• Korean journal of applied entomology
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• v.59 no.1
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• pp.41-54
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• 2020

Two mosquito species were collected in still-water near farming area in Andong, Korea. Based on morphological characters, these two mosquitoes were identified as Aedes koreicus and Culex vagans, respectively. DNA barcode analyses supported the identification. An entomopathogenic bacterium, Bacillus thuringiensis subsp. israelensis (BtI), exhibited insecticidal activities against the two mosquito species and its virulence was more potent than that of B. thuringiensis subsp. kurstaki. It has been known that the bacterial metabolites of Xenorhabdus spp. suppress insect immunity and enhance pathogenicity of B. thuringiensis. This study tested the effect of the bacterial culture broth of Xenorhabdus spp. on enhancing BtI pathogenicity. Among three Xenorhabdus spp., culture broth of X. ehlersii (Xe) was relatively effective to enhance BtI pathogenicity against both mosquito species. Indeed, organic extracts of Xe culture broth suppressed the hemocyte-spreading behavior, suggesting the presence of immunosuppressant in the culture broth. These results suggest a formulation of BtPlus by mixing BtI spore and Xe culture broth to be applied to control the two mosquito species.

• The Korean Journal of Zoology
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• v.27 no.2
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• pp.117-125
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• 1984

Mosquitoes were collected with light trap at a pig shed in the vicinity of Daegu city from mid-April to the end of November in 1981 and 1982. A total of 12,942 and 118,061 individuals were collected in 1981 and 1982 respectively. The collection comprised 77% females and 23% males in 1981, and 96% females and 4% males in 1982. The catches were classified into following 7 species: Culex (Culex) pipiens pallens, C. (C.) tritaeniorhynchus summorosus, Anopheles (Anopheles) sinensis, C. (C.) vagans, C. (C.) oritntelis, C. (C.) bitaeniorhynchus, Aedes (Aedimorphus) vexans nipponii. The former three species showed distinct seasonal prevalence. Arranged in the descending order in size of the catches, in 1981, Culex (Culex) pipiens pallens was 44.9% of the total collection (at sex ratio of 0.85), Anopheles (Anopheles) sinensis 42.9% (0.05), Culex (Culex) tritaeniorhynchus summorosus 12.1% (0.00). On the contrary, Culex (Culex) tritaeniorhynchus summorosus 70.4% (0.00), Anopheles (Anopheles) sinensis 25.2% (0.05), Culex (Culex) pipiens pallens 4.4% (2.19) in 1982. The monthly percentages of collected mosquitoes to the total collection were 0.1% (in 1981) and 0.0% (in 1982) in May; 3.5%, 1.3% in June; 50.0%, 33.9% in July; 37.1%, in August; 8.8%, 11.9% in September; 0.5%, 0.8% in October and 0.0% in November. As for seasonal prevalence, mosquitoes appeared in May in both years and began to increase in number from the first week of June in 1981, but from the second week of May, ahead of three weeks in 1982. The highest peak time in 1982 was the second week of August, two weeks later than the fifth week of July in 1981. Culex (Culex) pipiens pallens showed the maximum activity for the fifth week of July in 1981, but for the third week of July, ahead of two weeks in 1982. Culex (Culex) tritaeniorhynchus reached the highest peak for the second week of August in both years. Anopheles (Anopheles) sinensis showed the maximum activity for the fifth week of July in 1981, but for the third week of July, two weeks earlier in 1982. The highest peak times of three main species were compared respectively as folows. Culex (Culex) pipiens pallens had the highest peak time in common with Anopheles (Anopheles) sinensis, Culex (Culex) tritaeniorhynchus summorosus showed the maximum activity for the second week of August in 1982.

• Parasites, Hosts and Diseases
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• v.23 no.1
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• pp.139-150
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• 1985

In order to determine the seasonal prevalence and population density of vector mosquitoes in Kyungpook Province, a survey based on average numbers of female mosquito per trap-night, were carried out during the period from May to November in 1984. Among the 34, 571 mosquitoes collected in Kyungsan county in animal shelters and human dwellings by light traps, approximately 45.0 per cent were Culex tritaeniorhynchus, 34.0 per cent Culex pipiens pallens, and 19.0 per cent Anopheles sinensis. By comparison, distribution of mosquito species in Ankang town, in which Japanese encephalitis had been reported in the past, were quite different and A. sinensis was the most abundant species, being constituted in 75.8 per cent, followed by C. tritaeniorhynchus(23.2 per cent), and C. pipiens pallens(O.6 per cent). In the general pattern of seasonal prevalence, C. tritaeniorhynchus first appeared in mid-June, and trapped in large numbers during the periods from mid-August to early September, showing a simple sharply pointed one-peaked curve, while C. pipiens pallens was found to be active through almost the entire season showing irregular curves with several peaks. The trend of seasonal distribution of A. sinensis was similar to that of C. tritaeniorhynchus, but the earliest dates of appearance and disappearance differed from that of C. tritaeniorhynchus. The results of hourly catches of mosquitoes by human baited traps have clearly shown the differences in the biting rhythm among the vector mosquitoes of this Province, such as the facts that C. tritaeniorhynchus and A. sinensis are rather constantly active all through a night with more or less inconspicuous peaks twice a night, while C. pipiens pallens exhibits an irregular curve, and the numbers of A. vexans nipponii, C. vagans and Armigeres subalbatus are very small and are not sufficient for estimating the biting rhythm. Four genera and fourteen species of larval mosquitoes collected from eighteen kinds of habitats which classified according to the categories followed by Bates (1949). The main breeding sites contributing to peak C. tritaeniorhynchus adult densities in this surveyed areas were evidently ricefields, ground pools, puddles and swamps and marshes, etc. Summarizing the results, this study indicated that the highest population density of C. tritaeniorhynchus was encountered in late August and early September, showing a simple sharply pointed one-peaked curve.