• Journal of fish pathology
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• v.19 no.1
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• pp.55-64
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• 2006

Rhabdovirus-like virus were isolated from the fry (15~30 days post hatching, dph) and rearing water of the snakehead fish Channa arga exhibiting mass mortality in spring of 2003 and 2004 in Korea. The isolates were propagated in EPC and SSN-1 cells but not replicated in FHM cells. The bullet-shaped viral particles (45×100 nm) appeared to be compact and a similar morphology to those of the rhabdoviruses in the infected EPC cells. The optimum temperature for virus replication was 20 to 25℃ but they could not replicate at 15℃. The isolates ShFRV-3 and ShFRV-5 from snakehead fish showed high pathogenicity against the fry (15 dph) and fingering (40 dph) of snakehead fish but did not in the larger size (90 dph).

• Journal of fish pathology
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• v.16 no.2
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• pp.135-138
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• 2003

The research was carried out to know the occurrence trend of scuticociliatosis and mortality of fingerlings in flounder. The diseased fish were collected from on-land rearing farms lind hatcheries of flounder in Jeju Island from January 1991 to December 2001. Occurrence of scuticociliatosis was about 10% of total occurred diseases from 1991 to 1996, but increased to 34.5% in 2001. Although monthly occurrence of scuticociliatosis was not related to season from 1999 to 2001, the highest occurrence was revealed in July and August. Mixed infections of bacteria including Vibrio sp. Edwardsiella tarda, Streptococcus sp., and Flexibacter sp. with scuticociliates were observed. Among the bacteria, Vibrio sp. was the highest frequency(40.1%), and the lowest one(10.1%) was Streptococcus sp., Mortality of fingerlings by scuticociliates was different sharply according to size of fish. Mortality of infected fingerlings below 7 cm of total length was 53.8%, while that of normal fingerling above 7 cm of total length was 13.2%. When fish were grown above 25 cm, mass mortality by scuticociliates infection was decreased markedly.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.1
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• pp.13-22
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• 2002

Stink bug, Canthecona furcellatta (Hemiptera: Pentatomidae), is an important predator of silkworm larvae. Nymphs and adult attack the early stage silkworm larvae and causes about 10-15 per cent loss to silk industry. Synthetic organic pesticides has tremendous impact on minimizing the pest population but repeated and frequent use has created problems of residual toxicity, development of resistance to insecticides, pest resurgence and out break, phyto-toxicity and hazards to non target species and beneficial organism. Silkworms are very sensitive to pesticides; therefore, attempt has made to control the bug population through introduction of its native natural enemies in the silkworm-rearing field. Biological control has tremendous scope in sericulture because it is eco-friendly in nature and non-harmful farmers. Native natural enemies have been screened. Psix striaticeps, Trissolcus spp. and Telenomus spp. have been recorded as the most potential parasitoid against pentatomid bug. Life cycle, sex ratio and other various attributes of the par-asitoids have been recorded. The parasitization potential of the parasitoid is very high and they have the ability to discriminate between parasitized and unpar-asitized host. Mass propopagation technique under laboratory condition has been standaydized.

• Journal of Aquaculture
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• v.21 no.3
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• pp.167-171
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• 2008

Common co-existing organism Euplotes (Ciliate, Protozoa) well often observed in the rotifer mass culture tank of marine fish larval rearing stations. Ciliate protozoa (Euplotes) competed to condensed food (micoralgae, Nannochloropsis oculata) with rotifer (Brachionus rotundiformis). As results, rotifer density was rapidly decrease, and what is more, the rotifer was wiped out by dominant bacteria species at that time.

