Golden apple snails(GAS) are native to warm regions such as Central and South America and Southeast Asia, and were first introduced as a high-protein food. GAS are omnivorous and have a habit of eating plants submerged in water, so they have been used for eco-friendly weed control in rice fields since 1992. When the GAS was first introduced, it was thought that it would be impossible to overwinter in Korea. However after 2000, overwintering individuals were founded and damage to rice occurred and the development of means to control GAS has been required. In this study, we tested the effectiveness of an eco-friendly pest control agent using Styrax japonicus that grow naturally in Korea. As a result of exposing GAS to S. japonicus fruit powder, a 100% molluscicidal effect was confirmed at 66.7ppm. To investigate the duration of effect, treatment was performed at the same concentration and molluscicidal effect of more than 90% was up to 3 days after treatment. The killing effect of each part of the S. japonicus was compared, and the seed extracts showed no killing effect at all concentrations, while the sarcocarp extracts showed a 100% killing effect up to 33.3ppm, and the fruit extracts showed a 100% killing effect up to 200ppm.

Paddy fields provide important habitats for biodiversity conservation within the agricultural ecosystem. Their importance is gradually increasing as their ecological value is better understood. Benthic macroinvertebrates dominate paddy fields. They play an essential role in maintaining the biodiversity of paddy ecosystems. This study aimed to analyze characteristics of benthic macroinvertebrate communities and main environmental factors affecting the distribution of golden apple snails (Pomacea canaliculata). Results showed that the diversity index (H ′) of the benthic macroinvertebrate community was the highest at the Sangju site (St. 12) but the lowest at the Sancheong site (St. 18). Total Dissolved Solids (TDS), salinity, and Electrical Conductivity (EC) values were the highest in Gimhae and Yeongam based on Canonical Correspondence Analysis (CCA). Numbers of P. canaliculata (m-2) were relatively low in Gunsan and Iksan where water temperatures were high. Therefore, changes in geographical characteristics and environmental factors might affect the distribution of P. canaliculata and characteristics of benthic macroinvertebrate communities. Results of this study can be used as primary data for biodiversity conservation and ecosystem service evaluation in agroecosystems.

왕우렁이(Pomacea canaliculata)는 1983년에 식용으로 일본에서 한국으로 도입된 외래종으로서, 농업에서 벼의 직파 논의 잠재적인 해충이다. 본 연구에서는 해충화되고 있는 왕우렁이의 생육특성과 충남 및 전북지역에서의 월동생태를 구명하였고, 또한 농수로에서 수생식물과 수질에 미치는 영향을 조사하였다. 자연수로에서 조사결과를 보면 왕우렁이가 높은 밀도로 서식하는 수로에서는 왕우렁이가 서식하지 않을 경우에 많았던 검정말, 붕어마름, 개구리밥, 좀개구리밥 등의 수생식물들이 발견되지 않았다. 폐쇄형 인공수조실험에서는 왕우렁이가 수생식물들을 먹이로 섭식하면서 이들 식물들을 제거하고, 수질 지표인 EC, COD, T-N 및 T-P을 높이는 것으로 나타났다.

The golden apple snail was introduced to the Korea from Japan as a potential food for people in 1983. It is one of the pests of direct-seeded rice in korea. This study was conducted to investigate rice(Oriza sativa) consumption and the extent of damage by the golden apple snail(Pomacea canaliculata) in direct-sown paddy fields. Food consumption of the golden apple snail was highest at 30℃. When the emergence of the 1st, 3rd, and 5th leave of rice supplied food, the consumption of young(shell height 15㎜) and adult golden apple snail(over shell height 30㎜) at 30℃ were 19.0/79.8, 11.0/54.5, 5.5/18.5, and 0.0/2.0 individuals, respectively. Young rice seedings(before 5th leaves of rice) are very susceptible to golden apple snail damage because the young, tender leaves and stems favor the snail"s feeding habits. The field experiment with four treatments (0, 2, 5 and 10 individuals respectively per 10 ㎡) was carried out. The most serious yield loss was 16% from the plot with 10 adults released at emergency stage of rice.

This study was investigated the potential of ducks and fish trap for the control of golden apple snail, Pomacea canaliculata, in paddy field and water canals. The smaller size of duck (700 g) preyed snails than the bigger one (1,300 g). The consumption of two ducks was bigger under plastic house. They preyed over 90% on the second days of release. The release time of ducks was more effective at seven days after inoculation of snails than simultaneous. Duck could suppress the density of snails at any time from month after inoculation. Four ducks per 30 ㎡ could control snails in an irrigation canals. The number of attracted golden apple snail per week was 216 in big fish trap (Φ 15 ㎝) with menthol paste which for a carp.

This study was carried out to determine occurrence and damage of golden apple snail, Pomacea canaliculata on water seeding area in Jeonnam province. The density of golden apple snail maintained high until October 2003, but quickly decreased from November. They overwintered only in a portion of the water canals but could not find in dried paddy field. They reproduced from May and June in the canal water and paddy field, respectively. Feeding time of golden apple snail on rice seedlings was 235.2 seconds, feeding length of that was 8.4 ㎝. When golden apple snail fed rice seedlings, the stem remain only 2.5 ㎝ from areal part which could not recover. The more density of golden apple snail, the faster feeding rate. Density and number of eggs laid of golden apple snail after overwintering was higher on bank around of paddy field than on middle of that. The percent of shell size after over wintering was higher in small (below 25 ㎜) than big (over 36 ㎜). But in case of Boseong area, the size was reverse because the soil has soft mud. The survival rate of overwintering golden apple snail was lower than that of breeding. They did not move when the temperature changed rapidly, but the temperature increased they start to move. They dead almost below -3℃. The damage of rice by golden apple snail in the direct water seeding was 20%. In machine transplanting, rice damaged only fore-end of leaf and recovered subsequently. When golden apple snail release in direct water seeding field, the percent of damage was 5.6% in immediately release plot. The later release, the lower damage.