• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.554-557
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• 2018

A catch basin sump is one major habitat for mosquito larvae, especially in urban areas. This study developed a device for mosquito control, specifically for the catch basin sump. It consists of a housing, is a little smaller than the catch basin sump, numerous floating materials, which the key component for mosquito control, and mesh nets. The small balls or pyramid-shaped floating materials inhibit mosquito enclosures and spawning by significantly decreasing the surface area of the water, which is essential for the mosquito life cycle. These floating materials were designed to keep the water flowing. The mesh nets were installed to prevent the outflow of floating materials. The efficiency of the floating materials was tested with 3 conditions (1, 2, 3 layers of floating materials) and a control group. The emergence of mosquito adults decreased by 20% in one-layer, and 70-80% in second and third layers. Therefore, this device is expected to certainly contribute to mosquito population control in the catch basin sump.

• Korean Journal of Plant Resources
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• v.19 no.6
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• pp.721-726
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• 2006

Mosquitoes are carriers of malaria and encephalitis. This study performed for eco-friendly control of mosquitos by using genus Acorus. Several solvents were used for the extraction of genus Acorus; water, ethanol, and methanol. Grinded leaves and roots were also included. Acorus extracts killed mosquito larvae and the ethanol extract showed the best result. Autoclaved Acorus water needed long time to kill mosquito larvae. $LT_{50}$ of 1 % Acorus calamus decoction was 13.6 hrs and 1 % autoclaved Acorus water was 53.6 hrs. $LT_{50}$ of 0.05% Acorus calamus rhizome powder was 28.5 hrs. $LT_{50}$ of 0.5% Acorus calamus leaf powder was 10.8 hrs. $LT_{50}$ of 0.1 % Acorus calamus decoction was 63.4 hrs and 0.1 % Acorus calamus ethanol extracts was 48.6 hrs and 0.1% Acorus calamus methanol extracts was 53.9 hrs. $LT_{50}$ of 0.4% Acorus gramineus decoction was 45.5 hrs, 0.4% ethanol extracts was 10.9 hrs, 0.4% methanol extracts was 10.2 hrs. $LT_{50}$ of ethanol extracts was shorter than other extracts. Acorus calamus rhizome powder could be used for the eco-friendly control of the mosquito larvae.

• The Korean Journal of Pesticide Science
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• v.20 no.3
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• pp.181-188
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• 2016

BtPlus is a group of biopesticides that are made of Bacillus thuringiensis and immunosuppressant. A new BtPlus that exhibits high insecticidal activity against mosquito larvae has been investigated in control efficacy in field conditions and its environmental safety against aquatic system. This study assessed the control efficacy of BtPlus against mosquito larvae with two different application methods. In aerial spraying application (100 mL per $3.3m^2$), BtPlus was effective at 50% or above formulation concentrations to control mosquito larvae. For a direct application to aqueous mosquito habitat, a semi-field mimicking paddy rice field was constructed. In this condition, BtPlus showed 80% and 100% control efficacies at 0.1% and 0.2% concentrations, respectively. BtPlus also showed 40% mortality against adults at 0.1% concentration in 10% sugar bait. However, its control efficacies against adults were much less than against larvae. Safety assessment of BtPlus against ecosystem was evaluated using young carp (Cyprinus carpio), a water flea (Daphnia magna), and a honey bee (Apis mellifera). BtPlus did not give any adverse effects on these nontarget organisms. Based on these results, BtPlus can be applied to control mosquitoes by direct aqueous application to paddy rice field.

