氯硝柳胺3种剂型杀螺效果的比较研究

 目的  比较25%氯硝柳胺悬浮剂(SCN)、25%氯硝柳胺乳油(ECN)和50%氯硝柳胺乙醇 胺盐可湿性粉剂(WPN)的杀螺效果，为制定血吸虫病现场防治措施提供参考。方法  用脱氯自来水 配制SCN、ECN和WPN有效成分浓度分别为0.250、0.125、0.063、0.032 mg/L和0.016 mg/L药 液待用。将100 ml不同浓度的上述药液，分别倒入100 ml烧杯中，再放入10只钉螺成螺或幼螺，上 盖塑料纱网防止钉螺爬出液面。设立清水对照。在(25土1)℃的恒温实验室浸泡钉螺24、48 h和72 h 后，倒去药液，清水冲洗钉螺，用敲击法鉴别钉螺死活并计数，计算LCso并进行统计学分析。结果 25℃实验室，药液有效成分浓度0. 125 mg/L以上，SCN、ECN和WPN均有较高的杀成螺和幼螺作 用，杀螺率差异无统计学意义(P>0.05)；药液有效戍分浓度0. 063 mg/L，SCN和ECN的杀螺率高 于WPN，杀螺率差异有统计学意义(P

Comparison of the molluscicidal effect of three formulations of niclosamide against Oncomelania snails

Objective  To compare the molluscicidal effect of suspension concentrate of 25% niclosamide (SCN) and emulsifiable concentrate of 25% niclosamide (ECN) and wettable powder of 50% niclosanide ethanolamide salt (WPN) against Oncomelania snails, in order to give the reference for schistosomiasis control in the field. Methods   SCN, WCN and WPN were weighed and the so- lutions of 0. 250, 0. 125, 0. 063, 0. 032 and 0. 016 mg/L of the active ingredient (niclosamide) pre- pared in dechlorinated water. The 100 ml flasks were filled with the solutions and 10 adult or imma- ture snails added and the flasks were covered with the plastic gauze to prevent snails from crawling out the solutions. The controls only had dechlorinated water. After being immersed for 24, 48 h and 72 h at 25 'C , the snails were washed with dechlorinated water and fed for a further 48 h.  The death of snails was determined by the knocked method and the LCso was calculated. Results   In the 0.125 mg/L or more active content of the three formulations of niclosamide, there were high moI- luscicidal effects in laboratory, and there were no significant differences among the three formula- tions (P>O. 05).  In 0. 063 mg/L active content of the three formulations, the death rates of SCN and ECN were higher than that of WPN, there was a significant difference between SCN and WPN or between ECN and WPN (P