This present disclosure is related to the field of 3-alkyl-5-fluoro-4-substituted-imino-3,4-5 dihydropyrimidin-2(1H)-ones and their derivatives and to the use of these compounds as fungicides. Also provided are methods of controlling a fungal disease such as Septoria tritici, comprising administering an effective amount of the fungicide compound to at lease one surface associated with the plant, seed or soil.