• Korean journal of applied entomology
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• v.42 no.3
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• pp.257-262
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• 2003

Spider mites and their predacious mites were surveyed in an apple orchard where pesticides have not been applied for a long time, to understand the undisrupted predacious mite complex and their role in the controling spider mites. Spider mites occurring in the orchard were different to those in conventional orchards. A few Tetranychus urticae and Panonychus ulmi were observed, while T. kanzawai was abundant during growing season. Four species of phytoseiids, Amblyseius eharai, A. kokufuensis, A. womersleyi and Typhlodromus vulgaris, and one stigmaeid species of Agistemus terminalis were observed from leaf samples in the orchard. Among them, T. vulgaris occurred from early cool season with low T. kanzawai densities through to mid-and late-season. A. womersleyi was observed only during mid-season when T. kanzawai densities were high with hot weather. Amblyseius eharai and A. kokufuensis occured only in early season, but A. terminalis density increased from mid-season and lasted to late-season. The predacious mite complex regulated the density of T. kanzawai approximately under 8 mites per leaf. Tentatively concluding, T. vulgaris is an adaptable predator at lower prey density under cool weather condition, and A. womersleyi is effective predator at higher prey density under hot weather condition. Further, the biological control strategies of spider mites in Korean orchards were discussed based on the predacious mite complex.

• Journal of Aquaculture
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• v.19 no.2
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• pp.109-118
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• 2006

The recent decrease in wild stocks of seahorse, Hippocampus coronatus, has prompted the production of the species in captivity. We here present data on the body color changes of the species according to culture conditions. This investigation examined relationship between adult body size and clutch and growth in 60 days after parturition and survival of juveniles with four fed enriched Artemia nauplii, copepod nauplii and copepod adult. Seahorse adults ($77.77{\pm}9.84mm$, n=12) collected from Kamak Bay and Yeoja Bay from August 2003 to November 2004 gave a parturition of $6\sim75$ juveniles (Mean, 39 juveniles/male/time) for 14 times. A day old seahorses were $14.48{\pm}1.38mm$ (n=15) in standard length (SL) with 14 dorsal fin rays, 12 pectoral fin rays and 4 anal fin rays. Sixty-day old seahorses were $24.65{\pm}0.83mm$ (n=4) in SL. Growth rate of seahorses was 0.18 mm/day at 24 in 60 days after parturition. When offered Artemia nauplii and copepod nauplii, 5 day old sea-horses preferred copepod nauplii to Aremia nauplii with a maximum predation rate of 31 copepod nauplii/sea-horse/h. However 30-day old seahorses preferred selected Artemia nauplii with a maximum predation rate of 14 Artemia nauplii/seahorse/h. Survival was highest (49%) when offered copepod nauplii together with enriched Artemia nauplii.

• Journal of the Korea Society for Simulation
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• v.22 no.3
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• pp.1-6
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• 2013

The ecosystem is the complex system consisting of various biotic and abiotic factors and the factors interact with each other in the hierarchical predator-prey relationship. Since the competitive relation spatiotemporally occurs, the initial state of population density and species distribution are likely to play an important role in the stability of the ecosystem. In the present study, we constructed a lattice model to simulate the three-trophic ecosystem (predatorprey- plant) and using the model, explored how the ecosystem stability is affected by the initial density. The size of lattice space was $L{\times}L$, (L=100) with periodic boundary condition. The initial density of the plant was arbitrarily set as the value of 0.2. The simulation result showed that predator and prey coexist when the density of predator is less than or equal to 0.4 and the density of prey is less than or equal to 0.5. On the other hand, when the predator density is more than or equal to 0.5 and the density of prey is more than or equal to 0.6, both of predator and prey were extinct. In addition, we found that the strong nonlinearity in the interaction between species was observed in the border area between the coexistence and extinction in the species density space.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.1
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• pp.20-31
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• 2018

