Molluscicidal properties of organotin and organolead compounds.

Triphenyltin acetate has proved successful as a molluscicide in the laboratory and in small-scale field trials. However, in view of its cost and its toxicity to swamp rice at molluscicidal concentrations, an effort has been made to explore the molluscicidal value of other organotin and organolead compounds. Those that proved most toxic to snails were screened in the laboratory against swamp rice in order to obtain some measure of their phytotoxicity. This study yielded 6 compounds that were relatively non-toxic to rice. One of these, triphenyllead acetate, has been formulated as an emusifiable concentrate for use in the field and the results of trials in two parts of Tanzania are reported. Chemical analyses of water treated with triphenyllead acetate are discussed, and the reasons for the disappearance of the compound in the field are investigated. Some preliminary information on the toxicity of triphenyllead and triphenyltin derivatives to other organisms is also given.