• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.219-223
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• 2005

Torymus geranii was found to be a ectoparasitoid attacking the larvae of Dryocosmus kuriphilus. T. geranii has longevity of a $42.8{\pm}9.8$ days at $20^{\circ}C$ and $26.5{\pm}11.0$ day at $25^{\circ}C$ under conditions supplied with 100% honeydew. Oviposition numbers at 20 and $25^{\circ}C$ were $22.3{\pm}12.5$ and $42.2{\pm}18.4$, respectively. The eggs were oval in shape, measuring $0.56{\pm}0.33$ mm in length. The larvae, $2.94{\pm}0.18mm$ in length, was white and length of male and female pupae were $2.01{\pm}0.18mm$ and $2.73{\pm}0.09mm$, respectively. T. geranii had two generations with overwintering generation emerged on late May to early June at Chunchon, central part of Korea, however showed three generations with overwintering generation emerged on middle May to early June, the first one on late June to early July, and the second one on late July to earlyl August.

• Korean journal of applied entomology
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• v.33 no.2
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• pp.56-59
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• 1994

Life histoy of Nysius plebejrrs, the most injurious pest in chysanthemun cultivation in Korea, was studies both in field and inseday in Chinju during 1991 and 1992 seasons, and resulis are summarized as below 7hls insect has 3 generation per year, adult peaks on the mid April, mid June and late August, and the highest number of adults were attracted to the light tmp from the late August through mid September. Overwntered generation and needed 6-7weeks from egg rnatulity m spring, and 5-6 weeks, for both the first and second generation m summer, Incubation egg periods were 142, 9.3 and 7.2 days, nymphal penods were 45.2, 32.1 and 31.2 days, and total growth periods, were 59.4. 41 4 and 38.4 days, respect~vely for the overwintered, flst and second generation. Ovipositional penods were 25.6, 23.4 and 21.2 days. and number of eggs Iald by each female were 41.5. 37.2 and 35.4 days, respedively of each generation Longevities of female were 326, 27.5 and 25.1 days. and of male were 15 2, 12.3 and 12.1 days. respectively of each generation. Sex ratlo was about 1:1 in all generation, and eggs were laid in mass on the surface of leaves or stems of the host plants. This insed over-wmters as adult (90%) or 5th instar nymph (10%), however, over-wintering adults seem to be sexually premature, and mating take place actively in the following spring.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.300-307
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• 1995

This study was carried out to investigate the life cycle of Cephonodes hylas (Linne), that is damaging to Gardenia jasminoides Ellis in the seedbed at Namhae during 1984 and 1985. Results are summarized as follows. The eggs were laid in mass on the leaf surface of the host plants. The oviposition period lasts for 26 days after late-May. The average number of eggs and average hatching rate were 20.36 and 97.61% , respectively. It takes 14-16 days until hatching. The egg shape was oval which its size was 1.01 mm in diameter and 1.48 mm in length. The body length of each larval instar from the 1st to the 5th were $3.52\pm$1.01, $6.46\pm$0.45, $13.19\pm$4.27, $24.08\pm$2.22 and $43.71\pm$5.62 mm, respectively. The average weight of each larval instar were $13.34\pm$2.41, $29.83\pm$6.88, $76.64\pm$31.31, $292.09\pm$107.70 and 2,$144.84\pm$760.70 mm, respectively. The larval period was observed from July to October, and total duration of larval stage was 116 days in which duration of each larval instar from the 1st to the 5th were 12, 36, 32, 16 and 20 days, respectively. During larval stage, a larvae feed on 17~18 seedlings. The 5th instar larvae built its place in soil for overwinter and became pupa. The body length of pupa was 33.6 mm and average weight was 2,032 mg Adult was emerged from overwintened pupa from mid through late-May in the followings year. The sex ratio of female was 42.82% and the color ratio of brown was 89.93%.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.815-823
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• 2014

Green tea has been known to show beneficial effects on alleviating stress. The present study was conducted to determine the effects of dietary green tea on quality of eggs, during storage, laid by laying hens treated with corticosterone in order to mimic the current practice of the egg market. Hens were fed for 2 weeks one of three diets containing green tea at 0.0, 0.4 or 1.0%. Each dietary group was divided into two subgroups receiving corticosterone at 0 or 30 mg/kg for 1 week. Eggs, laid at 5-7 days following the initiation of corticosterone treatment, were stored at $10^{\circ}C$ for 1 or 5 weeks and then analyzed for egg quality. After 1 week of storage, egg weight was significantly increased by green tea (p<0.025) but decreased by corticosterone (p<0.0001), but no interaction was observed between both. Corticosterone decreased shell color (p<0.0001) but green tea significantly decreased shell strength (p<0.006). Yolk color, albumen height and Haugh unit were not affected by both treatments. After 5 weeks of storage, corticosterone resulted in reduced egg weight (p<0.01) and eggshell color (p<0.001) and increased shell strength, which were not attenuated by green tea. Taken together, the results of the current study show that dietary corticosterone reduces egg quality during storage, which are attenuated in part by dietary green tea.

