HYDROXYPYRIDONECARBOXAMIDE,ITS PRODUCTION,AND ITS USE AS HERBICIDE OR GROWTH CONTROL AGENT

1,2-Dihydro-4-hydroxy-2-oxo-pyridine-3-carboxamide derivs. of formula (I) and their salts are new: X = O or S; R1 = H or a 1-10C alkyl, 3-10C alkenyl, 3-10C alkynyl, 3-8C cycloalkyl or phenyl gp. opt. substd. by 1-5 halogen atoms and/or 1-3 of CN, 3-8C cycloalkyl, 1-4C alkoxy, 1-4C haloalkoxy, 1-4C alkylthio, 1-4C haloalkylthio, di(1-4C alkyl)amino, Ar, SAr, or OAr; Ar = phenyl opt. substd. by 1-3 of 1-4C alkyl, 1-4C alkoxy, 1-4C haloalkyl, 1-4C haloalkoxy, halo, CN or nitro; R2 = H, OH or a 1-8C alkoxy, 3-8C alkenyloxy, di(1-4C alkyl)amino, 1-10C alkyl, 3-10C alkenyl, 3-10C alkynyl or 3-8C cycloalkyl gp. opt. substd. as above or substd. by 1-5 halogen atoms and/or one or two 5- or 6- membered heterocyclic gps. which contain 1-3 heteroatoms (O, S or N) and are opt. substd. by 1-2 of halogen, 1-4C alkyl, 1-4C alkoxy, 1-4C haloalkyl or 1-4C haloalkoxy; or R1 + R2 = 4-7C alkylene opt. interrupted by O, S or NMe; R3 = H, halogen, nitro, 1-10C alkyl, 2-10C alkenyl, 2-10C alkynyl, 3-8C cycloalkyl, 7-15C aralkyl, 1-6C alkoxy, 1-6C (halo)alkylthio, 1-6C haloalkoxy, di(1-6C alkyl)amino, phenyl, phenoxy, phenylthio or 5- or 6-membered heterocyclyl contg. 1-3 heteroatoms (O, S or N), where (hetero)aromatic gps. are opt. substd. by halogen, CN, nitro, 1-4C alkyl, 1-4C haloalkyl, 3-8C cycloalkyl, 1-4C alkoxy, 1-4C haloalkoxy, 1-4C alkylthio, 1-4C haloalkylthio or di(1-4C alkyl)amino.