• Journal of Korean Society of Forest Science
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• v.110 no.2
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• pp.280-288
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• 2021

Understanding the occurrence characteristics of pine wilt disease (PWD) is essential for determining a suitable strategy to minimize the damage caused by PWD. Thus, in this study, we characterized various environmental conditions, including meteorological factors, geographical factors, and artificial factors influencing the occurrence of PWD. The occurrence data of PWD from May 2016 to April 2018 and spatial data of various environmental factors, including natural and anthropogenic factors, were collected. We evaluated the relative contribution of the environmental variables on the number of dead pine trees by PWD. In this study, among the 17 natural and anthropogenic factors, the factors affecting the occurrence of dead trees by PWD were verified. The results showed that altitude and temperature from May to August, among natural factors, and distance to building and forest road among anthropogenic factors were the most influential factors on the occurrence of PWD.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.490-494
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• 2011

Rice stripe virus (RSV) has been the main viral disease of rice plant in western coastal region of Korea since 2000. The control of the vector insect, small brown planthopper (Laodelphax striatellus), is the most effective management method of the persistently-transmitted viral disease. Thus, ecological study between RSV and the vector insect was needed and investigated in order to make effective control plan, especially about study on the feeding and transmission of the virus by the vector insect. Each larval stage of vector insect differed in vector competence; larvae over 4th stage were shown as higher transmission after feeding on RSV-infected rice plant. These 4th and 5th larvae had higher transmission rates, 69.2% and 67.9% respectively, than 44.8% of the adult stage. The vector competence, however, was changed according to temperature; the highest transmission rate was 93.3% on $30^{\circ}C$ in comparison to 70.6% on $25^{\circ}C$ and 43.8% on $20^{\circ}C$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.361-370
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• 1982

The effects of climatic factors on organisms lire variable and complex, and it, however, can be interpreted in terms of those on the distribution and those on the population densities. The distribution of an organism may largely be determined by the temperatures, except some temporal organisms which are depended on the air mass movements. Population density of an organism is determined by various climatic factors, such as previous winter temperature, temperature of growing season and rainfall. The start of growing season of the rice plants has been shifted to earlier since last decade in Korea. This may mean that the overall climatic condition during the growing season might be considerably different from those in past years, and such a difference in climatic conditions might have close relation with the recent status of the diseases and insect pests through direct effects on the physiology and population dynamics of the organisms, as well as through on the biotic associations of the pest organisms. The white back planthopper and brown planthopper have become the key insect pests in Korea in recent years. They are migratory and have high reproductive pontentials and more generations than average residential insects. The synchronization of the migrants and physiological condition of the rice plants seems to be the important factors in relation to the recent outbreaks of these insects; the high reproductive rate can be obtained with the growth stage of rice being 30-50 days after transplanting. The modication of the microclimate associated with high plant density and some other introduced new cultural techniques also have some relation with the outbreak. The key diseases of the rice are the blast disease, sheath blight and the bacterial leaf blight. For the rice blast, the seedling blast and leaf blast during the early growing season and the neck blast, have become more serious, the former may be related to hotbed nursery and the later may be related to the high humidity in early August, and synchronization of the heading time which has been shifted to early part from middle or late part of August. In general, for the rice diseases, the development of the new races have been the most serious which are largely resulted from the introduction of the new varieties, but it also seems to be related with the prolonged periods of the favorable condition associated with the shifted growing seasons. In general, the diseases and insect pest problems have become much more variable and complex, and control measures should be based on the thorough knowledge of the ecology of the pest organisms, that is, effects of various environmental factors on the disease cycle; spore release, spore deposition, infection, colonization and sporulation of the disease organisms, and those on the development, reproductive potentials, dispersal, age specific responses of the insects. The well organized real-time pest management systems, such as alfalfa weevil management system developed at the Purdue University in U.S., is the prime importance for the implementation of the pest management principles.