• The Korean Journal of Ecology
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• v.23 no.1
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• pp.65-70
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• 2000

Field collections were made from six gypsy moth (Lymantria dispar L.) Populations in Kyonggy and Cheju areas during the period 1987∼1997. Characteristics of gypsy moth populations at different phases were examined in terms of egg mass density, relative larval density, plant damage, and fecundity. Males captured in pheromone trap were recorded, and we examined if there was a relationship between numbers captured and the population density during the following generation. Egg mass density was closely related with larval density, and furthermore these densities were correlated with the level of plant damage, indicating that larval dispersion was limited in oviposition areas. The gypsy moth population cycle was short in Korea with the period from population development to innocuous level usually lasting 2∼3 years. Male caught by pheromone trap (mean number of males caught per trap per day in peak emergence period) was positively correlated with egg mass densities in the following season (r²=0.93). A low fecundity was detected from outbreak populations which accompanied defoliation. Fecundity of gypsy moth ranged from 538 to 601 at other phases.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.2
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• pp.79-87
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• 2013

Effects of pig manure with various composting periods(0, 15, 30, 50, 80 days) on feeding rate, biomass, cocoon production of earthworm(Eisenia fetida) population and physicochemical property of vermicast produced from pig manure were investigated. The feeding rate of earthworm was increased with longer composting period of pig manure. But the biomass production of earthworm population was highest upon the pig manure composted for 30 days. Upon the pig manure composted for 80 days, the biomass was severely reduced. Cocoon production was decreased with longer composting period and especially lower on the pig manure composted for 80 days. Values of pH, EC, C/N ratio of vermicasts produced from pig manure composts were lower than those of pig manures. And the organic material contents of vermicasts were uniformly reduced irrespective of composting duration of pig manure, whose values were 35.9-39.8%. From these results, the optimum composting period of pig manure for vermicomposting could be 15-30 days. And the application of vermicomposting upon the composted pig manure could be an efficient way for the treatment of pig feces, which can stabilize and recycle the organic wastes more rapidly than the conventional composting method.

• Food Science of Animal Resources
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• v.24 no.3
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• pp.277-282
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• 2004

This study was conducted to investigate changes of egg characteristics according to feeding of far infrared irradiated rice. The feeding of rice irradiated by far infrared rays did not affect the body weight of laying hens, but egg weight (3.6∼7.6%), yolk weight (3.9∼30.2%) and thickness of egg shell (5.4∼13.5%) together with the rate of laying eggs (5.4%) were positively increased than normal rice.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.281-289
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• 2022

The effect of five different constant temperatures (18, 21, 24, 27, and 30±1℃) and a photoperiod of 14 : 10 (L :D) h on the reproduction parameters of Spodoptera frugiperda was studied. The longevity of adult female S. frugiperda decreased with increasing temperature (22.4 days at 21℃ and 13.9 days at 30℃) but not at 18℃. The pre-oviposition period and oviposition period was the shortest at 30℃ compared to the other temperatures. The total fecundity egg count was 887.4, 1,246.4, 1,348.9, 1,154.9, and 1,034.2 at 18, 21, 24, 27 and 30℃, respectively, during its life span. The survival rate of female S. frugiperda decreased rapidly after 13 days at 18℃, after 14 days at 21℃, after 15 days at 27℃, and after 9 days at 24℃, and 30℃. On the third day after the start of oviposition, 50% of the total fecundity was accomplished. In corn fields at less than the 10-leaf stage, the distribution of S. frugiperda egg masses was observed in the middle and lower plant regions, corresponding to 46.8% and 41.4% of the total egg masses, respectively. Egg masses were mostly found on the underside of the leaf blade (abaxial) of corn(66.7%). After releasing S. frugiperda adults on May 12, May 17, May 25, and May 30, the number of eggs per egg mass was 89.9, 88.5, 126.6, and 127.9, respectively. Egg masses of the subsequent generations of S. frugiperda were observed from late June, and the number of eggs per egg mass was 155.8 in late June, 270.7 in early July, and 303.5 in mid-July.

• Korean journal of applied entomology
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• v.30 no.4
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• pp.265-270
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• 1991

Oviposition activities of the larger black chafer(HolotTichia mOTosa Waterhouse) and Korean black chafer(H. diomphalia Bates) were examined in the laboratory and field from 1985 to 1990. In H. mOTosa and H. diomphalia, total durations of oviposition were 31.70$\pm$17.33 days and 61.17$\pm$23.15 days, numbers of days of actual oviposition were 9.00$\pm$5.03 days and 22.33 $\pm$11.72 days, total numbers of eggs laid laid per female were 23.43$\pm$16.26 and 65.67$\pm$37.97, and numbers of eggs laid per female per day were 2.60$\pm$2.50 and 2.94$\pm$2.34, under laboratory conditions. Difference of total numbers of eggs per female between both species seemed to be due mainly to numbers of days of actual oviposition. Oviposition period under laboratory conditions was considerably delayed behind that in the field in H. morosa but the two oviposition periods were almost overlapped in H. diomphalia. In the field, rates of gravid females of H. diomphalia were obviously higher than those of H. mOTosa, but numbers of eggs per gravid female were almost same in the two species, H. diomphalia adults did not show marked oviposition and feeding preference among several species of weed plants in the insect net chamber.

• Korean Journal of Ichthyology
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• v.22 no.2
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• pp.121-125
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• 2010

To investigate the relationship between total length and fecundity of Pacific cod Gadus macrocephalus in Jinhae Bay, 45 individuals were sampled during the spawning period from Dec 2008 to Feb 2009. Fecundity ranged from 560,000 to 5,200,000 eggs for fish ranging from 64.0 cm to 74.0 cm in total length. The relationship between total length (TL) and fecundity (F) was F=103,273TL-5,124,302 and fecundity in Pacific cod from this study was correlated with total length. Average fecundity decreased from 2,620,000 eggs in early-spawning period to 1,650,000 eggs in late-spawning period. The wide range of relative fecundity at the same body size indicates that the timing of the spawning migration of Pacific cod in Jinhae Bay could be related to fecundity.