Mangrove Against Invasive Snails: Aegiceras corniculatum Shows a Molluscicidal Effect on Exotic Apple Snails (Pomacea canaliculata) in Mangroves.

Abstract

Apple snails (Pomacea canaliculata), one of the 100 most serious invasive species in the world, have invaded mangrove wetlands due to their salinity tolerance. We firstly prepared a plant molluscicide against apple snails based on the mangrove Aegiceras corniculatum in coastal wetland. The effects of four mangrove extracts from A. corniculatum, including ethanol extract (EE), petroleum ether extract (PEE), ethyl acetate extract (EAE), and n-butanol extract (BE), were studied for molluscicidal activity against apple snails in a saline environment. The LC₅₀ values at 48 h of EE, PEE, EAE, and BE were 25 mg/L, 123 mg/L, 170 mg/L, and 14 mg/L, respectively. BE had the highest molluscicidal value (96.7%) against apple snails at 48 h. At 48 h, BE of A. corniculatum leaves significantly decreased the soluble sugar content, soluble protein content, acetylcholinesterase, and glutathione of apple snails to 4.25 mg/g, 29.50 mg/g, 947.1 U/gprot, and 6.22 U/gprot, respectively, compared to those in the control. The increased BE concentration significantly enhanced the malondialdehyde and aspartate aminotransferase contents to 4.18 mmol/gprot and 18.9 U/gprot at 48 h. Furthermore, the damage in the hepatopancreas tissue of apple snails increased, and the cellular structure became necrotic as the concentration of BE from A. corniculatum increased. The content of palmitic acid in BE of A. corniculatum leaves was the highest (10.9%), possibly be a toxic ingredient against apple snails. The n-butanol extract of A. corniculatum leaves showed a potential to control apple snails in the brackish water, and its plantation was beneficial to control the further spread of apple snails in mangrove wetlands.