• Korean journal of applied entomology
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• v.39 no.4
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• pp.275-279
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• 2000

Development of Bracon hebetor Say parasitizing Indianmeal moth (Plodia interpunctella (Hubner) was studied at five temperature conditions (17, 20, 25, 28 and 32$\pm$0.5$^{\circ}C$) under a photoperiod of 16 : 8 (L : D). Developmental period (mean$\pm$s.e.) of B. hebetor from egg to eclosion decreased from 28.6$\pm$0.50 to 9.3 $\pm$0.09 days and 28.1 $\pm$0.51 to 9.2$\pm$0.09 days for female and male, respectively, as the temperature increased from 17 to $32^{\circ}C$. The combination model provided a good description of the relationship between temperature and development. The low temperature thresholds were estimated to be 14.0, 12.8, 15.1$^{\circ}C$ for development of egg, larva and pupa. The thresholds for normal development (outside of the boundary layer of the development) were 14.0, 17.5, $15.1^{\circ}C$ for egg, larva and pupa, respectively, indicating that the larval stage is more sensitive to the low temperature than the other stages. The results suggested that the present B. hebetor population could be another ecological race adapting to the seasonal temperature conditions of this area.

• The Korean Journal of Zoology
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• v.16 no.1
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• pp.25-41
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• 1973

Ultrastructural changes in the cells of the corpora allata of the pine moth, Dendrolimus spectabilis Butler, were studied by electron microscope to know the structural correlates of hormone production by the gland during the larval-pupal-adult transformations. Mitochondria are in active phases from the overwintered to the last instar larvae and from the pupae just after pupation to the 20-day old pupae, while they are in inactive phases from the making cocoon stage to the prepupae just before pupation. The peripheral allatum cells have electron dense granules in the intracellular vacuoles of smooth-surfaced endoplasmic reticulum in the larval life, particularly in the overwintered larvae and in the early adults but the swollen smooth-surfaced intracytoplasmic vacuoles made by expansion of an end of the tubular rough endoplasmic reticulum, some of which contain fibrous proteins, are observed in addition to the vacuoles in the intercellular spaces in which the vacuoles grow by fusing each other from the mature larvae to the prepupae, both of them disappearing during just before pupation. After pupation the cytolasmic vacuoles develop again in the allatum cells so that they seem to begin the secretory activity. The fact that the neurosecretory granules stored within the axons terminated in the corpus allatum are visible only from the 20-day old pupa about two days before abult emergence to the 5-day old adult means that the secretion from the allatum cells is under the control of the brain from the late pupal stage, while the secretion during from the larval to the early pupal life has no relation with the brain, because such granules are not observed within the axons. It is, therefore, suggested that at least two kinds of hormone are released with the ages as far as concerned with the production and secretion mechanisms of the allatum hormone: juvenile hormone is released until the last instar larvae without any direct stimlation of the brain and gonadotropic hormone is secreted from the late pupa to the adult by getting brain's stimulation and that the secretory phases observed from the mature larvae to prepupae are presumably concerned with the biosynthesis of protein owing to the ecdysone and those from the early pupal stage in uncontrolled condition of the brain with the prothoracotropic activity.

• Korean Journal of Environmental Biology
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• v.21 no.3
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• pp.286-291
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• 2003

We investigated the effects of molting-hormone insecticide tebufenozide on D7 (the day of hatching from egg) larvae of the midge Chironomus riparius in growth developments. D7 instar larvae were exposed test concentrations were chosen control, 10${\mu}g \;L^{-1}$, 30${\mu}g \;L^{-1}$, 60${\mu}g \;L^{-1}$ and 100${\mu}g \;L^{-1}$ of tebufenozide. In general, dead larvae showed 16% on the next day after insecticide treatments (D12), and observed 44% from D12 to D16 in this exposed days. Dead larvae of C. riparius was abruptly increased on D12 and also continuously increased along the days in 10${\mu}g \;L^{-1}$ treatments. The converged day was from D12 to D16 at move 30${\mu}g \;L^{-1}$ treatments in this study. Therefore, dead larvae obviously increased along these concentrations of tebufenozide. In control condition,78% of the test individuals have grown the pupae. But the larvae have developed the pupa stage from 5% to 17% of the test organism in 10${\mu}g \;L^{-1}$ and 30${\mu}g \;L^{-1}$ treatments. And 75% of the test individuals was arrived the adult through the molting process in control condition. While the other condition was rarely observed the adult. Usually, the emerged period of the test individuals was gathered the D26-D29 in control. The dead pupa showed from D19 to D20 in 30${\mu}g \;L^{-1}$ treatments, D32 in control and D33 in 10${\mu}g \;L^{-1}$ treatments. The observed periods of dead pupa were D32-D34 in control and D33-D37 in 10${\mu}g \;L^{-1}$ treatments. Consequently, due to molting hormone disruption, development of midge was postponed relatively low concentration such as 10 treatments of tebufenozide.

