In this study, we examined the spatial dependence and association of Ambrosia beetle, Platypus koryoensis, which is the vector of oak wilt disease caused by Rafaelea sp. using two geostatistical methods. Two adjacent sampling plots were selected and named as "Sector A" and "Sector B". Sector A area was 63 ha and Sector B area was 420 ha, respectively. We arbitrarily separated each sampling plot by 50m×50m grids. Sector A and B were separated by 19×15 and 43×41 grids, respectively. The oak wilt disease damage level of tree was classified by amount of frass of Ambrosia beetle near target oak tree as follows: Lost tree (LT), Severe damage (SD), Intermediate damage (ID), and Light damage (LD). Number of each damage level of oak tree was counted and recorded in each sampling grid. Spatial dependence and association of oak wilt damage was analyzed and compared using mathematical variogram models and spatial analysis by distance indices (SADIE). Variogram model ranges were 179~368m in Sector A and 634~1073m in Sector B, respectively. The damage levels of all trees in each sector were indicated as aggregated distribution by aggregation indices of SADIE (Ia > 1). Each damage level pair had strong association in the consecutive orders than in any random order based on the results of SADIE association test. The spatial dependence and association of oak wilt damage levels presented here provide the baseline information necessary to understand and manage oak wilt disease in Korea.

Male cicadas produced species-specific calling songs to attract conspecific receptive females. Male cicadas typically occupy tree trunks or tree branches during calling song production. We studied calling site preference in four species of cicada: Cryptotympana dubia, Meimuna opalifera, Oncotympana fuscata, and Meimuna mongolica. Several males were observed to sing together in a tree in C. dubia, but males of other species tended to sing singly in trees. There were also cases in which two or three individuals of different species sang together in a tree. Species differed significantly in height of and distance to trunk from calling site. Both tree height and tree crown were significant factors for calling site preference. The height of calling site was the highest in C. dubia, followed by M. opalifera, M. mongolica, and O. fuscata. The distance to trunk from calling site in M. opalifera was the farthest and was significantly different from those of other species. Males of other species tended to sing close to tree trunks. Males of M. opalifera were mobile when they produced calling songs, whereas males of other species were stationary. That is, males of M. opalifera sang only for short periods of time and moved around adjacent trees. Segregation of calling sites suggests that these four cicada species occupy different sections of trees, thereby avoiding competition for calling sites.

Myzus persicae, Heliothis assulta and Frankliniella occidentalis are the most severe pests of pepper in Korea. IPCC (Intergovernmental Panel on Climate Change) reported that the temperature would increase 7℃ at the end of this century. According to the elevated temperature, the pest population will be grow dramatically. We need to predict the pest-population size to maintain good crop productivity. DYMEX and CLIMEX are commercial software developed by CSIRO in Australia, to build and simulate population dynamics models. Using this software, we predicted population dynamics of M. persicae, H. assulta and F. occidentalis applying past climate data (1970) and future climate data (2070) which were generated by National Institute of Meteorological Research (NIMR). The population growth rates of M. persicae, H. assulta and F. occidentalis were 6300, 16 and 950 times, respectively, with 5 degree elevation. Therefore pest management should be conducted intensively in the future.

and evaluated mainly physico-chemical properties. In the present study, several biological indices were applied to determine whether biological indices could provide a more comprehensive understanding in terms of soil quality assessment in urban forests. Microbe and invertebrate biological indices (i.e. biodiversity of both microbe and invertebrate, enzyme activity of microbe, feeding activity of invertebrate) were examined at 6 urban forests with different levels of disturbance in Seoul, Korea. The results showed that feeding activity and biodiversity were significantly and positively intercorrelated, but not with the enzyme activity. We also examined whether these biological indices could be modeled as functions of soil physico-chemical characteristics. To develop a predictive model, we applied principal component regression. The results showed that first principal component represented more than 33% of the total variance of biological indices and gave a good relationship with soil physico-chemical characteristics (R2=0.71). The predictive model developed in this study can be used for qualitative but not for quantitative assessment of soil quality.

