Preliminary screening of some Thai indigenous plants for molluscicidal activity against Pomacea canaliculata (Lamarck)

Pomacea canaliculata (Lamarck) is one of rice pest and causes a serious problem because of rice fields devastation. In this study, a total of 91 Thai indigenous plant samples from 78 different plant species were prepared as aqueous plant extract from 100 g fresh plant per one liter of distilled water and tested against P. canaliculata (Lamarck) with 3-5 mm in operculum diameter. And it was found that % mortality of snail at 72 h of incubation of 25 plants samples from 23 different species were higher than 90%. The LC50 of aqueous extracts prepared from these twenty-five Thai indigenous plants to P. canaliculata (Lamarck) were determined. And it was found that Bougainvillea spectabilis (LC50 = 39.11 mg/l), Calotropis gigantea (LC50 = 86.00 mg/l) and Croton tiglium (LC50 = 73.60 mg/l) showed strong molluscicidal activities.