By Ravindra C. Joshi and Ratcha Chaichana
Invasive apple snails, formerly known as Golden Apple Snails (GAS), are an invasive species that pose a threat to crops, ecosystems and even humans. These natives of South America have spread to many other parts of the world, through both deliberate and accidental introductions. Called apple snails because they can grow to the size of an apple or a tennis ball, these molluscs can wreak havoc on both agriculture and the environment, and can also carry diseases that infect humans. Invasive apple snails have been listed among the world’s 100 most invasive species by IUCN/GISD. Belonging to the genus Pomacea, there are several species of apple snail that have become invasive. In Southeast Asia, the most important of these pest species are P. canaliculata and P. maculata (formerly known as P. insularum).