• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.51-56
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• 2007

The two species of rice bugs causing pecky rice, Cletus punctiger and Cletus schmidti are often observed coexisting in the rice fields of nearby fallow land. Direct feeding damage to rice by C. punctiger and C. schmidti can lead to a reduction in grain quality and quantity. These studies were carried out to investigate the development of C. punctiger and C. schmidti at various constant temperatures ranging from 20 to $30^{\circ}C$, 65% RH, and a photoperiod of 16L:8D. Egg hatchability of C. punctiger/C. schmidti at the temperatures of 20, 25 and $30^{\circ}C$ were 80.6/88.0, 91.7/96.3, 96.4/96.2%, respectively. The development periods of eggs of C. punctiger/C. schmidti at the temperatures of 20, 25, and $30^{\circ}C$ were 16.4/18.4, 9.4/10.2 and 6.4/7.3 days, respectively. Mean developmental periods of 1 st, 2nd, 3rd, 4th and 5th nymphs of C. punctiger/c. schmidti at $30^{\circ}C$ were 2.1/2.0, 3.5/4.0, 3.3/5.6, 3.2/4.8 and 5.8/6.9 days, respectively. Oviposition began 8.1 days after emergence at $25^{\circ}C$, and the longevity of female and male were 120.0 and 117.3 days, respectively. Total number of eggs through the life of female were 245.5 laying 2.2 eggs a day in average at $25^{\circ}C$. The development periods of egg and nymphs of C. punctiger were relatively shorter than those of C. schmidti. Availability of male had affected the egg hatchability greatly that laid at 30th day after 60 days period of oviposition in the presence of adult male of C. punctiger. The fertile eggs laid by the female together with male was 92.1% but those without male was only 9.6%.

• Korean Journal of Poultry Science
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• v.31 no.4
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• pp.237-244
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• 2004

This study was conducted to investigate the effects of dietary Animunin Powder$^{?}$ on the egg quality characteristics, blood components and nutrient digestibility in laying hens. A total of two hundred seventy laying hens were randomly allocated into three treaments with fifteen replications for eight weeks. Dietary treaments included 1) Control (CON), 2) Control + $0.1\%$ Animunin Powder$^{?}$ (AM1), 3) Control + $0.2\%$ Animunin Powder$^{?}$ (AM2). During the period of 0~4weeks, the birds fed the AM1 diet had an improved egg production compared to the birds fed the CON (P<0.05). During the period of 4~8weeks the birds fed AM1 diet showed a statistically improved egg production compared to the CON (P<0.05). However, no significant differences were founded in the egg weight. During the period of $4\~8$ weeks the hens fed the AM2 diet had improved egg yolk color compared to the hens fed CON and AM1 diets (P<0.05). In the Haugh unit for the period of $0~4$$weeks, the AM2 treatment showed significantly improved results compared to the CON (P<0.05). Average egg shell breaking showed no significant differences through the experiment period, but in the period of $4\~8$weeks the AM2 treatment tended to be improved compared to the CON and AM1 treatment (P<0.05). There was no significant differences in egg shell thickness. In the serum cholesterol, the AM1 and AM2 treatments were significantly lower than the CON (P<0.05). The concentration of RBC and WBC in the AM treatments tended to increase but there were no significant differences. For the differences of lymphocytes between the end and initiation of the experiment, the hens fed the AM1 treatment were significantly different compared to the hens fed the CON and AM2 treatment (P<0.05). During the period of the experiment, the hens fed the AM1 diet were tended to show higher DM digestibility than the hens fed the CON and AM2 diet, but it was not statistically different. In conclusion, dieatry fed of Animunin Powder$^{?}$ could improve egg production, egg yolk color, and haugh unit.

