Herbicidally-active phenylacetonitriles

A method for selectively controlling preemergence weed plant growth in transplanted rice fields under aquatic conditions which comprises applying to said plants or plant habitat in said rice fields before, at the time of, or after transplanting the rice plants an inhibiting amount of a compound having the formula:

• ##STR17## wherein X is selected from hydrogen, (C.sub.1 -C.sub.4)alkyl, F, Cl, Br, NO.sub.2 or SO.sub.2 C.sub.6 H.sub.5 ;
• R is selected from C.sub.6 H.sub.5, C.sub.6 H.sub.4 --X wherein X is as defined above, straight or branched chain (C.sub.1 -C.sub.8) alkyl, (C.sub.3 -C.sub.6) saturated or unsaturated cycloaliphatic groups, C.sub.6 H.sub.5 CH.sub.2 -- or C.sub.6 H.sub.5 S--;
• n is selected from 0, 1 or 2;
• m is selected from 0, 1 or 2;
• A is selected from CN and C.tbd.CH;
• and
• Z is a N-heterocyclic group selected from:
• ##STR18## or an agronomically acceptable acid addition salt thereof.