A soil treating agent or a seed treating agent having excellent prevention effects against various plant pathogens (particularly against rice blast) is provided.The soil treating agent or seed treating agent comprises one or more compounds of the general formula (Ia), (Ib) or (Ic):(wherein R1, R2: C1-C6alkyl (may be substituted), aryl (may be substituted), heteroaryl (may be substituted), aralkyl (may be substituted) and the like； R3, R4: H, C1-C6alkyl (may be substituted), halogen, C1-C6alkoxy and the like； X: halogen, C1-C6alkyl (may be substituted), C2-C6alkenyl (may be substituted), C2-C6alkynyl (may be substituted), aryl (may be substituted), heteroaryl (may be substituted), C1-C6alkoxy and the like； Y: halogen, C1-C6alkyl, C1-C6alkoxy, OH；n:0 to 4；m:0 to 6) or salts thereof as an active ingredient.提供對種種植物病原菌(尤其稻熱病)具有優異防治效果之土壤處理劑或種子處理劑。該土壤處理劑或種子處理劑含有1種以上如下式(Ia)、(Ib)或(Ic)化合物或其鹽為有效成分：(式中R1、R2:C1~C6烷基(取代可)、芳基(取代可)、雜芳基(取代可)、芳烷基(取代可)等；R3、R4:H, C1~C6烷基(取代可)、鹵素、C1~C6烷氧基等；X：鹵素、C1~C6烷基(取代可)、C2~C6烯基(取代可)、C2~C6炔基(取代可)、芳基(取代可)、雜芳基(取代可)、C1~C6烷氧基等；Y：鹵素、C1~C6烷基、C1~C6烷氧基、OH；n:0~4；m:0~6)。