• Korean journal of applied entomology
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• v.48 no.1
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• pp.11-19
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• 2009

This study was performed to investigate the seasonal occurrence, developmental characteristics of each nymphal stages with different temperatures (20, 25, $30^{\circ}C$), longevity and fecundity of ussur brown katydid, Paratlanticus ussuriensis, damaging by outbreaks in the orchard areas of Bitan-ri, Yeongdong, Chungbuk. Paratlanticus ussuriensis occurred from late-March to late-August with peak of mid-May. Newly emerged nymphs appeared from March and do damaged fruit orchards with peak of mid-May when P. ussuriensis existed as 4th and 5th nymphal stages. P. ussuriensis adult occurred from early-June to mid-Aug. with peak of mid-July. Total density of P. ussuriensis was showed highest in mid-May. Paratlanticus ussuriensis goes through nymphal stages to 7th nymph, the ovipositor began exposed to outside from the 4th instar and the body weight increased heavily from this stage and the wings were observed from 6th instar. Developmental period was longer as increased the nymphal stages. Sex ratio of collected insect was showed as 0.57; females more than males. As increased the temperature, developmental period was to be short. Preoviposition was also to be short as 5.0, 4.3, and 3.4 days at 20, 25, $30^{\circ}C$, respectively, and fecundity increased as 69.0, 87.1, and 104.3 at 20, 25, $30^{\circ}C$, respectively. Longevity of male and female at $25^{\circ}C$ was showed the longest with 35.7, and 32.9 days and showed the shortest with 30.1 and 28.1 days at $30^{\circ}C$, respectively. The difference of developmental period in male and female were showed longer in female without relation of temperature. The eggs laid were frequently distributed 3 to 4 cm from soil surface, and showed the behavior laying eggs intensively when early oviposition period.

• Korean journal of applied entomology
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• v.49 no.1
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• pp.17-22
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• 2010

Pachynematus itoi Okutani emerges three times a year, and overwinters as a pre-pupa in cocoon. First emergence of P. itoi was from 7th May to third June. Second and third emergence was from 20th June to 13th July and fourth to 25th August, respectively. Mean oviposited egg number was 59, and egg period was about 9 days. Hatching rate was >90%. Oviposited egg number was the highest in the first needle cluster of short shoot followed by second and third. P. itoi did not oviposit on single needle (long shoot) of Larix leptolepis (Sieb. et Zucc.). Larva had five instars, and larval period was about 20 days. Larva prefer needle cluster of short shoot to single needle of long shoot. Mature larva descended from host tree and pre-pupa in cocoon overwinter at topsoil.

• Korean journal of applied entomology
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• v.22 no.4 s.57
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• pp.262-270
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• 1983

The newly hatched nymphs of brown planthopper(BPH) were reared individually for two generations in test tubes, where young rice seedling was planted on agar solution, at $30^{\circ}C,\;25^{\circ}C\;and\;20^{\circ}C\;with\;95\%,\;75\%,\;65\%\;and\;35\%$ R.H. Effects of $30^{\circ}C$ on the development of BPH when compared with those of $25^{\circ}C$ are followings. Egg period, nymphal period, and adult longevity were shortened. Nymphal mortality was increased and the number of oviposited eggs was decreased. Hatchability was zero per cent because the eggs were either unfertilized or died before finishing the development. At the low temperature of $20^{\circ}C$, in comparision with $25^{\circ}C$, the developmental period of nymphs and eggs was considerably lengthened, and adult longevity was shortened, the number of oviposited eggs was decreased. The nymphal mortality was higher at high relative humidity $(above\;75\%\;RH)$ than that at low relative humidity $(under\;65\%\;RH)$. Under the condition of high relative humidities, the adult longevity was shortened, and the number of oviposited eggs was decreased.

• Korean Journal of Poultry Science
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• v.31 no.2
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• pp.73-78
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• 2004

The effect of supplemental yellow ${\beta}$-8-Apo-carotenoic acid ethyl ester (ACA) (0~300mg/kg feed) on its accumulation in each body part of laying hens and the pigmentation in egg yolk was determined. The chickens used in this study were 78-wk-old ISA brown laying hens. ACA significantly affected the color of the bodies of laying hens. The yellowness ($b^*$) but not the redness ($a^*$) and, the lightness ($L^*$) of the skin, and muscle as measured by a colorimeter significantly (P < 0.05) increased when ACA was fed at 50~100 mg/kg feed. Egg yolk color was also significantly affected by feeding ACA longer than 2 days (P < 0.05) at the levels higher than 50 mg/kg feed. Conclusively, ACA is recommended for improving yellowness of skin.

