• Korean journal of applied entomology
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• v.62 no.4
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• pp.227-243
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• 2023

The Asiatic pink stem borer, Sesamia inferens (Walker, 1856) (Lepidoptera: Noctuidae) is a pest that attacks rice stems. In this study, we estimated the annual generation of insect in several regions of the Republic of Korea. Adult trapping using a sex pheromone trap detected the occurrence of S. inferens adults in the three northernmost areas around 38° latitude and showed that the insect inhabits all of Korea. In most areas investigated, the seasons of the adult generations estimated using the single-sine degree-day model did not deviate from the corresponding observed seasons of adult occurrence. We estimated that the overwintering larvae hypothetically-estimated using the model could be originated from the last generation of adults. When larvae collected in paddy fields during the autumn season in a few middle and southern areas were reared at 25℃, ca. 70% of pupae did not show additional larval molting before their pupation. All larvae collected in early March in a southern area (Goseong, Gyeongsangnam-do) pupated without additional larval molting when reared at 25℃. Based on these results, we presumed that S. inferens could overwinter as mainly the last instar larval stage in the area. Taken together, we conclude that S. inferens primarily has two generations per year in areas around 38° latitude, and three generations in the areas between 35.3° and 37.3° latitude. In addition, approximately 35% of insects captured by the sex pheromone trap were species other than S. inferens, as determined by analyzing the nucleotide sequences of the cytochrome c oxidase 1 gene. These species were not morphologically misidentified as S. inferens.

• Research in Plant Disease
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• v.16 no.3
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• pp.238-246
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• 2010

In 2006 fall, a preliminary survey of viruses in two important medicinal plants, Cynanchum wilfordii and C. auriculatum, was conducted on the experimental fields at the Agricultural Research and Extension Services of Chungbuk province in Korea. On each experimental fields, percentage of virus infection was ranged from 20 to 80%, and especially an average of disease incidence propagated by roots was twice higher than that by seeds. The various symptoms were observed in Cynanchum spp. plants, such as mosaic, mottle, necrosis, yellowing, chlorotic spot and malformation etc. In electron microscopic examination of crude sap extracts, filamentous rod particles with 390-730 nm were observed in most samples. The virus particles were purified from the leaves of C. wilfordii with typical mosaic symptom, and the viral RNA was extracted from this sample containing 430-845 nm long filamentous rod. To identify the viruses, reverse transcription followed by PCR with random primers was carried out. The putative sequences of P3 and coat protein of potyvirus were obtained. From a BLAST of the two sequences, they showed 26-38% and 62-72% identities to potyviruses, respectively. In SDS-PAGE analysis, the subunit of coat protein was approximately 30.3 kDa, close to the coat protein of potyvirus. In bioassay with 21 species in 7 families, Chenopodium quinoa showed local lesion on inoculated leave and chlorotic spot on upper leave, but the others were not infected. RT-PCR detection using specific primer of C. wilfordii and C. auriculatum samples, all of 24 samples with virus symptom was positive, and five out of seven samples without virus symptom were also positive. On the basis of these data, the virus could be considered as a new member of potyvirus. We suggested that the name of the virus was Keunjorong mosaic virus (KjMV) after the common Korean name of C. wilfordii.

• Korean journal of applied entomology
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• v.58 no.2
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• pp.133-142
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• 2019

This study analyzed genetic variation of the Oriental fruit fly (OFF), Bactrocera dorsalis, which is designated to be a quarantine insect pest in Korea. OFF samples endemic to Taiwan were collected at three different locations (Taipei, Taichung, and Kaohsiung) for three days from July 30 to August 1 in 2018 and assessed in their age and mitochondrial DNA sequence variations. In these places, 1,085 OFF males were collected using methyl eugenol lure while 30 males of Zeugodacus cucurbitae and one male of Bactrocera tau were collected using Cuelure. A protein diet lure attracted 6 flies including one OFF and 5 flies of Z. cucurbitae. Male heads of OFF contained pterin, which increased in contents with age from 32 to $59{\mu}g/head$. There was a local variation in pterin amounts in OFF heads, in which Kaohsiung population had lower amounts of pterin than Taipei and Taichung populations. Genetic distance among these three populations were measured by random amplified polymorphic DNA and showed that Taipei population was separated from Taichung/Kaohsiung cluster. Genetic variation was also analyzed in sequence variations in cytochrome oxidase I (CO-I) and NADH dehydrogenase I (ND-I). There was 7.8% variation in CO-I sequence (360 residues) and 6.6% variation in ND-I sequence (213 residues). These polymorphic sites are proposed to be used to develop SNP (single nucleotide polymorphism) markers characteristic to Taiwan OFF populations.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.406-414
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• 2018

