• Journal of Ginseng Research
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• v.44 no.4
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• pp.544-551
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• 2020

Background: Previous studies have shown the insecticidal efficacy of ginsenosides. In the present study, we aimed to investigate the metabolic mechanism related to the inhibitory effect of panaxadiol saponins (PDSs) against the Asian corn borer Ostrinia furnacalis (Guenee). Methods: Third instar larvae of O. furnacalis were fed normal diets with different concentrations of PDSs for 4 days. The consumption index, relative growth rate, approximate digestibility, and conversion of ingested and digested food were recorded. A targeted gas chromatographye-mass spectrometry assay was performed to detect the profiles of amino acids, fatty acids, and carbohydrates in larvae of O. furnacalis. In addition, the activity of detoxification-related enzymes was determined. Results and Conclusions: PDSs decreased the consumption index, relative growth rate, approximate digestibility, and conversion of ingested and digested food in the 3rd instar larvae of O. furnacalis in a dose-dependent manner. PDSs decreased 15 free amino acids, 16 free fatty acids, and 5 carbohydrates and increased the levels of palmitoleic acid, palmitic acid, and 9-octadecenoic acid in the 3rd instar larvae. The activity of detoxification-related enzymes, such as acetylcholinesterase, glutathione S-transferase, cytochrome P450, carboxylesterase, trehalase, acid phosphatase, and alkaline phosphatase, was reduced in a dose-dependent manner in the 3rd instar larvae exposed to PDSs. These data confirmed the inhibitory effect of PDSs against growth, food utilization, and detoxification in the 3rd instar larvae of O. furnacalis and the potential for using PDSs as an efficient tool for insect pest management for O. furnacalis larvae.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.431-435
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• 2015

Riptortus pedestris (Fabricius) is one of the important insect pests of leguminous crops, which occurs in most areas of South Korea. It is hard to distinguish each generation in crop fields since not only the longevity of adult R. pedestris is long but also the developmental period is short. Especially, the 2nd generation adults cause enormous damage to soybean while the occurrence time is synchronized with the podding stage of soybean. Controlling the 1st generation of R. pedestris helps to decrease the damage by decreasing the 2nd generation density. This study was conducted to distinguish between the 1st generation and the overwintering generation by using differences in body coloration which is dependent on the day-length during the nymph stage. In addition, the difference was verified by the population dynamics model of R. pedestris. The occurrence time of 1st generation adults could be considered when the summer form is 20% or more. These results will be used for beneficial management decisions to reduce the 2nd generation population.

• Korean Journal of Environment and Ecology
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• v.26 no.4
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• pp.588-592
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• 2012

To examine the reason of empty samara production of Chinese elm, Ulmus parviflora, twenty two planted trees in Wonju-si were monitered for three years in terms of their flowering, pollinatiom system and samara characteristics. Inflorescences with bisexual flowers of Chinese elm are developed in the leaf axils on the twigs. Dichogamous flowers are varied with protogynuous and protandrous flower, and stamens in some bisexual flowers are developed in seperated time on a inflorescence or a tree. It is revealed newly that the flower of Chinese elm is out-crossed and partially insect(Apis mellifera) pollinated. The ratios of sound samara are significantly differed among years, the heighest values 65.5% were shown in 2009, lowered 42.9% in 2010, and the lowest 37.5% in 2011. This result might be affected by mean daily precipitation and number of rainy days during the flowering date, and lower temperature during the floral initiation stage, especially in 2011. These findings suggest that Chinese elm has self-incompatibility strategy and much pollination failure resulted in a production of much empty samaras. Further researches on the empty-seed production strategies and pollination system of major tree species might be needed.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.673-684
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• 2011

Shinan-gun in Jeollanam-do has 1,004 islands which is the biggest number in the whole country. As most of the islands in Korea are secluded from the mainland or other islands, biological surveys are very important for the biogeographical perspective. Especially, the species diversity of insecta on an island plays an important role in the food stability of top predators, including birds. This study provides baseline academic resources for the preservation and management of uninhabited islands by providing information about the status of insects on the uninhabited islands in Docho-myeon, Jeollanam-do, Korea. As far as the appearance aspects of the insects in 28 uninhabited islands were 921 individuals, 122 species, 60 families or 12 orders. Ga Island showed the highest appearance as 32 species, 22 families or 9 orders. Appearance of specific insects was investigated unknown species: 1 species, southern characteristic species: 3 species, coastal dune species: 1 species, climate-sensitive indicator species: 1 species.

