• Korean journal of applied entomology
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• 제30권1호
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• pp.10-17
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• 1991

Cuticular penetration and detoxication as mechanisms of resistance to the carbamate insecticides in fenobucarb-selected($R_{f}$) and carbofuran-selected($R_{c}$) strains of the brown planthopper (N. lugens Stal) were investigated. Rates of penetration were not significantly different in the susceptible and resistant strains. However, total amount of excretion of the $R_{f}$ and $R_{c}$ strains were much larger than that of the susceptible strain. Fenovucarb and carbofuran were in vivo metabolizd much faster in the $R_{f}$ strain than in the susceptible strain. OSBP(o-sec-butyl phenol) and 3-ketocarbofuran phenol were invitro the major metabolites of fenobucarb and carbofuran in the brown planthopper, respectively. Total amount of the two major metabolites were produced abotu 2 times larger in the $R_{f}$ and $R_{c}$ strains compared to the susceptible strain. OSBP and 3-ketocarbofuran phenol were not so toxic to the brown planthopper ($LD_{50}$ >100 $\mu\textrm{g}$/g hopper). Based on our data, detoxication plays a large role in resistance to fenobucarb and carbofuran in the resistant strain of BPH, although several resistance factors maybe involved.

• Korean Journal of Ichthyology
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• 제31권4호
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• pp.201-207
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• 2019

Temperature is one of the most important criteria considered in species preference for aquaculture. Acute drop in temperature during winter is a cause of disease and mass mortality in farmed fish. This study was carried out the low water temperature tolerance, oxygen consumption, hematologic and histological responses to use as basic data for the management of fish farming which frequently cause death due to winter water temperature drop. Low-lethal water temperature for 4 days of file fish Thamnaconus modestus (4day-LT₅₀) was 6.97℃ (6.69~7.27℃). Oxygen consumption rate decreased with decreasing water temperature, showing a significant difference between water temperatures. SOD activity increased significantly at 6℃ experimental group than control group (10℃) (p<0.05), but CAT did not show any significant difference between experimental temperatures (p>0.05). Cortisol increased with decreasing experimental water temperature compared to control group. Histological changes in the liver include decreased blood vessels in the blood vessels, proliferation of acid cells, condensation of the nucleus, atrophy of pancreatic exocrine gland cells, and enzyme source granules.

• Korean journal of applied entomology
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• 제30권1호
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• pp.1-9
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• 1991

Cross-resistance and inheritance of resistance in laboratory-selected strains of the brown planthopper to various types of the insecticides were investigated. The fenobucarb-selected ($R_{f}$), carbofuran-selected($R_{c}$), and diazinon-selected($R_{d}$) strains were 50.3, 49.2 and 5.8 times less sensitive to the corresponding insecticides than th susceptible strain. both $R_{f}$ and $R_{c}$ strains were highly resistant to the other carbamate insecticides, and moderately resistant to cypermethrin and deltamethrin, but nearly not resistant to fenvalerate and the organophosphorus insecticides except malathion and phenthate. Moderate resistance to malathion and phenthoate in the $R_{f}$ and $R_{c}$ strains was obtained at the rate of 13.0-12.0 and 8.5-7.5 times, respectively. The $R_{d}$ strain showed low levels of resistance to the carbamate, organophosphorus and pyrethroid insecticides, but negatively correlated cross-resistance to fenvalerate. Resistance of the brown planthopper to all the test insecticides was inherited by partially dominant autosomal factor(s).

