Acute Toxicity of Difenoconazole on Aquatic Organism

[Aims] The toxic effects of difenoconazole on aquatic organisms were evaluated. [Methods] The acute toxicity of common difenoconazole formulations on Scenedesmus obliquus, Daphnia magna and Brachydonio rerio were conducted by methods of alga growth inhibition test, static Daphnia sp. acute immobilisation test and semi-static fish acute toxicity test. [Results] The results of acute toxicity test showed that EC50(72 h) values of 10% difenoconazole water dispersing granule(WG), difenoconazole 20% micro-emulsion(ME), difenoconazole 15% suspension concentrate(SC), and difenoconazole 30 g/L flowable concentrate for seed coating(FS) for Scenedesmus obliquus were 1.58, 1.13,0.353, 1.18 mg a.i./L, respectively, while EC50(48 h) values for Daphnia magna were 4.07×10-2, 0.219, 0.461, 0.717 mg a.i./L,respectively, and LC50(96 h) values for Brachydonio rerio were 2.64, 4.75, 0.777, 7.05×10-2mg a.i./L, respectively.[Conclusions] The acute toxicity grade of difenoconazole 10% WG, difenoconazole 20% ME, difenoconazole 15%SC, and difenoconazole 30 g/L FS for Scenedesmus obliquus were moderate toxic, while hyper toxic, highly toxic,highly toxic, highly toxic for Daphnia magna, respectively, and moderate toxic, moderate toxic, highly toxic, hyper toxic for Brachydonio rerio, respectively.