• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.143-150
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• 1984

A field survey and experiment on aquaculture in Costa Rica including Nicoya Gulf was carried out for a month, December $2{\sim}28$, 1981. 1) Air temperature was $27{\sim}32^{\circ}C$, water temperature, $28{\sim}29.5^{\circ}C$ and salinity, $20{\sim}28.5\%$ both in the surface and 5 m layer on December 22, 1981. 2) Dissolved oxygen plentiful, $7.3{\sim}9.95\;ml/l$. 3) Mean precipitation for the past ten years in Nicoya Gulf area was $1298.6{\sim}2196.3$ mm near Puntarenas area and rainy days a year was 137.7, Most rainfalls was concentrated from May to November, the rainy season. 4) Precipitation in main oyster farms near Chungmu, Korea was 1836.0mm a year and it was similar to that of Costa Rica. 5) Diatoms were 16 species belonged to 13 genera and dinoflagellates, 3 species belonged to 2 genera. Standing crops was $639{\sim}130,211\;cells/l$ and dominant species were Chaeteocros curvisetus, Chaetoceros decipiens, Nitzschia serata. Thalassiothrix mediterranca, a tropical esturary species, was found. 6) Nicoya Gulf has the good environmental factors in the water temperature, salinity, dissolved oxygen and planktons, and it is desirable to experiment and culture the oyster (Crassostrea rhrizophorae).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.125-131
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• 1984

The horn fish, Hemiramphus sajori TEMMINCK et SCHLEGEL, is widely distributed in the coastal waters of Korea, Japan and Taiwan. On April 13, 1983, mature adults of the horn fish were collected from Changson channel, Namhae. The authors carried out artificial insemination on the field, and incubated the eggs and reared larvae in the laboratory. And these larvae were reared for about two weeks in glass jars, fed brine shrimp nauplii. The eggs of this species are demersal and adhesive, with 4 to 6 filaments at the animal pole and a filament at the vegetal pole. The diameter of these eggs varies 1.80 to 2.00 mm. The hatching took place in ca. 376 hours after fertilization. During the incubation period water temperature fluctuated between $13.5^{\circ}C\;and\;20.0^{\circ}C$. The newly hatched larvae were elongate in shape $7.40{\sim}8.00$ mm in total length with $40+16{\sim}17=56{\sim}57$ myomers. Many melanophore were distributed on the head, both sides of dorsal body contour, peritoneum and ventral line of the tail part. Four days after hatching, the larvae were from 9.00 to 9.65 mm in total length, at this tims the larvae absorbed the yolk completely, and became postlarvae. Fourteen days after hatching, the larvae attained 13.25 mm in total length, with 14 rays of the dorsal fin, 13 rays of the anal fin, and 4 rays of pectoral fin. The lower jaw has somewhat projected.

• Journal of Plant Biotechnology
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• v.43 no.1
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• pp.58-65
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• 2016

Powdery mildew is an important disease of the melon (Cucumis melo L.). Seven isolates of powdery mildew fungi were collected from five locations in Korea; Anseong (DH487), Icheon (BN103, BN625, BN968), Yeongam (YA141), Changnyeong (CN582), and Suncheon (SN102). All 7 fungi had a similar trend of conidial chain and conidiophore development as Podosphaera xanthii with fibrosin bodies in mature conidia. Among them, 2 isolates of powdery mildew fungi; CN582 and SN102 showed similar responses to resistance against powdery mildew as the previously reported race 1 and race N2. The isolates YA141 and BN103 showed similar responses as like as race A. However, three isolates of powdery mildew fungi (BN625, BN968, and DH487) showed different responses compared to the previously reported races (1, N1, N2, A, S, and 5). Therefore, these three isolates could be designated as new races in melon. Nine out of 15 commercial melon cultivars in Korea showed resistance to race 1 (CN582). However, the new race BN968 invaded all 15 cultivars. Results of the two molecular markers were consistent in response to disease development by race 1 of Podosphaera xanthii in case of the above mentioned cultivars. This study confirmed the presence of new melon powdery mildew fungi in Korea which are similarly notorious as like as the previously reported race 1. Therefore, breeders can use these two molecular markers for breeding melon in Korea that is resistant to race 1 and as well as to some other races.