• International Journal of Industrial Entomology and Biomaterials
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• v.37 no.2
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• pp.90-94
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• 2018

In the present study, we investigated the effects of temperature and photoperiod on oviposition of Protaetia brevitarsis. The effects of long- and short-day cycles on oviposition and egg hatching of P. brevitarsis were investigated at different temperatures. Three male-female pairs were confined to oviposition chambers maintained at $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$, and $35^{\circ}C$, with 16L:8D and 8L:16D photoperiod. Oviposition was observed at all temperatures. The total number of eggs laid per female was between 46.8 and 110.8, and the optimal temperature for oviposition and fertility was between $20^{\circ}C$ and $30^{\circ}C$. Furthermore, it was difficult for the eggs to hatch at $35^{\circ}C$. Fewer eggs were laid under short photoperiod than under long photoperiod at all temperatures. Hatching success was 93.5% at $20^{\circ}C$, 90.9% at $25^{\circ}C$, 71.5% at $30^{\circ}C$ and 37.3% at $35^{\circ}C$ under long-day(16L:8D) condition and Temperature had a strong effect on the time to hatching. Neither oviposition nor subsequent egg hatching was influenced by photoperiod and temperature. The information obtained will be useful for mass rearing P. brevitarsis.

• Journal of Aquaculture
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• v.14 no.3
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• pp.181-195
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• 2001

To stabilize the lantern cage culture system of Patinopecten yessoensis(Jay) in the eastern coast of Korean peninsula, optimum conditions such as time of transplantation, rearing density and depth, and time of harvest were identified. During the period from January 1991 to December 1998, the water temperature ranged from 4.7 to 21.4$^{\circ}C$ at 15-30 m depth and 4.9 to 25.7$^{\circ}C$ at the surface; these thermal ranges were within the optimal ranges (5-23$^{\circ}C$) prevailing at 15-30 m depth at surface water. Annual thermal changes indicated that the prevailing temperature during the years 1993 and 1996 was near optimum, but higher during the years 1994, 1997 and 1998, when mass mortality and growth retardation occurred. Salinity (32.0- 34.4$\textperthousand$) and dissolved oxygen (4.14 -8.11 $\mu\textrm{g}$/l) at 15 m depth were well within the optimum ranges. The chlorophyll concentrations (0.06 - 2.73$\mu\textrm{g}$/l) indicated that the study area was oligotrophic, although mass mortality did occur, when chlorophyll concentrations were high, especially in summer. Hence water temperatures and chlorophyll concentration are major factors related to survival and growth of the scallop. In terms of the shell height maximum growth occurred during spring (March-May; 8 - l3$^{\circ}C$) and fall (October-December; 11-l7$^{\circ}C$) in the lantern cage culture. Slow growth was recorded during late winter January-february; less than 7$^{\circ}C$) and mid-summer (August- September; more than 18$^{\circ}C$). Daily growth of shell height and total weight were 0.02∼0.24 mm and -0.07∼0.90 g at the rearing density of 12 individuals per net. Optimal .earing density in the lantern cage (ø50${\times}$20 cm) was 10∼15 individuals with the shell height of 5∼6 cm. The fastest growth rates were observed at 15∼20 m depth; however, it is recommended that 20∼30 m would be optimal. The scallops require 22 months to attain the commercial size of 10 cm shell height and 140 g total weigh, and are best harvested and sold during March-April.

• Korean journal of applied entomology
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• v.36 no.4
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• pp.323-330
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• 1997

The apple leafminer, Phyllonorycrer ringoniella (Lepidoptera: Gracillariidae), is the most important pest on apple leaves and is not easy to be controlled with insecticides because of leafmining habit of its larvae. This study was undertaken to develop an artificial diet for mass rearing of the moth, and to look at their reproductive behavior. For developing an artificial diet the problem of diet contamination with microorganisms and how to supply artificial diet to first instar larvae have to be solved first. Artificial oviposition trial was successful with shadowy bottomside of various papers sprayed with apple leaf extracts. The highest activity of both calling and mating was observed within 30 min. after the onset of photophase and 3- to 4-day -old adults showed the highest mating rate. A ring-shaped sex pheromone gland was found at the intersegmental membrane between the 8th and 9th abdominal segments of the female. (E, 2)-4,lOtetradecadienyl acetate was identified as the major component from the femall gland extracts by the gas chromatography (GC) and GC-mass spectrometry. Additionally it was thought that (a-10-tetradecenyl acetate could be the second component of their sex pheromone.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.101-108
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• 2012

