PYRIDONE DERIVATIVE AND HERBICIDE

[Object] To provide a pyridone derivative or an agriculturally acceptable salt thereof which enables control of various weeds growing in upland fields, orchards, paddy fields, and non-crop lands while showing a high safety to useful plants, useful crops, or the like; and a herbicide characterized by containing the pyridone derivative or a salt thereof as the active ingredient. [Means For Solving problems] A pyridone derivative represented by Formula [1] or an agriculturally acceptable salt thereof: [wherein R 1 is a C 1-6 alkyl group, a C 2-6 alkenyl group, a C 2-6 alkynyl group, or the like; R 2 and R 3 are each independently a hydrogen atom, a nitro group, a cyano group, or the like; and A is a group represented by Formula A-1, Formula A-2, Formula A-3, Formula A-4, or Formula A-5: [Effect] The compound represented by a general formula [1] and an agriculturally acceptable salt thereof enable control of various weeds growing in upland fields, orchards, paddy fields, and non-crop lands while showing high safety to useful plants, useful crops, or the like.