There are provided 3-(1,2- benzisothiazol- and isoxazol-5-yl)-2,4(1H,3H)-pyrimidinedione or thione compounds of formula (I) and 3-(1,2-benzisothiazol- and isoxazol-5-yl)- 4(3H)-pyrimidinone or thione compounds of formula (II). Further provided are compostions and methods comprising those compounds for the control of undesirable plant species.