This study was conducted to confirm the mass production of male pupae and sex-limited larval marking variety as a host for synnemata production of Isaria tenupes in RDA(Rural Development Administration). Silkworm pupation, infection rate and synnemate formation of I.tenuipes were examined. Among the silkworm varieties tested, male Hansaengjam showed the highest pupation rate at 98.7%. I. tenuipes infection rate of larvae of newly-exuviated 5th instar silkworm was 83.7 ~ 90.4% in the spring rearing season and 91.7 ~ 96.6% in the autumn rearing season. Synnemata production of I. tenuipes was execellent in female Yangwonjam with an incidence rate of 99.5% followed by male Yangwonjam(99.5%) and Baegokjam(99.4%) in the spring and autumn rearing season. Synnemata living weight ranged from 0.93 ~ 1.25 g in the spring rearing season. The female Hansaengjam had the heaviest synnemata weight(1.25 g). Synnemata dry weight ranged from 0.27 ~ 0.35 g in the spring rearing season. The female Yangwonjam had the heaviest synnemata weight(0.35 g).

• Korean journal of applied entomology
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• v.50 no.1
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• pp.55-63
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• 2011

This study was conducted to develop an artificial diet for the mugwort looper, Ascotis selenaria (Lepidoptera: Geometridae), which is an insect pest to leaves of citrus (Citrus unshiu). Corn and soybean powder were selected as main nutrient sources for larvae of A. selenaria after several diets consisted of wheat germ, corn, kidney bean and/or soybean were tested for larval development and survival. A higher amount of the main nutrients in the diet increased the larval survivorship. Addition of yeast and cholesterol in diet increased the larval survivorship. Finally the composition of diet was decided as followings; corn 100 g, soybean 100 g agar 25 g, Brewers' yeast 30 g, cholesterol 0.5 g, Vanderzant vitamin mixture 2 g, Wesson's salt mixture 2 g, sorbic acid 2 g, ascorbic acid 2 g, and methyl-4-hydroxybenzoate 2.5 g, and distilled water 1 liter. Development periods of larvae and pupae, survival rate and fecundity of A. selenaria reared on the diet were not significantly different with those on the host plant, citrus leaves. Larvae of early instars were reared in a group, while larvae of later instars (5-6th) were reared individually. Adult mating was conducted in a plastic cage and an oilpaper covered with a gauze was provided as an oviposition site.

• Korean Journal of Poultry Science
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• v.41 no.3
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• pp.173-179
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• 2014

While use of mass rearing systems improved poultry production, chances of exposing to contagious diseases have been increased, making flocks more vulnerable to diseases. Diseases of interest which affects egg production adversely include Low pathogenic avian influenza (LPAI), Infectious bronchitis (IB), Avian meta-pneumoviral infection (aMPV) and Egg drop syndrome'76 (EDS'76). This report collected and analyzed 5,385 serum samples, which were collected from 1,330 different chicken flock, provided by Chungbuk National University, Avian Disease Laboratory at 2009. Serums were analyzed based on rearing stages; 0~1.3weeks (wks) (maternal antibody period), >1.3~3 wks (starting period), >3~10 wks (growing period), >10~22 wks (developing period), >22~40 wks (peak laying period), >40~60 wks (late laying period) and over 60 wks (post-molting period). Results showed the 99.7% of the tested flocks were immunized against ND and73.8%, 97.1%, 78,2% and 78% of the flocks were immunized against other 4 agents (LPAI, IB, EDS'76, aMPV). Maternal antibody was transferred to enough quantity for NDV. Generally, antibody titers which were developed at 22 weeks were stabilized permanently for life. In case of IB and aMPV, infection titer emerged as early as 10 weeks and the titer was increased from 99.4% to 100% for life. EDS76 showed increase in titers, reflecting decreased frequency of vaccination programs. Overall, this study displayed general trends of major viral disease in layers, but considering the trend of development of preventive measures and evolution of pathogens, conducting serological surveys on a regular basis is important.