• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.454-459
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• 2013

Beet armyworm, Spodoptera exigua is difficult to control using chemical insecticides because of the fast development of insecticide resistance. For eco-friendly beet armyworm managements, various control agents are required. Entomopathogenic fungus is one of the promise control agents as an alternative to chemical control agent. We isolated entomopathogenic fungi from soil samples of Yangpyeong, Gyeonggi-do by insect-bait method using Tenebio molitor and conducted bioassay to larva of beet armyworm. The result of bioassay, a selected strain FT83 showed 100% mortality against third instar larva of S. exigua. On the basis of morphological characteristics and analysis of 18srRNA sequence for ITS, the strain FT83 was identified as a Metarhizium anisopliae. The mortality of beet armyworm showed $81.6{\pm}9.3%$ at $1{\times}10^6$ conidia/ml, 100% at $1{\times}10^7$ conidia/ml and 100% at $1{\times}10^8$ conidia/ml respectively. Therefore, we recommend to proper control efficacy against S. exigua in which more than $1{\times}10^7$ conidia/ml suspension of M. anisopliae FT83.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.115-121
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• 1978

Early developmental stages of Mactra chinensis were bioassayied to determin the water quality of the costal waters of Busan. The water samples were obtained at 12 stations from July 12 to July 17, 1977. Water quality evaluation was made in terms of the rates of normal development to abnormal development in three indicatory states, i. e. fertilization membrane formation, morula and trochophore larvae. The pollution degree of the waters brought from five swimming beaches was found to be highest at Haewundae followed by Songdo, Kwang-anri, Songjeong and Dadaepo with decreasing order. The highest value of the water at Haewundae was mainly due to the accidental oil spill from an oil tanker which happened on July 7, 1977. At Dongsamdong the rate of total abnormal development was $47.17\%$. This result is apparently attributable to fish byproducts discarded from a number of restaurants. At Chungmudong where a large fish-market is located, the rate of total abnormal development was $61.14\%$. At Suyeng Bay and Yongho Bay the rates of total abnormal development were $73.82\%$ and $72.90\%$ respectively. At these bays the drainage presumably contains a large amount of chemical pollutants from the industrial areas. This result shows that no organisms can normally breed in these regions.

• Journal of Life Science
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• v.18 no.6
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• pp.858-864
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• 2008

In the greenhouse fields for fruits and vegetables during the winter in Korea, there are serious damages by the sclerotium diseases due to the low temperature and humidity. This study was carried out to select an antagonic agent for the biological control of the sclerotium diseases. The 55 antagonic agents were selected from the rhizosphere in soil where the fruits and vegetables were cultivated in the green house fields, and strain AB02 among the tested isolates was estimated to be the strongest antagonist against the sclerotium disease. Using strain AB02, the antifungal spectrum was tested against 5 different plant pathogens. According to the results of the test, strain AB02 . showed the high antagonistic effect against Botrytis cinerea and Sclerotinia sclerotiorum. For the experiment of biological control against the sclerotium disease, it was estimated the suppression effect and the control effect by the strain in the pot experiment using the green perilla. According to the result of the pot experiments, the suppression effect was 40% and the control effect was 62%, respectively. For the stimulation effect of the tested plant growth by strain AB02 compared to the control, it was improved as 120% for the total length, 141% for the liveweight, 121% for the total number of leaves, 185% for the leaf area, and 327% for the liveweight of the root, respectively. Strain AB02 showing the antagonistic effect against the sclerotium disease and the stimulation effect for the plant growth was identified as Bacillus sp.

