Acute toxicity evaluation of the plant molluscicide, Apodytes dimidiata (Icacinaceae), to Eisenia fetida (Oligochaeta) and Oreochromis mossambicus (Cichlidae) in South Africa

The crude aqueous leaf extract of a South African tree, Apodytes dimidiata, has been identified as a potential molluscicide for snail control in anti-schistosomiasis programmes in rural communities. Before preliminary field trials could be implemented its acute toxic effects on two non-target organisms were examined in accordance with the OECD guidelines to identify any potential hazards that might arise from the plantʹs use. Laboratory results showed that working molluscicidal concentrations of the plant extract were non-toxic to earthworms suggesting that it is non-hazardous to soil-dwelling fauna. The plant extract proved toxic to fish and was assigned the risk phrase ‘harmful to the aquatic environmentʹ according to the EEC classification scheme. Based on these toxicity evaluations, aqueous extracts of A. dimidiata are considered safe for use in preliminary field trials.