Methyl bromide (MeBr) which is widely used in most of the countries for quarantine purpose, has been designated and under control as ozone depleting substance. This study is on the toxicity of ethanedinitrile as a MeBr alternative to control several wood-related insect pests. LC50 value of Ethanedinitrile(EDN) for Reticulitemes speratus, Tomicus piniperda adults at 21℃ was 0.26, 4.83 mg/L respectively. LC99 value of EDN for R. speratus at open status and closed wooden cubes was 0.65, 0.62 mg/L respectively, whereas MB was 13.96, 31.10 mg/L, which means that the toxicity of EDN for R. spratus is greater and EDN penetrates better into wood as compared with MB. The morality of EDN 20.3 mg/L(6hr) at 25℃ for Crytogenius lutats in wood was 90.3% in larvae, 58.6% in pupae and 89.5% in adults, which means that pupae were more resistant than larvae and adult. All stages of C. lutats were disinfected with EDN at or more than 29.9.mg/L, 6hr(CT product 89 mg hr/L) at 25℃. In sorption and application test, CT product of EDN 50 g/㎥(6hr) was 157 g hr/㎥ in the conditions of 21% wood moisture content with 25% loading, 171 g hr/㎥ in 54% wood moisture content with 25% loading and 158 g hr/㎥ in 54% wood moisture content with 50% loading, respectively. In all treatments, adults of Cryphalus fulvus and R. speratus were completely killed. The minimal CT product (158 g hr/m3) of 6hrs treatment was higher than CT product to disinfect C. lutats (89 mg hr/L). It is expected that it can be used as alternative fumigant of MeBr for woods.

In Korea very few studies have been conducted in relation to collembola sensitivity to pollutants in populations exposed to soil contaminants in particular heavy metals. The objective of the current research were to study the thermal effects of selected heavy metals on the survival and reproduction of P. rosea in order to assess its applicability as a test species. Petri dishes (87 mm diameter, 15 mm height) were used for compact soil toxicity test and were filled to a depth of 0.5 mm with 6 g artificial soil and 3.5 mL distilled water was added. 20 adults (6 weeks from egg stage) were introduced to each petri dish and placed in two incubators set at 20℃ and 25℃, respectively under continuous darkness. The 28 days EC50s for cadmium in compact soil at 20℃ and 25℃ were 48.9031 and 91.3585 mg/kg, respectively. This thermal toxicity test of P. rosea is advantageous for various environmental sudies, such as toxicity tests.

Myzus persicae, Heliothis assulta and Frankliniella occidentalis are major pepper pests in Korea. The objective of this study was to assess the pepper-yield decrease caused by population change of M. persicae, H. assulta and F. occidentalis. with temperature elevation. It is easy to expect that climate change will increase crop damage caused by pests. Therefore we should predict pest-population dynamics exactly and find the best available strategy for the pest management. Based on the many reported results of temperature development of the three kinds of pest, we simulated the future population dynamics using the computer softwater, DYMEX, developed by CSIRO. The results were that the population sizes and outbreak frequency of 3 kinds pest would increase with global warming. This work may be helpful to establish an effective pest management.

Heliothis assulta is the most severe pest of pepper in Korea. The management of this pest is very difficult because the larva live in the pepper fruit and emerge continuously. There are relatively abundant studies about temperature development of H. assulta, but few works are available to describe its future population dynamics which is caused by global warming. If we predict the long-term-population dynamics we can manage the H. assulta more effectively. Therefore we simulated the population size using the computer softwater, DYMEX, developed by CSIRO in Australia. Especially, we predicted population dynamics of H. assulta applying past climate data (1965-1985) and future climate data (2065-2085) which were generated by National Institute of Meteorological Research (NIMR). Comparing to past population dynamics, the epidemic size and frequency would increase in the future. This means that the population management of H. assulta should be conducted more sophisticatedly.

Two cherry tomato plant cultivars (Lycopersicon esculentum Miller, cultivars ‘Koko’ and ‘Pepe’) were supplied with high (395 ppm), medium (266 ppm) and low (199 ppm) concentrations of nitrogen to determine the influence of nitrogen fertilization on development, cultivar preference and honeydew production by greenhouse whiteflies, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae). The nitrogen, protein, andchlorophyll content of tomato leaves were higher in the high nitrogen supplied plants than in the medium or low nitrogen supplied plants, but the sugar content showed an inverse relationship. The developmental times of eggsand nymphs decreased as the nitrogen concentrations increased in both cultivars. The preference of T. vaporariorum was compared by counting the number of eggs deposited on leaves in choice and non-choice tests. In the non-choice test, no significant nitrogen treatment effects were observedbut the upper plant stratum was preferred for egg laying. In the choice test, there were significant main effects of cultivar and nitrogen concentration. T. vaporariorum laid eggs more on leaves of plants with higher nitrogen at the upper stratum. In both experiments, T, vaporariorum preferred the ‘Koko’ cultivar to the ‘Pepe’ cultivar. The honeydew production of T. vaporariorum nymphs increased with decreasing nitrogen treatment concentrations. The largest honeydew production was detected in the ‘Pepe’ cultivar grown at low nitrogen concentration. It is concluded that cultivar ‘Pepe’ had an advantage over ‘Koko’ in term of T. vaporariorum management program in tomato greenhouses.