• Korean journal of applied entomology
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• v.45 no.1 s.142
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• pp.51-57
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• 2006

Culex pipiens complex larvae were found at the septic tanks in Busan and Ulsan cities located in South-eastern area of Korean peninsula. The larvae were collected in 25, 35 and 75 septic tanks out of 3,527, 622 and 1,111 septic tanks which the breeding rates were averages of 0.7%, 5.6% and 6.8% in Busan from January to May, 2003; Busan from February to March, 2004; and Ulsan from January to April, 2005, respectively. The average numbers of the mosquitoes in the tanks were 38.8, 14.9 and 13.7 larvae/dip with a 355-ml dipper. The larval densities were from 25.4 larvae/dip in January to 43.7 larvae/dip in April. 2003 which were not significantly different between them. It was the first report to find mosquito breeding at septic tink in Republic of Korea. Culex pipiens larvae were found in 6 out of 379 septic tanks at complex buildings (over $2,000m^2$ in size) in Ulsan from June to September, 2005, having an average of 1.6% for mosquito breeding rate. The mosquito larvae were collected in 8 and 530 septic tanks out of 210 and 3,729 septic tanks at large (over 300 homes) and small apartments (below 300 homes) with 3.8% and 14.2% of the average breeding rates, respectively At the septic tanks of private houses for below 50 persons, 708 out of 7,178 septic tan had Cx. pipiens larvae and pupae with 9.9% of the average breeding rate. Total average of the mosquito breeding rate was 10.9% of the investigated septic tanks of residential buildings in Ulsan. The number of mosquito larvae in the septic tanks were 15 to 75 larvae/dip. The bent net sets of septic tanks prevented from mosquito breeding to the rate of 93.1%.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2001.11a
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• pp.62-62
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• 2001

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.173-177
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• 1996

Bacillus thuringiensis subsp. morrisoni PG-14 is a gram-positive soil bacterium producing mosquitocidal parasporal inclusions composed of several crystal proteins. Among these crystal protein genes, cryIVD gene is one of major component which has 72 kDa in size. However, these parasporal inclusions sink quickly from the surface of water where mosquito larval feeding occurred. To develope mosquitocidal cyanobacterium, therefore, we constructed the expression vector, pCYASK 5-1 harboring cryIVD gene. The expression vector, pCYASK5-1 was transformed into the cyanobacterium Syne- chocystis PCC6803 reported as a natural mosquito larval food source and the transformants were selected with kanamycin. Expression of IVD gene in transformant was characterized by SDS-polyacrylamide gel electrophoresis (PAGE) and immunoblot analysis. The mosquitocidal activity of a transformant was determined with Culex tritaeniorhynchus. The results showed that, the transformed cyanobacterium is toxic to mosquito larvae and will be expected as a potential agent that is used for mosquito control.

• Korean journal of applied entomology
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• v.38 no.2
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• pp.165-169
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• 1999

A study was performed on the susceptibility of Abate@ and Abate-S@ against 3rd instar larvae of 5 species of mosquitoes including Anopheles sinensis, Aedes dorsalis, Culex inatomii, Cx. pipiens pallens, Cx. tritaeniorhynchus and mosquito larvivorous fishes such as Chinese muddy loaches (Misgurnus muzolepis) and crucian carps (Carassius carassi~4s) in September, 1998. Cx. pipiens larvae showed that the LC5os of both Abatea and Abate-Sa were 0.006 ppm. The LC95 values of this mosquito species appeared 0.070 pprn of Abate@ and 0.035 pprn of Abate-S@ which were more susceptible than the dosage (1.0 ppm) recommended from WHO. An. sinensis larvae appeared 0.009 pprn of LC50 and 0.025 pprn of LCgs. The larvae of Cx. inatomii and Ae. dorsalis showed the most highly susceptible to Abate-S@ among the 5 mosquito species with LC50 values of 1.9 x pprn and 1.1 x pprn respectively, and the LC95 values were 5.2 x 10-hppm and 1.4 x ppm, respectively. On the other hand, Cx. tritaeniorhynchus appeared least affected by Abate-Sa. and was brought 0.048 pprn of LC50 and 0.808 pprn of LCg5. These two insecticides were much less toxic to the fishes than mosquito larvae showing the LC, value of Chinese muddy loaches at 24.145 pprn of Abate and 10.750ppm of Abate-S@. This fish species showed that the LCsos of Abate@ and Abate-S@ were 27.567 pprn and 14.775 ppm, respectively. In case of crucian carps, their LC, values were 7.914 pprn of Abate@ and 6.480 pprn of Abate-S@. Therefore, the maximum safe dosages of the insecticides to the fishes were 8 times as high as the values of LCg5 of the mosquito larvae. This study suggests that Abate@ and Abate-S@ demonstrated highly potential insecticides for further larger scale operational integrated control in some proper aquatic places if other aquatic invertebrates are also safe to the insecticides.

