• Journal of Korean Society of Forest Science
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• v.79 no.2
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• pp.115-126
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• 1990

This study was performed to find differences in phototaxis response of the larva, adult emergence, sex ratio and gall formation rate of Thecodiplosis japonensis Uchida et Inouye between two areas, north and south. Larvae from these two areas, Hweng-sung in north and Moo-an in south, both considered to be the sities of severe outbreak of the insect recently, were collected from the floor and transported to the entomology larboratory, Won-Kwang University in Iri, then overwintered. These larvae were used for various experimental purposes on various dates. The following results were obtained. 1. The sizes of larvae reached 2.45 in length, 0.70 in width for north, and 2.50 in length, 0.72 in width for sourth. It seems that the differents were not significant. 2. It is known that Leaving gall of larvae to the ground for the hibernation usually occurs on rainy days. For the larvae dispersion, the phototaxis response of the larvae was hypothesized. To check this, the author manipulated some different illumination intensities adjusting the distance between the glass tube in which 100 larvae were contained and electric bulb. The glass tubes were blackened all but except a small portion. The phototaxis responses between two areas seemed to be different particularly at low light intensities, 45, 145 and 1000 lux, The larvae from north assembled to the clear portion of the glass tube were more than 30 out of 100, however less than 30 in south sample regardless of the time passage. In either cases, the saturation points came after about 8 to 10 hours. If temperature units were used, the phototaxis curve= after 1 hour illumination between two areas provided significant differences. 3. The adult emergence of south area was lagged 10 days later than that of north area. The accumulated effective day-degrees of temperature for adult emergence were $934^{\circ}C$ for north area and $1180^{\circ}C$ for south area. The emerging duration of north area appeared to be in late May through the early of July and the peak emergence occurred in middle June that was approximately 15days earlier than that of south area. The sex ratio of female to male, regardless of area, was approximately 3 : 1. 4. The rates of gall formation of the red pine(Pinus densiflora Siebold et Zuccarini), 6-year-old seedlings, were as low as 9.94% for north area and 8.87% for south area. Through the close observation, the author presumed that the population reduction was greatly affected during the prepupa stage by relative moisture content and predators, such as spiders and ants presented on the ground.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.85.1-85.1
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• 2012

In this study we use three-dimensional magnetohydrodynamic simulations of flux emergence from solar subsurface layer to corona. In order to study the twist parameter of magnetic field we compare the simulations for strongly twisted and weakly twisted cases. Based on the results, we derive a flux expansion factor of selected flux tubes which is a ratio of expanded cross section to the one measured at the footpoint of the flux tube. To understand the effect of flux expansion factor, we make a comparison between magnetic field configuration and the expansion factor. By using a fitting function of hyperbolic tangent we derive noticeable correlations among the strength of the vertical magnetic field, current density and expansion factor. We discuss what these results tell about the relationship between the twist of emerging field and the mechanism for the solar wind.

• Environmental Analysis Health and Toxicology
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• v.23 no.2
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• pp.93-100
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• 2008

The ecotoxicological effects of 4-tert-octylphenol were observed on Harpacticoid copepoda Tigriopus japonicus s.l. gathered and cultured from tidal pool of Korean coast. There were no significant differences in survival rate (except 10 $\mu$g/L; 70.00%) and sex ratio (except 30 $\mu$g/L) on T. japonicus s.l. exposed to 4-tert-octylphenol. However, 4-tert-octylphenol induced developmental delay (copepodite emergence day and adult male mergence day) and retardation of first brooding day of adult female. Moreover the body size and biomass decreased at 4-tert-octylphenol exposure. As a result, detailed life-cycle research of T. japonicus s.l. may yield potential bioindicators for environmental monitoring and assessment.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.1
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• pp.33-36
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• 2002

Mulberry leaf roller, Diaphania pulverulentalis (Hampson), is a major pest of mulberry, Morus alba. The life table construction from present investigation reveals the age specific survival $(1_{x)}$ and the age specific fecundity $(m_{x})$ of the pest. The female contributed the highest egg production $(m_{x} ＝ 12.75)4 in the life cycle on the $27^{th}$ day and the lowest $(m_{x} = 0.8)$ on the 37$^{th}$ day of the pivotal age. The female progeny production was observed to be intensive for the first six days after the preoviposition period, beyond which it declines steadily, The fecundity of D. pulverulentalis varies between 60-140. The first female mortality within the cohort occurred 4 days after the adult emergence and mortality increased thereafter, One generation is completed in 33.08 days. The female dominated sex ratio (1: 7.18 days) was recorded.

• Environmental Analysis Health and Toxicology
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• v.23 no.4
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• pp.277-284
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• 2008

The ecotoxicological effects of 4-tert-octylphenol were observed on non-biting midge, Chironomus plumosus collected from Anyang stream in Seoul. The survival rate and adult emergence rate on C. plumosus exposed to octylphenol were not significantly affected. However, 4-tert-octylphenol induced developmental delay and disrupted sex ratio in high concentration of octylphenol. The mouth deformity such as tooth deletion or fusion in mentum, and tooth deletion in mandible were observed exposure to 4-tert-octylphenol. The deformity type of the mentum showed deletion (LT, 6.7%), and fusion (LT, 6.3%). Moreover, tooth deletion of mandible was observed in 4-tert-octylphenol treated groups (6.7%, 3 ppm).

