• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.213-217
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• 2005

Adult development and fecundity of the green peach aphid, Myzus persicae $S\H{u}lzer$, were studied at $15{\sim}32.5^{\circ}C$ with $60{\sim}70%$ RH under 16L:8D and the results were put together to build a life table. The longevity shortened as temperatures rose at and below $25^{\circ}C$ whereas it remained relatively constant at $27.5^{\circ}C$. Total fecundity was not significantly different at all temperatures except at $30^{\circ}C$. Daily fecundity gradually increased from $15\;to\;22.5^{\circ}C$. It was 5.1 at $25^{\circ}C$ and as temperatures either went down or up, it decreased to 2.8 at both $15^{\circ}C\;and\;30^{\circ}C$. Fecundity model built from total fecundity at various temperatures suggests that $18.3^{\circ}C$ was the optimum temperature for the maximum progeny of 51. Net reproduction rate RO was highest of 36.5 at $27.5^{\circ}C$. The intrinsic rate of increase per day $r_m$ and the finite rate of increase per day $\lambda$ were highest of 0.4 and 1.6, respectively and the doubling time Dt was shortest of 1.6. Constructed life table suggests that the optimum temperature for adult development for the green peach aphid was $27.5^{\circ}C$ at which the mean generation time was 8.1.

• Korean Journal of Food Science and Technology
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• v.39 no.4
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• pp.432-437
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• 2007

In this study, we examined the conditions for an auto-aging system placed within a kimchi refrigerator for optimal fermentation, and to prolong the storage time of kimchi. Various characteristics of kimchi fermented at different temperatures ($5-23^{\circ}C$) were compared. We observed that the higher the fermentation temperature, the less desirable the overall acceptability of the product. To establish the time point in which to convert the fermentation mode to the storage mode, kimchi was stored at $-1^{\circ}C$ for 1 week once it reached the designated acidity (0.4, 0.6, and 0.8%). The results indicated that the lower the kimchi acidity, the higher the sensory score. The storage temperature of $-1^{\circ}C$ was not low enough to retard microorganism growth completely; however, the kimchi stored at $-2{\pm}0.5^{\circ}C$ became frozen. Accordingly, $15^{\circ}C$ and $-2{\pm}0.5^{\circ}C$ are suggested as the fermentation and storage temperatures for the kimchi refrigerator, respectively. A kimchi acidity of 0.4% can be used as an index for the time point to convert fermentation to storage. Subsequently, the time required for the fermentation course can be calculated based on this.

• Journal of Korean Society of Forest Science
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• v.64 no.1
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• pp.33-41
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• 1984

This study was conducted to examine the physiology of pine mushroom mycelia cultured with various media for artificial culture of pine mushroom. The results obtained were as follows: 1) Among the various media, the medium composed of honey, boiled pine mushroom and soil extract fluid, fibrous root extract fluid, dry yeast, $KH_2PO_4$ inositol, folic acid, and biotin was the best for the growth of pine mushroom mycelium. 2) The optimum temperature for germinating pine mushroom spore and for culturing pine mushroom mycelium, was $24^{\circ}C$ and the optimum pH was 4.5. 3) There was no significant difference in growth between the mycelium separated from the tissue of pine mushroom sporophore and that separated from the spore. 4) No noticeable effect was found on the growth if such salts as $ZnSO_4$, $MnSO_4$, $MgSO_4$, $CaCl_2$ and ferric citrate were added to the Hamada's medium. 5) The addition of fibrous root extract promoted the growth of pine mushroom mycelium. 6) As a carbon source of artificial media, honey was more effective than glucose. 7) The culture infiltration of Mortierlla growing often in Fairy Ring was good for the growth of mycelium compared with the control. 8) The addition of fibrous root extract, inositol, biotin, and folic acid to artificial culture media was greatly effective in growth. When the temperature was lowered $19^{\circ}C$ after mycelium has appeared, the formation of primordium was observed.

