PROBLEM TO BE SOLVED: To provide a 5-methyl-3(2H)-isoxazolone derivative showing high controlling effect to pathogenic bacteria causing a disease of stems and leaves including wheat Septoria tritici bacteria.SOLUTION: This 5-methyl-3(2H)-isoxazolone derivative is represented by general formula (I). (In the formula, R represents R1, COR2, COOR3 or CONHR4. R1-R4 each representing a prescribed substituent).COPYRIGHT: (C)2013,JPO&INPIT【課題】コムギ葉枯病菌を含む茎葉病害を引き起こす病原菌に対して高い防除効果を示す5-メチル-3(2H)-イソキサゾロン誘導体を提供する。【解決手段】本発明に係る5-メチル-3(2H)-イソキサゾロン誘導体は、下記一般式(I)で示される。(式中、Rは、R1、COR2、COOR3、あるいはCONHR4を表す。R1~R4は、所定の置換基を表す。)【選択図】なし