Evaluation of a New Molluscicide for Counteracting the Intermediate Snail Host ofSchistosoma japonicum

A novel molluscicide, derived from niclosamide, the salt of quinoid-2′,5-dichloro-4′-nitrosalicylanilide (LDS) was recently developed in China. The molluscicidal activity of LDS was compared with the commonly used molluscicide niclosamide (WPN) by immersion at seven concentrations; 0.05, 0.1, 0.2, 0.4, 0.8, 1.6, and 3.2 mg/L, and with spraying and powdering methods (dosages of 0.2, 0.4, and 0.8 g/m2) in the laboratory and the field. We recorded mortality at 1 d, 3 d, and 7 d. The results showed that at 0.4 mg/L immersion exposure for 72 hours, snail mortalities for LDS and WPN were 100% and 96.70% respectively in the lab, and 100% and 95.33 ± 1.15% respectively in the field. With a dosage of 0.8 g/m2 exposure for 7 d by spraying, snail mortalities for LDS and WPN were 100% and 97.33 ± 2.30% respectively in the lab, and 99.27 ± 1.27% and 97.47 ± 3.11 % in the field. With a dosage of 0.8 g/m2 exposure at 7 d by powdering, snail mortalities for LDS and WPN were both 98% in the lab, and 100% in the f...