• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.282-288
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• 2013

In nature, the population of Nosema bombycis (Microsporidia) causing pebrine disease is small and their development is extremely slow and only few ultimately producing spores. Pebrine infected silkworm, Bombyx mori larvae collected from sericulture field were alive till $3^{rd}$ generation though the concentration of N.bombycis spore was very high ($2.4-3.0{\times}10^8$ spores. $mL^{-1}$). All larvae were died during $4^{th}$ generation with extremely high concentration of pebrine spores ($3.0-4.0{\times}10^9$ spores. $mL^{-1}$) and mostly contain long polar tube (LT). Alternately, all larvae were died immediately (at $3^{rd}$ stage of $1^{st}$ generation) when it was artificially inoculated with same concentration of N.bombycis spores harvested from field ($2.4-3.0{\times}10^8$ spores. $mL^{-1}$) though concentration of spores harvest was very less ($3.0-4.0{\times}10^6$ spores. $mL^{-1}$) and mostly contain short polar tube (ST). Artificially pebrine infected male moth when mated with healthy female moth took six generations to develop pebrine disease and all larvae were died at the $2^{nd}$ stage with very less spore harvest ($3.0-10.0{\times}10^6$ spores. $mL^{-1}$). Survival percentage was increased in all generations (~92.0% at $4^{th}$ generation) when silkworm rearing was conducted under new integrated disease management system.

• Journal of Apiculture
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• v.32 no.1
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• pp.27-39
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• 2017

PCR-chip-based ultra-rapid multiplex PCRs for detection of six major infectious pathogens in honeybee were developed. The 6 kinds of major infectious pathogens in honeybee included Paenibacillus larvae causing American Foulbrood, Melissococcus plutonius causing European Foulbrood as bacteria, Ascosphaera apis (Chalkbrood), Aspergillus flavus (Stonebrood), Nosema apis and Nosema ceranae (Nosemosis) as fungi. The developed PCR-chip-based ultra-rapid multiplex PCR showed successful amplification for all six major pathogens in the presence of more than $10^3$ molecules. The time for confirming amplification (Threshold cycles; Ct-time) was about 7 minutes for two species, and about 9 minutes for four species. Total 40 cycles of PCR took 11 minutes 42 seconds and time for melting point analysis was 1 minute 15 seconds. Total time for whole PCR detection was estimated 12 minutes 57 seconds (40 cycles of PCR and melting point analysis). PCR-chip based ultra-rapid multiplex PCR using standard DNA substrates showed close to 100% accuracy and no false-amplification was found with honeybee genomic DNA. Ultra-rapid multiplex PCR is expected to be a fast and efficient pathogen detection method not only in the laboratory but also in the apiary field.

• Korean journal of applied entomology
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• v.57 no.3
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• pp.233-233
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• 2018

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.2
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• pp.173-180
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• 2008

The influence of temperature and relative humidity in infection and cross-infection of Nosema bombycis and N. mylitta respectively in mulberry silkworm, Bombyx mori L. on larval mortality, multiplication of pathogens, larval weight and growth rate in three different seasons were studied. Seasons were selected in such condition, when very less fluctuations between minimum and maximum temperature and minimum and maximum relative humidity ($25{\sim}28^{\circ}C$ and $65{\sim}72%$ R.H) was observed i.e., season-1. Fluctuations between minimum and maximum temperature were less ($28.05{\sim}34.50^{\circ}C$) but R.H % was more ($55{\sim}81%$) in season-2. Fluctuations between minimum and maximum temperature and R.H % were more ($20.00{\sim}40.5^{\circ}C$ and $64.00{\sim}90.00%$) in season-3. Growth rate of microsporidian-infected silkworm is directly related to the prevailing temperature and relative humidity in silkworm. Silkworm can tolerate slight variation of temperature but slight variation of relative humidity disfavours the development of silkworm and favours the multiplication of pathogens.

• Korean Journal of Veterinary Service
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• v.35 no.2
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• pp.111-117
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• 2012

This study investigated the occurrence of honeybee diseases in Incheon area, at the point of great widespread of sacbrood disease in the country. Sixteen resident beekeeping apiaries; 3 native honeybee and 13 European honeybee apiaries were selected for this research. Over 20 adult bees were evenly collected from the most colonies of each apiary three times (March, June, November) within a year. In this work, 13 honeybee diseases including 7 viral diseases, 2 bacterial diseases, 2 fungal diseases, and 2 parasitic diseases were detected by preliminary inspections and PCR. As a result, viral infections were confirmed at 34 among 48 apiaries (70.8%) over the entire examination period. Parasitic diseases showed the highest detection rate of 45.8%, which are detected in 44 among 96 cases. In the seasonal prevalence, 30 cases (15.6%) of 7 pathogens were detected from 14 apiaries in March, 50 cases (24.0%) of 9 pathogens and 56 cases (26.9%) of 9 pathogens were detected from all apiaries in June and November, respectively. Nosema was shown to be the most prevalent pathogen from March to November, followed by sacbrood virus (SBV) and stonebrood. The spread of SBV infection in Incheon would be under-estimated by the increasing of detection rate over the time. Especially, Chinese sacbrood virus was detected from 4 European honybee apiaries, but clinical symptoms were not found. No chalkbrood, acute bee paralysis virus, and chronic bee paralysis virus were detected in this study. The effective therapy and preventive measures should be prepared for beekeeping industry.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.10a
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• pp.138-140
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• 2003

We report the development of a multiplex PCR-based procedure for rapid, sensitive, and specific detection of entomopathgenic microspordia and differentiation of the genus Nosema and Vairimorpha and identification of the vairimorpha necatrix. (omitted)

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.1-9
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• 2003

The silkworm, Bombyx mori, is prone to infection of various pathogenic organisms. Pebrine, one of the deadliest disease of silkworm caused by highly virulent parasitic microsporidian, Nosema bombycis has been understood since long. Infections of the disease range from chronic to highly virulent and can result in complete loss to the sericulture industry. Several strains and species of microsporidians have since been isolated from the infected silkworms; the disease is becoming increasingly more and more complex. Epizootiology, development of immunodiagnostic kit, use of chemotherapy and thermotherapy techniques has been addressed for identification and control of the disease. A technique of delayed mother moth examination, which plays a decisive role in the detection of the disease and harvestation of stable cocoon crop, has been described. An attempt has been made to review briefly the literature available on various aspects of the pebrine disease in order to develop efficient model(s) for the prevention and control of the disease and to suggest future avenues of investigation in the field of pebrine disease management.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.181.2-181
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• 2005

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.1
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• pp.69-72
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• 2005

Bleaching powder solution (1 to $5\%$), slaked lime solution (0.1 to $0.5\%$) and formalin (1 and $2\%$) were tested for their efficacy against cytoplasmic polyhedrosis virus and Nosema mylittansis spores to control virosis and pebrine respectively in tasar silkworm, Antheraea mylitta in indoor rearing condition. All the disinfectants tested were found effective in suppressing the infection of virosis and pebrine significantly. Complete inactivation of Antheraea mylitta cytoplasmic polyhedrosis virus (AmCPV) was recorded when treated with $4\%$ bleaching powder, $0.4\%$ slaked lime for 20 min and $2.0\%$ formalin for 30 min. Similarly treatments of $3.0\%$ bleaching powder solution for 20 min and $2.0\%$ formalin for 30 min were found effective in complete inactivation of N. mylittanis spores.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2002.05a
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• pp.140-140
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• 2002