• Parasites, Hosts and Diseases
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• v.33 no.1
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• pp.19-26
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• 1995

Ecological studies of Aedes togoi, the vector of malayan filariasis, were ci,wind out at Tolsando, Yosu and Sokcho area in 1991. The adult population of Aedes togoi was continuously appeared from the first week of April to the end of November showing the highest density in .truly. The larvae of Aedes togoi were found at rock pools from March to December in Sokcho area and the density was highest in July and August, whereas in the southern coastal area (Yosu), the larvae were found throughout the year and the density was the highest in Tune. The rate of larvae inhabited below 0.5% salinity was 45.7% in Sokcho and 51.7% in Yosu. The feeding activity of Aedes togoi was nocturnal, with the peak period of 01 :00-03:00 hours. Indoor feeding activities were slightly higher than outdoors showing the biting ratio of 1 :0.8 (indoor: outdoor). The average number of Aedes togoi attracted to CO2 gas was 8.5 whereas 117 Anophelei sinensis was attracted. The result indicates that CO2 is not an effective attractant for host seeking of Aedes togoi compared to Anopheles sineteis. The most common place was bedroom with 54.5% of total collections and next to stock place (18.2%), floor(9.1%) and kitchen (9.1%).

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.189-195
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• 2020

This research was carried out to find the proper number of stem training and position of fruit setting that can be stably produced for the cultivation in small and medium types of watermelon during winter. The treatments for the number of stem training were 2-, 3-, 4-stems, respectively. Growth characteristics (plant height, stem diameter, no. of node, etc.) by number of stem training were higher in 2-stem than in 3-4-stem. However, Fruit characteristics such as weight, length, width were high in the 4-stem. There is no significant difference between the soluble solids and fruit setting rate depending on the stem training. The position of fruit setting were three points: 2nd, 3rd, 4th female flower positions. The fruit setting is one fruit per plant. The average fruit setting nodes of 2^nd, 3^rd and 4^th female flowers were 11.5, 15.8 and 23.1 nodes, respectively. The 4^th female flower was 0.8 kg heavier than 2^nd female flower because of its increased weight as position of fruit setting was higher. However, the soluble solids decreased as the position of fruit setting increased, with the second female flower being 1.3°Bx higher than the 4^th female flower. The Fruit setting rate was no significant difference. Considering the growth and fruit characteristics, it is believed that the small and medium-sized watermelon in winter will have a high quality production of watermelon when the stem training is 3-stem and the position of fruit setting is 3^rd female flower. However, it is thought that additional studies are needed to stabilize the income of watermelon-growing farms, such as planting distance and adhesion of small and medium-sized varieties.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.385-389
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• 2006

This study was carried out to determine the effect of raising seedling at Hallasan area of sub-alpine (altitude of 600m above sea level) to improve fruiting.ate of Squash (Cucurbita maxima) in retarding culture. 'Ebis' cultivar was seeded in plug tray of 32 cells and the seedlings were grown for 25 days. They were transplanted on August 26, 2004, following L-stem training method under rain-shielding condition. Seedling height, number of nodes and leaf area were higher in lowland than in sub-alpine area. T/R ratio of seedling in sub-alpine was much lower as compared with that in the lowland. The first fruiting was on the 19th node in sub-alpine area, and on the 26th node in the lowland area(control). The succeeding fruiting nodes were lower by 3 to 5 node than those of control. Fruiting rate of second flower was improved by 17.2% compared with the 1.4% in control. The marketable yield was increased by 27% by raising seedling in sub-alpine area (4,460 kg/10a). This also brought out 20% labour saving effect. The environmental condition for raising seedling in the sub-alpine area of Hallasan was effective for the improvement of Squash (Cucurbita maxima) fruiting rate compared with lowland area.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.295-301
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• 2020

In this study, we aimed to investigate the changes in the catch rate of Monochamus saltuarius, based on sexual maturation by using aggregation-sex pheromone traps. Ovariole development of caught M. saltuarius females was compared to that of the ones not caught using traps. In a mesh cage set up at the Hongneung experimental forest, we placed a multi-funnel trap with or without an aggregation-sex pheromone lure. M. saltuarius adults, which emerged from pine logs, were grouped in four according to the emergence dates (0, 1, 7, and 10 days after emergence [DAE]). We released beetles into the mesh cage to investigate the catch rate using the traps. In each group, a total of 80 beetles (20 beetles × 4 replications) were tested, making it a total of 320 beetles. Among the four groups, M. saltuarius adults in the 7 DAE group were caught more frequently using the traps, especially with a pheromone lure; the other groups showed a low catch rate. A similar number of female and male beetles were caught using the traps. Regarding ovariole development, all the female adults in the 0 and 1 DAE groups were immature, while those in the other two groups were completely developed. Therefore, aggregation-sex pheromone traps might have a limitation in the prevention of pine wilt disease because of the transmission of pine wood nematode during maturation feeding of newly emerged M. saltuarius adults. However, aggregation-sex pheromone traps can be effective for collecting sexually mature M. saltuarius adults, for the investigation of seasonal occurrence of beetles in forests.

• Korean journal of applied entomology
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• v.40 no.1
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• pp.77-82
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• 2001

Flying behavior during nighttime and control methods of fruit sucking pests were investigated in yuzu (Citrus junos) groves at Koheung area from August to November in 1999. Among the 3 kind of bulbs with different color (white, blue and yellow), white bulb attracted the most number of fruit sucking pests . The 93 percent of the moths was attracted from sunset to 24 o\`clock. Main flying time of hemipteriods in early, mid, and late October were from 22 to 04 o\`clock, sunset to 02 o\`clock and sunset to 24 o\`clock, respectively. Their flying time become earlier as the night temperature declines. For control of fruit sucking pests, attraction liquid traps, light traps (100 W) and illumination light bulb were set up in the yuzu groves (1,000 $\m^2$) from the 1 st October to the 3rd November. Attraction liquid was composed of a raw rice wine 2,000 ml+black sugar 100 g+vinegar 100 ml. When established at 3 sites per 1,000 $\m^2$ orchard, attraction liquid trap reduced the number of sucking spots on yuzu fruit to 64% and its attracting effect maintained for 3 weeks after setting-up. Three light traps per 1,000 m2 which turned on from sunset to 02 o\`clock reduced the number of sucking spots by 60% .