• Korean Journal of Plant Resources
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• v.19 no.1
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• pp.88-92
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• 2006

Nerine was originated from South Africa and around 30 kinds of species are distributed in worldwide. In present study we have characterized the division methods and growing conditions for the bulb propagation of Nerine. Result indicated that new bulb formation, and growth of N. bowdenii cultivars was better after dormancy stage compared to post-harvest and dormancy stages, under twin-scale method at $20^{\circ}C$ Similarly, new bulb tissue density was higher at $20^{\circ}C$ compared to other temperatures. Moreover, N. bowdenii 'Favourite' exhibited better growth than N. bowdenii 'Stepanii' and vermiculite was found to be most suitable growing medium for Nerine bulb propagation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.401-411
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• 1995

Flavobacterium spp., Pseudomonas spp., and Vibrio spp. were isolated from samples(sediments) of Sagami Bay and Suruga Bay(in Japan) at 810-4,000m in depth. Among isolated strains, Vibvio sp.-86 and sp.-87 strains were identified as barophilic and psychrophilic ones. They grew in 400 atm and showed best growth at 100 atm. Marine bacteria grown at 400 atm were long rod shape and 30 to 50times longer than those grown at 1 atm. which were short rod shape and formed flocks (aggregates). Vibrio sp,-86 strain grew at $5-37^{\circ}C\;and\;0,5-9.0\%\;NaCl\;(3.0\%\;of\;optimum\;concentration),$ while Vibrio sp.-87 strain grew at $1-7\%\;NaCl\;(2,0\%\;of\;optimum\;concentration).$ The fatty acid compositions of Vibrio sp.-86 strain grown at 1 atm were $C_{20}-C_{22:0},\;C_{l6:1},\;and\;C_{16:0}$ in the order of their abundance and at 400 atm the order were $C_{18:1},\;C_{18:0},\;and\;C_{20}-C_{22}$, whereas those of Vibrio sp.-87 strain at 1 atm were $C_{6:1},\;C_{14:1},\;and\;C_{20}-C_{22}$ and at 400 atm the order were $C_{14:1},\;C_{12:0},\;and\;C_{16:1}$ The amino acids compositon of Vibrio sp.-86 strain grown at 1 atm were abundant in the order of aspartic acid, methionine, and glutamic acid and those at 400 atm were abundant in the order of methionine, glutamic acid, and aspartic acid. The amino acids composition of Vibrio sp.-87 strain grwon at 1 atm were abundant in the order of methionine, glutamic acid, and aspartic acid and those at 400 atm were abundant in the order of methionine, glutamic acid, and isoleucine.

• Journal of fish pathology
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• v.10 no.1
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• pp.1-14
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• 1997

Major object of this study was to investigate the causative organism of th e diseased cultured fingerling of sea bass, L japonicus. The experimental results are summarized as follows ; Staphylococcus epidermidis, isolated from the liver, kidney, spleen and brain, was considered to be the causative organism. External symptoms of this disease were congestion and hemorrhages in eyes. Anatomical symptoms were hemorrhage of brain, congestion of liver, and slight swelling of kidney and spleen. Growth of the isolates was good on BHIA, HIA and Staphylococcus No. 110. The growth occurred at a range(optimum) of $10\sim45^{\circ}C(35\sim40^{\circ}C)$, 0~9% (1~3%) of NaCl concentration and pH 4~10(8). DNase and coagulase production of all isolated strains were nagative, but was positive in hemolysis. Urease was positive reaction, and novobiocin resistance was nagative. Acid was produced anaerobically from glucose and maltose. Acid was produced aerobically from glucose, galactose, sucrose, maltose and dextrine. But gas was not produced from any carbohydrates. When the isolated strain was injected intramuscularly on fingerling of sea bass, L japonicus, it had virulence at $1.7{\times}10^{10}$ viable cells/$m\ell$ for all fish examined but no virulence at $1.7{\times}10^4$ viable cells/$m\ell$. Bacitracin, Erythromycin and Nofloxacin were observed as bacteriostatic agents to the strain, but Colistin, Gentamicin and Nalidixic acid were not. There were remarkable congestion of the brain, regressive necrosis of the liver, and showed necrosis of the epithelial cells of renal tubules in kidney tissues.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.298-306
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• 2016

Planting date shift is one of the means of adapting to climate change in Kimchi Cabbage growers in major production areas in Korea. This study suggests a method to estimate the potential yield of Kimchi Cabbage based on daily temperature accumulation during the growth period from planting to maturity which is determined by a plant phenology model tuned to Kimchi Cabbage. The phenology model converts any changes in the thermal condition caused by the planting date shift into the heat unit accumulation during the growth period, which can be calculated from daily temperatures. The physiological maturity is estimated by applying this model to a variable development rate function depending either on growth or heading stage. The cabbage yield prediction model (Ahn et al., 2014) calculates the potential yield of summer cabbage by accumulating daily heat units for the growth period. We combined these two models and applied to the 1km resolution climate scenario (2000-2100) based on RCP8.5 for South Korea. Potential yields in the current normal year (2001-2010) and the future normal year (2011-2040, 2041-2070, and 2071-2100) were estimated for each grid cell with the planting dates of July 1, August 1, September 1, and October 1. Based on the results, we divided the whole South Korea into 810 watersheds, and devised a three - dimensional evaluation chart of the time - space - yield that enables the user to easily find the optimal planting date for a given watershed. This method is expected to be useful not only for exploring future new cultivation sites but also for developing cropping systems capable of adaptation to climate change without changing varieties in existing production areas.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.4
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• pp.207-221
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• 2012

