• Journal of Sericultural and Entomological Science
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• v.20 no.2
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• pp.6-9
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• 1978

This experiment was attempted to investigate the effect of the specific gravity of silkworm eggs on the hatching and the practical hatching ratio depend upon six egg production companies for two silkworm races and their reciprocal crosses. 1. The hatching and the practical hatching ratio in the specific gravity of medium and heavy eggs were higher than in the specific gravity of light eggs. 2. Compare with Japanese or Chinese mother races each other, it was inclined that the former seems to be higher than the latter on the hatching ratio in the specific gravity of light and medium eggs, but the practical hatching ratio was high only in the specific gravity of light eggs. 3. Chinese mother races were different in the practical and the hatching ratio between the specific gravity of eggs. On the contrary in case of Japanese mother races were no difference for the hatching ratio but difference in the practical hatching ratio between the specific gravity of eggs. 4. On the egg production company, in case of the specific gravity of medium and light eggs, the hatching and the practical hatching ratio were high significance, but no difference in the specific gravity of heavy eggs.

• International Journal of Industrial Entomology and Biomaterials
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• v.18 no.2
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• pp.77-82
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• 2009

The egg shell of the tropical tasar silkworm, Antheraea mylitta is formed from the substances secreted by the follicular epithelium during the late vitellogenic stage. TEM study reveals the inner travecular and outer lamellar layer of chorion. The travecular layer is composed of the innermost wax layer, inner and outer chorionic layer. The inner and outer chorionic layers are connected to each other by vertical pillers forming of cavities. The lamellar layer is perforated by the aeropyles. SEM study reveals the differentiation of an anterior surface of the egg shell into four zones-micropylar, edge, aeropyles crown and disc zone. In the mycosis infected eggs the aeropyles and egg-shell surface are fully packed with the hyphae of the fungus, Aspergillus sydowi blocking of plastron respiration and causing the death of developing embryo so that mycosis infected eggs become sterile.

• Journal of Sericultural and Entomological Science
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• v.2
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• pp.41-47
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• 1962

This work was carried out to investigate the phenotypic, genotypic, and environmental correlations between the number of the egg markings and other metric characters, and their heritability, with eight varieties in Bombyx mori L. Five European varieties, ten Chinese varieties and ten Japanese varieties were used to know the average number of the egg markings and their variabilities for each strains. The results may be summarized as follows: 1) there were highly negatively phenotypic and genotypic correlations between the number of the egg markings and total cocoon weight, weight of cocoon layer, or denier, but not an environmental correlation. 2) The average number of the egg markings in Chinese strain was more than that in other strains. 3) The correlation between the motality and the number of egg markings seemed not to be found. 4) The heritability of the weight of cocoon layer and the bave length was less than that of total cocoon weight, denier and number of egg markings. 5) The more the number of the polyhedral particles in an egg marking group became, the more the total number of egg markings increased. 6) The variation of the number of the egg markings in European strain was larger than that in any other strains. 7) It is expected that the selection for the number of the egg markings may have genetic advances of total cocoon weight, weight of cocoon layer, or denier. Especially the selection for the number of the egg markings before rearing will save the silkworm rearing cost.

• Korean journal of applied entomology
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• v.41 no.2
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• pp.85-89
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• 2002

Development and reproduction of the rice armyworm, Pseudaletia separara, were investigated on different diets (corn leaf, rice leaf, Chinese cabbage leaf, cabbage leaf, sweetpotato leaf, soybean leaf and silkworm artificial diet). Egg and pupal periods were not different among the diets. But larval periods showed significant difference among diets. Developmental period from egg to adult was shortest as 32.5 d on corn leaf and longest as 46.6 d on soybean leaf. At 16 days after hatching, larval weights on rice and silkworm artificial diet were heavier than those on other diets. The larvae reared on cabbage leaf and sweetpotato leaf failed to pupate. Survival rates from larva to adult were highest (70.6%) on com leaf lowest (39.8%) on soybean leaf. The longevity of female adults was not affected by the larval diets. Female adults showed higher fecundity when the larvae were fed with corn leaf, rice leaf and silkworm artificial diet than other diets. Net reproduction rate (R$_{0}$) was highest as 1218.5 on silkworm artificial diet. The intrinsic rate of natural increase (R$_{0}$) ranged from 0.115 to 0.175, and was maximum on com leaf.

• International Journal of Industrial Entomology and Biomaterials
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• v.47 no.1
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• pp.44-50
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• 2023

The Daehwangjam has excellent marketability and quality. However, precise silkworm breeding data on the recent high-temperature environment is not enough collected, and it is necessary to check whether stable Daewhangjam silkworm egg production was possible in poor environments. In this study, the timing of metamorphosis of the Daewhangjam parents Jam323 and Jam324 silkworms, in an optimal condition and a general condition similar to breeding grounds, was investigated to confirm that appropriate mating was achieved. Surprisingly, a number of female moths were discarded due to the metamorphosis of Jam324 female moths much earlier than Jam323 male moths in either an optimal or a general condition. To improve this, during the Jam324 female pupation period, the mild low-temperature of 15℃ was treated for the pupation period to delay the metamorphosis into female moths. Depending on the treatment period, the metamorphosis of the female pupa was delayed by more than 4 days, allowing normal mating with the Jam323 male moth. The eye pigments in a pupa also slowly accumulated in these treatments. In order to discover the side effects of low-temperature treatments, the voltinism of the Daewhangjam eggs was investigated, but most of them remained univoltine. Taken together, the low-temperature treatment during the female pupation period made it possible to use Jam324 female moths that were should be discarded, which means that stable and efficient management of Daewhangjam egg production is possible.

