• Korean journal of applied entomology
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• v.36 no.3
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• pp.243-248
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• 1997

The local distribution and life cycle of Mahasma aurea (Butler) attacking Ginkgo biloba L. in Seoul and Incheon areas were studied during 1994 - 1996. The species had one generation a year. The overwintered 3rd larvae begin to feed on buds of the host plant from mid May and then on the leaves until early June. Newly hatched larvae mostly infested the leaves from mid August to late September. Pupation took place from mid June to early July, and the moths emerged in early July.

• Journal of the Korean association of regional geographers
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• v.18 no.3
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• pp.283-297
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• 2012

This study aims to analyze an evolutionary path and the dynamics of the Seoul Digital Industrial Complex in Korea based on the analysis of cluster life cycles. From the mid 1960s to the late 1990s, the life cycles and their characteristics of the Seoul Digital Industrial Complex (Guro Industrial Park) are examined as emergence-growth-sustainment-decline focused on the number of firms and employees. After the late 1990s, the number of firms and employees increases rapidly and the active actors of the growth and restructuring are transformed to the technology-intensive SMEs and knowledge-based service firms. Knowledge industry centers (apartment-type factories) help evolve into the life cycle of transformation as knowledge-based clusters after the mid 2000s.

• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.199-205
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• 2005

Seasonal occurrence and ovarian development of the bean bug, Riptortus clavatus Thunberg (Heteroptera: Alydidae), were studied at a soybean field and an university campus in which host plants are less available for the bug in Gyeongnam province with aggregation pheromone traps in 2004. It was assumed that the bug passed three generations per year at the university campus. Adults of the 1st generation might occur from early July to early August and that of the 2nd one from mid August to late September. Adults of the 3rd generation occurred from early October to mid November, entered reproductive diapause without carrying eggs in the ovaries of females during winter, and resumed activity from late March of the next year. Full-grown eggs in the ovaries of the overwintered females were first observed at the 1st half of May. Two peaks of occurrence, from early August to mid September and from mid October to mid November, were shown at soybean field that was sowed on May 24. The two peaks almost corresponded to those of the 2nd and 3rd generations at the university campus, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.431-437
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• 2023

This study evaluated the ecological characteristics related to spike heading time of three Korean foxtail millet cultivars, i.e., one early and two late maturities, and a finger millet cultivar in the north-central region of the Korean Peninsula, Kangwon Province. The changes in heading time occurred due to the changes in planting time from mid-May to late June. The heading time of the early-maturity cultivars was early August, with 80 days required for heading (DH) for the mid-May planting; late August, with 65 DHs for the late June planting; and mid-late August, with 100 DHs and mid-October, with 65 DHs, respectively, for the late-maturity cultivars. The accumulated temperature at heading time ranged from 1,700℃ of mid-May planting to 1,500℃ of late June planting in the early-maturity cultivars. In contrast, it ranged from 2,100℃ to 1,900℃ in the late-maturity cultivars. The photoperiod at heading time ranged from 14.0 h to 13.2 h in the early-maturity cultivars, whereas it was from 13.2 h to 12.5 h in the late-maturity cultivars. Considering that the limiting heading time of Korean foxtail millet and finger millet in the northern region of Kangwon Povince is late August, the limiting accumulated temperature at the heading time was evaluated to be approximately 1,500℃ and 2,000℃ for early and late-maturity cultivars, respectively. The mean daily temperature from planting to heading time showed a negative correlation with the DH, which was shortened with the increase in mean daily temperature. This suggests that delaying the planting time from May to June in the north-central region of the Korean Peninsula increases the mean daily temperature during vegetative growth periods, resulting in the decrease of the DH and the accumulated temperature.

