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        검색결과 69

        61.
        2012.10 구독 인증기관·개인회원 무료
        Spatial association of entomopathogenic and free-living nematode populations were analyzed at the landscape scale. Free-living nematodes were classified into functional guilds based on their trophic level (i.e. bacterivores, carnivores, fungivores, and omnivores) and life history characteristics (i.e. r-selected colonizing versus K-selected persisting species) in the soil ecosystem. Differences in life history traits were hypothesized to result in different spatial associations of populations. Spatial aggregation indices were calculated for each nematode group. Spatial associations were analyzed and compared for entomopathogenic nematodes (EPN) and each trophic/life history group of free-living nematodes based on spatial analysis of distance indices (SADIE). Spatial aggregation indices (Ia) revealed that taxa with more K-selected persisting life history were less aggregated in their habitat, whereas more r-selected colonizer life history types showed more aggregation. Spatial aggregation index of EPN populations was similar to that of relatively r-selected colonizer type free-living nematodes, which share several life history traits including high reproductive rates and insect phoresy. There were substantial spatial associations between EPN and r-selected colonizer life history free-living nematode taxa.
        62.
        2012.05 구독 인증기관·개인회원 무료
        Population dynamics of American serpentine leafminer, Liriomyza trifolii, were modeled and simulated to compare the temperature effects of air and tomato leaf inside greenhouse using DYMEX model simulator. The DYMEX model simulator consisted of series of modules with the parameters of temperature dependent development and oviposition model of L. trifolii from pre-published data. Leaf surface temperature of cherry tomato leafs was monitored according to three tomato plant positions using an infrared temperature gun. Air temperature was monitored at same three positions using a self-contained temperature logger. Data sets of observed air temperature and average leaf surface temperatures were prepared, and incorporated into DYMEX simulator to compare the effects of air and leaf surface temperature on population dynamics of L. trifolii. The number of L. trifolii larvae was counted by visual inspection in tomato plants to verify the performance of DYMEX simulation. The egg, pupa, and adult stage of L. trifolii were not counted due to its availability of visual inspection. Based on correlation analysis, L. trifolii was affected greatly by the leaf temperatures, rather than air temperatures.
        63.
        2011.10 구독 인증기관·개인회원 무료
        Population dynamics of greenhouse whitefly, Trialeurodes vaporariorum, were modeled and simulated to compare the temperature effects of air and tomato leaf inside greenhouse using DYMEX model simulator. The population phenology model of T. vaporariorum was developed and simulated. Leaf temperature on reversed side of cherry tomato leafs was monitored according to three tomato plant positions (top, >1.6m above the ground level; middle, 0.9 - 1.2m; bottom, 0.3 - 0.5m) using an infrared temperature gun. Air temperature was monitored at same three positions using a temperature logger. The leaf temperatures from three plant positions were described as a function of the air temperatures. The number of T. vaporariorum immatures was counted by visual inspection in three positions to verify the performance of DYMEX simulation. A significant positive correlation between the observed and the predicted numbers of immature and adults was found when the leaf temperatures were incorporated into DYMEX simulation, but no significant correlation was observed with air temperatures. This study demonstrated that the population dynamics of T. vaporariorum was affected greatly by the leaf temperatures, rather than air temperatures in cherry tomato greenhouses. This work was supported by Development of field-oriented model for forecasting outbreak of diseases or insect pests based on GIS and IT Program (R1003852) from Rural Development Administration, Republic of Korea.
        64.
        2011.10 구독 인증기관·개인회원 무료
        Pesticide application pattern for agricultural insect pest was modeled and simulated by temperature change scenarios using DYMEX simulator. For modeling pesticide application pattern, we evaluated bioassay using two-spotted spider mites (TSSM) in vitro. Four separated bioassay was evaluated at four different temperature conditions (20, 25, 30, and 35℃). Selected four commercial pesticides were Acrinathrin-Spiromesifen mixture, Fenpropathrin, Abamectin, and Azocyclotin, respectively. All the pesticide was used its recommended dose, except Abamectin (1/10 of recommended dose). Each mortality of TSSM were counted after 24 and 48 hours. Based on the bioassay results, increasing temperature made decreasing mortality in Acrinathrin-Spiromesifen mixture and Fenpropathrin, whereas increasing mortality in Abamectin and Azocyclotin, respectively. A TSSM model was developed and simulated under four temperature increasing scenarios (present condition, average 1, 2, and 3℃ increased conditions) using DYMEX simulator. The DYMEX results showed that the pesticides application pattern were different among four pesticides under climate change scenario. In conclusion, the pesticide application should be changed for sound management of agricultural insect pest under climate change scenario.
        65.
        2011.05 구독 인증기관·개인회원 무료
        This study was conducted to examine the potential of surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) to screen Tetranychus urticae resistance to pyridaben and dicofol. T. urticae is one of the most important pests in greenhouse and orchard, and huge expense is needed to control because of its strong resistance to acaricides. Consequently speedy and accurate monitoring of acaricidal resistance is the key factor of IPM for T. urticae. SELDI-TOF MS is a novel approach to biomarker discovery that combines two powerful techniques: chromatography and mass spectrometry. It can provide a rapid protein expression profile of acaricidal sensitive and resistant T. urticae. In this study we had different protein and peptide patterns between sensitive and resistant strains to pyridaben and dicofol. In the future this results could be a useful data to develop a good monitoring tool of site and host specific mite resistance to various acaricides.
        66.
        2011.05 구독 인증기관·개인회원 무료
        two different sizes of yellow sticky traps (small trap: 9.6×8.0cm; large trap: 9.6×16cm) for sampling greenhouse whitefly (GHWF), Trialeurodes vaporariorum (Westwood), adults in four commercial cherry tomato greenhouses. The patch size of GHWF immatures between plants was also estimated using visual counts. Two variogram models were fitted to the empirical variograms developed from the data collected by each sampling method. All the variograms reached the sill indicating the presence of spatial dependence among the spatial data obtained by the two sampling methods. For GHWF adults on sticky traps the range of variogram (a measure of attractive distance) was not different between the two trap sizes. This result indicated that the attractive distances of the two different yellow sticky traps were very similar. The ranges of the variograms for the visual count of immatures on plants were always less than those for adults, indicating that the attractive distance of the traps for GHWF adults extends beyond the patch size for immatures on cherry tomato plants. These data have implications for developing sampling plans for the management of GHWF in tomato greenhouses.
        67.
        2010.10 구독 인증기관·개인회원 무료
        Biological control of greenhouse whitefly, Trialeurodes vaporariorum in greenhouse tomatoes with the parasitoid Encarsia formosa has been evaluated in Korea. However implementation of biological control program is retarded due to the reasons that lacks of site specific strategies. Aims of the present research are: (1) To develop an effective biological control method of the whitefly in tomato plants; the following were studied: (a) development of proper introduction rate of parasitoid, E. formosa, for the control of whiteflies, and (b) development of the effective control method of American serpentine leafminers with a parasitoid, Diglyphus isaea. (2) To build a computer-simulation model in which all factors are incorporated which have been studied in the relationship between whitefly and the parasitoid. The computer-simulation models would be used to estimate the effect of future developments in the greenhouse industry on the biological control of the greenhouse whitefly using E. formosa. More general goals are to develop reliable evaluation techniques to test the pest-control ability of natural enemies prior to their use in practical situations and to determine which role simulation models may play in estimating the results of biological control in new situations.
        68.
        2010.10 구독 인증기관·개인회원 무료
        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.
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