• Journal of Sericultural and Entomological Science
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• v.13 no.2
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• pp.151-154
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• 1971

In the silkworm egg production, cutting of the cocoon's edge formed by silkworms forced to aid the emergence, and emergence is related to the amount of alkaloid liquid in the sucking stomach in certain varieties. In this study, there was no difference between cutting of portion and sex, and no significant between cutting of both sides and one side cocoons when comparing their emergence ratio. Expenditures and emergence ratio between both sides and one side cutting off must be studied in coming future.

• International Journal of Industrial Entomology and Biomaterials
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• v.26 no.2
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• pp.67-73
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• 2013

Antheraea mylitta Drury is basically a crossbreeding species, as such it seems to be potentially a good material for the exploitation of heterosis. In the present study F1 hybrid of wild ecorace Laria (L) and semi-domestic Daba (D) was raised and evaluated for various quantitative traits and biochemical parameters during larval stage. Improved fecundity ($+18{\pm}1.8%$ and higher egg hatching rate ($+10.96{\pm}1.3%$) was recorded in the F1hybrid ($L{\times}D$). Biochemical parameters studied in the hemolymph, midgut and fatbody of the larva showed significantly higher (P<0.05) total proteins and carbohydrate concentration besides digestive enzyme activity. Correspondingly SDS-PAGE revealed more number of protein bands in the hemolymph sample of F1s, ranging between 29 kDa to 66 kDa compared to parental lines. The present study demonstrates the positive heterosis effect in the F1 hybrid of Laria ${\times}$ Daba. Biochemical analysis indicates that, there is possibilities of exploitation of hybrids with specific parents targeted for desirable commercial traits (silk yield and fecundity). Moreover, most of these biochemical parameters can be used as markers to analyze the genetic improvement in the tasar silkworms.

• International Journal of Industrial Entomology and Biomaterials
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• v.19 no.1
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• pp.205-213
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• 2009

In order for further systematic maintenance of silkworm stocks kept in Korea we analyzed character quality of a diverse array of silkworm strains originated from several sericulture-practicing countries. The analysis of about ten qualitative characters from 67 strains (13 of Japanese strains, 15 of Chinese strains, 14 of European strains, 6 of Korean and Tropical strains, and 19 of unknown origin) revealed a significant difference in the ten different qualitative characters among silkworm strains. In the analysis of quantitative characters, Japanese and European strains were highest in hatchability, the Korean and Tropical strains were highest in pupation rate, and unknown origin and Chinese strains were highest in cocoon yield and number of egg laid. With the connection of molecular genetic analysis the current data may provide the advanced ground for further systematic maintenance of valuable genetic resources of silkworms, although more breeds should be investigated for further complete pictures.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.1
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• pp.7-14
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• 2006

Silkworm diseases are better prevented than cured. Disinfection and hygiene are the two important aspects in silkworm rearing to prevent the diseases. Suitable disinfectant is the primary need to disinfect the rearing house, its surroundings and appliances to eliminate the persistent pathogens from the rearing environment. In this direction, Serichlor, a new disinfectant in Indian Sericulture marketed as Serichlor-60 (contains 60,000 ppm of chlorine dioxide) and Serichlor-20 (contains 20,000 ppm of chlorine dioxide) has been evaluated for its germicidal effect against the pathogens of silkworm, viz., spores of Nosema bombycis, Bacillus thuringiensis, polyhedra of BmNPV and conidia of Beauveria bassiana both in vitro and in vivo. Results indicated that high concentration (2,500 ppm of chlorine dioxide) is required to kill all the pathogens at 100% level. The efficacy of the Serichlor was greatly enhanced by the addition of 0.5% slaked lime solution. 500 ppm of chlorine dioxide in 0.5% slaked lime solution was found effective against all the pathogens tested. This concentration of disinfectant was also found effective for disinfection of rearing house, rearing appliances and silkworm egg surface. The disinfectant is stable, non hazardous, least corrosive and most suitable for Indian Sericulture.

• Journal of Sericultural and Entomological Science
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• v.34 no.2
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• pp.13-19
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• 1992

This study was investigated the relationship between egg size and manifestation of quantitative characteristics such as larval growth, cocoon weight and cocoon shell weight etc. There was a high positive correlation between egg size and body weight of newly hatched larva. Until 2nd instar, larval growth was affected by egg size. The body weight of grown larva from big eggs were heavier on all strains except for strain El6 and the larval duration from big egg were shorter on the Japanese and the Chinese skins. These facts show that the characteristics of larval body weight and larval duration were affected more by the strain than by the egg size. The cocoon characteristics of big eggs were better in comparison than those of regular eggs.