• Korean journal of applied entomology
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• v.43 no.1
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• pp.35-41
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• 2004

Bacillus thuringiensis produces crystal proteins toxic to medically and agriculturally important pests during sporulation. To improve the activity of insecticidal crystal protein in applying to mosquito larval control, an expression vector, pSyn4D harboring the mosquitocidal cry11Aa gene under control of psbA promoter of Amaranthus hybridus was constructed. This expression vector was transformed into Synechocystis PCC6803 and a transformant, Tr2C was selected with kanamycin. The mosquitocidal cry11Aa gene was stably integrated Into genomic DNA of Tr2C in PCR detection using cry11Aa-specific primers. The transformant expressed 72-kDa Cry11Aa protein and median lethal time (LT$\sub$50/) was approximately 2.1 days for Culex tritaeniorhynchus larvae and 0.7 day for Anopheles sinensis larvae, respectively. These results suggest this transformant can be used for mosquito larval control as a biological control agent.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.694-700
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• 2018

To investigate the effect of heavy metals (Cu, Cd, Hg, Pb, Zn) on mosquito Culex pipiens, 50% lethal concentration ($LC_{50}$) concentration, total lipid content, lipid content composition, and total protein content were measured. The results showed that the Hg $LC_{50}$ was $0.45mg\;kg^{-1}$ and the Hg toxicity was higher than the other metals. The results also showed that cadmium (Cd) significantly retarded the growth of mosquito larvae among the tested heavy metals. Six types of lipid bands were isolated from mosquito samples exposed to heavy metals, and five of them were identified (phospholipid, cholesterol, fatty acid, triglyceride, and cholesterol ester). The total lipid content of all treatments decreased compared to the control. In addition, the protein content of the control group ($0.51mg\;ind.^{-1}$) was higher than that of the treated group, and the protein content of the larvae treated with Hg and Cd was very low. In conclusion, heavy metals not only lower the survival rate of mosquitoes, but also affect the protein content and lipids in the mosquito's body, thereby causing growth inhibition. These results indicate that heavy metal contamination will affect the size of mosquito population by inhibiting the survival and growth of mosquitoes, and it is expected that it can be used to measure the degree of contamination using mosquito through subsequent studies.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.600-606
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• 2019

The study site was the camping area in the Hwarang Amusement Park in Danwon-gu, Ansan-si. Study activities were conducted three times a week from July 20, 2018, to August 1, 2018. A control site, natural enemy site, and Bti(Bacillus thuringiensis israelensis) site were selected. The analyses included habitat environment and species composition analyses, community analysis, correlation analysis, and similarity analysis. The water quality analysis found no significant difference in water quality over the study period (p>0.05). A total of 4,818 individuals, 38 species, 22 families, and 11 orders were observed during the study period. The natural enemy site observed during the study period had a similar species composition as the control site. The Bti site differed from other sites by the low number of species and individuals present. According to the community analysis, the natural enemy site was a stable community and the Bti site was an unstable community during the study period. Diptera showed negative associations with temperature and water temperature and mosquito larvae showed significant correlations with temperature and water temperature. The similarity analysis showed that the control site and the natural enemy site were 61.11-73.68% and the Bti site showed 30.77-56.00% similarity.