Potential effects of commercial molluscicides used in controlling golden apple snails on the native snail Vivipara Costata (quoy & gaimard)

摘要

The effects of commonly used molluscicides at different rates were determined against the pest golden apple snail (GAS), Pomacea canaliculata (Lamarck), and the non-destructive native snails (NS), Vivipara costata (Quoy and Gaimard). So far, all molluscicides approved by the Fertilizer and Pesticide Authority (FPA) for trade in the Philippines are effective in controlling GAS. Niclosamide 250EC is more deadly to NS than metaldehyde formulations. Niclosamide 250EC at recommended dosage (1 I/ha) caused a significant mortality of GAS populations (58.3%) one day after treatment (DT). However, it is most lethal to NS at 7 DT, while metaldehyde formulations caused very low mortality (0-6.3%). At half the recommended dosage, it killed 87.5 percent of GAS only at 7 DT. The adverse effects on NS of compounds, except niclosamide 250EC, were not immediately evident after application: Educational campaigns are therefore needed to make farmers aware of the adverse effects of molluscicides to NS.