• Korean journal of applied entomology
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• v.42 no.1
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• pp.1-7
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• 2003

Morphological characteristics, developmental period, and seasonal occurrence of Adeia leucomelas (L.) were investigated from 1999 to 2000. In addition, consumption of sweetpotato as food was also examined. Adults of A. leucomelas were dark-brown and body lengths of females and males were 20.2 mm and 18.9 mm, respectively, Wing expanse of female and male was 33.7 mm and 29.4mm, respectively. Egg was flat round-shape. Larva was light yellow-green to dark-brown with 3.3-53.5 mm. Pupa was deep-brown and 15.1 mm in length. Developmental periods of A. leucomelas from egg to adult emergence at different temperatures of 15, 20, 25, and 30$^{\circ}$C were 108.5, 70.7, 40.2, and 29.1 days, respectively, Developmental threshold (DT) and effective accumulative temperatures were estimated as 10.7$^{\circ}$C and 67.5 DD in egg stage, 11.0$^{\circ}$C and 275.1 DD in larval stage and 9.3$^{\circ}$C and 244.6 DD in pupal stage, respectively. The longevity of adult female was shortened with increment of temperature, whereas the total numbers of eggs laid by a female were increased. The larvae of A.leucomelas occurred from mid-June to early October, and population reached its peak during early to mid-September in Jeonbuk province. Food consumption of A. leucomelas was highest at 20-25$^{\circ}$C. Food consumption of 1 st, 2nd, 3rd, 4th, and 5th larvae of A. leucomelas per day at 25$^{\circ}$C was 0.4, 3.6, 19.6, 40.7, and 78.9 $\textrm{cm}^2$, respectively.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.305-308
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• 2013

This study was conducted to describe the external morphology of Platypus-koryoensis Murayama in immature stage, to determine each instar based on larvae head-capsule, and to measure individual and local variations in the number of mycangia of adult. Egg of P. koryoensis, had oval shape and lengths of the major and minor axis were $0.67{\pm}0.051$ mm and $0.41{\pm}0.053$ mm, respectively. Body colour of $5^{th}$ instar was gloss white with well-developed mandible. Larvae of P. koryoensis grew up to $5^{th}$ instar and each instar was clearly classified by head capsule width. Head capsule width for $1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$, and $5^{th}$ instar larvae were $0.35{\pm}0.004$ mm, $0.45{\pm}0.010$ mm, $0.67{\pm}0.039$ mm, $0.94{\pm}0.069$ mm and, $1.12{\pm}0.007$ mm, respectively. The colour of pupa was pale yellow and its length was $4.64{\pm}0.044$ mm. The number of mycangia per female had individual variations from 5 to 12 and 83% of the adults had from 6 to 8 mycangia. There was no significant difference in number of mycangia collected from between Namyangju region and Honchen region.

• Journal of Sericultural and Entomological Science
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• v.35 no.2
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• pp.105-113
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• 1993

To produce F1 hybrid of silkworm sex discrimination has to be followed at the pupal stage by sexual organ. However it requires a lot of labour and may bring about a wrong classification. In these regards, this study has been implemented to find out an effective measure for the pupal sex discrimination by use of variation of cocoon weight and image analysis of cocoon. As a result, it was found that in case of the pupal weight the percentage of a wrong classification fell on 0.3% and in case of single cocoon weight 0.4%. The discrimination rate was 99% in the weight variables of cocoon but analysis by single cocoon weight and cocoon shape variables, it was 98.7%. Efficiency of discrimination was increased by 2.7% as compared to variable of single cocoon weight. The minimum cocoon sampling size may be 15 cocoons sexual-wise.

• Journal of Sericultural and Entomological Science
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• v.8
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• pp.51-62
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• 1968

This study was carried out to investigate the life cycle and the damage of Tricholyga sorbillans Wiedmann to silkworms(Bombyx mori L.). The results are summarized as follows. 1. This insect has 5 or 6 generations per year in Suwon area. 2. The egg, larval, and pupal stage are about 2, 8 and 18 days respectively. 3. The weather conditions considerably affect the life cycle, that is, the 3 rd generation is the shortest of all, lasting for 21 days and l4 hours, and the 5th generation is the longest for about 40 days. 4. The larvae come out of silkworm bodies, burrowing into the ground 3.5cm to 10.5cm in depth before changing into the pupae. 5. This insect does not overwinter as pupa, but seems to do as larva, parasiting on the field insects. 6. The damage of Tricholyga sorbillans Wiedmann to silkworm was 27.9％, it is so high that the silk worms could not be reared outside without a reasonable control method. 7. When the full-grown silkworm is parasited by one egg of these insects, there is not only enough possibility of spinning. but also without any effects of their larvae on the cocoon quality. 8. The damage of Tricholyga sorbillans Wiedmann throughout the country covers 6.36％ in spring, 4.09％ in fall, and 5.25％ yearly mean.

• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.1
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• pp.107-113
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• 2011

Infection effect of $Nosema$ $bombyics$ on the midgut of silkworm $Bombyx$ $mori$ and subsequent appearance of spores and the performance of larvae was studied. Autopsy of larvae showed white pustules on the surface of midgut at 5 days of post infection (pi). At later stage, important organs like midgut, silk gland and gonads reduced in size and all these organs showed white pustules. Light microscope observation of pustules revealed enormous spores. Spore multiplication was at a faster rate in young larvae. Infection of the adult larvae resulted in pebrinized pupa and moths. Larval weight, cocoon weight and cocoon shell ratio reduced as the post infection period increased. Transverse sections of midgut showed $N.$ $bombycis$ infection limited to a few columnar cells at 3-5 days of pi. At 7 days pi, cell volume increased, cells were swollen and elongated. Heavily infected cells looked like sacks filled with parasite and the apical region of certain cells were bulging into the gut lumen. Later at 8-9 days of pi, spores or its developing stages leaked into the lumen either freely or enclosed within the globules of host cytoplasm. Besides columnar cells, development of $N.$ $bombycis$ was observed in the regenerative cells and rarely in goblet cells. Development of $N.$ $bombycis$ was also observed in both longitudinal and circular muscles at the late pi period. The histopathological changes, deformities and spore production time in the host were all influenced by the spore dosage and age of the host.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.132-136
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• 1984

This study was conducted to investigate the bionomics of Curculio sikkimensis in Chonnam province from 1981 to 1983. Damage rates of the chestunt were $26.4\%$ in Damyang, $21.1\%$ in Gwangyang, and $12.9\%$ in Seungju. Adults occurred from the mid-July to the mid-September and showed peak from the mid-August to the early-September. Larvae escaped the chestnut from the early-October to the early-November. Overwintering larvae emerged $3.3\%$ in the first year, $22.78\%$ in the second year and continously overwintered $1.67\%$ in the third year. Larvae showed the highest distribution at $1.67\%$ of soil depth during the overwintering. Mortality of overwintering larvae and course of time showed the linearly correlation. Period of each stage was 5.9 days for egg and 17.17 days for pupa. Adult longevity was 9.10 days for female and 7.03 days for male.

• Korean Journal of Environmental Biology
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• v.21 no.1
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• pp.72-76
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• 2003

We investigated the effects of molting-hormone insecticide tebufenozide on fourth larvae of the midge C. flaviplumuon in growth development from fourth-instar to adult. Fourth-instar larvae were exposed test concentrations were chosen control, 10 $\mu\textrm{g}$$L^{-1}$, 30 $\mu\textrm{g}$$L^{-1}$, 60 $\mu\textrm{g}$$L^{-1}$ and 100$\mu\textrm{g}$$L^{-1}$. In control and 10 $\mu\textrm{g}$$L^{-1}$, 10~20% individuals succeed adults while low emergence rates were observed surplus 30 $\mu\textrm{g}$$L^{-1}$. Death larvae appeared a various day along the concentration. We observed the converged day: control, 10 $\mu\textrm{g}$$L^{-1}$, 30 $\mu\textrm{g}$$L^{-1}$ and 60~100 $\mu\textrm{g}$$L^{-1}$ were day 4 to day 18, day 13 to day 16, day 9 to day 17 and day 9 to day 15, respectively. Therefore we concerned a tendency that exposure concentration was high, death period was short. Also, due to molting hormone disruption, development of midge was postponed relatively low concentration such as 10 $\mu\textrm{g}$$L^{-1}$. The converged days of pupa stage revealed control, 10 $\mu\textrm{g}$$L^{-1}$, 30 $\mu\textrm{g}$$L^{-1}$ and 60~100$\mu\textrm{g}$$L^{-1}$ were day 11~15, day 16~20, day 9~15 and day 5~9, respectively. About 10% individuals grow up the pupa-stage in 60~100 $\mu\textrm{g}$$L^{-1}$ condition. Sex ratio of the emerged adults was not different in this study. Death pupae frequently appeared in day 13~16 in control, day 6~23 in 10 $\mu\textrm{g}$$L^{-1}$, day 13~16 in 30 $\mu\textrm{g}$$L^{-1}$ and day 6~16 in 60~100 $\mu\textrm{g}$$L^{-1}$.