Broadleaf crop control with 6-arylpicoline carboxylic acids, 2-arylpyrimidine carboxylic acids, or salts or esters thereof

A method of controlling a broadleaf volunteer crop, comprising:

• applying to the broadleaf volunteer crop, an area adjacent the broadleaf volunteer crop, or to soil or water to prevent the emergence or growth of the broadleaf volunteer crop, a herbicidally effective amount of a herbicide of Formula (I) or its salts or esters:
• wherein
• R1 is halogen, trifluoromethyl, cyano, substituted or unsubstituted C1-C4 alkyl, or substituted or unsubstituted C1-C4 alkoxy;
• R2 is hydrogen, halogen, trifluoromethyl, cyano, substituted or unsubstituted C1-C4 alkyl, substituted or unsubstituted C2-C4 alkenyl, substituted or unsubstituted C2-C4 alkynyl, or substituted or unsubstituted C1-C4 alkoxy;
• R3 is hydrogen, halogen, substituted or unsubstituted C1-C4 alkyl, or substituted or unsubstituted C1-C4 alkoxy;
• R4 is halogen, substituted or unsubstituted C1-C4 alkyl, substituted or unsubstituted C2-C4 alkenyl, substituted or unsubstituted C2-C4 alkynyl, or substituted or unsubstituted C1-C4 alkoxy;
• and
• X is N or CR5, wherein R5 is hydrogen or halogen, and
• wherein optionally R1 and R2 are combined to form —OCH2O, —OCHFO—, or —OCF2O—,
• wherein the broadleaf volunteer crop is genetically modified.