Succinate dehydrogenase inhibitors (SDHI) are EU crop protection active substances which are controversial regarding their toxicity and ecotoxicity. From the total number of SDHI fungicides known (24) up to twelve were approved at EU plant protection Regulation EC 1107/2009 between 2011 and 2016. All these active substances are listed in Part A, B and E of Regulation EU 540/2011.