• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.129-137
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• 2008

Alien apple snails (Pomacea canaliculata, Pomacea insularus) used in environmentally-friendly agriculture are different from indigenous snails found in Korea. Due to high herbicidal effects and cost-effectiveness, the number of farmers using the snails has been growing every year since 2000. Moreover, in 2008, because of the outbreaks of avian influenza throughout the country from March to May, 2008, central and local governments recommended the use of alien apple snails in agriculture as an alternative to the ducks-oriented environmentally-friendly agriculture. Therefore, it is expected that the use of alien apple snails in agriculture should be expanded in a near future. Since alien apple snails lay eggs with 95.8% of eclosion rate, they are considered to be potential pests unlike indigenous snails. In addition, Japan, Taiwan and most of the southeast Asian countries had already experienced severe ecological and agricultural damage by the alien apple snails. Subsequently, International Union for Conservation of Nature and Natural Resources (IUCN) designated P. canaliculata as one of "the 100 of the world's worst invasive alien species". It seems highly likely that the alien apple snails in Korea pose a potential threat to conservation of ecosystem and biodiversity since the snails were either found or invaded into the natural environments in some regions of Gangwon-Do and southern parts of Korean Peninsula. However, just recently, agricultural authorities and farmers using alien apple snails in agriculture opposed a proposition of designating the alien apple snails as an ecosystem-disturbing animal described by the Wildlife Protection Act. This is because there has been no concrete evidence of the ecological risk imposed by the alien snails up to now in Korea. Subsequently, in this paper, we analysed the ecological and agricultural risks imposed by the alien snails from the studies done in domestic and abroad. In addition, we proposed an urgent need and reasoning for ecological risk management of the alien snails at the national level as well as using the snails in agriculture.

• Korean Journal of Environmental Biology
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• v.40 no.2
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• pp.164-171
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• 2022

Frankliniella occidentalis is an invasive pest insect, which affects over 500 different species of host plants and transmits viruses (tomato spotted wilt virus; TSWV). Despite their efficiency in controling insect pests, pesticides are limited by residence, cost and environmental burden. Therefore, a fixed-precision level sampling plan was developed. The sampling method for F. occidentalis adults in pepper greenhouses consists of spatial distribution analysis, sampling stop line, and control decision making. For sampling, the plant was divided into the upper part(180 cm above ground), middle part (120-160 cm above ground), and lower part (70-110 cm above ground). Through ANCOVA, the P values of intercept and slope were estimated to be 0.94 and 0.87, respectively, which meant there were no significant differences between values of all the levels of the pepper plant. In spatial distribution analysis, the coefficients were derived from Taylor's power law (TPL) at pooling data of each level in the plant, based on the 3-flowers sampling unit. F. occidentalis adults showed aggregated distribution in greenhouse peppers. TPL coefficients were used to develop a fixed-precision sampling stop line. For control decision making, the pre-referred action thresholds were set at 3 and 18. With two action thresholds, N_max values were calculated at 97 and 1149, respectively. Using the Resampling Validation for Sampling Program (RVSP) and the results gained from the greenhouses, the simulated validation of our sampling method showed a reasonable level of precision.