• Journal of Sericultural and Entomological Science
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• v.52 no.2
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• pp.142-146
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• 2014

The purpose of this study was to determine the possibility of black soldier fly (Hermetia illucens) as a animal feedstuff. Insect resources have been widely recognized that it exhibits its own biological activity by whole body or its metabolic intermediates. To accomplish this, its general and biological activities were measured. The present study was conducted to compare antioxidant activity of black soldier fly larva, pupa and grasshopper by examining radical scavenging activity using DPPH (2,2 diphenyl 1-picryl hydrazyl). DPPH radical scavenging activity was conducted on the EtOH, MeOH, H2O fractions of black soldier fly larvae. Results showed that black soldier fly pupa on the H2O fraction contained the highest DPPH radical scavenging activity among the samples. FRAP assay are more suitable methods to evaluate antioxidant activity of black soldier fly extracts. Among the samples, the FRAP value showed higher antioxidant activity in the extracts from black soldier fly pupa extract on H2O fraction. These results suggest that black soldier fly larva and pupa extract has antioxidant activity and its fractions can be utilized to develop functional feedstuff.

• Journal of Sericultural and Entomological Science
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• v.55 no.2
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• pp.33-39
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• 2019

Freeze-dried silkworm powder has been approved as a functional ingredients for blood glucose control since 2009. Proximate and nutrient compositions of silkworm powder was summerized as bellow. Silkworm powder contained 4.7% moisture, 57.7% crude protein, 9.5% crude fat, 5.4% crude fiber, and 9.3% ash. The larval protein contained 18 known amino acid including glutamic acid and aspartic acid. Fat is composed of 3:7 ratio of saturated fatty acid to unsaturated fatty acid including various essential fatty acids. It contained 34.7 linolenic acid, 24.4% oleic acid, 20.2% palmitic acid, 9.2% stearic acid, and 7.7% linoleic acid. Five minerals, K, P, Ca, Mg, S were abundant in the silkworm powder with other minerals such as Cu, Mn, Fe, and Zn.

• Journal of Life Science
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• v.32 no.6
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• pp.455-462
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• 2022

This study examined changes in the body composition of Protaetia brevitarsis larvae fed sulfur and selenium. Among the general chemical components, an increase in protein was observed in the sulfur-fed group, whereas an increase in fatty acid was found in the groups fed selenium and sulfur/selenium. The structural amino acid showed some tendency to be increased compared to the control group, but this was especially true in the sulfur-fed group. The free amino acid were increased in the groups fed selenium and sulfur/selenium, with GABA, Glu, and Pro, in particular, being increased in the group fed sulfur/selenium. Among the essential amino acids, Met, Trp, and Val tended to be increased in selenium and sulfur/selenium groups. Saturated and polyunsaturated fatty acids showed a tendency to increase in the group fed sulfur/selenium, but monounsaturated fatty acid tended to be decreased in the group. In particular, no oleic acid was detected in the sulfur/selenium group, whereas palmitic acid, palmitoleic acid, and linoleic acid were increased. From observations of these body composition changes associated with the feeding of sulfur and selenium, it is estimated that the group fed sulfur/selenium would likely undergo a pronounced change in body composition. Therefore, we suggest that it is possible to manufacture a food that has enhanced functionality by appropriately adjusting the diet of Protaetia brevitarsis larvae.

• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.491-496
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• 2011

Breeding for pear resistance to pear psylla (Cacopsylla pyricola) is one of important objective of the National Institute of Horticultural and Herbal Science breeding program. One hundred thirty three accessions from 15 Asian, Chinese and European pear species were investigated for their resistance against pear psylla. The pear psylla resistance was determined based on the following four characteristics: overwintering adult population, the number of eggs and nymphs, and the degree of soot. The different pear species showed varied resistance to pear psylla. Pyrus calleryana and P. betulaefolia indicated the highest antixenosis as ovipositional preference and antibiosis as nymphal feeding and were the most resistant genetic resources. Likewise the European pears (P. communis), 'Conference' and 'Cascade', exhibited little occurrence and damage by pear psylla. These were proved to be promising genetic materials for breeding resistant cultivars because they had good fruit quality and showed resistance to pear paylla. The observed population of overwintering adult, the number of eggs and nymphs of psylla had significant correlation each other.

• Korean journal of applied entomology
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• v.54 no.3
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• pp.151-158
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• 2015

Chlorine dioxide ($ClO_2$) can be used as a fumigant to kill insects. However, some insects can exhibit an evasive behavior from chlorine dioxide. This evasive behavior decreases the efficiency of the insecticidal activity of chlorine dioxide. This study tested a hypothesis that heat treatment suppresses the evasive behavior and synergizes the control efficacy of chlorine dioxide. Chlorine dioxide fumigation killed the red flour beetle, Tribolium castaneum, under direct exposure condition to the chemical for 12 h with median lethal concentrations of 383.67 ppm (153.63 - 955.78 ppm: 95% confidence interval) for larvae and 397.75 ppm (354.46 - 446.13 ppm: 95% confidence interval) for adults. However, when they were treated with enough diet flour, they exhibited an evasive behavior by entering the diet, which significantly decreased the control efficacy of the fumigant. To clarify the evasive behavior, the choice test of the adults were performed in Y tube arena. The test adults significantly avoided the diet treated with chlorine dioxide, while the antennatectomized adults lost the avoidance behavior. Heat treatment using $46^{\circ}C$ for 6 h killed only 10% or less of T. castaneum. Interestingly, most adults were observed to come out of the diet under the heat treatment. Chlorine dioxide treatment even at 400 ppm for 6 h did not kill any T. castaneum. However, the combined treatment of chlorine dioxide with the heat treatment for 6 h resulted in 95% mortality. These results indicated that heat treatment suppressed the evasive behavior of T. castaneum and synergized the control efficacy of the chlorine dioxide fumigant.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.1-10
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• 2014

Essential oils of various plants have been known for potential biological effects such as antibacterial, antifungal, spasmolytic, antiplasmodial activities and insect-repellent property. Recently, the essential oils have attracted considerable interest in oral disease therapy. This essential oil has been known as being effective on easing sick house syndrome, giving forest aroma therapy effect and acting as repellent against pest. The essential oil of Pinus koraiensi, a native plant from Hongcheon-gun, Gangwon-do, was obtained by hydrodistillation. In light of its medicinal importance, in this study its composition, antibacterial activity and the reducing effect of offensive odor have been analyzed. The composition of essential oil was determined by GC and GC-MS. We have identified 14 compounds, of which 1R-${\alpha}$-pinene (19.38 %), 3-carene (10.21 %), camphene (9.82 %), limonene (9.00 %), bicyclo[2,2,1] heptan-2-ol (8.76 %) and ${\beta}$-phellandrene (7.98 %) were the main components. Essential oils from P. koraiensis, Chamaecyparis obtusa, Abies holophylla and Pinus densiflora were compared in terms of alleviating effect of malodors caused from formaldehyde, ammonia, trimethylamine and methylmercaptan. P. koraiensis essential oil was found to decrease the amounts of ammonia and trimethylamine by 75.17 % and 77.36 %, respectively. Antibacterial activity against Streptococcus mutans and Streptococcus sobrinus, which were known as oral cavity inducer, was investigated using the paper disc agar diffusion method. The inhibition zone was observed against S. mutans (5.97 mm) and S. sobrinus (1.40 mm), respectively. P. koraiensis essential oil shown effective deodorization and inhibitory activity against oral cavity in this study might be potential material in oral sanitary industry.