CONTACT UPTAKE OF METAL-COMPOUNDS AND THEIR MOLLUSCICIDAL EFFECT ON THE FIELD SLUG, DEROCERAS-RETICULATUM (MULLER) (PULMONATA, LIMACIDAE)

Control of terrestrial slugs and snails by contact molluscicides acquired passively by crawling animals is potentially more efficient than the bait-delivery method currently used. An attempt was made to exploit the known molluscicidal activity of some common metals as contact-action poisons by comparing their rate of uptake and toxicity in different chemical forms. Uptake of iron and aluminium was faster from salt (sulphate)-coated than from chelate-coated surfaces and the rate of uptake also varied widely between chelates. Toxicity was dependent on metal uptake, but was modified by the ligand used. High mortality rates were associated with comparatively low metal uptake levels after contact with the lower members of an iron (III) pentanedionate and an iron (III) diazaalkanolate series of chelates.