• Korean journal of applied entomology
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• 제46권2호
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• pp.261-267
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• 2007

Bioassay of mosquito, Culex pipiens molestus, larva was investigated by several environment-friendly insecticides. These insecticides were Novaluron as chitin synthesis inhibitor, Metho-xyfenozide as ecdysone agonist, Pyriproxyfen as juvenile hormone mimic, and Spiromesifen as lipid biosynthesis inhibitor. The 50% lethal concentration $(LC_{50})$ of these insecticides were 0.00039, 0.07193, 0.65006 and 0.04839 ppm, respectively. Novaluron has lower concentration than any other insecticide. To determine the treatment time against larval stages, insecticides were applied to different larval stages of C. pipiens molestus. Mortality ratios of mosquito larva treated with Novaluron were 100.0, 84.5, 71.0 and 48.5% on 2, 4, 7 and 10 days after hatching from eggs, respectively. Otherwise, with the other insecticides, mortality ratios were under 80% with 2 days old larva. When exposure periods were tested to 3 or 4 days old larva against 4 insecticides, at least 3 hours were needed to 100% control effect against Novaluron, and over 12 hours with other insecticides.

• Korean journal of applied entomology
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• 제46권2호
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• pp.313-318
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• 2007

Entomopathogenic nematode, Steinernema carpocapsae GSN1 strain was evaluated for the environmentally sound control of Tebenna issikii (Lepidoptera: Choreutidae) in the laboratory. The corrected mortality of Tebenna issikii larvae was 100% at the 40 infective juveniles (Ijs)/larva 3 days after treatment with S. carpocapsae GSN1 strain in Petri dish. $LC_{50}$ value of S. carpocapsae GSN1 strain against Tebenna issikii was 5.7 Ijs. The mean penetration numbers of Ijs of S. carpocapsae GSN1 strain at the 5, 10, 20, 40 and 80 Ijs/larva in a Tebenna issikii larva were 1.4, 1.4, 3.2, 5.6 and 11.9 Ijs/larva, respectively. However penetration rate of Ijs of S. carpocapsae GSN1 strain at 5 Ijs/larva was the highest among other nematode concentrations. Progeny of S. carpocapsae GSN1 strain in a Tebenna issikii larva was higher with increasing nematode concentration.

• Journal of Life Science
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• 제24권6호
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• pp.626-632
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• 2014

The genetic structure and phylogenetic relationship were investigated in Korean red spotted grouper populations using the nucleotide sequence polymorphisms of the mitochondrial DNA (mtDNA) cytochrome c oxidase subunit I (COI) gene. The COI gene was sequenced showed 99.1-99.8% identity with the EF607565 sequence previously reported. A total of twenty haplotypes were found, and the Korean population showed nineteen haplotypes. Among those, Hap_03 and Hap_08 showed Jeju-do and China-specific COI sequences, respectively. However, Hap_07 had twelve COI sequences from South Korea and records from Hong Kong and Taiwan. Neighbor-joining (NJ) trees constructed from the phylogenetic analyses based on the polymorphisms of the COI haplotypes showed a monophyletic branching pattern within the genus Epinephelus. This indicated that the red spotted grouper populations had evolved from common maternal ancestors. In addition, the Hap_08, which had the COI sequence recorded only from China Sea, was found in the middle of the NJ tree nearby Hap_07 and showed a close relationship with Hap_07. This indicates that Chinese red spotted grouper is also maternally related to other populations in East Asia. Consequently, East Asian red spotted grouper populations are maternally related, as well as sharing the same evolutionary history, and are still affected by the East Asian ocean current (Kuroshio). These findings help to explain the genetic structure and phylogenetic relationship of red spotted grouper and also contribute to research on artificial breeding and industrialization.

• Journal of Preventive Medicine and Public Health
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• 제9권1호
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• pp.117-122
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• 1976

The occupational skin diseases in an industry of silk reeling located in Daegu city of Korea were analyzed by inspection through a mass survey for improving the workers' health, November, 1975. The subjects, 177 persons were all females, and were distributed at 18-38 years old. About two thirds were under 25 years old. The meanage was 23.6 years. The incidence of skin diseases was about 53%. It was generally divided into three groups;- the epidermic changes of those were most frequent, 47.5%, the allergic reactions were 14.7%, and athlete's foot was only four cases, 2.3%. Most frequent signs of epidermic changes was the worn-out nail, 32.3%; and the keratolysis, 28.8%; and the callus, 15.3% were followed in order. Theses were significant in five per cent level between the sections of the silk reeling and the manufacturing;-Allergic reactions and worn-out nail were more frequent in the manufacturing group than the silk reeling, and keratolysis and callus were inverted proportionally. Allergic reactions were occurred within a few months from first entrance time, and it was more frequent in the group exposed to same allergen in the past than the continuing group from first. Most of the appearing sites of theses were hands, and infrequently, it was occurred in the face, neck, trunk, knee anfeet. These epidermic changes except allergic phenomena were appeared in the fingers, palmal and dorsal surface of hands frequently contacted. But these changes and allergic reactions were generally combined with two or more kinds.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제26권2호
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• pp.137-145
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• 1981

