• Korean Journal of Agricultural Science
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• v.41 no.3
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• pp.177-185
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• 2014

Aspiring to the new raw materials of insecticides is one of the plant extracts. The material structure of a variety of plant extracts have because the material to the defense of the plant itself, the case of insecticides, using plant extracts, safe, has low toxicity and has the advantage of highly distinctive and fall. Coltsfoot (Tussilago farfara L.) is belonging to the family Compositae, and distributed in all parts of China as medicinal plants and indigenous plants used. Coltsfoot is known that it is effect to respiratory disease and has an antiviral effect. However, the reported insecticidal activity of coltsfoot could be not found. Fortunately, I found insecticidal activities when I was screening the bioassay against several insects with a lot of plant extracts. Using the ethanol extract of the Tussilago farfara, there were insecticidal activities against Culex pipiens pallens and Tetranychus urticae. There were several fractions in ethanol extract of coltsfoot by using various organic solvents. Hexane fraction showed a higher insecticidal activity than any other fraction. It is confirmed that hexane fraction contained pyrethrin by using HPLC analysis. So, it might be suggested that extract of coltsfoot has an insecticidal activity and its effect due to a ingredient of pyrethrin.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.357-362
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• 2006

Bacillus thuringiensis strains were isolated from the domestic soil and a strain was selected that had a new host range and high toxicity against agriculture insect pest. The 142 samples of soil were sampled from the mountains, paddy fields and patches, in Daejon, Chungnam, Chungbuk and Jeonbuk and used for the investigation. Sixteen B. t strains were isolated from 12 samples among collected samples. There were 11 strains that showed toxical activity on Plutella xylostella (Lepidoptera: Yponomeutidae), 7 steins on Spodoptera litura (Lepidoptera: Noctuidae), 5 strains on Arete coerulea (Lepidoptera: Noctuidae), 5 strains on Culex pipiens pallens (Diptera: Culicidae) among the 16 isolated B. t strains. But there were not any strains that showed activity against Hyphanria cunea (Lepidoptera: Arctiidae) and Sitophilus oryzae (Coleoptera: Rhynchophoridae). And also some of B. thuringiensis strains showed insecticidal activity with 2, 3 or 4 kinds of insects. But there were also 3 strains that did not show any activities to the 6 insects which were used in the experiment. When examined with a phase-contrast microscope, the insecticidal crystal protein produced from 16 selected strains had 13 bipyramidal and 3 spherical shapes. The insecticidal bioactivity of the S. litura showed 100% mortality when there were $1.3{\times}10^{7}\;(cfu/ml)$ of CAB109 isolates.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.3
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• pp.336-343
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• 2019

In order to investigate the density of seasonal incidence of mosquitoes, a vector of infectious diseases in Jeju region, this study collected mosquitoes using a Black light trap (BL) and Biogents' Sentinel 2 Mosquito Trap (BG), dividing the region into cattle sheds, habitats for migratory birds, and the downtown area, twice a month for 9 months from March through November 2018. Then, this study conducted identification and classification and checked for the presence of Flavivirus using reverse transcription polymerase chain reaction (RT-PCR). As for the mosquito population, 1,847 mosquitoes (six genera, 12 species) were collected. The places where most mosquitoes were collected were copses near craft workshops in habitats for migratory birds and Jungang-dong in the Seogwipo downtown area. For the population, Culex pipiens pallens was the dominant species (76.9%), followed by Aedes albopictus (8.9%). Most of the population was collected in June, followed by August and October. This study conducted a RT-PCR test with 1,847 collected mosquitoes, which were divided into 50 pools if they had Flavivirus. All turned out to be negative. However, the results of the investigation show the presence of Culex tritaineniorhychus, Aedes albopictus, and Anopheles sinensis and can be used as a basis for the comprehensive prevention management of mosquitoes.

• Korean journal of applied entomology
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• v.42 no.2
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• pp.125-132
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• 2003

Seasonal fluctuations in density of mosquito species were investigated at two cow sheds near to a large, reedy marsh with fairly polluted brackish water near the coast of Yongam-ri, Cheongryang-myon, Ulsan, Korea. Female mosquitoes were collected biweekly using Nozawa light traps from March to September, from 1999 to 2001. On average, 4,416.1, 5,505.9 and 6,863.8 females per trap night were collected from 10 species in 5 genera in 1999, 2000 and 2001, respectively. Among them, An. sinensis was most abundant (53.4% in species ratio), followed by Cx. tritaeniorhynchus (43.0%), Cx. inatomii (1.6%), Ochlerotatus dorsalis (1.3%) and Cx. pipiens pallens (0.5%). A malaria vector, An. sinensis and a Japanese encephalitis vector, Cx. tritaeniorhynchus were collected 3,663.3 females and 3,142.5 females per trap night from June to September for the years, respectively. According to the biweekly population changes at the area, Cx. inatomii which was dominant species in 1997, was the most abundant in the early July during 1999-2001.

• 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.