Toxicity Effect of Temephos on Bulinus globossus and Lymnaea natalensis

Abstract: The acute toxicity of temephos on freshwater pulmonate snails Bulinus globossus on Lymnaea natalensis was determined in short-term toxicity test. The 24h LC50 (95 % Confidence intervals) was 0.021 mg l (0.01-0.03 mg l) for the adults of B. globossus and 0.021 mg l (0.007-0.066) mg l for the1 1 1 1 juveniles of the same species. While 24h LC50 (95 % Confidence intervals) was 0.021 mg l (0.007-0.064) mg l1 1 for the adults of L. natalensis and 0.019 mg l (0.011-0.032) mg l for the juveniles respectively. Abate1 1 was also found to be ovicidal to the eggs of both species at 0.03 mg l and above where it gave a 100%1 mortality. However, the 1 mg l concentration used in killing Cyclops in the control of dracunculus is1 higher than the lethal concentration to the snails, which are not really focused in the application of Abate. Abate is therefore found to be toxic to the intermediate hosts of Schistosoma species and Fasciola species which coexisted with the cyclopoid copepoids against which the chemical has been widely used to eradicate guinea worm. Abate can therefore be said to be effective in controlling Schistosomiasis, Fascioliasis as well as Dracunculiasis. Key words: Abate Bulinus globossus Lymnaea natalensis and toxicity INTRODUCTION has a low mammalian toxicity, is easy to apply and it is Temephos is an non-systemic organophosphorus store under tropical conditions. One recommended rate o