钩吻总碱及粗提物的杀螺活性研究

实验用钩吻的甲醇、氯仿粗提物以及钩吻总碱进行了杀螺研究，室内生测结果表明：钩吻的甲醇粗提物和钩吻总碱对幼螺具有极高的毒杀作用，特别是钩吻粗提物，60mg/L处理药后24h死亡率为84.47%，48h死亡率为100%，20mg/L处理药后72h死亡率为100%,5mg/L处理药后72h死亡率达60%，其24hLC50为13.17mg/L，72h的LC50为4.80mg/L，和对照药剂45%百螺敌可湿性粉剂的相应毒力(分别为6.91mg/L和2.18mg/L)相差不远，钩吻的氯仿粗提物对幼螺的浸杀效果较差，400mg/L处理72h后平均死亡率仅为24%。对成螺的浸杀效果也表明，钩吻甲醇粗提物、钩吻总碱也有极好的效果。钩吻甲醇粗提物24h和72h的LC50分别为221.63mg/L、82.28mg/L；钩吻总碱24h和72h的LC50分别为81.74mg/L、41.99mg/L。但毒力低于对照药剂(分别为41.58mg/L和 8.36mg/L)。

Research of GEB Extracts on the Snail, Ampullaria gigas Spix

Experiments in laboratory were conducted to test the efficacy of methanol extract of Gelsemium elegans Benth(MGEB), Chloroform extract of Gelsemium elegans Benth(CGEB) and Gelsemine hydrochloride(GH) against the snail Ampullaria giga. The results showed that, MGEB and GH, Especially GH, had satisfactory molluscidal effects against young snail. The snail mortality was 84% in the concentration of 60mg/L in the 24 hours after treatment, and 100% in 48 hours. 100% in concentration of 20mg/L, and 60% in concentration of 5mg/L in 72 hours. LC50 was 13.17mg/L in 24 hours and 4.80mg/L in 72 hours. It showed no much difference while compared to 45% Fetin Acetate WP (LC50 was 6.91mg/L and 2.18mg/L, respectively). But CGEB had lower toxicity to young snails. The snail mortality was only up to 24% in 72 hours. As to the adult snail, MGEB and GH also have better effect than CGEB. The LC50 of MGEB was 221.63mg/L and 82.28mg/L in 24 hours and 72 hours, respectively; the LC50 of GH was 81.74mg/L and 41.99mg/L in 24 hours and 72 hours, respectively. It showed lower toxicity than 45% Fetin Acetate WP (LC50 was 41.58mg/L and 8.36mg/L, respectively).