• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.2
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• pp.117-125
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• 2003

To know the impact of female pupal weight corresponding to the male cocoon shell weight upon fecundity, hatchability and percentage of non-viable eggs, the experimental multivoltine breeds namely BL67 and 96A were categorised into low, medium and high batches according to the weight of female pupae and male cocoon shells and moths emerged from low, medium and high female pupae were allowed to mate withmoths emerged from low, medium and high male cocoon shells. Both the experimental breeds of BL67 and 96A revealed a fairl trend in fecundity for high batch ＞ medium batch ＞ low batch. When data were statistically analysed, a significant (p ＜ 0.05) and a highly significant (p ＜ 0.01) increase in fecundity was observed in the medium and high batches of BL67 during November - December, 2002 whereas highly significant (p ＜ 0.01) increase was observed in the high batches of 96A during November - December, 2002. Data revealed a highly significant (p ＜ 0.01) increase in fecundity in medium and high batches of both the breeds during January - February, 2003. More interestingly, a significant (p ＜ 0.05) reduction was noted in percentage of non-viable eggs in high batches of 96A during January - February, 2003. But no significant variation in hatchability was noticed due to the effect of differential female pupal weight and male cocoon shell weight.

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.2
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• pp.61-67
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• 2010

The bivoltine tropical tasar ecoraces of Antheraea mylitta Drury produces cocoons for seed production under seed crop rearing (July-August with $22{\sim}30^{\circ}C$ temperature and 50~70% relative humidity) and for silk production under commercial crop rearing (September-December with $17{\sim}27^{\circ}C$ temperature and 60~80% relative humidity). To consider the impact of hybrid vigour on egg, larva, cocoon and silk related commercial traits, the $F_1$ hybrids made among Daba, Jata and Raily ecoraces were assessed successively for three years. The hybrid vigour in the $F_1$ hybrid of Daba$\times$Jata ($T_7$) was positive for egg fertility (+23.1%), shell weight (+25.6%), silk yield (+79.0%) and filament length (+68.1%), with filament of high denier (11.98d) and reduced larval span (-7.1%). The Jata$\times$Daba ($T_8$) hybrid has shown negative heterosis in egg fertility (-8.0%) compared to the other F1 hybrids, Daba$\times$Raily ($T_9$) and Raily$\times$Daba ($T_{10}$), when they rise simultaneously during the commercial crop season. The better performance of parental ecoraces ($T_4$ to $T_6$) in their commercial traits during commercial crop over parents of seed crop ($T_1$ to $T_3$) and the superior performance of $F_1$ hybrids ($T_7$ to $T_{10}$) over parents of commercial crop ($T_4$ to $T_6$) during commercial crop season indicates the apparent hybrid vigour in tasar $F_1$ hybrids. As the Daba$\times$Jata ($T_7$) and Jata$\times$Daba ($T_8$) $F_1$ hybrids have shown highest hybrid vigour, their rearing during commercial crop can optimize the silk productivity and commercial sustenance of the tasar silk industry.

• Journal of Sericultural and Entomological Science
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• v.14 no.1
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• pp.9-13
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• 1972