• The Korean Journal of Financial Management
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• v.24 no.2
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• pp.81-111
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• 2007

The agency relationship between managers and shareholders has the potential to influence decision-making in the firm which in turn potentially impacts on firm characteristics such as value and leverage. Using an agency framework, we examine the relation between ownership structure and capital structure during post-IMF period. We used the balanced panel data for 378 korean listed companies during the 1999-2005. The panel data sets consist of time-series observation on each of 378 cross-sectional units. The results indicate a non-linear U-shaped relation between the level of managerial share ownership and leverage with the relation reaching a minimum at 58.48 per cent of management share ownership. As managerial share ownership increase from a low level, managers have incentive to reduce the debt level for decreasing the financial risk, resulting in a lower lever of debt. However, when corporate managers hold a significant proportion of a firm's shares, managers have incentive to increase the debt level for leverage effects, resulting in a higher lever of debt.

• Korean journal of applied entomology
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• v.47 no.2
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• pp.141-147
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• 2008

Male adults of bean bug, Riptortus clavatus Thunberg (Heteroptera: Alydidae), release aggregation pheromone (AP) attracting both sexes of adult and nymphs, which its egg parasite, Ooencyrtus nezarae (Hymenoptera: Encyrtidae) exploits the pheromone to find host. The AP consists of three components; (E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H), (E)-2-hexenyl (E)-2-hexenoate (E2HE2H), and tetradecyl isobutyrate (TI). We analyzed composition of the pheromone components of bean bugs from different geo graphical locations of Korea and Japan. The attractiveness of different blends of AP components to R. clavatus was also tested in the fields in Jinju, Korea and in Kumamoto, Japan. Composition ratios (E2HZ3H: E2HE2H:TI) of the AP of Jinju and Iksan populations were 1:1.4:0.2 and 1:0.8:0.2, and those of Tsukuba and Kumamoto populations were 1:2.8:0.2 and 1:1.5:0.1, respectively. In field tests, traps baited with ratio of 1:1:1 (E2HZ3H:E2HE2H:TI=16.7:16.7:16.7mg/rubber septum) and 1:1:0.5(E2HZ3H:E2HE2H:TI= 20:20:10mg/rubber septum) attracted significantly greater number of adult bugs than that of 1:5:1 (E2HZ3H:E2HE2H:TI=7.1:35.7:7.1mg/rubber septum).

• Korean journal of applied entomology
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• v.61 no.4
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• pp.615-622
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• 2022

In this study, we sought to determine an appropriate LED light source that can be applied for the quality control of Aphidius colemani. Four LED light sources (385, 405, 450, and 660 nm) were evaluated in a Y-tube experiment (choice test) using a 5,000-k white LED as a control. The 385 nm LED light source was found to have attractant effect on A. colemani. In a no-choice test (Y-tube experiment) evaluating the remaining three LED light sources (385, 405, and 450 nm), the attractiveness of these light sources for A. colemani was high in the order 450 nm > 385 nm > 405 nm light, with no statistically significant differences between 450 nm and 385 nm. Given that 385 nm LED illumination may cause skin damage, we selected 450 nm LEDs for application in a device used for the quality control of A. colemani, which we subsequently demonstrated to have an attraction rate of 87.4%. We believe the findings of this study will make a valuable contribution to the quality control of natural enemies.

• Environmental and Resource Economics Review
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• v.12 no.2
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• pp.275-298
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• 2003

This paper compares the economic effects of climate policy options in Korea. The impacts and implications of carbon and Btu tax schemes are analyzed using the META Net modeling system, which was developed at the Lawrence Livermore National Laboratory (LLNL). Findings indicate that carbon tax is more cost effective compared to Btu tax, but this does not necessarily mean the former is more desirable than the latter. Energy market stability and national energy security is equally important in choosing policy options. Moreover Btu tax is more effective in reducing energy consumption in general. It reduces not only carbon intensive energy sources, but non-fossil fuel like electricity. Korean economy consumes too much energy and energy efficiency is very low compared to other OECD countries. So the reduction of energy demand growth should be the first priority of the national energy policy in Korea.

• Korean Journal of Plant Resources
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• v.12 no.3
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• pp.204-208
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• 1999

We carried out this study to confirm the possibility of C. wilfordii cultivation using crop as a substitute for stake or net, and tested sit support crops, i.e., soybean, peanut, Perilla frutescens var. acuta Kudo, Job's tears, sorghum, and corn compared with net support. Effects of support crops on growth and root yield of C. wilfordii were as follows. Attracting efficiency of vine showed 94∼100% among crops. The number of branches per plant was 1 or 2 more in p. frutescens var. acuta Kudo, Job's tears, and sorghum support than in net support. Fresh root yield per 10a was 919kg in net support, while it was 717kg in P. frutescens var. acute Kudo, 656kg in Job' tears, and 652kg in sorghum support. However, the problem of decreased yield in these support crops could be overcome by cost saving of staking installation and by harvesting support crops. Therefore, C. wilfordii cultivation using P. frutescens var. acute Kudo, Job's tears, and sorghum as support crops showed most effective in labor and cost saving.