In this study, egg hatching and larval development of Paranura rosea were experimented at different temperature conditions. The development was studied at four different temperatures, ranging from 15 to 30℃ (in 5℃ intervals), under a dark. As a result, the egg hatching time decreased from 21.67±1.99 to 6.57±1.96 days as the temperature increased from 15 to 30℃. The highest egg hatching rate was 49.27±20.69% at 25℃, where as the lowest rate was 27.97±23.06% at 15℃. The developmental rate increased gradually with temperatures from 15 to 30℃, and the developmental rate was highest at 30℃. The survival rate was highest at 15℃ (85.27 %) and lowest at 30℃ (57.53 %). This wide thermal adaptation in egg hatching and larval development of Paranura rosea is advantageous for various environmental sudies, such as toxicity tests.

Acetaminophen (CAS 103-90-2) is one of the most used pharmaceuticals around the world. In Korea, it was produced 1,069 tons in 2003. This chemical is not eliminated in wastewater treatment plant and may flow into the ecosystem through various routes. Therefore, there is a possibility that it can make an adverse effect on aquatic organisms. To examine its ecological toxicity, we used three native Korean aquatic invertebrate species, Daphnia sp., Chironomus yoshimatsui, and Ephemera orientalis. The acute toxicity on Daphnia sp. was moderately high, and its 48 hour median immobilization concentration (EC50-immobilization) was 51.7 mg/L. On the other side, the reproductive toxicity was very high, and its EC50 of 25 day reproduction test was 0.005 mg/L. In E. orientalis egg hatching test, the median egg hatching inhibition concentration was 0.199 mg/L. C. yoshimatsui was most tolerant to acetaminophen, in which 48 hour median lethal concentration (LC50) was 400.0 mg/L and 45 day median emergence inhibition concentration (EC50-emergence) was 45.27 mg/L. From this results, we concluded that acetaminophen is hazardous to freshwater macroinvertebrates, especially to water flea. Therefore we need to study more about pharmaceuticals' ecotoxicology including acetaminophen and to assess their potential ecological risk.

In soil ecosystems, chemicals are often found as mixtures. Therefore, the toxicity data generated by single toxicity tests are inadequate for assessing the potential risk of complex mixtures of chemicals for soil ecosystems. In the present study, the mixture toxicity of copper and manganese on the reproduction of Paronychiurus kimi were assessed using a Toxic Unit approach (1TU=EC50). The concentrations of each metal in the mixture were summed as follows: TUmixture = CCu/EC50 of Cu + CMn/EC50 of Mn, where CMetal are the concentrations of copper and manganese in the mixture. From the Sum TU based dose-response relationships, sum of a toxicunit (TU50) at 50% reduction for the mixture (EC50mix) was calculated. The binary mixture toxicity was defined as being concentration additiv (EC50mix=1TU) or as being more or less than additive (EC50mix<1TU or 1>TU, respectively). Also, values of the mixture (TUi) at i% reduction found were predicted to get more insight regarding the relationship between mixture toxicity and various effect levels (ranging from EC10 to EC90). The toxicities of copper and manganese mixtures were less than additive at the EC10 level, whereas more than additive at the EC90 level. These findings imply that the effect levels are important for determining the toxicity of metal mixtures.

Determining age distributions of insect is required for many basic ecological studies. Most of insect developmental studies, the head capsule width and other developmental traits have been widely used to distinguish the instars. Unlike to other insect species, collembolan continues to molt after they reach sexual maturity. So these traits sometimes make it difficult to conduct developmental studies. Model animal used in this study was Paranura rosea a native collembolan speciese. To determine the age groups of P. rosea, we periodically (1week) made digital images of P. rosea (over 100 different images) under the magnifier (DIMIS-M) for consecutive 20 week. And then the head capsule width and the surface area of P. rosea were analyzed using a image software (ImageJ). In this test the head capsule widths and surface area were set as developmental parameters. Both two developmental parameters showed time-dependent increase patterns. And they gave good agreements between predicted developmental parameters and observed parameters (r2=0.83 and 0.71). Based on the reproducibility of juveniles and statistical mean separation tests (tukey's test), both two developmental parameters could be divided into 3 age groups. The information given this study will be used as a basis for understanding the population dynamics and other ecological research.

