• 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.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.1
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• pp.85-102
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• 1993

This study was conducted to achieve develop organic sludge recycling technology as sludge make a prey of earthworm. Therefore sludge treatment and recycling technology is an important field by which this research project to solve landfill site and reduction treatment expense using vermicomposting treatment process on the waste sludge from the biological wastewater treatment plant. In experimental results on the optimum conditions of vermicomposting of nightsoil treatment sludge, survival rates were observed 98.3% in temperature of $10-15^{\circ}C$, 75% in pH 5.8-7.5 and 100% in density of $1/79.8cm^3$, respectively. Liveweight changes of earthworm were increased 266% in temperature of $10-15^{\circ}C$, 227% in pH 5.8-7.5 and 325 % in density $1\;cap./79.8cm^3$, respectively. Casting production rate were generated 0.06 g/cap./day in temperature $20-25^{\circ}C$, 0.065 g/cap./day in pH 5.8-7.5 and 0.1 g/cap./day in density $1\;cap./79.8cm^3$, respectively. Cocoon production numbers were observed 3.8 ea. /cap.in $10-15^{\circ}C$, 2.95 ea./cap.in pH 5.8-7.5 and 3.16 ea./cap. in $1\;cap./79.8cm^3$ during 6 weeks, respectively. pH was droped by 6.2 to 5.7, volatile solids was decreased by 2.9%, $NH_3-N$ were also reduced by $6.984{\mu}g/g$ to $0.991{\mu}g/g$. $NO_3-N$, however, were increased by $3.213{\mu}g/g$ to $7.706{\mu}g/g$. Fecal coliforms and pathogenic bacteria are analyzed by microbiological method to assess public health safety of casting. Number of fecal coliform groups were reduced 88.6-99.1% (Avg. 95.7%) approximately. And pathogenic bacteria such as Salmonella, Shiegella and Vibrio, were not isolated from the earthworm cast.

• Korean journal of applied entomology
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• v.57 no.2
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• pp.97-104
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• 2018

The larva of the white-spotted flower chafer, Protaetia brevitarsis seulensis (Coleoptera: Cetoniidae), is known to have important medicinal properties, such as anti-cancer activity. However, the consumer market for the larvae is depressed because of its high production cost which needs to be reduced. This study was carried out to evaluate two spent mushroom substrates as food source for chafer larvae to improve the productivity and reduce production cost. The larvae were fed with spent substrates of king oyster mushroom (Pleurotus eryngii) (P-SMS) and shiitake mushroom (Lentinula edodes) (L-SMS), with a control of fermented oak sawdust. Effects of the diets on the development of P. brevitarsis seulensis and contents of minor nutrient components in the larvae produced were examined. In the P-SMS diet, the larval rearing period was shorter at 16.2 days, while the rate of larval weight gain and the cocoon weight were higher at 156.3% and 4.1 g, respectively, than that in the L-SMS diet. The pupation rate was 100% and the adult emergence was higher at 93.3% in the P-SMS diet than in the L-SMS diet with no difference to the control diet. In the P-SMS diet, the total nitrogen content during rearing was higher at 10.28% and the minor nutrient component, particularly Fe (145.8 mg/kg), was higher than that in other diets. The oviposition preference of adults showed no significant difference among the diets. Economic analysis showed that P-SMS costs approximately 667,960 Won less per 100 kg of larvae produced, compared to that of the control diet.

• Journal of Sericultural and Entomological Science
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• v.23 no.2
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• pp.37-49
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• 1982

Larvae of the silkworm (Bombyx mori L.) were reared during the 5th instar on the four kinds of artificial diets on the basis of the different amounts of soybean meal used as the protein source. In this experiment it was shown that the various levels of protein in the diet affected not only the growth and silk production but the digestibility of the diet. haemolymph protein and uric acid excretion. The results obtained are summarized as follows; 1. By an increase of the level of protein in the diet the apparant digestibility was increased. but the protein digestibility was comparatively decreased. 2. Larval body weight increment was not observed by the 3rd day of the 5th instar, but was increased from the 4th day as the level of protein was increased in the diet. 3. After the 3rd day of the 5th instar, protein content in the hemolymph was increased steeply by an increase of the protein content in the diet. However, the percentage of hemolymph protein to the ingested protein was decreased from the 2nd day of the 5th instar and increased more or less after the 4th day. 4. An increase of the uric acid excretion was observed as the content of protein in the diet was increased but the pattern of the uric acid excretion was different between high and low-protein diet. However, the percentage of the uric acid excretion to the ingested protein and to the hemolymph protein were both decreased steeply after the 2nd day of the 5th instar. 5. It was also evident that the high-protein diet increased the cocoon productivity. 6. It showed that the feed efficiency for body weight increment and silk formation was high by an increase of the level of protein in the diet, but the protein efficiency was not.

• Journal of Sericultural and Entomological Science
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• v.2
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• pp.49-61
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• 1962

The insect Diplosis mori Yokoyama is causing extensive destruction of mulberry trees in Korea with a resultant loss in silk production. This study was made to determine an effective method of control. Methods and Materials Used Preliminary studies were made to determine more exactly the life cycle of the insect. Based on this information, various control measures were tested, including the use of spray methods with BHC and control of larvae by tilling. Results Obtained 1. Life cycle studies (a) In the Suwon area, this-insect has 5 generations per year. The first starts in the later part of June and the final cycle ends in the later part of September. (b) The adult insects appear about 7: 00-8: 00 P.M. and live for 2-5 days. Females live in longer periods than the male. (c) Larvae lives inside the second and third stipules (A. B.) before mulberry leaf development. They cause extensive damage to the leaves at the point where they are attached to the stem. (d) Weather conditions considerably affect the life cycle. The pupa particularly are affected and not be able to change into the moth stage when there is a long period of no rain. (e) Larvae are large......0.3 to 2.0mm......and are milky-white immediately after hatching but turn to pinkish as the worm matures. The matured worm has a jumping ability up to 15-20cm. The worm burrows into the ground 1.5 to 3.0 cm before changing into the pupal stage. (f) The pupal stage usually lasts 7-8 days, in summer weather conditions and the pupa is surrounded with a coarse cocoon. (g) These insects, as a general rule, overwinter as pupae but sometimes as larvae. 2. Control measures (a) BHC dust applied on the ground seem most effective. It should be done 4-5 days after the worm has burrowed into the ground. For this control, it is recommended that 6kg of a 2% formation Tanbo(l0ares) be used. (b) For the effective spraying against the fly, it is recommended that a formulation of liquid BHC spray terials be used at the rate of 400-600 liters per Tanbo. (c) Tillage methods which provide a cover of soil 5cm or more in depth above infested areas will effect-maively prevent the emergence of the fly from the pupal stage. 3. Conclusions Methods of control against Diplosis mori Yokoyama can be tied more closely to the life cycle of the insect with more effective results. Further studies are needed to complete information on possible controls during or after hibernation. Economic studies on the cost of these control measures are also needed.