Ecology and Management of Apple Snails in Rice

Abstract

Apple snails (Ampulariidae) occur throughout tropical and subtropical rice-growing regions. Native apple snails rarely damage rice; however, in hot and humid tropical regions, some native species will damage wet-direct-seeded rice (i.e., Pomacea spp. in Suriname and Brazil). Similarly, exotic apple snails in wet, temperate regions can damage direct-seeded rice (i.e., Pomacea canaliculata in Japan). However, if left unmanaged, exotic apple snails in warm tropical regions (i.e., P. canaliculata and P. maculata in South East Asia) can cause significant economic losses even to transplanted rice (which is more robust that direct-seeded rice). The negative impact of apple snails on rice yield can be reduced by reducing seedling vulnerability or controlling snail population densities. Reducing vulnerability is a more sustainable solution to apple snails but requires new methods such as seedling broadcasting and machine transplanting to decrease labor costs. To avoid further spread of apple snails, the implementation of effective quarantine directives is recommended for tropical countries that are vulnerable to exotic apple snails.