This study was conducted to develop environmental risk assessments and biosafety guides for insect-resistant genetically modified rice in an LMO (Living Modified Organism) isolation field. In the LMO quarantine area of Kyungpook National University, the species diversities and population densities of non-target insects found on insect-resistant genetically modified rice (Bt-T), rice resistant to Cnaphalocrocis medinalis, and non-GM rice (Dongjin-byeo and Ilmi-byeo) were investigated. The Bt-T plants were, therefore, evaluated under field conditions to detect possible impacts on above ground insects and spiders. In 2016 and 2017, the study compared transgenic rice and two non-GM reference rice, namely Dongjin-byeo and Ilmi-byeo, at Gunwi. A total of 9,552 individuals from 51 families and 11 orders were collected from the LMO isolation field. From the three types of rice fields, a total of 3,042; 3,212; and 3,297 individuals from the Bt-T, Dongjin-byeo, and Ilmi-byeo were collected, respectively. There was no difference between the population densities of the non-target insect pests, natural enemies, and other insects on the Bt-T compared to non-GM rice. The data on insect species population densities were subjected to principal component analysis (PCA) without distinguishing between the three varieties, namely GM, non-GM, and reference cultivar, in all cultivation years. However, the PCA clearly separated the samples based on the cultivation years. These results suggest that insect species diversities and population densities during plant cultivation are determined by environmental factors (growing condition and seasons) rather than by genetic factors.

• Horticultural Science & Technology
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• v.32 no.2
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• pp.202-209
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• 2014

This study was conducted to investigate the effects of low temperature shipping condition and precooling treatments (forced air and room cooling) on everbearing strawberry through export simulation of 'Goha' and 'Flamenco' cultivars. After harvest, it took two days to prepare export procedure such as precooling, sorting, storage, transportation, quarantine and handling, and then everbearing strawberry was carried out shipping at room ($20-25^{\circ}C$) or low ($8^{\circ}C$) temperature conditions. In the case of shipping at room temperature, weight losses of both cultivars were increased up to 10% after 2 days where 'Goha' being 2% higher than that of ' Flamenco'. In 'Flamenco' cultivar, shipping temperature and precooling treatment were not effective in firmness and soluble solids contents during transporting periods. However, in 'Goha' cultivar, room cooling treatment and low shipping temperature were effective in maintaining firmness until 4 days after shipping. Especially titratable acidity was affected by shipping temperature ($P{\leq}0.001$) and precooling treatments ($P{\leq}0.05$) in 'Goha' cultivar. Also shipping temperature under $8^{\circ}C$ delayed coloring and decay incidence of both strawberry cultivars, and precooling treatments of both forced air and room cooling reduced frequency of decay. The shelf life of everbearing strawberry at low shipping temperature was extended more than 4 days compared with shipping at room temperature. Precooling treatment including forced air or room cooling will be useful for the two cultivars when they are transported at low temperature. In 'Flamenco' cultivar, the effect of forced air and room cooling was similar, whereas in 'Goha' room cooling was more effective.

• Research in Plant Disease
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• v.16 no.1
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• pp.27-34
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• 2010

This study was performed to develop a formulation using an antagonistic bacterium Bacillus amyloliquefaciens A-2 to control tomato leaf mold caused by Fulvia fulva. B. amyloliquefaciens A-2 was grown in a medium with rice oil and mixed with various carrier and additives. One of the formulations, A2-MP, showed the best disease control value among the tested formulations. The disease control value of A2-MP at 100-fold and 500-fold diluted treatment was not significantly different from that of chemical fungicide triflumizole in a growth chamber. Although disease control effect was decreased by serial diluted treatment of the prepared A2-MP, 1,000-fold diluted treatment of A2-MP still showed high disease control value of 72.0%. For the green house experiments, the disease control values of A2-MP was indicated as 79.4% which is similar to that of chemical fungicide, triflumizole showing 79.6%. When the disease control activity of the formulation A2-MP was compared in tomato production conditions, disease control values of 100-fold diluted A2-MP and 3,000 fold diluted triflumizole exhibited 60%, 81.6%, respectively. The disease control efficiency by A-2MP was 73% of the disease control value of chemical fungicide. The formulation A-2MP maintained the stable bacterial viability and disease control activity when stored at $4^{\circ}C$. This result suggested that A-2MP develped from B. amyloliquefaciens A-2 could be used to control tomato leaf mold.

• Korean journal of food and cookery science
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• v.32 no.4
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• pp.390-399
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• 2016

Purpose: The objective of this study was to examine the effect of plant scale and cooking conditions on the quality characteristics of sausages during refrigerated storage. Methods: Sausages used in this study were classified into two groups: those submitted to $1^{st}$ cooked treatments and those submitted to $2^{nd}$ cooked treatments. The pH, volatile basic nitrogen (VBN), gas production ratio, and microorganisms were measured in triplicate. Results: The change of quality in the products was assessed every 7 days by measuring pH, VBN levels, total microbes, coliform bacteria, Escherichia coli, and pathogenic bacteria in the products. Pathogenic bacteria such as Staphylococcus aureus, Listeria monocytogenes, Clostridium perfringens, and E. coli were not detected in the sausages with $1^{st}$ cooked treatments. The results showed that the pH of the sausages decline as storage time increased. The pH value of the sausages with $2^{nd}$ cooked treatments changed gradually. VBN levels were generally lower in products with $2^{nd}$ cooked treatments than in those with $1^{st}$ cooked treatments, but they varied with the type of products. On the $35^{th}$ day, the number of total microbes ranged between 6.13-7.12 log CFU/g in products with $1^{st}$ cooked treatments and 3.44-6.92 log CFU/g in products with $2^{nd}$ cooked treatments, showing fewer bacteria in the latter products. Conclusions: $1^{st}$ cooked treatments were effective in microbial control, but $2^{nd}$ cooked treatments could prolong the shelf life of the sausages, indicating a need for differential management of each product.

