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

We assessed the lethality of a bait containing both Iimonene 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 4- Iimonene, and values of 5.45, 4.41 and 5.60% were obtained for bait containing starch 4- Iimonene. A significant positive rank correlation was observed between different concentrations of Iimonene 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 Iimonene 4- proline in May. Our results indicate that snail populations can be controlled by a Iimonene bait formulation applied in a specific month rather than all the year round. [ABSTRACT FROM AUTHOR]