A compound of the Formula: wherein X is N or CY, wherein Y is hydrogen, halogen, C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkoxy, C 1 -C 3 alkylthio or C 1 -C 3 haloalkylthio; R 1 is OR 1' or NR 1" R 1", wherein R 1' is hydrogen, C 1 -C 8 alkyl, or C 7 -C 10 arylalkyl, and R 1" and R 1''' are independently hydrogen, C 1 -C 12 alkyl, C 3 -C 12 alkenyl, or C 3 -C 12 alkynyl; R 2 is halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 2 -C 4 alkenyl, C 2 -C 4 haloalkenyl, C 2 -C 4 alkynyl, C 1 -C 4 alkoxy, C 1 -C 4 haloalkoxy, C 1 -C 4 alkylthio, C 1 -C 4 haloalkylthio, amino, C 1 -C 4 alkylamino, C 2 -C 4 haloalkylamino, formyl, C 1 -C 3 alkylcarbonyl, C 1 -C 3 haloalkylcarbonyl, cyano, or a group of the formula-CR 17 =CR 18 -SiR 19 R 20 R 21, wherein R 17 is hydrogen, F, or CI; R 18 is hydrogen, F, Cl, C1-C4 alkyl, or C 1 -C 4 haloalkyl; and R 19, R 20, and R 21 are independently C 1 -C 10 alkyl, C 3 -C 6 cycloalkyl, phenyl, substituted phenyl, C 1 -C 10 alkoxy, or OH; R 3 and R 4 are independently hydrogen, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 3 -C 6 alkenyl, C 3 -C 6 haloalkenyl, C 3 -C 6 alkynyl, formyl, C 1 -C 3 alkylcarbonyl, C 1 -C 3 haloalkylcarbonyl, C 1 -C 6 alkoxycarbonyl, C 1 -C 6 alkylcarbamyl, C 1 -C 6 alkylsulfonyl, C 1 -C 6 trialkylsilyl, C 1 -C 6 dialkylphosphonyl, or R 3 and R 4 taken together with N is a 5- or 6-membered saturated or unsaturated ring, or R 3 and R 4 taken together represent =CR 3' (R 4'), wherein R 3' and R 4' are independently hydrogen, C 1 -C 6 alkyl, C 3 -C 6 alkenyl, C 3 -C 6 alkynyl, C 1 -C 6 alkoxy or C 1 -C 6 alkylamino, or, R 3' and R 4' taken together with =C represent a 5- or 6-membered saturated ring; Ar is one of groups Ar1 to Ar4: R 5, if applicable to the Ar group, is hydrogen, halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 2 -C 4 alkenyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 haloalkylthio, amino, C 1 -C 4 alkylamino, or C 2 -C 4 haloalkylamino; R 6 is hydrogen, halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 haloalkylthio, amino, C 1 -C 4 aminoalkyl or C 2 -C 4 haloaminoalkyl; R 6' is hydrogen or halogen; R 6", if applicable to the Ar group, is hydrogen, halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, cyclopropyl, halocyclopropyl, C 2 -C 4 alkenyl, C 2 -C 4 haloalkenyl, C 2 -C 4 alkynyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 haloalkylthio, amino, C 1 -C 4 aminoalkyl or C 2 -C 4 haloaminoalkyl, CN, or NO 2; or an N-oxide or an agriculturally acceptable salt thereof. X is N or CY, wherein Y is hydrogen, halogen, C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkoxy, C 1 -C 3 alkylthio or C 1 -C 3 haloalkylthio; R 1 is OR 1' or NR 1" R 1", wherein R 1' is hydrogen, C 1 -C 8 alkyl, or C 7 -C 10 arylalkyl, and R 1" and R 1''' are independently hydrogen, C 1 -C 12 alkyl, C 3 -C 12 alkenyl, or C 3 -C 12 alkynyl; R 2 is halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 2 -C 4 alkenyl, C 2 -C 4 haloalkenyl, C 2 -C 4 alkynyl, C 1 -C 4 alkoxy, C 1 -C 4 haloalkoxy, C 1 -C 4 alkylthio, C 1 -C 4 haloalkylthio, amino, C 1 -C 4 alkylamino, C 2 -C 4 haloalkylamino, formyl, C 1 -C 3 alkylcarbonyl, C 1 -C 3 haloalkylcarbonyl, cyano, or a group of the formula-CR 17 =CR 18 -SiR 19 R 20 R 21, wherein R 17 is hydrogen, F, or CI; R 18 is hydrogen, F, Cl, C1-C4 alkyl, or C 1 -C 4 haloalkyl; and R 19, R 20, and R 21 are independently C 1 -C 10 alkyl, C 3 -C 6 cycloalkyl, phenyl, substituted phenyl, C 1 -C 10 alkoxy, or OH; R 3 and R 4 are independently hydrogen, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 3 -C 6 alkenyl, C 3 -C 6 haloalkenyl, C 3 -C 6 alkynyl, formyl, C 1 -C 3 alkylcarbonyl, C 1 -C 3 haloalkylcarbonyl, C 1 -C 6 alkoxycarbonyl, C 1 -C 6 alkylcarbamyl, C 1 -C 6 alkylsulfonyl, C 1 -C 6 trialkylsilyl, C 1 -C 6 dialkylphosphonyl, or R 3 and R 4 taken together with N is a 5- or 6-membered saturated or unsaturated ring, or R 3 and R 4 taken together represent =CR 3' (R 4'), wherein R 3' and R 4' are independently hydrogen, C 1 -C 6 alkyl, C 3 -C 6 alkenyl, C 3 -C 6 alkynyl, C 1 -C 6 alkoxy or C 1 -C 6 alkylamino, or, R 3' and R 4' taken together with =C represent a 5- or 6-membered saturated ring; Ar is one of groups Ar1 to Ar4: R 5, if applicable to the Ar group, is hydrogen, halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 2 -C 4 alkenyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 haloalkylthio, amino, C 1 -C 4 alkylamino, or C 2 -C 4 haloalkylamino; R 6 is hydrogen, halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 haloalkylthio, amino, C 1 -C 4 aminoalkyl or C 2 -C 4 haloaminoalkyl; R 6' is hydrogen or halogen; R 6", if applicable to the Ar group, is hydrogen, halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, cyclopropyl, halocyclopropyl, C 2 -C 4 alkenyl, C 2 -C 4 haloalkenyl, C 2 -C 4 alkynyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 haloalkylthio, amino, C 1 -C 4 aminoalkyl or C 2 -C 4 haloaminoalkyl, CN, or NO 2; or an N-oxide or an agriculturally acceptable salt thereof.