• Asian-Australasian Journal of Animal Sciences
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• v.32 no.5
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• pp.665-674
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• 2019

Objective: In tropical regions, as in temperate regions where seasonality of forage production occurs, well-preserved forage is necessary for animal production during periods of forage shortage. However, the unique climate conditions (hot and humid) and forage characteristics (high moisture content and low soluble carbohydrate) in the tropics make forage preservation more difficult. The current study used natural ensiling of tropical forage as a model to evaluate silage characteristics under different temperatures ($28^{\circ}C$ and $40^{\circ}C$). Methods: Four tropical forages (king grass, paspalum, white popinac, and stylo) were ensiled under different temperatures ($28^{\circ}C$ and $40^{\circ}C$). After ensiling for 30 and 60 days, samples were collected to examine the fermentation quality, chemical composition and microbial community. Results: High concentrations of acetic acid (ranging from 7.8 to 38.5 g/kg dry matter [DM]) were detected in silages of king grass, paspalum and stylo with relatively low DM (ranging from 23.9% to 30.8% fresh material [FM]) content, acetic acid production was promoted with increased temperature and prolonged ensiling. Small concentrations of organic acid (ranging from 0.3 to 3.1 g/kg DM) were detected in silage of white popinac with high DM content (50.8% FM). The microbial diversity analysis indicated that Cyanobacteria originally dominated the bacterial community for these four tropical forages and was replaced by Lactobacillus and Enterobacter after ensiling. Conclusion: The results suggested that forage silages under tropical climate conditions showed enhanced acetate fermentation, while high DM materials showed limited fermentation. Lactobacillus and Enterobacter were the most probable genera responsible for tropical silage fermentation.

• Korean Journal of Organic Agriculture
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• v.31 no.1
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• pp.95-106
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• 2023

Entomopathogenic fungi are one of the microorganisms distributed worldwide, and they inhabit not only insects but also soils of various regions such as agricultural land and forest areas. In this study, entomopathogenic fungi distributed in the soil of forest areas in Korea were isolated using the insect-baiting method, and the relationship between the distribution and diversity of entomopathogenic fungi and the physical/chemical characteristics of the soil was analyzed. The soils were collected from five forest areas in Korea, and a total of 42 entomopathogenic fungal isolates were isolated from the collected soils. Among them, Beauveria bassiana (42.9%) and Metarhizium anisopliae (45.2%) were mainly isolated. In particular, it was confirmed that the distribution of M. anisopliae varies depending on the total nitrogen (g/kg) and organic matter content (%) of the soil. The soils in forest areas in Korea have a low pH of 4-5. Among all isolates, >50% of entomopathogenic fungi were isolated from silt loam. This study suggests that it will be helpful in understanding the relationship between the distribution and diversity of entomopathogenic fungi and the physical and chemical characteristics of soil.

• Korean Journal of Ecology and Environment
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• v.55 no.1
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• pp.84-98
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• 2022

Estuary is important in terms of biodiversity because it has the characteristics of transition waters, created by the mixing of fresh- and seawater. The estuarine water circulation provides a variety of habitats with different environments by inducing gradients in the chemical and physical environment, such as water quality and river bed structure, which are ultimately the main factors influencing biological community composition. If the water circulation is interrupted, the loss of brackish areas and the interception of migration of biological communities will lead to changes in the spatial distribution of biodiversity. In this study, among the sites covered by the Estuary Aquatic Ecosystem Health Assessment, we selected study sites where changes in biodiversity can be assessed by spatial gradient from the upper reaches of the river to the lower estuarine area. The α-, γ- and β-diversity of diatom, benthic macroinvertebrates, and fish communities were calculated, and they were divided into open and closed estuary data and compared to determine the trends in biodiversity variation due to estuarine circulation. As results, all communities showed higher γ-diversity at open estuary sites. The benthic macroinvertebrate community showed a clear difference between open and closed estuaries in β-diversity, consequently the estuarine transects were considered as a factor that decreases spatial heterogeneity of their diversity among sites. The biodiversity trends analyzed in this study will be used to identify estuaries with low γ- and β-diversity by community, providing a useful resource for further mornitoring and management to maintain estuarine health.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.123.2-124
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• 2003