On the seventh day of mounting male and feamale cocoons are distinguished. A part of those male and female pupae is irradiated for 40 min. with 1,000r-ray irradiation. Those eggs obtained from the irradiated pupae are divided into six groups of 5, 15, 45, 90, 720 and 2,400 minutes after laying. The cahanges of accid soluble phosphorus in the each group of eggs are as follows. 1. In the control group of the maximum quantity in acid soluble phosphorus was 1,456r/100mg D.P. in the 2,400 minutes group, while the minimum quantity was 1,233r/100mg D.P. in the 720 minutes group. 2. In the mated group of ＊irradiated female moths and control male moths, the quantity of acid soluble phoshorus was small as compared with the control group in the five minute group of 1,288r/100mg D.P. and in the 15 minutes group of 1,299r/100mg D.P. while the quantity increased to 1,484r/100mg D.P. in the 45 minutes group. The quantity began to decrease again to 1,400r/100mg D.P. in the 2,400 minutes group which was smaller than that of the control group. The quantity was slightly small in the silkworm eggs laid in the early stage when compared with that of mated group of ＊irradiated male moths and control female moths. Both groups showed the larger quantity in the 720 minutes group than that of the control group. The quantity of acid soluble phosphorus in the mated group of control female moths .and ＊irradiated male moths was larger in variation than in the mated group of control male moths and ＊irradiated female moths. 3. In the mated group of ＊irradiated male and female moths the largerst quantity was 1,760r/100ms D.P. in 2,400 minutes group and second was 1,736r/100mg D.P. in 90 minutes group, and third was 1,288r/100mg D. P., in 5 minutes group. Generally the quantity was small in silkworm eggs laid by the irradiated one in the early stage than the control group, but in the later period of egg the quantity began to increase more than that of control group.

• Current Research on Agriculture and Life Sciences
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• v.1
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• pp.67-83
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• 1983

The new microsporidia S80 isolated from, Bombyx mori L. in Korea showed ovoid in the morphology of the spores and the size were measured $2.9{\pm}0.28{\mu}$ in length and $1.7{\pm}0.29{\mu}$ width. No other microsporidian spore like this has not been so far isolated from Silkworm. The length of the polar filament extruded in hydrogen peroxide ($H_2O_2$) at $30^{\circ}C$ was $26{\mu}$ of a round cytoplasm on the top. The spores were partly stained with Giemsa, Safranin-O and Gram as the same staining properties as Nosema bombycis, Microsporidia K 79 and other microsporidian spores. The fine structures were observed under scanning eleceron microscope through ultrathin sectioning. The spore wall was composed of three layers ; the thin exospore of an electron dense rippled layer, the thick electron lucent endospore which was thinning considerably at the polar filament insertion point, and the inner limiting membrane. Polar cap present at the sporeapex, with a long polar filament of 12-13 coils, subtending angle of $60^{\circ}$ to spore axis, which is tubular made up of a multilayered and are a benes core, light ring structure enclosing the dance core, the dark ring structure enclosing the inner light ring structure and the other than and light ring structure bounded from cytoplasm. Lamellate polaroplast occupied the anterior part of the spore, and the two neclei with dense nucleoplasm bounded by a double nuclear envelope were cited in the slight downer middle portion of spore. From the characteristics of the shape, size and fine structures, it is certain to reason the Microsporidia S80 belong to the phylum Microspora, class Microspora, order Microsporida, order Microsporida. The shape of two nuclei cited seems to be genus Nosema, but in the classification for the suborder it should be defined wheather pansporoblasts be formed or not and for the genis especial attempts have been made to define the characters which distinguish the disporous genera in the life cycle. Survey through the infection of the bad cocoons during 1980 to 1982 in South Korea the areas contaminated with new microsporidia were revealed 5 provinces of Kyung-Gi, Kang-Won, Chung-Nam and Chun-Nam. Pathological effects inoculated per os at second instar larvae of silkworm, the LD 50 was $7.1{\times}10^7/ml$ as lower pathogenecity than that of Nosema bombycis Naegeli of $1.2{\times}10_7/ml$. While on the other hand the inoculation of the microsporidia at fourth instar larvae lowerd the whole cocoon weight and cocoon shell weight and significant at 1% level. The microsporidia S80 defined it can not be transmitted transovarially from the result of predictive and collective examination of 21 egg batches from the infected female moth.

