• Journal of Microbiology
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• v.34 no.4
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• pp.370-373
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• 1996

Three strains (KW-1, KW-14, KW-15) of Bacillus thuringiensis were isolated from soil in Wonju area and characterized. The three strains produced parasporal inclusion bodies (crystals) and spores in their cells. The KW-1 strain produces spherical crystals. The crystals of strain KW-14 are bipyramidal crystal. The KW-15 strain harbors irregular crystals. Only minor biochemical characteristics of the three isolates were different and distinctive, however general characteristics were similar to the known serotypes of B. thuringiensis. Three strains were resistant to penicilin G, oxacillin and cephalothin. Three strains were highly toxic to Bombyx mori larvae, but not to the Culex pipiens larvae.

• Journal of Sericultural and Entomological Science
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• v.36 no.1
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• pp.26-29
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• 1994

The topical application of methoprene a kind of juvenile hormone(JH) on 4th instar larvae at 48th hour after ecdysis-3 , followed by insulin on 5th instar larvae and silkgland weights, cocoon weight and cocoon shell weight, and fecundity ; and significantly decreases percent of cocooning and moth emergence. After treatment with methoprene followed by insulin, cocoon weight increase by 17~20% and cocoon shell weights by 18~32% respectively.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.1
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• pp.41-43
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• 2006

Lamerin breed of the silkworm Bombyx mori L. is the only mulberry silkworm breed which survives with an associated microsporidian $(Lb_{ms})$ infection from generations. This present comparative investigation has produced information on the influence of $Lb_{ms}$ on the growth and development of the breed. The $Lb_{ms}$ transmits tranovarially as well as perorally at low level. Larvae developed from the eggs laid by female, infected with $Lb_{ms}$ were as normal as larvae developed from the eggs laid by healthy female. In infected tissues early developmental stages and mature spores located intracellularly but did not show hypertrophy of cells of the host. The meronts and sporonts measures $0.46{\pm}0.25,\;1.11{\pm}0.05{\mu}m$ in length and $0.32{\pm}0.05,\;0.78{\pm}0.10{\mu}m$ in width respectively. The mature spore measures $4.36{\pm}0.06{\mu}m$ in length and $2.14{\pm}0.01{\mu}m$ in width.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.2
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• pp.157-162
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• 2001

The effect of topical application with naphthoxyacetic acid on economic parameters was analyzed following treatment of fifth instar larvae. Larvae treated during the fifth instar showed significant increase in larval weight along with other enhanced larval, cocoon and adult parameters. The larval period was significantly shortened in all the treated groups with increased cocoon and shell weights in male and shell weight in female in 400 ${\mu}g$/ml treated group and filament length in all the treated groups. Fecundity increased significantly in dose dependent manner in all the treated groups, when compared to that of the carrier control group. This suggests that naphthoxyacetic acid, in addition to affecting larval growth, also affect silk production and reproductive performance.

• Journal of Sericultural and Entomological Science
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• v.35 no.1
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• pp.69-72
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• 1993

Effects of topical application with 1, 5 and 10 ${\mu}$g/ml testosterone on the precocooning and post cocooning traits of the polyvoltine. Pure Mysore breed of silkworm were studied. Each concentration was treated independently at 36th to III, IV and V instar larvae(Treatment-1), at 48th to IV and V instar larvae(Treatment-2_ and at 72th to V instar larvae(Treatment-3). The repeated application with each concentration of testosterone propionate in treatment, and 2 larvae or single application in treatment 3 variously affected the precocooning and post cocooning traits. Repeated applications of all doses of testosterone propionate(Treatment-1) and single application of 1 & 5 ${\mu}$g of the chemical(Treatment-3) increase the fecundity and decrease the percentage of cocooning and moth emergence.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.451-454
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• 2020

Sericulture is a main insect industry in Sangju (Kyungpook, Korea). This study reports an occurrence of a viral disease in the sericulture farms in 2020. More than 20% silkworm larvae (Bombyx mori) suffered diarrhea and melted tissues with pathogenic lethality at 4th or 5th instars. PCR diagnosis showed a positive response against B. mori nucleopolyhedrosis virus (BmNPV) infection. Tissue extract of the infected larvae was applied to healthy larvae by a leaf-dipping method and exhibited the same viral symptoms. The viral extract was used to be overlaid on Sf9 cells. The infected Sf9 cells showed polyhedra in the cytoplasm. These results indicate that the silkworm larvae reared in the sericulture farms in Sangju were infected with BmNPV.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2001.11a
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• pp.112-112
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• 2001

• Proceedings of the Zoological Society Korea Conference
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• 2001.10a
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• pp.209.2-209
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• 2001

No Abstract, See Full Text

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2002.10a
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• pp.77-77
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• 2002

No Abstract, See Full Text

• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.1
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• pp.131-135
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• 2004

Oral supplementation with potassium permanganate (30, 50 and 100 $\mu\textrm{g}$) to fifth instar larvae of the ${CSR_2}{\times}{CSR_4}$ race of the silkworm, B. mori resulted in a significant increase in the glycogen content of the fat body and haemolymph trehalose. The protein content of the fat body is also significantly increased in all the potassium permanganate treated groups where as that of the haemolymph is significantly increased only in the 30 ${\mu}g4 fed group. The total lipids content of the fat body increased significantly in all the potassium permanganate treated groups. This indicates that the potassium permanganate may stimulate metabolic activity, there by influencing the biochemical contents in the fat body and haemolymph of the silkworm, B. mori.