Marine parasitoid Amoebophrya infects and kills various bloom-forming dinoflagellates and strongly influences the harmful algal bloom dynamics. We investigated the effect of temperature on survival, infectivity, generation time of the parasite from the parasitoid Amoebophrya sp. and the harmful dinoflagellate host Akashiwo sanguinea system. Temperature had a significant effect on the parasite generation time and infectivity. While the lower temperature ($15^{\circ}C$) arrested parasite intracellular development and infectivity, resulting in the longer generation time ($115{\pm}0.1h$), the higher temperatures ($25^{\circ}C$ and $20^{\circ}C$) accelerated the parasite development, with the generation times of $58{\pm}0.1h$ and $83{\pm}0.1h$, respectively. Parasite prevalence (percent of host infected) was $71.5{\pm}0.30%$, $54.3{\pm}1.68%$, and $29.6{\pm}1.42%$ at $25^{\circ}C$, $20^{\circ}C$, and $15^{\circ}C$, respectively. These results suggest that biological control by parasitism on A. sanguinea bloom would not be highly effective during low water temperature season. Further, water temperature would be an important factor of bottom-up controls for the host-parasite population dynamics.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.83-84
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• 2001

우리나라 연안 해역의 공동어장과 패류양식장에 서식하는 굴, 가리비, 반지락등 유용 조개류를 무차별 포식하는 불가사리는 패류양식 어민에게는 해적생물이라 불리우져, 이들을 퇴치하기 위한 대대적이고 적극적인 포획작업이 이루어지고 있다. 제주도의 경우도 마을 어장의 주요수산물인 전복, 소라, 오분자기등의 자원보존을 위한 불가사리 제거작업을 실시함과 동시에, 자원조성을 위한 종패 살포를 지속적으로 실시하고 있다. (중략)

• 우유
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• s.45 summer
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• pp.6-14
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• 1991

• Life and Agrochemicals
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• v.27 no.8 s.221
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• pp.22-25
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• 2006

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.333-341
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• 2012

To investigate the feeding habits of the Kaloula borealis, the stomach contents of 52 out of 56 specimens collected around Daejung-up, Jeju Island in June 2011 were studied. The stomach contents were analyzed with the stomach flushing method. According to the results, the main preys of the Kaloula borealis were Diptera sp., Harpalidae, Formicidae and Drosophilidae. the Kaloula borealis of all sizes fed on small preys, while individuals with large SVL fed on big preys. By feeding on a large amount of food with a small number of activities, the individuals with large SVL is considered to enhance energy efficiency. In many cases, the Kaloula borealis fed on Diptera sp. or Drosophilidae, which are slow but active and capable of flying. As a result, the Kaloula borealis take the sit-and-wait form of preying rather than actively searching for food. The results of this research on feeding habits of the Kaloula borealis will provide valuable resources to protect the endangered Kaloula borealis experiencing a sharp decline in their population and to prepare plans for population preservation strategies for them.

• Journal of Forest and Environmental Science
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• v.14 no.1
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• pp.128-137
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• 1998

In Fukuoka, the natural enemies of Protopulvinaria mangiferae were confirmed as six primary parasitoids, three hyperparasitoids, and six predators. Among the primary parasitoids, Aneristus ceroplastae, Microterys flavus, and Coccophagus yoshidae were relatively abundant in Fukuoka. Aneristus ceroplastae and Coccophagus yoshidae were solitary endoparasitoid, whereas Microterys flavus was a gregarious endoparasitoid. Tetrastichus sp. was a hyperparasitoid and solitarily ectoparasitic to the pupae of Aneristus ceroplastae and Microterys flavus. The seasonal fluctuation of parasitisim and adult emergence of the important parasitoids was investigated in Fukuoka. Among the predatorys, Rhyzobius forestieri and Chilocorus kuwanae were relatively abundant, and seasonal fluctuation of adult emergence and consumption of the host were studied. As the first record from Japan, Rhyzobius forestieri was collected on leaves of Elaeocarpus sylvestris with heavy infestation of Protopulvinaria mangiferae.

• Journal of Life Science
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• v.10 no.4
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• pp.403-407
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• 2000

For the biological control of the root-lesion nematodes, Pratylenchus spp., which damage directly and indirectly to the leaf perilla, the nematical effect of three nematode-trapping fungi, Arthrobotrys oligospora, A. conoides and A. dactyloides was evaluated in the field. Three species of Arthrobotrys were isolated from the culture soil of leaf perilla in 1998 and were observed the capture of the root-lesion nematodes, Pratylenchus spp. by adhesive hyphal networks or constricting rings on agar. At 40 days after treatment, the plant-parasitic nematodes and root-lesion nematode populations were approximately increased 3.5 fold in untreated control plot, while the nematode population in fungi treatment plots was similar to initial population. In the A. dactyloides plot, however, the population of plant-parasitic nematodes and Pratylenchus spp. was approximately reduced 65% and 53%, respectively. Thus, the fungus A. dachyloides should provide as biological agent for the control of Pratylenchus spp.