Molluscicidal particle, bait and method of controlling harmful molluscs

A process for controlling harmful mollusks, comprising providing an effective amount of a molluscidal bait to harmful mollusks, said molluscicidal bait being in divided form comprising at least one molluscicidal particle formed from a solid suitable for use as an ingested poison for harmful mollusks, said solid comprising metaldehyde and at least one metallic compound, the metallic compound comprising at least one metal selected from the group consisting of iron, copper, zinc and aluminum, wherein

• the solid comprises metaldehyde in a proportion that varies discontinuously towards the interior of said metaldehyde containing solid,
• the molluscicidal particle is formed from an outer surface layer and an inner core inscribed within the outer surface layer and enveloped thereby, said outer surface layer and said inner core being formed from two solids containing different proportions of metaldehyde,
• the proportion of metaldehyde in the outer surface layer is less than the proportion of metaldehyde in the inner core, and the at least one metallic compound is present in the solid of the outer surface layer of the particle in a mass proportion greater than the mass proportion of metallic compound in the inner core,
• the distribution of metaldehyde in the solid of a particle being so chosen to yield an enhanced molluscicide efficiency against harmful mollusks consuming a molluscicide amount of said solid within a period of 3 days at the maximum following the onset of consumption of the solid by said harmful mollusks and affording a rapid protection of plants and crops against said harmful mollusks.