• Korean journal of applied entomology
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• v.56 no.3
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• pp.261-265
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• 2017

Currently, clearwing moths and peach fruit moths are considered economically important pests of jujube in Boeun, Chungbuk, Korea. However, until now, specific studies on occurrence of the major pests of jujube in Boeun area, which could be useful for pest control, have not been carried out. In this study, seasonal occurrence of three pest moths (Synanthedon bicingulata, S. haitangvora, and Carposina sasakii) in jujube orchards was monitored using sex pheromone traps. Synanthedon bicingulata and S. haitangvora were monitored from 2013 to 2015. Adults of both species were captured from May to October, with two peaks in their occurrence: mid-June and mid-September for S. bicingulata, and mid- to late-June and mid- to late-September for S. haitangvora. However, S. haitangvora occurred in lower numbers than S. bicingulata. Adults of C. sasakii were captured from 2014 to 2016. From May to October, two peaks were observed in their occurrence in mid-June and in late-August to mid-September and the second peak was lower than the first. Thus, the life histories of these pest moths of jujube should be studied in detail for an effective pest control.

• Journal of Ecology and Environment
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• v.36 no.4
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• pp.223-233
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• 2013

Acid deposition is one of the most serious environmental problems in ecosystems. The present study surveyed the effects of simulated acid rain on leaf litter mass loss and microbial community in the decomposing leaf litter of Sorbus anifolia in a microcosm at $23^{\circ}C$ and 40% humidity. Microbial biomass was measured by substrate-induced respiration (SIR) and phospholipid fatty acids (PLFAs), and the microbial community structures were determined by composition of PLFAs at each interval of decomposition in litter sample and at each pH treatment. The microbial biomass showed peaks at mid-stage of decomposition, decreasing at the late stage. The leaf litter mass loss of S. anifolia decreased with decreasing pH during early and mid-decomposition stages; however the mass loss becomes similar between pH treatments at late-decomposition stage. The acidification remarkably lowers the microbial biomass of bacteria and fungi; however, microbial diversity was unchanged between pH treatments at each stage of litter decomposition. With changes of decomposition stage and pH treatment there were considerable differences in replacement and compensation of microbial species. Fungi/bacteria ratio was considerably changed by pH treatment. The PLFA profile showed significantly larger fungi/bacteria ratio at pH 5 than pH 3 at the early stage of decomposition, and the difference becomes smaller at the later decomposition stage. At low pH, pH 3 and pH 4, the fungi/bacteria ratios were stable according to the litter decomposition stages. Simulated acid rain caused decreases of 10Me17:0, 16:1${\omega}$7c, 18:1${\omega}$7, 15:0, but increase of 24:0. In addition, litter mass loss showed significant positive correlation with microbial biomass measured by SIR and PLFA on the decomposing leaf litter.

• Korean journal of applied entomology
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• v.16 no.3 s.32
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• pp.139-144
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• 1977

The green peach aphid Myzus persicae(Sulzer), is known as the most important vector of potato leaf-roll virus and PVY. Yield of potato plants infested with these viruses are remarkably lower than non-infested plants. A study was conducted to investigate the life history of the green peach aphid at Suweon, Korea (Lat. $37^{\circ}$'N., Long. $126^{\circ}59$'E). The following were obtained: 1. Overwintering eggs hatched from late March to early April, with a hatching rate averaging ninety-five percent. 2. The fundatrigeniae leave the primary host(Punus persica) in early to mid May and migrate to the secondary hosts. 3. From mid to late Oct., the gymnoparae migrate from the secondary hosts to the primary hosts. 4. From early to mid Nov., gymnoparae lay fertilized eggs around buds, in bark crevices, or between bifurcated twigs of the primary hosts. 5. The early-born progeny have 23 generations and the late-born progeny have 9 generations on peach trees, potatoes and raddish from Apr. to Oct. 6. The average length of life was about 28.5 days, with a developmental period of approximate 10.8 days and a reproductive period of 15.8 days. 7. The average number of nymphs produced by a female was fifty, with a maximum number of 118. 8. The average number of nymphs produced by a female per day was about 3.2, with a maximum number of 13.