Air temperature in Korea has increased by $1.5^{\circ}C$ over the last 100 years, which is nearly twice the global average rate during the same period. Moreover, it is projected that such change in temperature will continue in the 21st century. The objective of this study was to evaluate the potential impacts of future climate change on the rice production and adaptation methods in Korea. Climate data for the baseline (1971~2000) and the three future climate (2011~2040, 2041~2070, and 2071~2100) at fifty six sites in South Korea under IPCC SRES A1B scenario were used as the input to the rice crop model ORYZA2000. Six experimental schemes were carried out to evaluate the combined effects of climatic warming, $CO_2$ fertilization, and cropping season on rice production. We found that the average production in 2071~2100 would decrease by 23%, 27%, and 29% for early, middle, and middle-late rice maturing type, respectively, when cropping seasons were fixed. In contrast, predicted yield reduction was ~0%, 6%, and 7%, for early, middle, and middle-late rice maturing type, respectively, when cropping seasons were changed. Analysis of variation suggested that climatic warming, $CO_2$ fertilization, cropping season, and rice maturing type contributed 60, 10, 12, and 2% of rice yield, respectively. In addition, regression analysis suggested 14~46 and 53~86% of variations in rice yield were explained by grain number and filled grain ratio, respectively, when cropping season was fixed. On the other hand, 46~78 and 22~53% of variations were explained respectively with changing cropping season. It was projected that sterility caused by high temperature would have no effect on rice yield. As a result, rice yield reduction in the future climate in Korea would resulted from low filled grain ratio due to high growing temperature during grain-filling period because the $CO_2$ fertilization was insufficient to negate the negative effect of climatic warming. However, adjusting cropping seasons to future climate change may alleviate the rice production reduction by minimizing negative effect of climatic warming without altering positive effect of $CO_2$ fertilization, which improves weather condition during the grain-filling period.

• Korean journal of applied entomology
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• v.56 no.2
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• pp.195-201
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• 2017

The entomopathogenic fungus Zoophthora radicans (Entomophthorales: Entomophthoraceae) was found to infect Cnaphalocrocis medinalis, Plutella xylostella, Myzus persicae and one unidentifed species. Samples of the fungus were collected from three areas (Jinan, Gimje, and Iksan) in Jeollabuk-do, Korea. Infected insects appeared in July and September, during which time population infection rate of Z. radicans on C. medinalis reached up to 46%. Zoophthora radicans hyphal bodies are rod-like to hyphoid, and primary conidia are bullet-shaped to long ovoid. The fungus was isolated from the surfaces of larvae and cultured in Sabouraud dextrose agar with yeast extract (SDAY). The optimal temperature range for mycelial growth was $20{\sim}28^{\circ}C$. Mycelium growth on SDAY supplemented with egg yolk and milk (SDAY-EM) was higher than on SDAY alone. Zoophthora radicans may play an important role in controlling insect population density using naturally induced epizootics.

• The Korean Journal of Mycology
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• v.24 no.3 s.78
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• pp.214-222
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• 1996

This study was carried out to obtain the basic data on artificial culture of Phellinus linteus. The optimum condition for the mycelial growth was $25{\sim}30^{\circ}C$ and pH $6.0{\sim}7.0$. The carbon sources such as D-glucose, D-mannose and Dextrose were favorable to mycelial growth. As nitrogen sources, peptone, cassamino acid and glutamic acid appeared to be favorable. The optimum C/N ratio was about 20:1, when 2% of glucose was provided as a carbon source. The better organic acids and vitamin among tested ones were gallic, silicic acids and biotin. The mineral nutrients of $KH_2PO_4,\;FeSO_4{\cdot}7H_2O,\; MgSO_4{\cdot}7H_2O,\;ZnSO_4{\cdot}7H_2O$ were effective and the optimum concentrations were 0.05, 0.001, 0.02 and 0.003%, respectively.