• 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.

• Korean Journal of Ecology and Environment
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• v.37 no.2 s.107
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• pp.227-235
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• 2004

Fish fauna and community structure were surveyed in the Nakdong River, Gumi City, Kyeongpook province from April 2001 to July 2002. During the surveyed Period, 39 species, 32 genera belonging to 10 families were collected. Cyprinid fish occupied 64.1% (25 species) and cobitid fish had 7.7% (3 species). Fourteen species(35.9%) of observed species were known as endemic species. The exotic fish was Micropterus salmoides (2.5%) . The dominant species were Zacco platypus (relative abundance: 36.7%) and Opsariichthys uncirorstris amurensis (22.7%). Carassius aurafus and Microphysogobio rapidus were numerous (4.0${\sim}$4.3%). The rare species comprising less than 0.15% were Acheilognathus koreensis, Aphyocypris chinensis, Iksookimia longicorpus, Coreoleuciscus splendidus, Rhinogobius giurinus, Sarcocheilichthys variagatus wakiyae, Silurus asotus astus, and Channa argus. It was found that the population density of carnivorous Opsariichthys uncirostris amurensis increased drastically in the mid-reach of the Nakdong river since it had been introduced from the other native rivers in the middle 1990s. Gobiobotia nakdongensis inhabit riffle (water velocity : 0.43${\sim}$0.67 m $s^{-1}$) of which the river bed is mainly sand. This species is considered to be in need of conservation. As the result of analyzing fish community in the surveyed area, the species diversity, evenness and dominant indices were 1.008, 0.663 and 0.196 respectively. The findings showed that the tributary, which the waterside plants were abundant and had various habitats, had a higher species diversity (1.112) than the main river (0.787). Sand mining had been disturbing the river ecosystem of the study stations 3, 11, 13 & 14, and these stations showed a quite low species diversity (0.421 ${\sim}$0.574).

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.495-501
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• 2011

Bacterial strains were isolated from forest soils of Halla mountain, Jeju island in Korea. The soil samples were collected at each altitude of 100m from 1,000 m above sea level. Total 398 strains were isolated and tested for their physiological characteristics of antagonistic and proteolytic activities, and auxin production. Among the isolates, 172 strains were selected as antifungal strains showing antagonistic activity against at least one of 8 plant fungal pathogens (Alternaria alternata, Botrytis cinerea, Collectotrichum acutatum, Fusarium oxysporum, Phytophthora capsici, Pythium ultimum and Sclerotinia sclerotiorum). In addition 203 strains for proteolytic activity and 26 strains for auxin production were characterized for further study. Je28-4 (Rhodococcus sp.) were showed 80% of control value against tomato gray mold in vivo. Thus, it is suggested that soil bacteria isolated from forest soils of Halla mountain can be important sources of bioactive compounds for improving plant growth or promising biocontrol agents.

• Korean journal of applied entomology
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• v.43 no.1
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• pp.7-14
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• 2004