• Microbiology and Biotechnology Letters
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• v.40 no.1
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• pp.66-69
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• 2012

Five strains out of 200 candidate strains (SG 1-9, 1-12, SG 2-8, 2-10, and 2-17) were selected to determine their antifungal activity against Raffaelea quercus-mongolicae. The 16S rDNA sequences of the five strains were determined by sequencing analysis and analyzed by the homology of the blast program at NCBI. The homology search showed that SG 1-9 and 1-12 had a 98% homology with Streptomyces cinnamoneus and 98% homology with Burkholderia cepacia, while SG 2-8, 2-10, and 2-17 had a 99% homology with Streptomyces fradiae, a 97% homology with Staphylococcus epidermidis, and a 99% homology with Staphylococcus epidermidis. Out of the five selected strains, organic extract and protein extracts of SG2-17 strain broth were employed to determine antifungal activity against Raffaelea quercus-mongolicae. The organic extract exhibited antifungal activity, but the protein extracts did not demonstrate such an activity. Three organic solvents, butanol, benzene, and ethyl acetate, were also used for determination of antifungal activities. The activity measurements revealed that benzene extract possessed the greatest inhibitory effect on the growth of Raffaelea quercus-mongolicae, with the next highest being butanol extract, and ethyl acetate extract being the lowest.

• Food Science and Preservation
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• v.12 no.5
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• pp.482-488
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• 2005

Oxidant stress is well-known for a pivotal parameter related to neuro-inflammatory diseases including Alzheimer's disease, Parkinson's disease, and ALS (Lou Gehrig's disease). In order to effectively screen for anti-inflammatory agents, we first established the infrastructure of high throughput screening for anti-oxidant agents from medicinal insect library extracted with water, methanol, ethanol, and dimethyl sulfoxide. By the screening system, we found that Tenodera angustipennis Saussure, Pyrocoela rupa Olivier and Papilio maackii Mntris had strong anti-oxidant activity. Moreover, Tenodera angustipennis Saussure and Tenodera aridifolia (Stoll) exhibited protection effects of cellular damage by treatment of an oxidant hydrogen peroxide. Together, the results suggest that some selected hits could be a potential agent against neuro-inflammation, although the in vivo studies should be clearly tested.

• Journal of Korean Society of Forest Science
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• v.96 no.6
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• pp.750-755
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• 2007

This study was investigate to ecological characteristic of Trioza ukogi (shinji) on the Acanthopanax senticosus for. inermis Harms during 2004-2005 in Korea. The sizes of Trioza ukogi (shinji) were $0.40{\pm}0.03mm$ in eggs, $0.36{\pm}0.03mm$ in 1st instar nymphs, $2.50{\pm}0.25mm$ in mature nymphs and $5.17{\pm}0.28mm$ in adults (to tip of folded wings), respectively. T. ukogi has two generations per year. First generation appeared from mid-July to late August with peak in early August. Second generation appeared from mid-September to mid-October with peak in late September. Overwintering adults move to host tree and mate from the early April to late May with peak in late April. Overwintering female laid on the new leaves and first generation prefers to lay on the seeds. The number of ovarian eggs was 5$57.5{\pm}23$.

• Research in Plant Disease
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• v.24 no.4
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• pp.265-275
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• 2018

Cashew (Anacardium occidentale L.) is an export crop and source of income in Tanzania. However, its productivity is challenged by insect pests and diseases. Cashew Leaf and Nut Blight Disease (CLNBD) caused by Cryptosporipsis spp. has been cited as one of the most devastating diseases in Tanzania. Studies were conducted to investigate incidences and severities of CLNBD on cashew in farmers' fields and elite cashew hybrids developed in 1996 and 1998 in eastern and southern zones of Tanzania. Furthermore, a screen house experiment was conducted to screen these hybrids against CLNBD at Naliendele Agricultural Research Institute (NARI), Mtwara, Tanzania. The results indicated significant differences (P<0.001) in CLNBD incidences and severities in cashew in farmers' fields across Bagamoyo, Nachingwea and Mtwara districts. Further, there were significant differences (P<0.001) among hybrids in CLNBD severities in the screen house experiment. In ranking the elite cashew hybrids, 38 were tolerant and 14 were susceptible to CLNBD. This observation suggests that elite cashew hybrids developed in 1996 and 1998 are more tolerant to CLNBD compared to cashew found in farmers' fields. These findings strongly suggest that the elite cashew hybrids can be recommended for commercial farming in Tanzania.