• Korean journal of applied entomology
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• v.35 no.1
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• pp.58-65
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• 1996

This experiment was carried out to evaluate the effect of sublethal doses of BPMC, etofenprox, and buprofezin on N. lugens. and its predator C. lividipennis. Buprofezin was found to be the most toxic to N. lugens and the most safe to C. lividipennis among the three insecticides, based on LD50 values. Selective toxicity index calculated by dividing LDSo value of C. lividipennis by that of N. lugens indicated that buprofezin was very safe to C. lividipennis, showing selective toxicity of 2703.3. Longevity and fecundity of N. lugens treated with LDIU and LDm of buprofezin and BPMC were not significantly different with those of untreated brown planthoppers. However, egg hatchability' of N. lugens was greatly reduced when treated with LDm of buprofezin, having the highest inhibition rate of 17.7%. Hatchability of eggs from insects treated with BPMC was similar to that of control. The oviposited peak of treated hoppers appeared late as compared to the untreated which showed the peak at early part of the ovipositional period. The longevity and fecundity of C. lividipennis treated with BPMC were significantly reduced as compared with the untreated. Etofenprox also induced fecundity reduction when treated with LDlo, and LDm. However, C. lividipennis treated with sublethal doses of buprofezin showed no redution in logevity and fecundity. From these results, it may be said that buprofezin can be used to control brown planthopper without disrupting of C. lividipennis population in the rice field.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.2
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• pp.111-114
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• 2000

The female pupae of the silkworms Bombyx mori, were injected with recombinant Autographa californica nuclear polyhedrosis virus (AcNPV) expressing green fluorescent protein (GFP) by percutaneous inoculation. When the 4 day-old female pupae were injected with 1x10$^{7}$ or 2${\times}$10$^{7}$ plaque forming units (pfu) of the recombinant AcNPV, oviposited number and egg weight were significantly decreased. Furthermore, the shape of the eggs was obviously divides into normal and abnormal shapes. The percentage of the eggs with an abnormal shape was 7.8% and 57.1% at 1${\times}$10$^{7}$ and 2${\times}$10$^{7}$ pfu inoculation, respectively. PCR analysis of the genomic DNA extracted from the eggs revealed that gfp and AcNPV ecdysteroid UDP-glucosyltransferase genes were amplified from both types of eggs with normal and abnormal shapes. The results demonstrate that AcNPV DNA, and gfp gene cloned into the AcNPV genome, injected in pupal stage were transmitted to eggs and remained stable through at least next generation.

• Journal of Sericultural and Entomological Science
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• v.46 no.2
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• pp.65-71
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• 2004

Long term preservation experiment through refrigeration was conducted for 2 year on 300 lines of silkworm races preserved, as one method for the development of long term safe preservation technique. Experiment with 6 treatments was conducted for 680 days from July 1 st 2000 to May 1st 2002. Embryonic development was conducted to each treatment. There are no differences among treatments and races in 400 days preservation, the stage of whole embryonic development was Eul B and condition of eggs was good. In 650 days preservation experiment, differences were reveled among races and treatment, the level of whole embryonic development was Byeong A and condition of eggs was good. The order of embryonic development is European races >Tropical, Korean races >Japanese, Chinese races, thus European races showed fast embryonic development. Control(treatment A) and treatment C showed faster development than other treatments. And treatment D and F showed stable individual stage among all treatments. The test of shape characteristics and embryo which were conducted in hatching period showed 61% of high line succession possibility in average of 6 treatments. But treatment A and B showed no hatching, 3 lines of treatment C, 48 lines of treatment D, 1 line of treatment E, and 29 lines of treatment F showed slow development. And treatments D and F which showed stable embryo condition had highest possibility. The two treatments D and F showed good result among six treatments, and the preservation period of treatment D and F are 235 days and 310 days, and exposure period in $-2.5^{\circ}C$...was longer than other treatments. Numbers of hatched lines of treatment D and F are 48 and 29, and occupied 15.6% and 9.4% of all tested lines, respectively. Average hatching ratio of treatment D and F were 54.% and 71.6%, and average dead egg ratio were 12.6% and 2.4%, respectively. These results show that average ratio of hatching dead eggs in treatment D and F are higher than general line. Thus reconsideration of hatching condition on treatment D and F is needed.

