单甲脒农药对的毒性研究

TOXICITY OF N′-(2,4 DIMETHYLPHENYL)-N-METHYLFORMADINE TO DAPHNIDS

在２０℃条件下应用换液的方法研究单甲脒农药对大型（Ｄａｐｈｎｉａｍａｇｎａ）、方形网纹（Ｃｅｒｉｏｄａｐｈｎｉａｑｕａｄｒａｎｇｕｌａ）、老年低额（Ｓｉｍｏｃｅｐｈａｌｕｓｖｅｔｕｌｕｓ）的急性毒性和慢性毒性．结果表明，单甲脒对类的毒性中等，４８ｈＥＣ５０值在５５２—１５１４ｍｇ／Ｌ之间，老年低额比较敏感，大型耐性较强．２１ｄ繁殖实验结果获得单甲脒对老年低额的最大无影响浓度（ＮＯＥＣ）为００３２ｍｇ／Ｌ，最低有影响浓度（ＬＯＥＣ）为００６３ｍｇ／Ｌ，其最大允许浓度（ＭＡＴＣ）估计为００５ｍｇ／Ｌ，应用系数为００１．溶液ｐＨ值对单甲脒毒性有明显影响。

Study of acute and chronic toxicity of N′-(2 ,4 dimethylphenyl)-N-methylformamidine(DMA) to Daphinia magna, Ceriodaphnia quadrangula and Simocephalus vetulus has been carried out by using renewal method under conditions of 20±1℃ and pH 8 0—8 3. The 48h EC 50 values for 3 species of daphnids ranged from 5 52—15 14mg/L. The S.vetulus was more sensitive to DMA than the other 2 species. Results from 21d reproductive test of S.Vetulus indicated that the application factor 0 01 was suitable for estimating MATC of DMA to daphnids based on 48hEC 50 . The pH value of experimental solution affected DMA toxicity to daphnids significantly: the higher pH value the lower toxicity. The S.vetulus was demonstrated to be a good toxicity test organism for this insecticide.