• Korean journal of applied entomology
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• v.44 no.1 s.138
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• pp.43-50
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• 2005

Parasitism of the egg parasitoid, Trichogramma evanescens, to its main host insect, the Asian corn borer, Ostrinia furnacalis in Korea was compared with that of T. ostriniae that is the dominant species in China on the same host insect. Parasitoid adults of both species emerged more than 50 percent within 4 hours after lights-on in 16L/8D photo period regime and showed a circadian rhythm of emergence. The developmental period from oviposition to emergence in both parasitoids was ca. 11 days and there were no significant differences between the two species and between female and male of each species, either. Both species also showed superparasitism even when the parasitic rates in one egg mass were below 100 percent. Both species oviposited by 5 days after emergence, and maximum longevities of each female adult of both species were 8 day for T. evanescens and 6 day for T. ostriniae. The total number of eggs parasitized by T. evanescens was ca. 38 eggs and ca. 31 eggs by T. ostriniae. Newly emerged female parasitoid laid eggs on about $50\%$ of the host insect egg mass, and the parasitism decreased with the adult age of egg parasitoids in both species. The sex ratio of two species was female-biased about $80\%$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.11-19
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• 1982

The average weight of larvae, the percentage of survival larvae and the percentage of moth emergence in first and second generation of striped rice borer showed lower values in Akibare(Japonica variety) compared with those in Milyang 23 (Indica variety). At higher nitrogen level the larvae weight in second generation of striped borer was increased. The percentage of survival larvae in second generation was gradually decreased by applying the silicate fertilizer in both cultivars. The moth emergences in both generations of striped rice borer were also lower at high levels of silicate fertilizer. The percentage of white head of rice plant was reduced by the application of silicate fertilizer. The ratio of SiO$_2$ to T-N of the rice stem was related negatively with the percentage of survival larvae and the moth emergence in second generation of striped rice borer, and also with the percentage of white head of rice plant.

• Korean Journal of Medicinal Crop Science
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• v.24 no.3
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• pp.207-213
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• 2016

Background: This study aimed to investigate the flowering and fruits formation characteristics of Korean Panax ginseng varieties. The results will provide basic data for ginseng seed production and breeding program. Methods and Results: The characteristics investigated included flowering date, seed setting rate, seed type and seed production. The ginseng variety Chungsun had the earliest emergency and flowering dates, whereas Sunhyang showed late emergence and flowering dates. The emergence date of Chunpoong was not later than that of the other varieties, but the flowering date was delayed. The seed setting rate was 64.6%, 75.8%, 78.5% and 74.4% for three, four, five and six-year-old varieties, respectively. The ratio of double seed (RD) for Sunhyang and Chungsun were higher than those for the others, whereas the RD for Chunpoong was the lowest. Yunpoong and Sunone had many stems per plant and a high seed production rate. Seed production was 21.7, 67.7, 74.4 and 89.0kg/10 a in three, four, five and six-year-old varieties, respectively. Conclusions: The emergence date ranged from April 15 to 25, and the flowering date was from May 10 to the 19 for the new ginseng varieties. The average seed multiplication of the ginseng varieties was about 8.5 and 21.1 times a year for varieties in which, seed-production occurs once a year for over four years and four times over six years, respectively.

• Journal of Bio-Environment Control
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• v.13 no.3
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• pp.135-142
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• 2004

The objective of this study was carried out to determine which method is effective for improving seed germination in carrot and onion among osmotic or solid matrix priming. Seeds were osmotic primed with -0.5 MPa polyethylene glycol 8000 (PEG) solution and solid matrix primed with Micro Cel E (seed, Micro Cel E, and water mixed with the ratio of 4.0：2.0：8.0 by weight for carrot, and the ratio of 4.0：1.2：5.0 for onion at $20^{\circ}C$ for 4 days). Seeds were rapidly absorbed water after osmotic priming and solid matrix priming treatment. The moisture content of solid matrix primed seeds was lower than that of osmotic primed seeds in carrot and onion. Osmotic priming and solid matrix priming did not influenced on increasing of percent germination, but $T_{50}$ of treated seeds was shorter than those of untreated seeds at four temperature regimes. The effects of osmotic or solid matrix priming in reducing the $T_{50}$ was greater when the seeds were germinated at $15^{\circ}C$ than at $25^{\circ}C$ and $30^{\circ}C$ temperature. Solid matrix primed seeds germinated faster than osmotic primed seeds at all temperature in both carrot and onion. After priming, surface-dried seeds germinated faster than dried-back seeds in carrot and onion. Emergence speed of carrot and onion seeds was faster than untreated seeds by osmotic priming or SMP treatment although the final emergence percentage was not significantly influenced. On the other hand, early growth was not significantly influenced by osmotic priming or SMP treatment of carrot and onion seeds.

• Korean Journal of Ecology and Environment
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• v.52 no.1
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• pp.13-20
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• 2019

Heavy metals resulted from the increase of human industrial activity are introduced into the environment through rainfall and wastewater, and have harmful effects on inhabitants. In this study, we investigated biological responses such as survival rate, growth rate, emergence rate and sex ratio, and morphological effects of mentum deformity in Chironomus plumosus, an indicator organism to evaluate pollutions on aquatic ecosystem. The survival rate of C. plumosus showed time- and dose-dependent decrease after chromium and copper exposures. Growth rate decreased at $4^{th}$ day after chromium exposure and significantly reduced at exposure to relatively high concentration (copper $1000mg\;L^{-1}$) for all exposure times. In addition, we observed that the emergence rate by exposure to copper $1000mg\;L^{-1}$ was significantly lower than that of the control group. The imbalance of sex ratios showed at relatively low concentrations (chromium 10 and $50mg\;L^{-1}$) with the high proportion of female and at the relative high concentration (copper $1000mg\;L^{-1}$) with the high proportion of male. Furthermore, the morphological mentum deformities of C. plumosus observed in the exposed group according to chromium and copper exposure. These results suggest that the heavy metal exposure in environment may influence biosynthetic and morphological stresses of benthic invertebrate C. plumosus, and aquatic midge C. plumosus are potential indicators for toxicity assessment of heavy metals such as chromium and copper.