• Journal of Sericultural and Entomological Science
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• v.10
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• pp.1-25
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• 1969

Since widely use of anthracite for the radiating purpose in a rearing room in Korea, the weakness of silkworm, poor uniformity of the worm growth, the increase of missing worm ratio, unusual cocoon assorting ratio, and the decrease of cocoon layer ratio have been realized by the author, therefore, he has started out to search the mechanism of these evil influences regarding with various gas densities and terms of the gas treatment which will be supposed to be a warning for temperature control during the silkworm reading work. Among the anthracite gas components, CO or SO$_2$ influence and their complexed harm effect were investigated through the use of anthracite gas, CO and SO$_2$ gas. Meantime, each treatment was applied, separately, during the worm egg stage, young instar, adult instar and whole instar, because the harm intensity for any improperable rearing condition is flexible by the growing stages. Meantime, the gas density and term variation were applied for the above each treatment such as in case of anthracite and CO gas, the following treat methods were used. 1) 0.06% for 30 mins. 2) 0.06% for 1 hour. 3) 0.1% for 1 hour. 4) 0.15% for 1 hour. on the other hand, SO$_2$ gas was used as 1) 120ppm for 30 mins. 2) 200ppm for 30 mins. 3) 400ppm for 30 mins. The measurement of gas density was proceeded by using CO tester (Carbon Monoxide Indicator) and SO$_2$ tester (Indicator Sampler Cgf) which could keep any specific density before each treatment.

• Korean journal of applied entomology
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• v.53 no.3
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• pp.199-207
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• 2014

It is true that the proper environmental risk assessments for many GM (Genetically Modified) insects almost have not been executed in Korea. Therefore, we tested the environmental risk assessment about GM silkworms if there is any difference between GM silkworms and non-GM silkworms by the following three measurements. First, we measured their mobility in the breeding environment conditions with food and without food. Secondly, we measured their viability at the artificial extreme environmental conditions (low and high temperature and humidity, absent/present of foods,) after escaping from their breeding environments. Thirdly, we observed the number of laying eggs and their hatchability between GM silkworms and non-GM silkworms with four different pair experiments. The mobility of GM silkworms and non-GM silkworms statistically did not differ, and the egg productivity and hatchability were not also different. The hatchability by couple of GM female silkworms and non-GM male silkworms was lower than by non-GM male and female couple between the GM silkworms and non-GM silkworms, and there was statistically different. Relatively, the viability of GM silkworms was lower than non-GM silkworms. We could not exactly test for viability of silkworms in low temperature conditions because of their hibernating. Although there was any difference in viability and hatchability between GM silkworms and non-GM silkworms, all ability of GM silkworms was lower than non-GM silkworms. Conclusively, the environmental risk of GM silkworm was relatively lower than non-GM silkworm in this study.

• The Korean Journal of Mycology
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• v.27 no.4 s.91
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• pp.243-248
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• 1999

To compare the morphological and cultural characteristics of Cordyceps militaris, forming conditions of artificial fruiting body production were investigated in this experiment. The stroma shapes of artificial fruiting body were confirmed to club and/or stick. However, both shapes were same color as a orange. Perithecia of stroma was semi-egg shape and was ranged from $30{\sim}90{\times}90{\sim}130\;{\mu}m$ and it's asci was narrowly cylindric. Ascospore of perithecia was belong to filiform and multiseptate. The conidia of C. militaris was centurally grown and shaped with globose, long clavate type, floccose, centrally raised during anamorph stage. When it was cultured between glass and PP bottle, production of artificial fruiting body, pinheading ratio and total yield were higher in PP bottle. The optimum illumination was 1,000 lx for the those production. The culture medium of barley, wheat and hulled rice showed higher artificial fruiting body compared to that of silkworm. Pinheading and yield of it's isolates was decreased at more than three subsequent transculture.