• Journal of Animal Science and Technology
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• v.50 no.3
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• pp.343-354
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• 2008

The objective of this study was to investigate the effect of restricted feeding to pullet on growth and endocrine profile in layers(Isa brown). One thousand eighty brown-layer chicks were divided into three treatments; conventional feeding(ad libitum) and two restricted feedings(80% of conventional diet) for 70 weeks. One of restricted feeding started from seven to seventeen weeks of age, and the other started from twelve to seventeen weeks of age. Diets were formulated by NRC(1994) recommendation. Body weight and feed intake were measured every two weeks, and body composition and organ weight analyzed every week in rearing period and every eight weeks in laying period. Blood was collected at weighing body weight and was analyzed for the concentration of insulin-like growth factor-Ⅰand estradiol. Body weight and feed intake decreased as restriction of feeding begins comparing to ad libitum group(P<0.05), but reached to similar body weight and feed intake at 20 wk of age regardless of restriction. There were no significant differences in development of digestive tract and attached organs among the treatment groups. During rearing period, however, they were slightly higher in restricted group which was low in body weight. In terms of body composition, fat contents of restricted group were significantly lower(P<0.05) than that of ad libitum group around 1,000 grams of body weight. High concentration of IGF-Ⅰwas observed.

• Korean journal of applied entomology
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• v.43 no.2
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• pp.123-127
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• 2004

This study was conducted to determine the effect of food combinations of leguminous seeds on the nymphal development and adult fecundity of Riptortus clavatus Thunberg. Nymphal duration ranged from 20 to 28 days depending on food combinations with the shortest on the seed of soybean (Glycine max Linnaeus), soybean + kidney bean (Phaseolus vulgaris Linnaeus) and soybean ＋ peanut (Archis hypogaea Linnaeus) and the longest on the seed of kidney bean. Instar duration was longer with increasing instar from 2.4 to 2.5 days in the 1st instar to 5.3 to 7.3 days in the 5th instar Accordingly, instar duration was significantly different on food combinations exception of 1 st instar Percent emergence varied from 3.5％ on peanut to 65.0％ on the seed of soybean ＋ peanut. Nymphal mortality was the highest in the 1 st instar regardless of food combinations. Adult longevity was in range of 5.5 days to 11.2 days which was the shortest on the seed of kidney bean+peanut and the longest on soybean ＋ peanut and was about 8.0 days on the other food combinations. Total number of eggs laid by female was most on soybean+peanut and was least on kidney bean ＋ peanut. Accordingly, it can be recommended that food combination of the seed of soybean ＋ peanut was the best and then was soybean only while other food communications of leguminous seeds was hard to use for mass rearing of R. clavatus.

• The Korean Journal of Malacology
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• v.25 no.2
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• pp.127-133
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• 2009

The common octopus, Octopus vulgaris is commercially important species in Korea. Korean fishing vessels have actively caught it. However, the study of this species has been poorly known. Therefore, the purpose of this study is to provide information about maturation and spawning period of this species. Samplings have been monthly collected in Tongyoung and Sacheon of Gyeongsangnam-do, using traps. A total of 748 individuals were sampled from February 2007 to January 2008. We analyzed monthly changes in maturity stages, gonadosomatic index, total weight at 50% group maturity. The octopus total weight was between 128.6 and 3381.4 g. Females were distributed between 129.8 and 3381.4 g and males between 128.6 and 2378.4 g. The spawning periods were May to June and September. The total weight at 50% group maturity was estimated to be 919.6 g.

• Korean journal of applied entomology
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• v.37 no.2
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• pp.137-142
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• 1998

The regional distribution and some ecological characteristics of Chinese white-wax scale, Ericerus pela Chavannes, were investigated from 1996 to 1997. It was found that 10.8% of the stems of the privet, Ligustrum obtusifolium infested with the scale in Chtingpyijng, whereas only 1.1% of them infested in Y6ngwol and Pyongtaek. The average survival rate of the female adult marked 85.3% after it hibernated on the privet, Ligustrum obtusifolium. A female laid 7,783.5 eggs in average and 36.7% of females fell on the range of 7,000-10,000 eggs. It sized 0.40 mm in length and 0.21 mm in width. The hatchability was highest at 27$^{\circ}$C with 66.8% and it seemed the optimum temperature for incubation. The pupation rate was lower than 50.0% at the above experimental temperatures and the emergence rate marked 67.3% at 25$^{\circ}$C. When the egg was preserved at the various low temperatures, it was found that the egg could be preserved at lS$^{\circ}$C for 50 days in maximum.