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.623-629
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• 2011

The detectable levels and population fluctuations of phytoplasmas infecting dwarf mulberry trees were investigated using nested-PCR and competitive-PCR methods. Samples of five different types were studied : A. petiole of a leaf that displays dwarf symptoms, B. petiole from apparently healthy leaf residing on a branch also supports a leaf with dwarf symptoms, C. the branch portion that supports a leaf with dwarf symptoms, D. the leaf petiole from healthy appearing leaves on branch with no dwarf symptoms, and branch portion of branch with no dwarf symptoms, E. the rootlets of trees with dwarf symptoms. These 5-parts were collected from each tree during June - April, once in every two months. The phytoplasma was detected from all parts of collected mulberry samples during all seasons using nested-PCR with AS-1/AS-2 primer pairs. The phytoplasma was detected until $10^4$ dilution using direct-PCR method, but it was detected until $10^{13}$ dilution by the nested-PCR method. The density of pytoplasma was found to be $7.94{\times}10^{18}-10^{12}copies/{\mu}L$ in mulberry trees. The density of phytoplasma was observed throughout the year in all samples of mulberry trees. The highest rates of phytoplasma was found in the samples B and C during the early growing season followed by the sample A and D during the dormant season. Samples C and E displayed the highest phytoplasma density followed sample D. The density of phytoplasma appeared stable during all the seasons for samples C and A. The result of the present study demonstrates the utility of nested-PCR and competitive-PCR for detection and determination of population fluctuations of phytoplasmas in plant tissues.

• Journal of Life Science
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• v.34 no.5
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• pp.304-312
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• 2024

This study was conducted to characterize strain Y10, isolated from discarded chicken feathers. Strain Y10 was identified as Bacillus amyloliquefaciens through phenotypic and 16S rRNA gene analysis. B. amyloliquefaciens Y10 exhibited plant growth-promoting activities, including the production of fungal cell-degrading enzymes (cellulase, lipase, protease, and pectinase), siderophores, ammonia, and indoleacetic acid. Furthermore, strain Y10 was able to inhibit the mycelial growth of several phytopathogenic fungi. When 0.1% sucrose as a carbon source and 0.05% casein as a nitrogen source were added to the basal medium, adjusted to pH 10, and cultured at 35℃, the degradation rate of chicken feathers by strain Y10 was about two times higher than that of the basal medium, with the feathers almost completely degraded in four days. Strain Y10 also degraded various keratin substrates, including duck feathers, wool, and human nails. It was confirmed that the feather hydrolyzates prepared using strain Y10 exhibited antioxidant activities, such as 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (EC₅₀ = 0.38 mg/ml) and superoxide dismutase-like activity (EC₅₀ = 183.7 mg/ml). These results suggest that B. amyloliquefaciens Y10 is a potential candidate for the development of bioinoculants and feed additives applicable to the agricultural and livestock industries, as well as the microbiological treatment of keratin waste.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.7
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• pp.1044-1049
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• 2014

This study was conducted in order to investigate whether the presence of light or different colors of light would influence the energy expenditure and behavior of broiler chickens. Eight 8-week-old broiler chickens were adapted to a respiration chamber (Length, 28.5 cm; Height, 38.5 cm; Width, 44.0 cm) for one week prior to the initiation of the experiment. In experiment 1, energy expenditure and behavior of the chickens were analyzed in the presence or absence of light for four days. Chickens were exposed to 6 cycles of 2 h light/2 h dark period per day. In experiment 2, the broiler chickens that had been used in experiment 1 were used to evaluate the effect of 4 different wavelength light-emitting diodes (LEDs) on the energy expenditure and behavior of broiler chickens. The LEDs used in this study had the following wavelength bands; white (control), red (618 to 635 nm), green (515 to 530 nm) and blue (450 to 470 nm). The chickens were randomly exposed to a 2-h LED light in a random and sequential order per day for 3 days. Oxygen consumption and carbon dioxide production of the chickens were recorded using an open-circuit calorimeter system, and energy expenditure was calculated based on the collected data. The behavior of the chickens was analyzed based on following categories i.e., resting, standing, and pecking, and closed-circuit television was used to record these behavioral postures. The analysis of data from experiment 1 showed that the energy expenditure was higher (p<0.001) in chickens under light condition compared with those under dark condition. The chickens spent more time with pecking during a light period, but they frequently exhibited resting during a dark period. Experiment 2 showed that there was no significant difference in terms of energy expenditure and behavior based on the color of light (white, red, green, and blue) to which the chickens were exposed. In conclusion, the energy expenditure and behavior of broiler chickens were found to be strongly affected by the presence of light. On the other hand, there was no discernible difference in their energy expenditure and behavior of broiler chickens exposed to the different LED lights.