak 1, Line 10-2, and Senga Sengana were highly resistant, and Harunoka and Empire were moderate resistant whereas Northwest and Hokowase were highly susceptible to the fungus under field condition.

• Journal of Ginseng Research
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• v.33 no.2
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• pp.127-131
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• 2009

The plant protection rate of the marketed microbial products for ginseng cultivation was investigated against Rhizoctoina solani and Pythium sp. in a seedling pot experiment. A significant difference was found among the mean plant protection rates (Pm) of the microbial products, including Tolclofos-methyl (Rhizolex). The best microbial product, C-ISR2, showed a 33% and 33.6% net Pm (total Pm-control Pm) in the two tests against Rhizoctonia solani. In one test with a 58.6% control plot Pm, the total pm was 91.6%, indicating that plant protection can be done only with a microbial product in a well-conditioned field. The net Pm of C-ISR2 against Pythium sp. was 26.4%. The net Pm of a microbial product against a pathogen seems to be fixed. A significant negative linear correlation was found between the Pm and the coefficient of variation (CV) of the protection rate in all the three experiments. This indicates that the protection processes of control, microbial products, and chemical pesticides are in the same system. Pm was only dependent on CV, probably due to each seedling's microenvironment. In the linear correlation equation between the Pm and the CV of the microbial products and the control plot, the intercept of the vertical axis will be the theoretical Pm when CV is zero.

• The Korean Journal of Mycology
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• v.46 no.1
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• pp.58-68
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• 2018

Sunn hemp (Crotalaria juncea) is used as a nitrogen-fixing green manure in Korea to improve soil quality, reduce soil erosion, and suppress weeds and nematodes. In 2014, wilting sunn hemp plants were observed in green manure-cultivated fields in Wanju, Korea. Leaves of the infected plants began yellowing, starting with the lower leaves, eventually leading to their death. Moreover, a number of dark perithecia were observed on the wilting stems. Six isolates were obtained from these perithecia by single spore isolation. Based on their morphological characteristics, the isolates were identified as Fusarium udum (teleomorph: Gibberella indica). Macroconidia were slightly curved with almost hooked apical cell, and microconidia were formed on false heads by monophialides. Chlamydospores were produced abundantly in the hyphae, either singly or in clusters. To confirm the identification, multilocus sequence analysis was conducted using translation elongation factor 1 alpha (TEF), calmodulin (CAL), and histone 3 (HIS3). The sequences of TEF, CAL, and HIS3 showed 94.4~96.2%, 99.7%, and 99.6~99.8% similarity to the reference sequences of F. udum in NCBI GenBank, respectively. Pathogenicity was tested on sunn hemp and two soybean cultivars using the inoculation method of soil drenching with spore suspension. The wilting symptoms were observed only in sunn hemp and one cultivar of soybean (cv. Teagwang) after 14~21 days of inoculation. This is the first report of wilt disease in sunn hemp caused by Fusarium udum in Korea.

• The Korean Journal of Mycology
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• v.48 no.3
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• pp.297-312
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• 2020

Wilted soybean plants were collected from soybeans cultivation fields in Korea from 2014 to 2016. Fusarium spp., Colletotrichum spp., Rhizoctonia spp., Macrophomina sp., Phytophthora spp., and Calonectria ilicicola were obtained from the infected samples. Out of these, Fusarium spp. were the dominant species (79.1%). In total, 53 isolates were identified as F. solani species complex, F. oxysporum species complex, F. graminearum species complex, and F. fujikuroi species complex based on mycological characteristics. Sequence typing analysis was conducted using translation elongation factor 1 alpha (TEF) to confirm the identification of isolates. All isolates were identified as F. solani, F. oxysporum, F. commune, F. asiaticum, and F. fujikuroi based on phylogenetic analysis of TEF sequences. Pathogenicity of 44 isolates was tested on three cultivars of soybean using the root dip inoculation method. Out of 5 Fusarium species, only F. asiaticum could not cause the symptoms or be weak. Ten isolates were selected based on pathogenic characters and species identification to investigate the host range and screen soybean cultivars for resistance. Fusarium solani, F. oxysporum, and F. commune were aggressive only to soybean, and F. fujikuroi was aggressive to kidney bean, yellow cowpea, black cowpea, adzuki bean as well as soybean. All 13 Korean soybean cultivars were susceptible to F. commune and F. fujikuroi. Out of 13 cultivars, cv. Janggi, cv. Poongsannamul, and cv. Socheongja were resistant to Fusarium wilt, while cv. Hwanggeumol and Chamol were susceptible to Fusarium wilt.