• The Plant Pathology Journal
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• v.34 no.6
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• pp.459-469
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• 2018

Plants and microorganisms (microbes) use information from chemicals such as volatile compounds to understand their environments. Proficiency in sensing and responding to these infochemicals increases an organism's ecological competence and ability to survive in competitive environments, particularly with regard to plant-pathogen interactions. Plants and microbes acquired the ability to sense and respond to biogenic volatiles during their evolutionary history. However, these signals can only be interpreted by humans through the use of state-of the-art technologies. Newly-developed tools allow microbe-induced plant volatiles to be detected in a rapid, precise, and non-invasive manner to diagnose plant diseases. Beside disease diagnosis, volatile compounds may also be valuable in improving crop productivity in sustainable agriculture. Bacterial volatile compounds (BVCs) have potential for use as a novel plant growth stimulant or as improver of fertilizer efficiency. BVCs can also elicit plant innate immunity against insect pests and microbial pathogens. Research is needed to expand our knowledge of BVCs and to produce BVC-based formulations that can be used practically in the field. Formulation possibilities include encapsulation and sol-gel matrices, which can be used in attract and kill formulations, chemigation, and seed priming. Exploitation of biogenic volatiles will facilitate the development of smart integrated plant management systems for disease control and productivity improvement.

• Parasites, Hosts and Diseases
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• v.59 no.3
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• pp.319-324
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• 2021

Incidence of tsutsugamushi disease (scrub typhus) caused by Orientia tsutsugamushi, is steadily increasing. It is a mite-borne disease transmitted by chigger mites. In this study, the chigger mites were collected from field small mammals in Hwaseong-si (city), Gyeonggi-do (province), Korea, 2019 and 2020. The field small mammals captured were 56 Apodemus agrarius (94.9%) and 3 Crocidura lasiura (5.1%). A total of 7,531 chigger mites were collected from the captured small mammals. Using PCR test, 153 chigger mite pools were examined and 17 pools were reported positive for O. tsutsugamushi. The O. tsutsugamushi were identified to 5 strains; Jecheon strain was most prevalent, followed by Boryong strain. The other strains were OI011, Taguchi, and Shimokoshi. Collectively, these results provide essential regional information on mite-borne tsutsugamushi disease in the Hwaseong-si, and further contribute to bring awareness and rapid diagnosis for the tsutsugamushi disease.

• Animal cells and systems
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• v.14 no.1
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• pp.31-36
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• 2010

The pinewood nematode Bursaphelenchus xylophilus causes pine wilt disease and is a serious economic concern for the forest industry of South Korea. To achieve effective control with limited resources, it is necessary to clarify the transmission routes and mechanisms of dispersal of this organism. Highly polymorphic and easy-to-use molecular markers can be used for investigating this aspect. In this study, we evaluated the usefulness of amplified fragment length polymorphisms (AFLPs) for investigating the genetic variations of B. xylophilus and related individuals from China, Japan, and South Korea. The AFLP patterns obtained in our study were similar to the microsatellite patterns reported in a previous study; our AFLP patterns indicated high genetic variability and cryptic genetic structure, but did not indicate any peculiar geographic structure. Moreover, the genetic distances between individuals suggested that the Korean population was affected to a greater extent by the Chinese population than the Japanese population. Further, the gene flow among the related species appeared to be limited; however, there may be also the possibility of genetic introgression among species. These results confirm the usefulness of AFLPs for understanding the epidemiology of pine wilt disease, thereby contributing to the effective control of this disease.