A compound of Formula: or an agronomically acceptable salt thereof, wherein X is CH or N, R 1 is selected from the group consisting of hydrogen, C 1 -C 10 alkylC -, C 1 -C 10 alkylOC -, C 1 -C 10 alkylSC - and R 5 R 6 NC -; R 2 is selected from the group consisting of halogen NO 2, CN, C 1 -C 6 haloalkylS p -, C 1 -C 6 alkyl-S p -, C 2 -C 4 alkenyl-, C 2 -C 4 alkynyl-, C 1 -C 4 haloalkyl and C 1 -C 4 haloalkoxy-; R 3 is selected from the group consisting of hydrogen, halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 1 -C 4 alkoxy- and C 1 -C 4 haloalkoxy-; R 4 is phenyl or a five or six-membered heteroaryl, the heteroaryl containing from one to three heteroatoms each independently selected from the group consisting of oxygen, nitrogen and sulphur, and wherein the phenyl or heteroaryl may be optionally substituted by one or more substituents independently selected from the group consisting of halogen, C 1 -C 6 alkyl-, C 2 -C 4 alkenyl-, C 2 -C 4 alkynyl-, C 1 -C 6 haloalkyl-, C 1 -C 6 alkoxy-, C 1 -C 6 alkoxyC 1 -C 3 alkyl-, C 1 -C 6 alkoxyC 1 -C 3 alkoxy-, C 1 -C 6 haloalkoxy-, C 1 -C 6 alkyl-S p -, C 1 -C 6 haloalkyl-S p -, C 3 -C 6 cycloalkyl- (optionally substituted by 1 or 2 halogen), cyano and nitro; or R 4 is R4 a and R 5 is hydrogen or C 1 -C 10 alkyl; R 6 is hydrogen or C 1 -C 10 alkyl; R 7 and R 8 are independently selected from the group consisting of hydrogen and halogen; and p = 0, 1 or 2; wherein said compound is not selected from the group consisting of 2-(3-bromo-5-cyano-2-hydroxyphenyl)pyridine, 3-chloro-2-ethoxy-4-hydroxy-5-phenyl-benzonitrile, 4-hydroxy-3-nitro-5-[3-(trifluoromethyl)phenyl]benzonitrile and 2'-fluoro-6-hydroxy-5-nitrobiphenyl-3-carbonitrile. X is CH or N, R 1 is selected from the group consisting of hydrogen, C 1 -C 10 alkylC -, C 1 -C 10 alkylOC -, C 1 -C 10 alkylSC - and R 5 R 6 NC -; R 2 is selected from the group consisting of halogen NO 2, CN, C 1 -C 6 haloalkylS p -, C 1 -C 6 alkyl-S p -, C 2 -C 4 alkenyl-, C 2 -C 4 alkynyl-, C 1 -C 4 haloalkyl and C 1 -C 4 haloalkoxy-; R 3 is selected from the group consisting of hydrogen, halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 1 -C 4 alkoxy- and C 1 -C 4 haloalkoxy-; R 4 is phenyl or a five or six-membered heteroaryl, the heteroaryl containing from one to three heteroatoms each independently selected from the group consisting of oxygen, nitrogen and sulphur, and wherein the phenyl or heteroaryl may be optionally substituted by one or more substituents independently selected from the group consisting of halogen, C 1 -C 6 alkyl-, C 2 -C 4 alkenyl-, C 2 -C 4 alkynyl-, C 1 -C 6 haloalkyl-, C 1 -C 6 alkoxy-, C 1 -C 6 alkoxyC 1 -C 3 alkyl-, C 1 -C 6 alkoxyC 1 -C 3 alkoxy-, C 1 -C 6 haloalkoxy-, C 1 -C 6 alkyl-S p -, C 1 -C 6 haloalkyl-S p -, C 3 -C 6 cycloalkyl- (optionally substituted by 1 or 2 halogen), cyano and nitro; or R 4 is R4 a and R 5 is hydrogen or C 1 -C 10 alkyl; R 6 is hydrogen or C 1 -C 10 alkyl; R 7 and R 8 are independently selected from the group consisting of hydrogen and halogen; and p = 0, 1 or 2; wherein said compound is not selected from the group consisting of 2-(3-bromo-5-cyano-2-hydroxyphenyl)pyridine, 3-chloro-2-ethoxy-4-hydroxy-5-phenyl-benzonitrile, 4-hydroxy-3-nitro-5-[3-(trifluoromethyl)phenyl]benzonitrile and 2'-fluoro-6-hydroxy-5-nitrobiphenyl-3-carbonitrile.