Fusarium graminearum (telomorph：Gibberella zeae), an important fungal pathogen of cereal crops with ubiquitous geographic distribution, produces mycotoxins on diseased crops that has threaten human and animal health. Recently severe epidemics of scab diseases of barley and rice by this fungus occurred in Korea, causing serious economic losses. To determine genetic diversity of F. graminearum from rice in Korea, a total of 269 isolates were obtained from Southern part of Korea during 2001-2002. A phylogenetic tree of the isolates was constructed by using amplified fragment length polymorphism (AFLP). Population structure of the rice isolates consists of a single lineage (lineage 6). Frequency of female fertility among these Isolates was relatively low (37％) compared to that among lineage 7 isolates from Korean corn. PCR amplification using chemotype specific primers derived from Tri7 and Tri13 genes at the trichothecene biosynthesis gene cluster revealed that most isolates (260) were NIV chemotype；9 isolates were identified as DON chemotype by Tri13 but as either NIV chemotype or unknown by Tri7. The result of chemical analysis also supported the chemotype determination；all of the NIV chemotype isolates produced NIV, whereas the 9 isolates produce either DON or no toxin.

• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.231-247
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• 2020

The seasonal variation in the zooplankton community and hydrographic conditions were examined in three regions (inner, central, and outer regions) of Gamak Bay, Korea. Zooplankton samples were collected over a period of 12 months from January to December 2006. The hydrographical parameters of temperature, salinity, chlorophyll-a concentrations, dissolved oxygen, and chemical oxygen demand were measured. The total zooplankton density varied from 411 to 58,485 ind. m^-3, with peaks in early summer. A total of 65 taxa accounted for approximately 86.9% of the annual mean zooplankton density: Noctiluca scintillans (30.9%) Paracalanus parvus s. l.(24.3%), Acartia omorii(11.9 %), Eurytemora pacifica (5.7%), cladocerans (4.1%), cirriped larvae (3.8%), Oithona similis (3.7%), and Pseudevedne tergestina(2.5%). Copepods dominated numerically throughout the year and comprised 54.3% of the total zooplankton. Most of the dominant copepods showed a well-defined seasonal pattern. The density and diversity of zooplankton in Gamak Bay were influenced by the hydrographic environment that was subject to significant spatial and temporal variations. Multivariate statistics showed that seasonal temperature was the most significant predictor of zooplankton taxa, density, and diversity, as well as the density of dominant taxa. Our results suggest that fluctuations in the zooplankton populations, particularly copepods, followed progressive increments in the temperature and COD concentrations.

• Journal of Korean Society of Rural Planning
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• v.21 no.4
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• pp.45-53
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• 2015

Agriculture, rural landscapes are accompanied by a variety of environmental issues. Therefore, it is necessary to study on biodiversity and ecosystem services. Horticulture complex is low groundwater recharge function, it can be evaluated as a facility that biodiversity is impaired. The ecosystem services in agricultural landscapes were obtained 19 kinds of functions. Experts survey Groundwater recharge function (4.13) teeth chapter higher, Water storage (4.05), Amphibian & Reptile habitat (3.96), Aquatic insect habitat (3.92), Flood control (3.87), Water purification (3.86), Avian habitat (3.76 ), Creating landscape (3.74), Vegetation diversity (3.71), Experience, Education (3.69), Biological control (3.48), Fishery habitat (3.42), Climate regulation (3.30), Mammal habitat (3.30), Air quality regulation (3.25 ), Mainenance of genetic diversity (3.25), were analyzed in order Rest area (3.14). Improving capabilities in the Detention Pond, Wetland, Green space, Corridor, Non-Chemical, Program development, Green spaces, Rainwater storage facilities, Water cycle system, Surface water storage facilities, Infiltration trench, Water purification facilities, Permeable pavement. Environmentally friendly, and to contribute to sustainable agricultural development through ecological planning.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.987-994
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• 2010

To investigate the effect of long term application of organic matter in upland soils, plots for treatments of NPK, NPK+pig manure compost, rape seed cake, rice straw compost, and green manure were set up. Populations of Bacillus and Gram negative bacteria were high in the plot treated with green manure application, but microbial biomass was increased with chemical fertilizer or pig manure compost in upland soils. Activities of phosphomonoesterase and dehydrogenase were high with organic matter application comparing to control. Cluster patterns analysed using phospholipid fatty acid of plots treated with rice straw and or pig manure compost were clearly different comparing with other treatments. Dominant bacteria in upland soils were Bacillus flexus, B. subtilis and B. megaterium. And the strains isolated from upland soils had amylase, protease and lipase activities.