• Korean journal of applied entomology
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• v.39 no.4
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• pp.245-250
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• 2000

These studies were conducted to investigate the effect of temperature on the development and seasonal occurrence of Chrysopa pallens Ramber, a predator of aphids. Mean developmental periods of C. pallens from egg to adult emergence at four different temperatures of 17, 22, 27, and $30^{\circ}C$ were 39.5, 32.0,25.0, and 19.8 days, respectively. The longevities of adult females of C. pallens at the four temperatures were 84.7, 79.6, 77.7, and 69.8 days, respectively, whereas the total numbers of eggs laid by a female were 973, 1085, 1637, and 1735, respectively. Egg hatchability, rate of adult emergence, and sex ratio of C. pallets were slighty higher with increased temperature with 84.1~95.9%, 67.6~86.3%, and 1:1. Under three humidity conditions of 35, 55 and 75% RH, the mean developmental periods of C. pallets from egg to adult emergence at the $27^{\circ}C$ were 26, 24, and 22.9 days, respectively, while the number of eggs laid by a female were 1042.8, 1526.5, and 1640.0, respectively. Oviposition of C. pallets usually began 5~6 days after the emergence at $27^{\circ}C$. Then females laid ca. 30~40 eggs a day, reaching a peak of 80~90 eggs a day about 22~28 days after the emergence. Population fluctuation of M. persicae and A. gossypii showed the highest peak in late May through the mid-June, and the second peak appeared in early~mid-September. The adult occurrence of C. pallens by the light trap record started from mid-May, and show two peaks, in mid-late July and mid-late September in Chonbuk area.

• Journal of Ginseng Research
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• v.14 no.3
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• pp.421-426
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• 1990

Field and laboratory works were conducted to Investigate the life history, ginseng damage and chemical control effect of the field slug, Deroceras varians A. Adams. D. varians laid eggs from April to June, but a small number of eggs were also found from July to September in the field. Most young slugs grew through the slimmer months to maturity by October. overwintered beneath the moist soil surface, and began feeding and egg-laying in the following April. indicating that D varians have a life cycle in a year. Damage of ginseng plants by D. varina occurred mainly from late April to mid May in the 3rd to 5th year ginseng fields with rice-straw mulching. It seems that this damage is caused by the adults in oviposition periods and related to rice-straw mulching of ginseng fields. In the experiment, ethoprop 5% granule and metaldehyde 6% bait showed relatively high effectiveness in the control of D. varians adults. Bordeaux mixture was more effective when the chemical was sprayed after infestation of the slug than before the infestation and when the 6-12 mixture was used.

• Korean Journal of Agricultural Science
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• v.29 no.1
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• pp.32-43
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• 2002

The peach pyralid moth (Dichocrocis punctiferalis) is reported as import ant pest insect to chestnut fruits in Asia including Korea. For seasonal occurrence of D. punctiferalis in 1996, 1998 and 1999, D. punctiferalis adults were collected by light trap and sex pheromone wing trap in the chestnut orchard. Also, damaged rate of chestnut fruits were examined each collecting site. In 1996, according to examination by using light trap at three different site in Kongju, the occurrence peak of 2nd gene ration of D. punctiferalis adults was early August. Collected individuals after September were cons ide red as 3rd generation. Damaged rate due to maturation type was 26.5% averagely. The order of damaged rate were early, late and middle maturation type as 35.04%, 19.35% and 26.03%, respectively. Using synthetic sex pheromone trap at Kongju, Cheungyang and Buyeo in 1998, occurrence peaks were occurred mid-August to 2nd generation and late September to 3nd gene ration in Kongju. However, from early-August to late-September 5 peaks were occurred sequentially in Cheungyang. Second generation adults were occurred in mid-August and 3rd ones were occurred from late-September to early-October in Buyeo. In 1999, occurrence peaks of 3rd generation were early, middle and late September in Kongju, Cheungyang and Buyeo respectively. Damaged rate were 6.8%, 6.6% and 15.3% in Kongju, Cheungyang and Buyeo, respectively. Damaged rate order due to variety were Eunki, Chukpa, Danpa, Bokpa, Wangjung, Byunggo57, Yuoma at Buyeo and were Chukpa, Dukmyung, Byunggo57 at Cheungyang in 1999. Damage rate of chestnut were different with variety. Eunki and Chukpa in Buyeo and Chukpa and Dukmyung in Cheungyang were more damaged by D. punctiferalis respectively.