The invention concerns a suspension concentrate comprising, expressed by weight based on the total weight of the composition: a) 40 to 80% particles of dodecylguanidine or an acid salt of dodecylguanidine of the structure (1), wherein X represents an acid residue of a monocarboxylic, dicarboxylic or a mineral acid, b) 0 to 10% of an anti-freeze compound, c) 1 to 10% of a wetting agent and/or d) a dispersing agent, e) 0 to 5% of an antifoaming agent, f) remainder water characterized in that, the median diameter of the particles (d 50 ) is at least 7 µm and below 40 µm； and its use for the treatment of a fungicidal disease on crops or ornamental plants.