Using the milled, blast infected leaves (BIL) as an inoculum source on the screening for the resistance to blast of rice plant was a simple and useful technique. The temperature with high (25^\circ C\sim 35^\circ C) and low (15^\circ C\sim 28^\circ C) and the water stressed or not, was conditioned of to the inoculation with the BIL to the test varieties in seedling stage. In low temperature, most of the varieties were more infected with blast, however the Indica-Japonica hybrids were more infected in high temperature conditions. The water stressed was more infected with blast than the not stressed. The interaction of variety with water stress was not so much as that of variety with temperature. Resistant reaction to blast (BIL) was not affected by the temperature and water stress, but the moderately resistant or susceptible one was much affected by them. Inoculum of BIL was virulent to the newly bred Indica-Japonica hybrid cultivars such as Tongil, Nopung, etc, but not virulent to the Japonica cultivars such as Nongbaek, Jinheung, etc. The discrete, mixed or variable lesions were observed mainly in the moderately resistant or susceptible cultivars such as Kanto 51, Yashiromochi, Ishikari-shiroke, etc.

• Korean Journal of Environmental Agriculture
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• 제7권1호
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• pp.58-64
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• 1988

The acute oral, intraperitoneal and subacute toxicity of monocrotophos, an insecticide, was studied in albino rats. The acute oral $LD_{50}$ values for female and male rats were 5.0mg/kg and 8.7mg/kg, respectively. Conversely the intraperitoneal $LD_{50}$ values for female and male rats were 4.9mg/kg and 6.0mg/kg, respectively. Plasma cholinesterase (ChE) activity in rats treated with a single dose was the most depressed 4 hours after administration, but returned to normal within 72 hours of administration. Significant depression of body weight gain and food consumption was observed in rats receiving the 3.5mg/kg/day dose level for 28 days as compared with the controls. Additionally plasma ChE activity depression was also observed.

• The Korean Journal of Pesticide Science
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• 제10권4호
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• pp.335-343
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• 2006

Five strains of Korean entomopathogenic nematodes(EPN), steinernematids and heterorhabditids(Steinernama carpocapsae GSN1, Steinernema sp. GSNUS-10, Steinernama sp. GSNUS-14, Heterorhabditis bacteriophora Hamyang, Heterorhabditis sp. GSNUH-1) were evaluated and tried in petri dish, pot, and vegetable greenhouses for environmentally friendly control of beet armyworm, Spodoptera exigua. $LC_{50}$ values of five EPN strains against beet armyworm was different depending on nematode strain and beet armyworm instar. $LC_{50}$ value of Steinernema carpocapse GSN1(GSN1) was 3.8-5.1 infective juveniles(Ijs) in 2nd to 4th instars of beet armyworm. Pathogenicity of five EPN strains against beet armyworm different in nematode strain, concentration, application times, and vegetable species in pot and greenhouse. Steinernema spp. was more effective than Heterorhabditis spp. against beet armyworm. Two or three times of applications of EPN were found to be effective regardless of nematode strain and concentration in pot and greenhouse. ENP showed different reactions on vegetable species. Efficacy of EPN was higher on Chinese cabbage than that on cabbage and kale. GSN1 was one of the most effective nematodes and 100,000 infective juveniles per $m^2$(720,000 Ijs/$7.2m^2=1{\times}10^9$Ijs/ha) resulted in higher mortality in greenhouse.