• Environmental and Resource Economics Review
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• v.22 no.3
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• pp.521-545
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• 2013

This study applied choice experiment(CE) method(which is included in the stated preference method) to estimate values of some important attributes(i.e. type of estuary, water quality of river in estuary, water quality of sea in estuary, biodiversity level of estuary) of 4 major river(Hangang, Guemgang, Yeongsangang, Nakdonggang) estuaries in Korea. Although the multinomial logit model(MNL) is generally applied to analyse the CE data, testing for IIA assumption with the Hausman and McFadden test in MNL model shows that the IIA assumption in our data is rejected. Therefore, the heteroscedastic extreme value model(HEV) and the multinomial probit model(MNP) which are not based on the IIA assumption are used to analyse our CE data. As results, the coefficients and the elicited economic values of MNL model are seriously distorted if the IIA assumption is not satisfied in MNL model. The estimation results of MNP model show that the economic values are elicited as 352.3 billion won(95% C.I. 261.1 - 477.8 billion won) for natural estuary, 411.5 billion won(95% C.I. 338.5 - 525.5 billion won) for one grade improvement of river water quality in estuary, 358.9 billion won(95% C.I. 292.5 - 457.0 billion won) for one grade improvement of sea water quality in estuary, and 151.9 billion won(95% C.I. 99.0 - 218.6 billion won) for one grade improvement of biodiversity level of estuary. Therefore, the value of estuary is reached to 2,197.0 billion won(95% C.I. 1,721.0 - 2,879.9 billion won) if any natural estuary in 4 major rivers has good water quality of river in estuary(i.e. 2nd grade), good water quality of sea in estuary(i.e. 1st grade), and good biodiversity level of estuary.

• Korean Journal of Environmental Agriculture
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• v.23 no.4
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• pp.203-210
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• 2004

This study was conducted to assessment organic compound and bioassay (density of inhabited animal, fluctuation of predominant fungi, and survival ratio of earthworm) for finding damage on red pepper by heavily amount application of sludges in soil, which was treated with 3 pharmaceutical byproducts and a cosmetic industry wastewater sludge as raw materials of compost, and for establishing estimation method. HEM contents in the soil treated with pharmaceutical byproducts sludge2 (PS2) and cosmetic sludge (CS) were 0.51, 1.10 mg/kg respectively. PAHs content of PS2 treatment in the soil was 3406.8 ug/kg on July 8. In abundance of soil faunas, the pharmaceutical byproducts sludge2 treatment was the most highest. The next was decreased in the order of pig manure (PM) and the cosmetic sludge treatment. However the other pharmaceutical sludge treatments were remarkably reduced populations of soil inhabited animals. In upland soil treated with organic sludges, the numbers of bacteria and fungi of the pharmaceutical sludge treatment were 736, 909 cfu/g and those of the cosmetic sludge treatment were 440, 236 cfu/g, respectively. The pharmaceutical sludge treatments and the cosmetic sludge treatment in identification of predominant bacteria were not any tendency to compare with non fertilizer and pig manure treatments, but they had diverse bacteria than NPK treatment. In microcosm tests, the survival of the tiger earthworm in five soil samples was hardly affected against the soil of PSI (20%) after three months treated in the upland But after six months, survival of PS1 was 80%. At present, raw material of compost was authorized by contents of organic matter, heavy metal (8 elements), and product processing according to 'The specified gist on possible materials of using after analysis and investigation among raw materials of compost', however, for preparing to change regulation of raw material of compost and for considering to possibility of application, this study was conducted to investigate toxic organic compound and bioassay methods using inhabited animal, fungi, and earthworm without current regulation.

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.176-181
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• 2010

Brown patch (Rhizoctonia solani AG1-1), dollar spot (Sclerotinia homoeocarpa), pythium blight (Pythium spp.), anthracnose (Colletotrichum graminicola), yellow patch (Rhizoctonia cerealis) and Zoysia patch (Rhizoctonia solani AG2-2) are the major turfgrasses diseases in Korea. In this study, 23 medicinal plant extracts were tested for antifungal activities against turfgrass pathogenic fungi. In paper disk diffusion method, 12 medicinal plant extracts, including Sophora flavescens, showed antifungal activity. Also, in the test of antifungal activity on media contained the extracts of S. flavescens, Curcuma longa, Rheum undulatum, Coptis chinensis and Asiasarum sieboldi showed above 80% inhibitory effects on the mycelial growth in 110 mg/10 ml concentration of the extracts. S. flavescens, in particularly, showed antifungal activity against the six turfgrass pathogenic fungi. The inhibition rate of S. homoeocarpa was 100% in 10 mg/10 ml, 5 mg/10 ml and 2 mg/10 ml concentrations of C. longa extract. In case of Pythium spp., the extracts of S. flavescens, R. undulatum and C. chinensis showed 100 % inhibition rate on the test media.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.831-841
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• 2017