This study was carried out to survey and confirm the occurring sites of Parnassius bremeri in Korea, and to investigate ecological characteristics to develop a mass rearing technique. In the field survey, adults were found in the two previously known sites in Gyungnam Province and another site was newly found in Samcheok, Gangwon Province. Emergence period of adults was from middle of May to middle of June. Oviposition took place on various material, including hostplant, debris, dead leaves, etc. Eggs were laid singly, up to 126.7 eggs per female. The egg-period was 221.3${\pm}$2.3 days, eggs were hatched from 11th to 22nd of January in the natural condition, and started to feed for about 10 days after hatching. Survival rate of the 1st larvae was 67.6%. Developing period of each instar in the insectary (25$^{\circ}C$, 75% RH, 16L:8D) was 11.2 days for the 1st instar, 7.3 days for 2nd, 12.8 days for 3rd, 16.2 days for 4th, and 18.2 days for 5th, and the pupal period was 21.3 days. The average longevity of adults was 26.2 days. Oviposition rate was higher in the natural condition with enough space to fly for 3♀ : 1 ♂ coupled, at least 3 ${\times}$ 3${\times}$4 m-sized room, than in smaller cage. In a comparison of the preference for visiting on sugar source, black sugar and fructose were effective.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.469-477
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• 2012

Ostrinia larvae feed the pods and stem of red bean and seriously damage the bean production from farmers. In this study we investigated biological and developmental characteristics including field collection, host feeding preference, artificial rearing diet, morphological and molecular taxonomical identification, and pheromone analysis for an Ostrinia sp. in Korea. The male adults have massive tibia in the middle legs and 3-lobed uncus in the genitalia. The partial nucleotide sequences of mitochondrial cytochrome oxidase I (COI) and II (COII) were not corresponded to those DNA sequences from other Ostrinia species reported previously in Japan and China. Host plants for this species are also different from the previous species reported. In the gas chromatography (GC) analyses, (Z)-9-tetradecenyl acetate was not detected from the pheromone gland of our species while the component as a sex pheromone was found in O. zaguliaevi and O. zealis, With taken results, we conclude this Ostrinia species in Korea is Ostrinia scapulalis or closely related species. When larvae collected in a fall were incubated in the outdoor condition, they emerged to adult between June and July in the next year. The result indicates that the winter diapause could be started in late larval stage. In addition, we developed a semi-synthetic artificial diet adopted for mass rearing of the O. scapulalis in laboratory.

• Korean Journal of Weed Science
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• v.12 no.2
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• pp.166-172
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• 1992

The identification on blue-queen algae which were collected from paddy rice fields of the whole nation was carried out in 1991. The blue-green algae identified were 20 species in 5 families including 7 species in the Chroococcaceae. 1 species in the Chamaesiphonaceae. 1 species in the Pleurocapsaceae, 6 species in the Nostocaeae and 5 species in the Oscillatoriaceae. Among the blue-green algae, 6 species in 4 genera including Cylindrospernum, Anabaenopsis, Anabaena and Nostoc were characterized by heterocysts concerning with nitrogen fixation capacity. A concentrated population of Oscillatoria spp. induced soil flakes with blue tint in paddy rice fields. The genera. Spirulina and Oscillatoria, showed their specific motility.

• Korean journal of applied entomology
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• v.57 no.4
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• pp.415-423
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• 2018

Aphid is a typical vector that transfers various kinds of viruses to potatoes. Therefore, it is very important to control aphids moving into potato fields. We investigated the seasonal movement pattern of aphids and its virus transmission rates mainly in the three seed potato production regions at highland in Gangwon-do, Korea. In addition, we identified the aphid species with over-wintering eggs collected from barks or twigs of total 57 tree species around potato fields in winter season. The peak time of summer and winter migration of aphid was at the mid-June and the early October, respectively. A 2.8% of total aphid trapped in yellow water-pan trap was turned out PLRV-borne, and the virus transmission rate was 15.4% by Myzus persicae and 9.1% by Macrosiphum euphorbiae. PLRV-borne aphids started to flow in from the late May, and virus transmission rate of aphid trapped in mid-June was the highest with 10.4%. Totally 14 species of aphid eggs wintered in the 17 species of trees including Acer pictum subsp. mono and Acer pseudosieboldianum at the 11 sites. In particular, because it is not certain that Betula platyphylla var. japonica and Yamatocallis hirayamae do transmit potato virus, but they over-wintered in host plants distributed over a wide area, further research on transmission ability is necessary.