Arsenic is a naturally occurring element in the earth's crust and is found throughout the environment, but compared with other toxic elements, little toxicological work has been conducted on arsenic. In this study, we tested the effect of two different arsenic compounds (arsenite (NaAsO2) and arsenate (Na2HAsO4)) on the reproduction of soil inhabiting collembolan species (Paronychiurus kimi). The toxicity tests for each arsenic compound were conducted in accordance with the ISO 11267. The estimated EC50s for reproduction of each arsenic compound were 20.43 (16.97-24.60) and 32.86 (25.64-42.13) mg/kg, respectively. There were statistically differences in the toxicity of two different arsenic compounds based on overlapping 95 % confidence intervals. The relative toxicity ratio of arsenite to arsenate (approx. 0.62) as well as the concentration-dependent decrease in reproduction of P. kimi was steeper at arsenite than that of arsenate. These results show that arsenite was more toxic to P. kimi than arsenate.

As a fundamental study for chronic test (definitive test), the range finding test must have been done prior to conducting chronic test. The aims of this study were 1) to search the effective concentration range of two different heavy metals (cadmium and nickel) to indigenous collembolan species (Paranura rosea) 2) to compare the toxicity of cadmium and nickel depending on exposure durations. Toxicity tests were conducted in accordance with the standardized toxicity test proposed by OECD. In this study, there were no mortality occurred at all test concentrations for 7-days exposure. In contrast to 7-days exposure, there were slight increases in mortalities were observed at the concentration higher than 400 mg/kg for both heavy metals for 14-days exposure. The estimated LC50s for cadmium and nickel were 3980.65 (2036.08-64668.61) and 1597.85 (1087.87-3817.61) mg/kg, respectively. The results of this study may be used as a fundamental toxicity data for two heavy metals to proceed in chronic test in the future study.

Traditionally oxygen demands and concentrations of variable pollutant have been used for the assessment of lentic or lotic water quality. But there is a high probability that newly synthesized chemicals flow into the aquatic ecosystem, and it is very hard to investigate that many kinds of chemicals interact even though they exit at lower level than legal standards. As a consequence of limitation of chemical assessment for media, biological assessment techniques for accepters which are affected by pollutants or physicochemical properties have been developed. However, it still has several weak points because it does not have the ecological relevances using the internationally standard test species which do not inhabit Korea. Besides, the assessment using just one or two species may have a possibility of overestimation or underestimation because a certain species can be extremely sensitive or insensitive to a certain chemical or physicochemical property. Therefore, we used four kinds of indigenous aquatic invertebrates to assess the local stream quality and integrated their responses into a new index which ranges from 0(bad) to 1(good). We assessed four streams throughout Ansan and one stream in Gapyeong, and index values of two streams near residential and industrial area in Ansan were under 0.9 and the others were over 0.9.

충남부여에 위치한 임업화훼단지내의 유리온실에서 아치형재배(Arching method)장미에 피해를 주는 점박이응애(Tetranychus urticae Koch)의밀도를 엽당 응애수로 조사하였다. 이항표본 조사법은 엽당 점박이응애의 평균밀도(m)와 점박이응애가 T 개체보다 많이 존재하는 엽의 비율()과의 관계를 기본으로 하며, T는 경험적 이항분포모형(ln(m)=+1n(-1n(1-)))에서의 tally threshold 로서, 본 실험에서는 1, 3, 5, 7, 9를 사용하였다. 일반적으로 표본단위 수의증가는 T와 상관없이 이항분포 모형의 정확도에 영향을 거의 주지 않게 된다. 본 실험에서는 상이한 T에 따라 이항분포모형의 정확도가 차이가 났으며 T가 증가할수록 정확도가 높아졌다. 본 실험결과 점박이응애의 밀도추정을 위한 이항분포모형의 정확도를 비교한 결과, T=7인 경우가 최적의 tally threshold인 것으로 나타났다. 또한 이항분포조사법의 검정을 위하여, 동일한 포장의 독립적인 표본을 추출, 조사하였다. 본 실험결과 이항표본조사법을 이용한 상업적 유리온실의 아치형재배 장미해충인 점박이응애 평균밀도 추정에는 T=7인 경우가 가장 적절한 것으로 사료된다.