Different timings of coverage by a small paper bag at the young fruit stage were tested in order to evaluate the effect on the protection of fruit damage occurred by disease or pest, and quality deterioration during organic cultivation of 'Hwasan' (Pyrus pyrifolia Nakai) pear cultivar. The occurrence of four major moth populations and two major diseases in pears were monitored from April to September 2015. Among major moths and diseases, Grapholita molesta and pear rust were found often in the organic pear orchard, and they were observed frequently in May. Coverage by a small paper bag at the young fruit stage resulted in better fruit quality and a higher proportion of commercial fruits compared to a coverage timing of conventional paper bag. Interestingly, the fastest coverage timing of a small paper bag at the young fruit stage (when it was covered in April) showed the lowest occurrence of damaged fruits, which indicates that it successfully protected fruits from the damage caused by moths and diseases during April and May. Moreover, this timing of small paper bag coverage did not negatively affect the major qualitative and quantitative characteristics of fruits. These results suggest that early coverage by a small paper bag at the young fruit stage can be considered an efficient management strategy for organic cultivation of 'Hwasan' pear cultivar.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.1
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• pp.55-59
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• 1978

This study was carried out to investigate the sea sonal changes of the contents of inhibitors in leaves and fruits of Ginseng plant during ripening. Three kinds of inhibitors in leaves and all parts of fruit, i.e., seed, sarcocarp and endocarp were recognized at the Rf 0.1, 0.4-0.6 and 0.8-1.0 zones by the bioassay of lettuce seed germination. Among them, the level of the inhibitor at the Rf 0.4-0.6 zone in leaf and seed increased most significantly in accordance with fruit ripening. The activities of three inhibitors found in endocarp gradually decreased during ripening.

• Korean journal of applied entomology
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• v.35 no.2
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• pp.153-158
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• 1996

Methanol extracts from 79 domestic plant species in 41 families and the crude oil of one Japanese plant species were tested for their larvicidal activities against Thecodiplosis japonensis Uchida et Inouye, using filter paperimpregnated and insect-dipping methods. In a test with 10 mgtpaper, strong larvicidal activity (>90% mortality) was obtained from the extracts of roots from three domestic plants belonging to Ranunculaceae (Aconitum pseudo- leave var. eretum, A. carmichaeli and Clematis florida) and the crude oil of sawdust from a Japanese plant, Thujopsis dolabrata var. hondai (Cupressaceae). However, only the crude oil from the Thujopsis sawdust revealed strong larvicidal activity when tested with 5,000 ppm by insect-dipping method. It is concluded that the Thujopsis sawdust-derived materials could be useful as a new control agent against T. japonensis.

• Analytical Science and Technology
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• v.21 no.2
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• pp.84-92
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• 2008

A method for the determination of trace amount of caffeine in urine and various drink samples using hollow fiber-liquid phase microextraction (HF-LPME) and capillary gas chromatograph/nitrogen phosphorus detector (GC/NPD) has been established. HF-LPME method has been optimized with respect to several experimental parameters including the effects of the hollow fiber length, extraction solvent, stirring mode, pH and salt concentration for the determination of caffeine from aqueous samples. The correlation coefficient of calibration curve for caffeine was 0.9994. The average recovery was 102%(n=3). The established method is feasible for the determination of trace amounts of caffeine in several aqueous sample. The limit of detection (LOD) and the limit of quantitation (LOQ) have been found to be 2.5 and 10 ng/mL, respectively. The established HF-LPME method for the analysis of caffeine from aqueous sample can be used for the determination of biological, food and environmental samples.