Toxicity of Euphorbia milli latex and niclosamide to snails and nontarget aquatic species

The toxicity of Euphorbia milii molluscicidal latex and niclosamide (NCL) t o target snails (Biomphalaria glabrata and Biomphalaria tenagophila) and no ntarget aquatic organisms is evaluated. Planorbidae snails were killed by v ery low concentrations of lyophilized lates (48-h LC50, mg/L: B. glabrata, 0.12; B, tenagophila, 0.09; Helisoma duryi, 0.10). Lates was less toxic (48 -h LC50 or EC50, mg/L) to oligochaeta (Tubifex tubifex, 0.31), planktonic c rustacea (Daphnia similis. 0.38; C, dubia, 1.07; Artemia sp,, 0.93), and fi shes (Danio rerio, 0.96; Poecilia reticulata, 1.39), and considerably less toxic to Ampullariidae snails (Pomacea sp., 10.55) and frog tadpoles (Rana catesbeiana, 7.50), Latex (up to 100 mg/L) was not toxic to bacteria (P. pu tida and V. fischeri), algae (Selenastrum capricornutum and Chlorella vulga ris), and mosquito larvae (Anopheles albitarsis, Aedes aegypti, Aedes fluvi atilis). NCL was very toxic (48-h LC50 or EC50, mg/L) to Planorbidae snails (B. glabrata, 0.15, B. tenagophila, 0.13; N, duryi, 0.10), T. tubifex (0.1 1), crustacea (D. similis, 0.19; Ceriodaphnia dubia, 0.47; Artemia sp. 0.18 ), fishes (D, rerio, 0.25; P. reticulata, 0.29), R, catesbeiana (0.16), and Pomacea sp. (0.76). NCL was toxic to bacteria, algae (96-h IC50, mg/L: S, capricornutum, 0.34; C. vulgaris, 1.23) and slightly toxic to mosquito larv ae. In conclusion, E, milii latex, as compared with the reference molluscic ide niclosamide, presents a higher degree of selectivity toward snails whic h are intermediate hosts of Schistosoma trematodes, (C) 2000 Academic Press .