Mechanisms of Molluscicidal Activity of Citrus hystrix against Pomacea canaliculata

Pomacea canaliculata (Golden apple snail) is an invasive pest that seriously affects rice cultivation. It causes one of serious agriculture problems in many Asian countries. To control these snail populations, synthetic chemical molluscicides were mainly used. However, these molluscicides may cause long-term disadvantage to the environment and also impact on ecological system. Finding natural substances that kill golden apple snails, therefore, is an alternative way to decrease number of snails and their epidemic. The molluscicidal activity of peels and pulps Cirus hystrix (C. hystrix) extracts on Pomacea canaliculata were evaluated under controlled laboratory conditions. C. hystrix peel methanol extract was toxic to the snail with LC50 71.66 mg/L. Conversely, no snail was found dead in C. hystrix pulp methanol extract. The molluscicidal mechanism of C. hystrix peel methanol extract on P. canaliculata was also evaluated through change of selected biochemical parameters, including acetylcholinesterase activity, glycogen and protein contents. There was no signifi cantly change in any biochemical parameters. These results suggest that methanol extracts from peels of C. hystrix had molluscicidal activity which could be utilized as bioherbicide for future weed control. However, the mechanisms of molluscicidal activity were still unclear.