The present invention is directed to novel pyrazole derivatives and their use as pesticidal agents. The pyrazole derivatives have Formula I: or a salt thereof, where R1 is amino, hydrogen, alkyl, hydroxy, halo, alkoxy, alkylamino, dialkylamino, alkylthio, alkylsulfinyl, alkylsulfonyl, trifluoroalkylsulfinyl, trifluoroalkylsulfonyl, hydroxy, amino, trifluoromethyl, acetylamino, —OSO2R2, —OS(O)R2, —OC(O)R2, —OC(O)NHR2, or —NHC(O)NHR2 where R2 is C1-4 alkyl or optionally substituted aryl; X, Y and Z are each independently (CH)n, (CR3R4)n, S, S(O), or SO2, wherein n is 1-2, R3 and R4 are defined herein; Q is N or C—R6, wherein R6 is fluoro, chloro, bromo, or iodo; R5 is halo, C1-C6 alkyl, C1-C4 alkenyl, C1-C4 alkoxy, C1-C4 alkylamino, C1-C4 dialkylamino, C1-C4 alkylthio, C1-C4 alkylsulfinyl, C1-C4 alkylsulfonyl, C1-C4 trifluoroalkylsulfinyl, C1-C4 trifluoroalkylsulfonyl, hydroxy, amino, or trifluoromethyl; and with the proviso that only one of X, Y and Z can be S, S(O) or SO2.