Control the egg hatchling process of Pomacea canaliculata (Lamarck) by water spraying and submersion

Pomacea canaliculata (Lamarck) is an invasive snail species that has become a serious pest of rice and other hydrophytes. Usually it is aquatic but likes to lay its eggs higher than the waterline. In order to seek a feasible and efficient way to control the egg hatchling of this pest, here we systematically studied the effects of water spraying and submersion on its egg hatchling rates and durations. Our results demonstrated that water spraying and submersion could dramatically decrease the hatchling rates to maximal 5.8% and increase the hatchling duration up to 26.4 days on P. canaliculata. Not only the beginning time of water treatment, but also the frequencies of the water spraying is critical to control the hatchling rate and duration of P. canaliculata. Water submersion that began in 12 h after the eggs laid and lasted at least 48 h will significantly decrease the snails’ hatchling rates and extend the hatchling time. In addition, compared to spraying, the water submersion could achieve more remarkable effects. The capsule of the snail’s egg is able to withstand the water treatment. Based on our water spraying and submersion results, it can be inferred that 0–6 h after egg being laid, egg capsule precipitates are beginning to form, and this process will complete after 12–24 h. This special breeding characteristic of P. canaliculata makes the physical control by water treatment become feasible.