• 한국해양학회지
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• v.29 no.2
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• pp.132-144
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• 1994

The relationship of zooplankton communities and distributions of copepods as indicator species to environmental variables, such as temperature, salinity, chemical oxygen demand (COD) and total inorganic nitrogen (TIN) was studied in Pusan Harbor in October 1990 and January, April and July 1991. Zooplankton communities were analysed by using cluster analysis and species diversity index. Four groups of copepods as indicator species were Acrocalanus gacilis, Euchaeta plana, pareuchaeta russell and Pleuromamma gracilis as the oceanic warm water species; Cemtropages abdominalis as the neritic cold water species; Meridian lucens as the oceanic cold water species Acartia omorii as the polluted water species. the offshore waters of Pusan harbor was dominated by the oceanic warm water species in October and by the neritic cold water species in January and April. This area showed the low values of COD and Tin. the inshore waters of Pusan harbor, where the high values of cod And Tin and the low value of diversity were recorder was represented by A.. omorii. Cluster analysis of the zooplankton community revealed two or three regional areas in Pusan harbor. Area I, the offshore area of Pusan harbor, not only was represented high species diversity and low density of A. omorii but also was dominated copepods in zooplankton roups. Areas II and III were grouped horizontally from offshore to inshore of Pusan harbor. Area II was showed intermediate values in diversity, density of A. omorii and percentage composition of copepods. Area III was revealed the lowest diversity,density of A.omorii and percentage composition of Cladocerans.Coperpoda was a dominant zooplankton group in each area during the study periods except two special cases.Area II was dominated by Noctiluca scintillans in April and Area III was occupied by Cladocerans in July.Distribution of Indicator species and areas demarcated based on cluster analysis showed a close relationship with environments.

• Korean journal of applied entomology
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• v.60 no.1
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• pp.49-61
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• 2021

Integrated mite management provided a basic direction to early the fruit tree IPM. The early IPM concept was based on incorporation of the biological control for mite pests with the existing chemical control compatibly. Since then, the hypotheses and mechanisms of the interaction between species diversity and pest population dynamics have provided a broader understanding of mite-centered pest management in fruit tree ecosystems. Based on the principle of the ecosystem, biological control and pest management through habitat modification or manipulation are developing to the concept of agro-ecological engineering. In particular, the natural enemy diversity is dynamically changed according to the different cultivation environment in the management of mite pests, and the species composition of phytophagous mites is also changed by the environment for orchard management. This paper reviews the biological control of mites, which was the basis of apple IPM, and also re-examines the topics of species diversity and pest management, predacious mite diversity in relation to mite control and the change of species composition of mite pests in the sight of ecological engineering. Finally, we suggest a strategy for biological control of spider mites in apple orchards in Korea.

• The Plant Pathology Journal
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• v.33 no.2
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• pp.140-147
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• 2017

Fusarium wilts of strawberry, caused by Fusarium oxysporum f. sp. fragariae, is a serious soil-borne disease. Fusarium wilt causes dramatic yield losses in commercial strawberry production and it is a very stubborn disease to control. Reliable chemical control of strawberry Fusarium wilt disease is not yet available. Moreover, other well-known F. oxysporum have different genetic information from F. oxysporum f. sp. fragariae. This analysis investigates the genetic diversity of strawberry Fusairum wilt pathogen. In total, 110 pathogens were isolated from three major strawberry production regions, namely Sukok, Hadong, Sancheong in Gyeongnam province in South Korea. The isolates were confirmed using F. oxysporum f. sp. fragariae species-specific primer sets. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses were executed using the internal transcribed spacer, intergenic spacer, translation elongation factor1-${\alpha}$, and ${\beta}$-tubulin genes of the pathogens and four restriction enzymes: AluI, HhaI, HinP1I and HpyCH4V. Regarding results, there were diverse patterns in the three gene regions except for the ${\beta}$-tubulin gene region. Correlation analysis of strawberry cultivation region, cultivation method, variety, and phenotype of isolated pathogen, confirmed that genetic diversity depended on the classification of the cultivated region.