• Korean journal of applied entomology
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• v.51 no.2
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• pp.141-148
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• 2012

An outbreak of Ricania sp. occurred in the Kurye, Jeonnam area in 2011. This outbreak damaged many kinds of fruit trees such as Cornus, Persimmon and Chestnut. This experiment was conducted to survey the occurrence ecology of Ricania sp. such as host plants, oviposition characters, morphological characters and life cycle, as well as to select environmental friendly control agents. Ricaina sp. host plants included 51 species such as 32 xylophytes, and 19 herbaceous plants. Ricaina sp. preferred Cornus officinalis, Diospyros kaki, Castanea crenata, Eucommia ulmoides, Styrax japonicus for oviposition. Adults laid eggs on new inner twigs with 28.8 eggs per egg-mass. Egg size was 1.24 mm(length), 0.55 mm(width) in an oval shape. Nymphs molted four times. Every nymph stage had an x shape of yellow or white beeswax around the anus. Overwintered eggs of Ricania sp. hatched from the mid May to early June. Nymphal periods were from mid May to mid August and adults appeared from mid July but spawning began in mid August. Ricania sp. damaged new twigs by oviposition and retarded growth by sucking nutrients and producing a sooty mold. Sophora and natural plant extracts were effective environmentally friendly agricultural materials used to control the nymph and adult Ricania sp. Mortality was > 80%.

• Korean Journal of Environment and Ecology
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• v.28 no.2
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• pp.215-234
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• 2014

The purpose of this study is to identify the type and characteristics of the domestic natural streams in order to establish a basis for stream restoration and evaluation. To this end, 95 domestic natural stream areas, which have various natural environments, were selected except for the province of island and then the characteristics of natural environment, hydromorpholoy, plant and vegetation were investigated and analyzed in each stream area. As a result, 95 stream areas were classified into total 24 types according to 3 criteria such as stream size (4 types), altitude (3 types), bed material (5 types). Depending on altitude class that is the environmental factor showing the highest correlation with each stream types, the emergence of vegetation and plant, 24 stream types were reclassified into 3 types such as lowland (altitude less than 200m), mountain (altitude from 200m to 500m), highland (altitude more than 500m), and hydromorpholoy, plant and vegetation characteristics of each stream type were compared. First, when compared to the mountain and highland streams, the typical features of lowland streams were as follows: Stream size was large but bed material size was small and there were many valley forms where flood plane were developed well. In addition, the more large stream size was, the more cross-section width variability, bars and sinuosity were in good conditions. In lowland stream, representative vegetation community was Salix koreensis community. On the other hand, when compared to the lowland streams, the typical features of mountain and highland streams were as follows: Stream size was small but bed material was coarse-grained and its size was large. Mountain and highland streams valley form where flood plane was not developed well was narrow, and sinuosity and bars development were weak. Representative vegetation communities of mountain streams were Quercus serrata -, Quercus variabilis -, Styrax japonica community and representative vegetation communities of highland streams were Pinus densiflora -, Quercus mongolica -, Fraxinus rhynchophylla community.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.347-355
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• 1997

For the selection of plants contained pesticidal active conpounds, 31 families 59 species of native plants were collected and biological activites of their crude extracts against brown planthopper (Nilaparvata lugens), Xanthomonas oryzae pv. oryzae and allelopathy were examined. Among the screened plants, the crude extracts from the leaves of Ricinus communis and Sophora angustifolia showed 100% and 82% of mortality on brown planthopper at the concentration of 1% (w/v) respectively. Mixed crude extracts of Sophora angustifolia root and Melia azedarach seed exhibited 128${\sim}$155% of synergistic effects on the mortality of brown planthopper. In case of fungicidal activity, the crude extracts from the leaves of 8 plants including Chrysanthemum indicum were inhibitory of the growth of Xanthomonas oryzae pv. oryzae at 1%(w/v) soluction. Seed germination of radish (Raphanus sativas) and barnyardgrass (Echinochloa crus-galli) was inhibited by 0.5%(w/v) leaf extracts of Pinus densiflora and Quercus acutissima. MeOH extracts of Pinus denislora leaves gave 100% inhibition in seed germintion of radish at 2%(w/v) soluction and showed a complete inhibition in seedling growth of barnyardgrass as well as radish at 5% solution.