Acute toxicity of lambda-cyhalothrin, imidaclopid and avermectin on Physa acuta
3种常用杀虫剂对尖膀胱螺的急性毒性试验

The freshwater snail Physa acuta has been identified as an invasive species in China and it distributes more and more widely all over the world in recent years. Currently, people have found that it has occurred in freshwater located in many provinces of China. Scientists have taken physa acuta as a model animal for aquatic environmental toxicity tests. The present study aims to evaluate the acute toxicity of the lambda-cyhalothrin, imidaclopid and avermectin on Physa acuta using Up-and-Down Procedure and the method of Karber. The results of Up-and-Down Procedure showed that 48 h LC50 of lambda-cyhalothrin, imidaclopid and avermectin for the snail were 2.581 mg L-1, 10.03 mg L-1, 0.097 mg L-1, respectively. Moreover, the Karber results showed the acute 24 h LC50 of lambda-cyhalothrin, imidaclopid and avermectin to the physa acuta were 4.447 mg L-1, 12.676 mg L-1, 0.11 mg L-1, indicating there is no difference between these two kinds of acute toxicity testing methods. The results also reveal that Physa acuta are very sensitive to pesticides and this kind of snail may be a model animal for acute toxicity testing.