Molluscicidal Activity of Aqueous Extract from Five Plants Species against Golden Apple Snails (Pamocea canaliculata)

Abstract

The quest for botanicals with molluscicidal activity became essential research when the Golden Apple Snails (Pomacea canaliculata) became a pest that invaded rice fields and resulted in a significant decrease in rice harvested in Malaysia. This study was conducted to screen the aqueous extracts of leaves of Acacia mangium (Fabaceae), Allamanda cathartica (Apocynaceae), Catharanthus roseus (Apocynaceae), Euphorbia hirta (Euphorbiaceae) and Stachytarpheta jamaicensis (Verbenaceae) as potential molluscicides. For each plant species, one kg of freshly crushed leaves was blended with 5000 ml of water and soaked at room temperature. After 24 hours, it was filtered, and this extract was named 100% aqueous extract. The two diluted concentrations of extracts, i.e., 10% and 50%, were prepared based on a 100% extract. Ten adult snails were treated at each concentration for molluscicide testing for 24 hours. Then it was replaced with chlorine-free water and left for 24 hours. Snails were considered mortal when they remained motionless if stimulated by a needle or if the body emerged from the shell or remained within it. The results showed that the most potent extracts were Stachytarpheta jamaicensis leaf extracts, followed by Allamanda cathartica, Acacia mangium, Euphorbia hirta and Catharanthus roseus. Therefore, this study suggested that Stachytarpheta jamaicensis warrants further investigation of the molluscicidal effect on controlling Golden Apple Snails.