Influence of abiotic factors on the molluscicidal activity of a bait containing limonene targeted at the pest snail Lymnaea acuminata

摘要

We assessed the lethality of a bait containing both limonene and an attractant (starch or proline) against the pest snail Lymnaea acuminata for every month of the year 2010-2011. Simultaneously, levels of temperature, pH, dissolved oxygen, carbon dioxide and electrical conductivity in test water were measured. In 24 h toxicity assays, carried out in May, June and July, lethal concentration (LC50) values of 3.99, 4.47 and 4.44% were obtained for bait containing proline -I- limonene, and values of 5.45, 4.41 and 5.60% were obtained for bait containing starch + limonene. A significant positive rank correlation was observed between different concentrations of limonene in bait and acetylcholinesterase activity in the nervous tissue of the snail. There was maximum inhibition (57.93%) of acetylcholinesterase activity in snails fed bait containing 80% of the 24-h LC50 of limonene + proline in May. Our results indicate that snail populations can be controlled by a limonene bait formulation applied in a specific month rather than all the year round.